Implementation of a lung cancer screening initiative in HIV-infected subjects.

In this pilot program of low-dose computed tomography (LDCT) for the screening of lung cancer (LC) in a targeted population of people with HIV (PWH), its prevalence was 3.6%; the number needed to screen in order to detect one case of lung cancer was 28, clearly outweighing the risks associated with lung cancer screening. While data from additional cohorts with longitudinal measurements are needed, PWH are a target population for lung cancer screening with LDCT.

Introduction

In a number of countries, life expectancy of people with HIV (PWH) has approached that of the general population, as screening, prevention, and treatment of non-AIDS comorbidities can become their main health issue [1, 2]. Among PWH, lung cancer (LC) is a leading neoplasia [1, 3, 4], and its incidence is expected to increase in the next decade [5].

The United States Preventive Services Task Force (USPSTF) first recommended screening for smokers and former smokers, aged 55–80 years, with at least 30 pack-years history, and no more than 15 years after quitting [6]. Recently, the USPSTF enforced more strict criteria, with a wider age interval from 50 to 80 years, and 20 pack-years history [7]. Given the higher burden incidence of LC among PWH and its poorer prognosis [8], as well as the burden of lung comorbidities, there is now a clear debate on optimal LC screening strategies in PWH. Given that a higher prevalence of false-positive findings, compared to HIV-uninfected individuals, is expected in PWH, it has been argued that LC screening could result in more harm than benefits in this population. Here, we report the experience of a LC screening program for PWH, with adapted criteria seeking higher sensitivity.

Methods

PWH on follow-up in a tertiary hospital between January 2015 and September 2019 were offered LC screening with LDCT. Inclusion criteria were age 45 years or older, 25 pack-year history of smoking or more, current smokers, or those who quit within 15 years of screening, and absence of a previous LC diagnosis. We registered the following radiological data: presence of lung nodules, enlarged (>1 cm) lymph nodes, coronary calcium score, aortic dilatation, bone marrow attenuation (at the level of vertebral L1 body), lung emphysema, and non-nodular lung opacities. A single low-dose unenhanced CT (60 mA, 120 kV) was performed on every patient without intravenous contrast; CT machine: high-speed, 16-slice CT machine − Philips (Best, The Netherlands) was used without intravenous or oral contrast. The test was considered positive if a noncalcified nodule was more than 500 mm3 and was considered indeterminate if the solid nodule was 50–500 mm3 or if the diameter of non-solid nodule was greater than 8mm. In those subjects with intermediate results, a follow up scan was performed 3 months after first CT. If at that time the lesion had volume doubling time of less than 400 days, the final result was declared to be positive and if not it was considered negative [9]. Our study takes no consideration on second-round scan (although recruitment is still ongoing). In those subjects in which a LC was suspected, a variety of different diagnostic procedures were performed in accordance to each specific situation. Reading and report of the images were conducted by 2 radiologists specialized on chest radiology. Discrepancies in interpretation between the two thoracic radiologists were resolved by consensus. The images were transferred to the workstation where multiplanar reformatted images were obtained. All images were displayed with two different windows for interpretation (lung window ‘1500 width/600 level’ and mediastinal window ‘400/40’). The Computed tomography lung analysis was performed using 3D synapse software (Fujifilm Medical, Tokyo, Japan).

We analyzed the findings obtained by the first LDCT of each patient. Descriptive analysis was performed using frequency distributions. We used logistic regression to assess the relationship between baseline variables of interest and the diagnosis of lung cancer. Due to the small number of events, the model has not been adjusted for any confounder. All probabilities were two-tailed, and p value of < 0, 05 was considered to indicate statistical significance. Statistical analyses were performed using Stata v. 16.0 (StataCorp LP College Station, TX, USA).

The Ethics Committee (ceic.hrc@salud.madrid.org) approved the study. The study conformed to the principles of the Declaration of Helsinki and the Good Clinical Practice Guidelines and was approved by the local Ethics Committee; study participants gave their written informed consent to participate in the study.

Results

A total of 141 patients underwent LDCT, of whom 86% were men and 14% were women. Median age was 57 years (25th-75th percentile, 53–60), 87 (62%) with positive HCV antibodies: median nadir CD4 count was 179 cells/uL (75–305), current CD4 count was 666 cells /uL (403–911), and HIV RNA count < 20 copies/mL was seen in 138 (97.1%) subjects. Median pack-year was 34 (25–41), 122 (82%) were active smokers. Radiological abnormalities were common: pulmonary emphysema in 90 patients (64%), lung non-nodular opacities in 29 (21%), lymph nodes > 1 cm in 10 (7%), aortic atherosclerosis in 48 (34%), aortic dilation in 4 (2.8%), and radiological bone marrow attenuation in 21 (15%) (Table 1).

Table 1

Patient baseline characteristics.

Caracteristics	Values
AGE (Median) (IQR)	57 (54–60)
40–44 (number) (%)	1 (1%)
45–49	9 (6%)
50–54	40 (28%)
55–59	52 (36%)
>60	39 (27%)
GENDER (Number) (%)
Male	122 (85%)
Female	20 (14%)
TOBACO USE (Number) (%)
Current	122 (86%)
Previous	12 (9%)
Never	0 (0%)
Unknown	7 (5%)
PACK-YEARS (Median) (IQR)	34 (33–40)
HCV (Number) (%)
Active	12 (9%)
Cured	70 (50%)
Clearance	5 (3%)
No infection	54 (38%)
Unknown	0 (0%)
NADIR CD4+ (Cells/μl) (Median) (IQR)	179 (75–305)
CURRENT CD4+ (Cells/μl) (Median) (IQR)	666 (403–911)
HIV Viral load (log) (%)
< 1,57 log	138 (97,00%)
> 1,57 log	3 (3,00%)
LUNG CANCER PATIENTS (n)	5 (3.5%)

Lung nodules were found in 52 subjects (37%); < 4 mm in 21 (15%), 4–8 mm in 18 (13%) and > 8 mm in 13 (9%). Only 6 nodules were found to be suspicious for cancer, with patients undergoing invasive procedures. In patient number 2, bronchoscopy was performed without obtaining a representative sample. Due to highly malignant suspicion, video-assisted thoracic surgery (VATS) with inferior right lobectomy and right paraesophageal and paratraqueal limphadenectomy was performed with the final diagnosis. In patient number 3, bronchoscopy without diagnosis was firstly performed. A CT guided fine needle puncture aspiration (PAAF) showing cytologic examination suggestive of malignancy that was followed by a surgical lobectomy which proved the definitive diagnosis. Following diagnostic procedures, a total of 5 cases of LC was made, yielding a prevalence of 3.6% (95% Confidence Interval [CI] 1.5 to 8.3%) and accounting for the number needed to screen to detect one lung cancer as 28 (95% CI 12–66) (Table 2). Histological examination revealed 4 cases of squamous cell carcinoma and 1 adenocarcinoma. Compared to the rest of our cohort, patients with lung cancer had a similar age (both with a median age of 57 years, p = 0.705), a lower median CD4 nadir count (71 [95% CI 43–105] vs. 179 [95% CI 80–309] cells/uL), lower current CD4 count (352 [95% CI 242–517] vs. 672 [95% CI 430–921] cells/uL), and a higher median pack-year (71 [95% CI 50–91] vs. 32 [95% CI 35–40]).

Table 2

General characteristics of patients with lung cancer.

	Age	Gender	Smoking habit	Pack-years	Previous IV drug user	HCV status	HIV Viral load (log copies/ml)	Nadir CD4+ (cells/ml)	Current CD4+ (cells/ml)	Cancer Stage at diagnosis	Lung cancer histology
Patient 1	57	male	Active	40	Yes	Clearance	< 1.57	43	243	Stage IV (pT1bN3M1c)	Squamous cell carcinoma
Patient 2	61	male	Active	100	Yes	Cured	< 1.57	10	352	Stage IA3 (pT1c N0 M0)	Squamous cell carcinoma
Patient 3	57	male	Active	> 40	Yes	Cured	< 1.57	105	182	Stage IA (pT1 N0 Mx)	Squamous cell carcinoma
Patient 4	59	male	Active	60	Yes	Cured	< 1.57	71	517	Stage IIIA (pT2N2M0)	Squamous cell carcinoma
Patient 5	56	male	Active	82	Yes	Cured	< 1.57	180	850	Stage IV (cT4N3M1b)	Adenocarcinoma

Excluding patients diagnosed with LC, only 4 patients with lung nodules underwent diagnostic procedures. Flexible bronchoscopy was performed in all of them, but only 2 biopsies were taken (1 CT guided biopsy and 1 surgical biopsy). The only related adverse event was due to surgical biopsy in 1 of the patients who suffered prolonged and mild thoracic pain after the procedure.

Among the 48 patients with radiologic evidence of aortic or coronary atherosclerosis, 5 had already known ischemic cardiomyopathy. Excluding these 4 instances, 15 consultations to cardiology department were performed, resulting in 11 ergometries, 2 dobutamine echocardiograms and 1 coronary angiography. Only 1 diagnosis of ischemic heart disease was made by percutaneous coronary intervention with stenting of medial and distal right coronary artery.

Discussion

In this pilot screening program of LDCT, in a single-centre cohort of PWH, a total of 5 lung cancers were detected among 141, yielding a prevalence of 3.6% (95% CI 1.5–8.3). Overall, subjects with LC had a low CD4 cell count nadir, incomplete immune recovery, and previous HCV infection, probably indicating underlying chronic immunodeficiency and inflammation, and contributing to LC pathogenesis [1, 3, 4, 10, 11] (Table 2).

As stated above, number needed to screen to detect one lung cancer was 28 (95% CI 12–66). Our results show a higher proportion of LC diagnosis than that appreciated in other LDCT screening trials. In the Nederlands-Leuvens Longkanker Screenings Onderzoek (NELSON) trial, 2.6% of participants [12] were diagnosed with LC. In the study by Makinson et al., a prevalence of 2.0% of LC was found [1], and in another cohort study by Brock et al., [13] there was only one LC amongst 678 patients. A possible explanation driving this lower rates of LC in previous study is the younger median age of the participants in the study by Brock et al. (48 years) and Makinson et al. (median age of 49.8 years). However, in NELSON trial, the baseline characteristics were comparable to our cohort, apart from the HIV condition of all our study participants. Lifestyle factors associated with our study population, such as higher prevalence of previous injection drug than in the general population, could explain in part the high prevalence of LC in our cohort. However, the small sample, and the limited number of cancers must be considered when interpreting the results. Also, our study is not powered enough to estimate the number needed to screen to prevent one death from lung cancer, which is a limitation of our study.

PWH tend to have higher rates of abnormal findings on CT. Although this could pose a problem due to increased false-positive results and related negative consequences due to unnecessary invasive procedures, these complications are infrequent [3, 8, 14–16]. Nevertheless, this issue could be resolved with emergent technologies such as volume-based nodule-management protocols, 64-multidetector CT systems and positron emission tomography [15, 17]. Eventually, this novel technology might imply a reduced number of LDCT required for follow-up in these patients, which remains an unanswered question in this field. In our study, we identified no harm with this LC screening program, beyond uncertain long-term consequences of low radiation exposure, which has been estimated as one death of a radiation-related malignancy in 2,500 patients, from what is received during screening [18].

The histological findings deserve some consideration. Our cohort showed a higher burden of squamous cell carcinoma than adenocarcinoma, in striking contrast with that observed in other series of HIV and non-HIV populations [2, 16, 19, 20]. Although this finding could be affected by the low sample in the study, clinical determinants such as advanced immune suppression at diagnosis, the history of intravenous drug use, or the high prevalence of HCV coinfection, may have influenced the outcomes. These factors could also explain the higher prevalence of LC in our cohort, compared to previous studies [1, 3]. One might note that the potential benefit of LDCT is not only limited to the early detection of LC [14, 21]. As illustrated in the description of the LDCT findings, this program resulted in the detection of conditions in which early management could improve outcomes, such as lung emphysema, osteopenia/osteoporosis and coronary calcifications, all of which may benefit from early detection.

Smoking cessation plans are likely the key intervention to reduce the incidence of lung cancer in PWH. It is important to highlight the high cumulative exposure to tobacco in patients with lung cancer [22], as it can be noted in our cohort the high number of pack-years. Of note, all participants diagnosed with lung cancer were active smokers. Also, in this pilot program, LDCT screening of LC in a targeted population of PWH seems to show results that suggests greater rates of diagnosed lung cancer than in the general population [23], which can be explained by the number of comorbidities in PWH as well as the higher pack-years history compared with people without HIV. In the light of our findings and given the greater risk of LC in PWH, we think that LDCT screening could particularly outweigh the risks in this susceptible population.

In conclusion, while data from larger cohorts with longitudinal measurements are needed, our study reinforces the idea that PWH are a target population for lung cancer screening with LDCT.

(XLS)

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30 Mar 2021

PONE-D-21-03298

Implementation of a lung cancer screening initiative in HIV-infected subjects

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Reviewer #1: This manuscript is a pilot evaluation of LDCT using adapted screening criteria for people with HIV. Given the high rates of smoking among PWH and the increased lung cancer-specific morbidity and mortality in this population, descriptions of screening outcomes in this population (especially at younger ages than USPSTF guidelines) are needed.

Introduction:

-The USPSTF recently published updated guidelines for LCS in JAMA. The criteria are now 50-80 years of age and minimum 20 pack year history. Obviously, this study was conducted prior to the publication of these new criteria. But in paragraph 2 of the Intro, you should specify that these are the original screening criteria.

Results:

-Line 89, what kind of invasive procedures? Would be helpful to list at least one example of subsequent procedures for these 6 patients.

-On line 90, the authors report that the "number needed to screen" NNS is 28. However, this needs to be specifically defined as "the number needed to screen to detect one lung cancer." NNS is typically reported (i.e., as in the NLST) as the "number needed to prevent one death" which is not what you are referring to here. So please define NNS.

-For Table 1, please provide more detail than "Values" for the top of the table. One column is not labeled.

-In lines 92-95 you are providing outcomes comparing the cancer group to the rest of the cohort. Were these comparisons conducted statistically? Please report stats.

-This is not a suggested revision, but just a comment, that I am overwhelmed at the pack year history reported in the lung cancer patients and their relatively young ages. Screening and tobacco treatment efforts in this population are desperately needed.

Discussion:

-Again, on line 105, the authors report their NNS as 28. This needs to be specified as the "number needed to screen to detect one cancer." Further, comparing 28 in this study to 320 in the NLST is an inappropriate comparison. In the NLST study, NNS was defined as "number needed to screen to prevent one death from lung cancer" and was calculated as the reciprocal of the reduction in the absolute risk of death from lung cancer in one group as compared with the other. You could compare prevalence rates between your study and NLST. But not NNS. Are you able to calculate "number needed to screen to prevent one death from lung cancer" from your dataset? If so, this should be calculated and reported. If not, please list this as a limitation.

-I appreciate the line re: smoking cessation being the key intervention to reduce incidence. Could you expand on this a little more? Perhaps tie it back in to the pack year history observed in your lung cancer group and the fact that all cancer patients were current smokers. You could also cite Tanner et al. 2016 (DOI: 10.1164/rccm.201507-1420OC)

-On Line 141 it is stated "LDCT screening of lung cancer in a targeted population of PWH resulted in greater rates of lung cancer than in the general population." I think this statement needs to be clarified and I'm not sure it is totally accurate. What is the comparison here? The NLST? If so, this is an inappropriate comparison as described above. If you are referring to the general population incidence, then please specify the rates in the population. And do you mean "results in greater rates of [diagnosed] lung cancer"?

-As previously mentioned, there are new LCS criteria. Your study still recruited a younger age (45) than the current guidelines for the general population, but your pack year history (25) is actually higher than the new criteria. I think it would be worth discussing your findings in light of these new guidelines.

Reviewer #2: Thank you for letting me review the research paper by Serrano-Villar and colleagues entitled “implementation of a lung cancer screening initiative in HIV-infected patients”. The paper is well written and of value, and implementation of lung cancer screening in specific populations important to publish, as to assess feasibility of strategies.

May I also apologize here for the delay.

I do have some major comments.

- The reading and report of the images were conducted by 2 radiologists specialized on

62 chest radiology. How were discrepancies managed ?

- Screening procedures are not detailed at all. Specifically is this a single low dose chest tomography, or repetitive each year in case of negative results. What procedures were followed for lung cancer work-up.

- 62% with HCV positive serology, thus I suppose a cancer high risk population, as reflected as 82% of active smokers. I suppose HIV risk in this cohort were primarily due to IDU. This may explain some discrepancies between your study and the published studies (Brock et al. JTO), and more so with Makinson et al. AIDS.

- You do not discus you results in perspective of these previous HIV-screening trials, nor with the NELSON results.

- I would be more careful in my conclusion. What arguments do you have for writing that you participants had impaired immune response, as the median levels of CD4 cells was 666. I suppose you assume as these people had low nadir CD4, their immune system is still very impaired, but I do not think your data shows this. Moreover, nearly all subjects had controlled HIV-disease. You could also add the CD4/CD8 ratio to show that some subjects did not fully restore immune function.

- A descriptive synthetic table of the 5 cancer cases could be interesting with stage at diagnosis, age, etc…I wonder if any cases occurred < 50 years. Should PLHIV at risk be screened a such young ages. Stage at diagnosis is essential, because it may be that diagnosing cancer at advance stages may not be at all beneficial.

- Why so few people between 45-49 were included, as median age of most HIV population is around 50? The pack-years necessary was low, and so the threshold does not seem to me to be an explanation.

- Discussion could be enriched on false positive management : how many had additional procedures, and specifically surgery. How many underwent biopsies…and had adverse events from procedures ? And even bettr, how many people had additional procedures outside the lung cancer work-up procedures (i.e. cardiologist and coronary artery calcification). These are important outcomes in any lung cancer screening strategies.

- Please be clear on the numbers needed to be screened. I believe there is a mistake in the text. In NLST, NNS to detect one lung cancer is 27, and to prevent one lung cancer death 300, which are two very different measures.

- Any data on adherence on the study protocol. Is screening validated in Spain, as clinical practice, and does not necessitate a clinical trial.

- Please mention low numbers, and though 3.6% is an important proportion of subjects with lung cancer, this number is subject to high variability as total numbers were low…(you could give us an CI95%)

Minor comments : why is the NLST trial referenced in the introduction at the end of the fist sentence, as you underscore there the fact that PLHIV have comorbidities as their main issue. For reference 7, and the higher burden of lung cancer in PLHIV I would suggest looking at studies calculation standardized incidence rate ratios…For instance Engels Aids 2006 ; (2) Dal Maso Br J Cancer 2009 ; (3) Grulich Lancet 2007 (4) Bedimo JAIDS 20095 ; (5) : Van Leuween Aids 2009 (6) Robbins Aids 2014 ; (7) Hleyhel CID 2013 ; (8) Hleyhel Aids 2014 ; (9) Hernandez-Ramirez Lancet HIV 2017; (10) Shiels CID 2017.

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22 Jul 2021

Response to Reviewers

Title: Implementation of a lung cancer screening initiative in HIV-infected subjects

The authors would like to thank the Reviewers and Editors for their careful review of our manuscript, and for providing us with their very helpful comments and suggestions to improve the quality of the manuscript. The following responses have been prepared to address all of the referees’ comments in a point-by-point fashion.

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Authors: we have revised the style and followed PLOS ONE's requirements.

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1. Is the manuscript technically sound, and do the data support the conclusions?

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Reviewer #2: Partly

- Authors: We have made our best to carefully report and analyse the data and provide a fair interpretation of our findings. We think that the Review process has significantly improved this new version of the manuscript.

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Reviewer #2: I Don't Know

This study is mainly descriptive, so the scope of statistical inference is limited. We have detailed the statistical methods in the discussion. The descriptive analysis was performed using frequency distributions. We used logistic regression to assess the relationship between baseline variables of interest and the diagnosis of lung cancer during follow-up. Due to the small number of events, the model has not been adjusted for any confounder. All probabilities were two-tailed, and p value of < 0, 05 was considered to indicate statistical significance. Statistical analyses were performed using Stata v. 16.0 (StataCorp LP College Station, TX, USA).

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5. Review Comments to the Author:

Reviewer #1:

- Introduction:

The USPSTF recently published updated guidelines for LCS in JAMA. The criteria are now 50-80 years of age and minimum 20 pack year history. Obviously, this study was conducted prior to the publication of these new criteria. But in paragraph 2 of the Intro, you should specify that these are the original screening criteria.

- Authors: The point raised by the Reviewer is well taken. Indeed, our study was conducted before the publication of the updated USPSTF guidelines for LCS. We have made clear this point in the introduction and also added the reference of the updated paper in JAMA.

- Results:

Line 89, what kind of invasive procedures? Would be helpful to list at least one example of subsequent procedures for these 6 patients.

- Authors: Thanks for the suggestion. We have followed the suggestion and have detailed the diagnostic procedures performed in two cases.

On line 90, the authors report that the "number needed to screen" NNS is 28. However, this needs to be specifically defined as "the number needed to screen to detect one lung cancer." NNS is typically reported (i.e., as in the NLST) as the "number needed to prevent one death" which is not what you are referring to here. So please define NNS.

- Authors: Thank you for noting this inaccuracy. We have followed this suggestion.

For Table 1, please provide more detail than "Values" for the top of the table. One column is not labeled.

- Authors: Thank you, we have reviewed the headings at include a new column “Cancer stage at diagnosis”.

In lines 92-95 you are providing outcomes comparing the cancer group to the rest of the cohort. Were these comparisons conducted statistically? Please report stats.

- Authors: We have used logistic regression to explore the associations between the diagnosis of cancer and the general characteristics. Because the sample size in the cancer group is very small (n=5), to avoid overstating the significance of the p values (all were non-significant), we have listed the confidence intervals and described the results: The new paragraph reads as follows:

“Compared to the rest of our cohort, patients with lung cancer had a similar age (both with a median age of 57 years, p=0.705), a lower median CD4 nadir count (71 [95% CI 43-105] vs. 179 [95% CI 80-309] cells/uL), lower current CD4 count (352 [95% CI 242-517] vs. 672 [95% CI 430-921] cells/uL), and a higher median pack-year (71 [95% CI 50-91] vs. 32 [95% CI 35-40])(Table 1)”.

- Discussion:

Again, on line 105, the authors report their NNS as 28. This needs to be specified as the "number needed to screen to detect one cancer."

Further, comparing 28 in this study to 320 in the NLST is an inappropriate comparison. In the NLST study, NNS was defined as "number needed to screen to prevent one death from lung cancer" and was calculated as the reciprocal of the reduction in the absolute risk of death from lung cancer in one group as compared with the other. You could compare prevalence rates between your study and NLST. But not NNS. Are you able to calculate "number needed to screen to prevent one death from lung cancer" from your dataset? If so, this should be calculated and reported. If not, please list this as a limitation.

- Authors: Thank you for this thoughtful comment. We have specified that we calculated that the number needed to screen to detect one cancer throughout the manuscript. Unfortunately, our study has not enough statistical power to provide accurate estimates of the number needed to screen to prevent one death from lung cancer. We have acknowledged this limitation in the discussion.

I appreciate the line re: smoking cessation being the key intervention to reduce incidence. Could you expand on this a little more? Perhaps tie it back in to the pack year history observed in your lung cancer group and the fact that all cancer patients were current smokers. You could also cite Tanner et al. 2016 (DOI: 10.1164/rccm.201507-1420OC)

- Authors: We have outlined the importance of smoking as one of the main drivers in LC and highlighted that within LC patients packs-year is substantially higher than in the rest of the cohort. Thank you for suggesting the citation by Tanner et al., that we have properly referenced.

On Line 141 it is stated "LDCT screening of lung cancer in a targeted population of PWH resulted in greater rates of lung cancer than in the general population." I think this statement needs to be clarified and I'm not sure it is totally accurate. What is the comparison here? The NLST? If so, this is an inappropriate comparison as described above. If you are referring to the general population incidence, then please specify the rates in the population. And do you mean "results in greater rates of [diagnosed] lung cancer"?

- Authors: Following this comment, we have discussed in more detailed our findings in the context of previous studies. A new reference has been added to better frame our results.

As previously mentioned, there are new LCS criteria. Your study still recruited a younger age (45) than the current guidelines for the general population, but your pack year history (25) is actually higher than the new criteria. I think it would be worth discussing your findings in light of these new guidelines.

- Authors: We intended to be more permissive than the LCS criteria that were then enforced. In the light of our findings and given the greater risk of LC in PWH, we think that LDCT screening could particularly outweigh the risks in this susceptible population. However, the performance of the less restrictive new USPSTF criteria should be addressed in next studies in PWH. To give consideration to this Reviewer’s comment, we have included this ideas in the closing remarks in the discussion.

Reviewer #2:

The reading and report of the images were conducted by 2 radiologists specialized on chest radiology. How were discrepancies managed?

- Authors: Discrepancies in interpretation between the two thoracic radiologists were resolved by consensus. We have included this information in the methods.

Screening procedures are not detailed at all. Specifically is this a single low dose chest tomography, or repetitive each year in case of negative results. What procedures were followed for lung cancer work-up.

- Authors: In this analysis, only a minority of patients had undergone a follow-up CT scan. So, we analyzed the findings obtained by the first LDCT of each patient. We are planning to perform a subsequent analysis with the follow-up data in the future. Following this comment, we have specified this information in the methods. Also, we have detailed the radiological criteria to consider the LDCT finginds suspicious of malignancy, that were those established in the NELSON trial by Van klaveren et al.

62% with HCV positive serology, thus I suppose a cancer high risk population, as reflected as 82% of active smokers. I suppose HIV risk in this cohort were primarily due to IDU. This may explain some discrepancies between your study and the published studies (Brock et al. JTO), and more so with Makinson et al. AIDS. You do not discus you results in perspective of these previous HIV-screening trials, nor with the NELSON results.

- Authors: We agree with the Reviewer. Not only HIV itself or the linked immune suppression, but also several lifestyle factors such as previous IDU could explain the high prevalence of LC in our cohort.

As requested by the Reviewer, we have compared our findings in the framework ot previous screening trials and cohort studies, and we have included the above-mentioned consideration as a possible factor affecting the results.

I would be more careful in my conclusion. What arguments do you have for writing that you participants had impaired immune response, as the median levels of CD4 cells was 666. I suppose you assume as these people had low nadir CD4, their immune system is still very impaired, but I do not think your data shows this. Moreover, nearly all subjects had controlled HIV-disease. You could also add the CD4/CD8 ratio to show that some subjects did not fully restore immune function.

-Authors: We understand the point raised by the Reviewer’s concern. Our intention was to highlight the characteristics of our 5 cases of LC: very low CD4 nadir, all previous HCV diagnosis, and 3 of them CD4 counts below 500 counts. The sentence was confusing because lead the reader understand that we were referring to the overall population. We have reworded the sentence, to make this point clear.

A descriptive synthetic table of the 5 cancer cases could be interesting with stage at diagnosis, age, etc…I wonder if any cases occurred < 50 years. Should PLHIV at risk be screened a such young ages. Stage at diagnosis is essential, because it may be that diagnosing cancer at advance stages may not be at all beneficial.

- Authors: We share the concern raised by the Reviewer with regards to the age of cancer onset. This concern actually motivated adapting our screening criteria to include a younger population thatn that recommended by the USPSTF . However, all cases pf lung cancer occurred in subjects with older than 55 years. Following this Reviewer’s suggestion, we have added in Table 2 the CDC stage at diagnosis to complete the description of the 5 cases of LC, where the age is also shown.

- Patients number 1: Stage IV (pT1bN3M1c)

- Patients number 2: Stage IA3 (pT1c N0 M0)

- Patients number 3: Stage IA (pT1 N0 Mx)

- Patients number 4: Stage IV (pT2N1M1a

- Patients number 5: Stage IV (cT4N3M1b)

Why so few people between 45-49 were included, as median age of most HIV population is around 50? The pack-years necessary was low, and so the threshold does not seem to me to be an explanation.

- Authors: In our clinics, the younger patients were less motivated to undergo such a screening intervention than the older ones. In addition, in our clinics most of the younger patients are MSM and have a lower prevalence of tabacco use than the older patients, which a larger proportion of IDU as a risk factor for HIV, and a larger prevalence of tobacco use. Also, these older patients with previous IDU and many of them AIDS-related conditions had AIDS in the past and are more willing to participate in this kind of preventive initiatives than younger patients. There may be other socio-demographic factors, and even reasons associated with the managing clinician, which are difficult to analyze in the absence of this information in the dataset.

Discussion could be enriched on false positive management : how many had additional procedures, and specifically surgery. How many underwent biopsies…and had adverse events from procedures ? And even bettr, how many people had additional procedures outside the lung cancer work-up procedures (i.e. cardiologist and coronary artery calcification). These are important outcomes in any lung cancer screening strategies.

- Authors: The comment raised by the Reviewer is well taken. The risk of false positive results is one of the most critical issues realted to LC Screening programs, even more in PWH who have a higher proportion of radiological stigma. Following this Reviewer’s comment, we have reviewed the clinical records to include this information.

Excluding patients diagnosed with lung cancer, only 4 patients with lung nodules underwent diagnostic procedures. While flexible bronchoscopy was performed in all of them, only 2 biopsies were carried out (1 TC guided biopsy and 1 surgical biopsy). The only related adverse event related to the surgical biopsy was chronic thoracic pain in 1 of the patients.

Among the 48 patients with radiologic evidence of aortic or coronary atherosclerosis, 5 had already known ischemic cardiomyopathy. Excluding these 4 instances, 15 consultations to cardiology department were performed, resulting in 11 ergometries, 2 dobutamine echocardiograms and 1 coronary angiography. Only 1 diagnosis of ischemic heart disease was made by percutaneous coronary intervention with stenting of medial and distal right coronary artery (Table 1).

Please be clear on the numbers needed to be screened. I believe there is a mistake in the text. In NLST, NNS to detect one lung cancer is 27, and to prevent one lung cancer death 300, which are two very different measures.

- Authors: Thank you for noting this. We have reviewed and amended the related statements.

Any data on adherence on the study protocol. Is screening validated in Spain, as clinical practice, and does not necessitate a clinical trial.

- Authors: Unfortunately, the screening of lung cancer is not currently implemented in Spain. We have justified at the end of the discussion that the aim was to evaluate the experience of a pilot screening program for PWH with adapted criteria seeking higher sensitivity.

Please mention low numbers, and though 3.6% is an important proportion of subjects with lung cancer, this number is subject to high variability as total numbers were low…(you could give us an CI95%)

Authors: Thank you for this suggestion. We have acknowledged in the Discussion the small number of cases as a limitation, and we have included the 95% confidence intervals for LC prevalente (3.6% [95% CI 1.5 – 8.3]) and for the NNT (28 [95% CI 12-66]).

For reference 7, and the higher burden of lung cancer in PLHIV I would suggest looking at studies calculation standardized incidence rate ratios…

- Authors: We appreciate the suggestion. We have changed the reference nº 7 for Robbins HA, Shiels MS, Pfeiffer RM Egels eA. Epidemiologic contributions to recent cancer trends among HIV-ifected people in the United States. AIDS. 2014; 28 (6): 881-90

Submitted filename: Response to Reviewer.docx

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21 Sep 2021

PONE-D-21-03298R1Implementation of a lung cancer screening initiative in HIV-infected subjectsPLOS ONE

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Reviewer #1: This manuscript is greatly improved. All of my comments have been addressed. Thank you for your thorough revisions. I have a few remaining small edits:

Table 1. The IQR is missing for Pack years.

On line 148, I think a word is missing. I think it should read: “…2.6% of participants were diagnosed with LC.”

On line 189 I think that should read “pack-years” not “packs-year”.

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21 Oct 2021

The authors would like to thank the Reviewers and Editors for their careful review of our manuscript, and for providing us with their very helpful comments and suggestions to improve the quality of the manuscript. The following responses have been prepared to address all of the referees’ comments in a point-by-point fashion.

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We have reviewed our reference list and we havent been able to find any anomaly related to the issues highlighted.

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6. Review Comments to the Author

Reviewer #1:

This manuscript is greatly improved. All of my comments have been addressed. Thank you for your thorough revisions. I have a few remaining small edits:

- Table 1. The IQR is missing for Pack years.

We have included IQR in table 1.

- On line 148, I think a word is missing. I think it should read: “…2.6% of participants were diagnosed with LC.”

We have included the error, the word LC has added to the paper.

- On line 189 I think that should read “pack-years” not “packs-year”.

We have checked this error and we have changes the term “pack-years” for packs-year”. We have also changed “PACKS-YEAR” in table 1 into “PACK-YEARS”.

We have spotted some minor errors in the paper after a thorough recheck. Below we show these changes we have made as long as you accordant with them.

- On line 24 and 34, LC has been added in order to explain the meaning of the acronym LC (which in our article means lung cancer)

- On line 42, 44, 46, 123 and 190 the words “lung cancer” has been replaced by the acronym “LC”

- On line 45 and 179 “– “has been changed by a “,”.

- On line 47, the word “cancer” was missing after lung and before screening so we have added LC to address the issue that screening program is for lung cancer

- On line 155 the word “a” was a mistake and it was meant to be “as” so it has been changed.

- On line 193, “pack-year” has been changed for “pack-years”.

Submitted filename: Response to Reviewer.docx

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3 Nov 2021

Implementation of a lung cancer screening initiative in HIV-infected subjects

PONE-D-21-03298R2

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15 Nov 2021

PONE-D-21-03298R2

Implementation of a lung cancer screening initiative in HIV-infected subjects

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