The interactions between cancer and susceptibility to coronavirus disease 2019 (COVID-19) are poorly understood. Early reports suggested a higher COVID-19 risk in patients with cancer not specifically selected for recent anticancer treatment,1,2 but data on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission among patients undergoing antitumor treatment are lacking.
To calculate the rate of SARS-CoV-2 infection among patients receiving antitumor treatment, data on patients treated at 118 Medical Oncology Units affiliated with the Collegio Italiano dei Primari Oncologi Medici Ospedalieri (CIPOMO)3 were collected in a retroprospective study (CIPOMO-ONCO-COVID-19).
For each center, aggregate data were registered on all patients who received at least 1 course of an active anticancer treatment between January 15 and May 4, 2020. Individual data were collected for those developing COVID-19 as assessed through polymerase chain reaction (PCR) test from a nasopharyngeal swab (driven by either symptoms or contact with a known positive case). Results were compared with those reported for the general Italian population over the same time period.4 This study was approved by the Ethics Committee of the Lazzaro Spallanzani National Institute of Infectious Diseases with informed consent waiver for critically ill patients because all data were deidentified.
Of 59 989 patients receiving antitumor treatment between January 15, 2020, and May 4, 2020, 406 developed COVID-19 with a positive nasopharyngeal PCR test result (0.68%; 95% CI, 0.61%-0.75%).
The median (range) age of infected patients was 68 (28-89) years. Most were symptomatic (n = 339, 83%), and 314 (77%) required hospitalization. Lung cancer was the most common tumor (n = 91, 22%), and chemotherapy the most represented antitumor treatment (n = 252, 62%) (Table 1). The infection rate was higher compared with the general Italian population during the same time period and varied between different geographical areas (Table 24).
To our knowledge, this study represents the largest investigation on the incidence of SARS-CoV-2 in patients with cancer and the first to focus specifically on patients receiving antitumor treatment. The 0.68% rate of infection that we found is low compared with the benefits achievable with most oncologic treatments. Notably, the infection rate remained below 1% even in the area with the greatest COVID-19 spread, partly reflecting reorganization measures implemented in medical oncology units in Italy at the onset of this outbreak.3
Our estimates should be regarded as conservative because this was not a screening study and could not capture asymptomatic patients without a known contact. Patients receiving antitumor treatment, however, are frequently visited in an oncologic day hospital with lower thresholds for testing. Underestimation is thus unlikely compared with incidences reported in the community. On the other hand, the strict definition of positive cases (PCR test) minimizes overestimation errors compared with previous reports.2
Compared with the general Italian population, patients receiving antineoplastic treatment appeared to have a higher risk of developing COVID-19 (Table 2). Rather than reflecting a higher biologic susceptibility to SARS-CoV-2, this could depend on the different age distribution of the 2 groups, with patients with cancer being on average older than the general population, and on a higher likelihood of viral exposure for patients owing to multiple and continued hospital visits. The lower rates of infection among patients with cancer in areas with lower degrees of COVID-19 spread seems to be consistent with this hypothesis (Table 2).
To our knowledge, this study provides the first estimate of the rate of SARS-CoV-2 infection among patients receiving antitumor treatment on a large population of approximately 60 000 patients treated at more than 110 oncology units. From a clinical point of view, the low probability of SARS-CoV-2 infection among these patients (<1%) supports the continuation of most oncologic treatments in the adjuvant and metastatic setting. Based on the present data, delaying active antitumor treatment to avoid SARS-CoV-2 transmission should not be routinely recommended.