Serial Screening for COVID-19 in Asymptomatic Patients Receiving Anticancer Therapy in the United Arab Emirates.

Patients with cancer, especially those receiving anticancer therapy, are at risk amidst the coronavirus disease 2019 (COVID-19) pandemic.[1,2,3] Given the frequency of asymptomatic COVID-19,[2,4,5] and presymptomatic transmission,[5] symptom-based screening may inadequately triage patients to safely resume anticancer therapy.[2,6]

We thus implemented a pilot microbiologic screening program in Al Zahra Hospital in the United Arab Emirates (UAE), identifying presymptomatic COVID-19 in nearly 1 in 10 patients with cancer.[2] We have since expanded this program across serial anticancer therapy cycles.

Methods

Asymptomatic patients with solid tumors receiving anticancer therapy were consecutively enrolled at Al Zahra Hospital, Dubai, between March 13, 2020, to May 26, 2020, and followed until June 29, 2020. Patients were asymptomatic at enrollment.

Specific screening schedules were developed: 48 hours before each cycle of anticancer therapy for systemic chemotherapy or immunotherapy, weekly for daily radiation therapy or concurrent chemoradiation therapy, and monthly for daily targeted or hormonal therapy.

All patients were prospectively screened for COVID-19 symptoms,[2] and underwent a nasopharyngeal swab for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) polymerase chain reaction (PCR) at each screening. Patients underwent additional screening for new pulmonary infiltrates, symptoms, or at physician discretion. Anticancer therapy, besides hormonal therapy, was held until 2 consecutively negative PCR results and clinical recovery or per physician discretion. Patients with COVID-19 ceased further PCR screening. Health care workers underwent daily self-screening for symptoms and weekly PCR screening.

The Al Zahra Hospital research ethics board approved the study and waived written informed consent for this quality improvement project because all patients with cancer and health care workers were mandated to undergo testing. Data were summarized as percentages and median (SD) range. A prespecified α of .05 was used; 95% confidence intervals for proportions via the binomial method, and proportions compared via the Fisher exact test. Data analysis was undertaken using Microsoft Excel (version 16.35, Microsoft).

Results

Overall, 109 asymptomatic patients with cancer were enrolled, undergoing 384 screening swabs across a median of 2 cycles (range, 1-8). Demographic characteristics are shown in Table 1.

Table 1.

Patient Demographics and Clinical Outcomes for Patients With Cancer Undergoing Serial Screening for COVID-19

Variable	No. (%)
	Overall cohort (n = 109)	Patients with COVID-19		Without COVID-19
		Asymptomatic (n = 25)	Symptomatic (n = 7)	Asymptomatic (n = 77)
Demographics
Age, median (range), y	55 (17-78)	45 (17-76)	55 (45-66)	54 (48-66)
Female sex	55 (50.5)	14 (56)	3 (42.9)	38 (49.4)
Cancer type
Breast	31 (28.4)	7 (28.0)	2 (28.6)	22 (28.6)
Colorectal	22 (20.2)	6 (24.0)	2 (28.6)	14 (18.2)
Lung	6 (5.5)	2 (8.0)	1 (14.2)	3 (3.9)
Head/neck	8 (7.4)	2 (8.0)	0	6 (7.8)
Thyroid	11 (10.1)	1 (4.0)	0	10 (13.0)
Sarcoma	7 (6.4)	2 (8.0)	0	5 (6.5)
Other	24 (22.0)	5 (20.0)	2 (28.6)	17 (22.1)
Outcomes
Hospitalization	17 (15.6)	7 (28.0)a	2 (28.6)	8 (10.4)b
ICU	8 (7.3)	2 (8.0)	2 (28.6)	4 (5.2)b
Death	8 (7.3)	3 (12.0)	1 (14.2)	4 (5.2)b
Anticancer therapy delay, median (range), d	13 (0-26)	16 (0-26)	14.5 (11-18)	4 (0-21)

Abbreviations: COVID-19, coronavirus disease 2019; ICU, intensive care unit.

Three admissions were not related to COVID-19.

Not related to COVID-19.

Thirty-two (29.4%, 95% CI, 21.0%-38.9%) patients acquired COVID-19; among them, 25 (78.1%) were diagnosed while asymptomatic and 7 (21.9%) presented with interval symptoms after negative PCR screening results. The asymptomatic screening swabs had a yield of 6.4% (25 of 384 screening tests) (Table 2).

Table 2.

COVID-19 Diagnoses at Screening per Cycle

Screening cycle	No. of asymptomatic patients screened	Confirmed COVID-19 cases, No. (%)
1	109	7 (6.4)
2	102	6 (5.9)
3	88	4 (4.5)
4	53	5 (9.4)
≥5	32	3 (9.4)

Abbreviation: COVID-19, coronavirus disease 2019.

Among patients diagnosed with COVID-19, most had mild infection (27/32, 84.4%), with 6 (18%) remaining asymptomatic. Nine (28.1%) patients with COVID-19 were admitted to the hospital, 6 owing to COVID-19 and 3 for others reasons (1 adverse drug reaction, 1 palliation, and 1 rectal abscess). Four patients (12.5%) with COVID-19 required intensive care, and 4 died (12.5%).

Patients with COVID-19 were significantly more likely to be hospitalized (28.1% vs 10.4%; P = .04) (Table 1) and died numerically more frequently (12.5% v. 5.2%; P = .23). All surviving patients with COVID-19 resumed chemotherapy after a median of 16 days (0-26) vs 4 days (range 0-21 days) for uninfected patients.

Three presymptomatic clinicians (3/12, 25%; 1 physician, 2 nurses) were diagnosed with COVID-19 by PCR screening and developed mild symptomatic infections. Epidemiologic investigation traced 2 health care infections to care of presymptomatic patients with COVID-19.

Discussion

Our microbiologic screening program identified a high rate of COVID-19 among patients with cancer, with 32 of 109 (29.4%) patients developing COVID-19 during the study period. In comparison, the cumulative prevalence of COVID-19 in the UAE was 496.3 per 100 000 residents as of June 29, 2020. Most infections were identified in the presymptomatic phase. In the absence of this microbiologic screening, such patients would have proceeded with anticancer therapy unaware of their COVID-19 infection, which may have increased their complication risk.[3]

Although limitations of this study included small sample size and no control group, implementation of microbiologic screening for SARS-CoV-2 among patients with cancer guided continuation of anticancer therapy. As we work to provide safe uninterrupted oncologic care amidst the COVID-19 pandemic, microbiologic screening should be considered for patients with cancer receiving anticancer therapy.