An analysis of cancer patients with asymptomatic infection of SARS-CoV-2 in a cancer center in Wuhan, China.

The asymptomatic infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has now become the focus of epidemic control in Wuhan. Patients with cancer, a large population of immunocompromised individuals, have been observed to have a higher risk of coronavirus disease 2019 (COVID-19) infection. However, reports on cancer patients with asymptomatic infection are still scarce.

A retrospective study was performed to evaluate asymptomatic infections in 5119 individuals without typical symptoms of COVID-19 infection (including 2818 patients with cancer and 2301 caregivers without cancer). These individuals received an oropharyngeal swab test for SARS-CoV-2 nucleic acid by RT-PCR and/or serum specific antibody [immunoglobulin M (IgM) and IgG] test from 29 March to 23 April 2020, in Hubei Cancer Hospital, Tongji Medical College, Huazhong University of Science and Technology (Wuhan, P. R. China). The asymptomatic infections were identified by positivity to nucleic acid and/or antibodies (IgM/IgG). The incidence of infection was calculated as the proportion of infected individuals in the population.

The incidence of asymptomatic infection was 2.9% (81/2818) in patients with cancer, whereas it was 2.1% (49/2301) in their caregivers. There was no statistical difference in infection risk between patients with cancer and their caregivers [relative risk 1.36, 95% confidence interval (CI) 0.95–1.95]. Furthermore, positive results were not simultaneously observed in both patients and their caregivers. The close contacts and index patient were followed up for 10–32 days, and none of them developed symptoms.

We also evaluated the correlations between age, sex, or anticancer treatment, and asymptomatic infection in patients with cancer (Table 1 ). All the infected patients with cancer received anticancer treatment within the past 2 months. A total of 12 patients (14.8%) were diagnosed with stage IV cancer. Breast cancer was the cancer type with the most frequent infections. Among patients with cancer, chemotherapy [odds ratio (OR) 4.65, 95% CI 2.39–9.06] and targeted therapy (OR 1.90, 95% CI 1.18–3.05) were the risk factors for infection.

Table 1

Association analyses of age, sex, anticancer treatment, and tumor diagnosis in cancer patients with asymptomatic infection

	With asymptomatic infection	Without asymptomatic infection	Pa	OR (95% CI)
Total	81 (2.9)	2737 (97.1)
Age, mean (SD), years	56.4 (10.9)	54.8 (12.3)	0.27	—
≥60	34 (41.98)	1036 (37.85)	0.45	1.19 (0.76–1.86)
<60	47 (58.02)	1701 (62.15)
Sex
Male	35 (43.2)	1368 (50.0)	0.23	0.76 (0.48–1.19)
Female	46 (56.8)	1369 (50.0)
Anticancer treatment
Surgery
Yes	48 (59.3)	1377 (50.3)	0.11	1.44 (0.92–2.25)
No	33 (40.7)	1360 (49.7)
Radiotherapy
Yes	13 (16.1)	309 (11.3)	0.18	1.50 (0.82–2.75)
No	68 (83.9)	2428 (88.7)
Chemotherapy
Yes	71 (87.7)	1832 (66.9)	<0.01	4.65 (2.39–9.06)
No	10 (12.3)	905 (33.1)
Target therapy
Yes	26 (32.1)	546 (19.9)	<0.01	1.90 (1.18–3.05)
No	55 (67.9)	2191 (80.1)
Immunotherapy
Yes	4 (4.9)	203 (7.4)	0.40	0.65 (0.24–1.79)
No	77 (95.1)	2534 (92.6)
Tumor diagnosisb
Breast cancer	24 (29.6)
Lung cancer	16 (19.8)
Liver cancer	12 (14.8)
Gastrointestinal cancer	11 (13.6)
Brain tumor	3 (3.7)
Endometrial cancer	3 (3.7)
Lymphoma	3 (3.7)
Cervical cancer	2 (2.5)
Prostatic cancer	2 (2.5)
Glottic cancer	1 (1.2)
Tumor stagec
Stage I/II/III	69 (85.2)
Stage IV	12 (14.8)

Data are presented as n (%) unless noted otherwise.

Continuous variables were analyzed with Student's t-test and categorical variables were analyzed with the χ2 test.

Only the top 10 tumor diagnoses are listed.

Tumor stage according to the AJCC (American Joint Committee on Cancer) Cancer Staging Manual, version 7.

It remains largely unclear how to prioritize the treatment of patients with cancer in the postpandemic period. The available evidence is limited. Our research originally suggested some highlights on ‘truly’ asymptomatic infection in patients with cancer in Wuhan, China, who were symptom free over the preceding 14 days. In our present study, patients with cancer exhibited the equivalent susceptibility of asymptomatic infection compared with their caregivers. However, these patients with cancer possess a higher risk than those without, suggesting that frequent exposure to SARS-CoV-2 can increase the infectious risk of patients with cancer who receive anticancer treatment, but not cancer itself. Moreover, our findings indicated feeble virulence and transmission of asymptomatic infections. Therefore, admission of cancer patients with asymptomatic infection might not trigger a nosocomial infection if the rigorous infection control and personal protection procedures are followed. We also evaluated the risk factors of the infection in patients with cancer, and our data indicated that chemotherapy and targeted therapy could increase the infectious risk. To develop a reasonable and balanced treatment strategy between cancer and infection, analyses should be performed to evaluate whether anticancer treatments might predispose patients to the more severe outcome of asymptomatic infection, particularly chemotherapy and targeted therapy.