An Analysis of COVID-19 Screening in Asymptomatic Patients Undergoing Anticancer Treatment

A study observed a high prevalence of COVID-19 among asymptomatic patients undergoing anticancer treatment.

“Patients with cancer, especially those receiving anticancer therapy, are at risk amidst the coronavirus disease 2019 (COVID-19) pandemic. Given the frequency of asymptomatic COVID-19, and presymptomatic transmission, symptom-based screening may inadequately triage patients to safely resume anticancer therapy,” the study authors explained.

They enrolled asymptomatic patients with solid tumors who were receiving anticancer therapy at Al Zahra Hospital, Dubai, between March 13 and May 26; follow-up was conducted until June 29. Screening schedules were determined based on anticancer therapy. Systematic chemotherapy or immunotherapy patients were tested 48 hours before each cycle of therapy, daily radiation therapy or concurrent chemoradiation therapy patients were screened weekly, and targeted or hormonal therapy patients were screened monthly. Patients were screened prospectively for symptoms of COVID-19 and were tested with a nasopharyngeal swab at each screening. They were screened further for new pulmonary infiltrates, symptoms, or at physician discretion. Those who tested positive terminated additional polymerase chain reaction (PCR) screening; health care workers self-screened daily and underwent weekly PCR screening.

A total of 109 asymptomatic patients underwent 384 screening swabs across a median (range) 2 (1-8) cycles, of whom 32 patients (29.4%; 95% confidence interval, 21.0%–38.9%) developed COVID-19. Of those who contracted the virus, 25 patients (78.1%) were diagnosed while asymptomatic, and seven patients (21.9%) presented with interval symptoms following a negative PCR screening. Asymptomatic screening swabs yielded a 6.4% rate. Most patients who developed COVID-19 had a mild case (n=27, 84.4%); six patients (18%) remained asymptomatic. Nine patients with COVID-19 (28.1%) were admitted to the hospital either due to COVID-19 (n=6) or otherwise (adverse drug reaction, palliation, and rectal abscess, n=1 each). Four patients who developed COVID-19 required intensive care, and four patients died.

Those who developed COVID-19, compared to patients who did not, were much more likely to be hospitalized (28.1% vs. 10.4%; P=0.04) and die numerically (12.5% vs. 5.2%; P=0.23). COVID-19 survivors resumed chemotherapy after a median 16 days, compared to four days for patients who did not develop COVID-19.

Per PCR screening, three presymptomatic clinicians received a COVID-19 diagnosis, all of whom went on to develop mild symptoms. Two of the infections were traced to presymptomatic care of patients with COVID-19.

The study was published in JAMA Oncology.

“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,” the researchers wrote. “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.”