Introduction The dissemination of SARS-Cov2 may have delayed the diagnosis of new cancers This study aimed at assessing the number of new cancers during and after the lockdown Methods We collected prospectively the clinical data of the 11 4 million of patients referred to the Assistance Publique Hôpitaux de Paris Teaching Hospital We identified new cancer cases between January 1st 2018 and September 31st 2020, and compared indicators for 2018 and 2019 to 2020 with a focus on the French lockdown (March 17th to May 11th, 2020), across cancer types and patient age classes Results Between January and September, 21,681, 20,778 and 16,764 new cancer cases were identified in 2018, 2019 and 2020, respectively The monthly median number of new cases reached 2,520 (interquartile range, IQR, 2,328;2,586), 2,322 (IQR 2,307;2,399) and 1,949 (IQR 1,586;2,045) in 2018, 2019 and 2020, respectively From March 1st to May 31st, new cancer decreased by 33% in 2020 compared to the 2018-19 average;then by 19% from June 1st to September 31st This evolution was consistent across all tumor types: -33% and -19% for colon, -30% and -8% for lung, -29% and -13% for breast, -30% and -18% for prostate cancers, respectively For patients aged &lt; 70 years, the decrease of colorectal and breast new cancers in April between 2018-2019 average and 2020 reached 46% and 44%, respectively Conclusion The SARS-Cov2 pandemic led to a substantial decrease of new cancer cases Delays in cancer diagnoses may affect clinical outcomes in the coming years
New cancer cases at the time of SARS-Cov2 pandemic and related public health policies: A persistent and concerning decrease long after the end of national lockdown