COVID-19 clearance among patients with cancer during the Delta and Omicron waves

ABSTRACT

Background: COVID-19 presents a particular challenge in oncology, as in-person visits and treatments can be delayed during infection and patients are at risk for prolonged viral shedding. Our center uses two consecutive negative PCR tests for patients to return to clinic. As vaccination rates increase, we questioned the need for this strategy vs a time-based clearance approach. Method(s) We identified cancer patients who tested positive for COVID-19 from 10/1/2021 to 3/31/2022 at a single tertiary care center and performed chart review under an IRB-approved protocol. Subgroups were compared using the Welch's t-test and Welch's ANOVA for 2 or > 2 groups, respectively. Result(s) 169 patients were identified. 153 had documented clearance defined as two consecutive negative PCR tests. The mean clearance time was 35.7 days (95% CI 32.3-39.0). There was a trend toward longer clearance time in patients with hematologic vs solid tumors (39.6 vs 33.2, p =.06) and a significant increase in patients treated with B cell depletion (58.0) vs chemo/targeted therapy (35.7, p =.01) or immunotherapy (29.0, p =.004). No significant difference was found by vaccination status or between the Delta and Omicron waves. If defined as one negative test, mean clearance time was 25.9 days (95% CI 23.6- 28.1), and there was a significant difference in patients with hematologic vs solid tumors and in those treated with B cell depletion vs other therapies. However, 16.0% (27/169) of patients had a subsequent positive test after a first negative result, with increased incidence in patients with hematologic malignancy (26.2%, 16/61) and stem cell/adoptive cell transplant (46.2%, 6/13). Conclusion(s) COVID- 19 is a significant barrier to oncologic care, and clearance times remain longer than reported for the general population. In this single center study, clearance time was > 1 month and further increased in patients with hematologic malignancy or on B cell depleting therapy. While adjusting clearance criteria to a single negative test or specific timeframe may be an attractive option to reduce delays, a large proportion of patients may have further positive PCR testing.