Incidence of asymptomatic COVID19 positivity in cancer patients and effects on therapy

Ross, N.; Handorf, E. A.; Meeker, C. R.; Chen, G.; Baldwin, D.; Vijayvergia, N.

Background: As the coronavirus disease 2019 (COVID-19) pandemic threatens the delivery of cancer care, challenges to providing safe and quality care persist. Screening measures including SARS-CoV-2 polymerase-chain reaction (CovPCR) testing prior to invasive procedures, therapy administration, were instituted to address risk of spread from asymptomatic (AS) pts. Studies have documented poor outcomes with COVID-19 in cancer pts with rate of AS COVID-19 ranging from 0.6%- 8%. (Liang et.al, 2020;Al-Shamsi, et.al, 2020, Shah et.al. 2020). In the general population, rates of AS cases was estimated to be 17% (Byambasuren, O., 2020). This study aimed to examine the incidence and characteristics of AS COVID -19 in cancer pts, and determine its effect on cancer care delivery at a tertiary care center. Methods: With IRB approval, a retrospective chart review was conducted on cancer pts undergoing CoVPCR screening. Pts were considered AS if they had no recent fever (≥100.5 °F), cough, headache, loss of taste/smell, shortness of breath, diarrhea, or high risk exposure. This analysis compared cases (positive CoVPCR) identified by screening of AS pts to control (negative CoVPCR) pts (matched by planned procedure type and month of screening). Each COVID case was matched to 2 negative controls on month and planned procedure type. Patient characteristics and outcomes were compared between cases and controls using conditional logistic regression or Mantel-Haenszel tests. Results: Between 03/2020 and 09/2020, 4143 AS pts underwent CovPCR testing and 75 were chosen for analysis (25 cases;50 controls). The incidence of AS COVID-19 in cancer pts was 0.6% (25/4143). Median age was lower in the cases (64 vs 70y, p = 0.04). Gender, race, primary cancer diagnosis, and co-morbidity distribution was similar between cases and controls. Of the cases, 10 pts (40%) never underwent the planned oncologic intervention while 11 (44%) had a delay related to the positive CoVPCR (2 pts had no intervention planned). Only 1 pt (2%) in control arm didn't undergo the planned procedure. The mean duration of delay was 18 days (range 0-49 days, SD 16.72) in cases versus Zero days in control. Four (16.7%) cases developed symptoms within 14 days of positive CoVPCR testing but the PCR value did not predict this conversion. Conclusions: Incidence of AS COVID in our cancer pts was significantly lower than general population. Active screening delayed oncologic care but with institution of safety measures like separate treatment rooms and scheduling procedures at the end of the day have ensured safe and prompt cancer care delivery during the pandemic. Future research needs will address incorporating vaccination status into the screening algorithm to limit widespread CoVPCR screening, thus improving care delivery and cost effectiveness.