Background Cancer patients are thought to have an increased risk of developing severe Coronavirus Disease 2019 (COVID-19) infection and of dying from the disease. In this work, predictive factors for COVID-19 severity and mortality in cancer patients were investigated. Patients and Methods In this large nationwide retro-prospective cohort study, we collected data on patients with solid tumours and COVID-19 diagnosed between March 1 and June 11, 2020. The primary endpoint was all-cause mortality and COVID-19 severity, defined as admission to an intensive care unit (ICU) and/or mechanical ventilation and/or death, was one of the secondary endpoints. Results From April 4 to June 11, 2020, 1289 patients were analysed. The most frequent cancers were digestive and thoracic. Altogether, 424 (33%) patients had a severe form of COVID-19 and 370 (29%) patients died. In multivariate analysis, independent factors associated with death were male sex (odds ratio 1.73, 95%CI: 1.18-2.52), ECOG PS ≥ 2 (OR 3.23, 95%CI: 2.27-4.61), updated Charlson comorbidity index (OR 1.08, 95%CI: 1.01-1.16) and admission to ICU (OR 3.62, 95%CI 2.14-6.11). The same factors, age along with corticosteroids before COVID-19 diagnosis, and thoracic primary tumour site were independently associated with COVID-19 severity. None of the anticancer treatments administered within the previous 3 months had any effect on mortality or COVID-19 severity, except cytotoxic chemotherapy in the subgroup of patients with detectable SARS-CoV-2 by RT-PCR, which was associated with a slight increase of the risk of death (OR 1.53; 95%CI: 1.00-2.34; p = 0.05). A total of 431 (39%) patients had their systemic anticancer treatment interrupted or stopped following diagnosis of COVID-19. Conclusions Mortality and COVID-19 severity in cancer patients are high and are associated with general characteristics of patients. We found no deleterious effects of recent anticancer treatments, except for cytotoxic chemotherapy in the RT-PCR-confirmed subgroup of patients. In almost 40% of patients, the systemic anticancer therapy was interrupted or stopped after COVID-19 diagnosis.

Markers of chemotherapy efficacy in metastatic colorectal cancer (mCRC) are essential for optimization of treatment strategies. We evaluated the applicability of early changes in circulating tumor DNA (ctDNA) as a marker of therapeutic efficacy. This prospective study enrolled consecutive patients with mCRC receiving a first- or second-line chemotherapy. CtDNA was assessed in plasma collected before the first (C), second (C) and/or third (C) chemotherapy cycle, using picodroplet-digital PCR assays based either on detection of gene mutation () or hypermethylation (). CT scans were centrally assessed using RECIST v1.1 criteria. Multivariate analyses were adjusted on age, gender, ECOG performance status (PS), metastatic synchronicity, and treatment line. Eighty-two patients with mCRC treated in first- (82.9%) or second- (17.1%) line chemotherapy were included. Patients with a high (>10 ng/mL) versus low (≤0.1 ng/mL) ctDNA concentration at C had a shorter overall survival (OS; 6.8 vs. 33.4 months: adjusted HR, 5.64; 95% CI, 2.5-12.6; < 0.0001). By analyzing the evolution of the ctDNA concentration between C and C or C (C), we classified the patients in two groups (named "good" or "bad ctDNA responders"). In multivariate analysis, patients belonging to the group called "good ctDNA responder" ( = 58) versus "bad ctDNA responder" () had a better objective response rate ( < 0.001), and a longer median progression-free survival (8.5 vs. 2.4 months: HR, 0.19; 95% CI, 0.09-0.40; < 0.0001) and OS (27.1 vs. 11.2 months: HR, 0.25; 95% CI, 0.11-0.57; < 0.001). This study suggests that early change in ctDNA concentration is a marker of therapeutic efficacy in patients with mCRC. .

This study supports the use of adjuvant chemotherapy with fluoropyrimidine plus oxaliplatin in stage III dMMR CC.