COVID-19 impact on diagnosis and staging of colorectal cancer: A single tertiary Canadian oncology center experience.

Abstract

33 Background: COVID-19 pandemic urged public health to imposed drastic reduction on endoscopic activities and surgery, leading to delays that still not have been caught up today. The Ministry of Health and Social Services (MSSS) of Quebec conducted a study of the impact of those measures and reported a 66% reduction of colonoscopy and a 30% reduction of colorectal cancer (CRC) surgery activities during the first wave (March to May 2020). Whether those reduction had an impact on diagnosis and staging of CRC remains unknown. Methods: Demographic information of CRC diagnosed at Centre Hospitalier de l’Université de Montréal (CHUM) between January 1 2018 and March 12 2020 (pre-pandemic period), and March 13 2020 and June 30 2021 (pandemic period) were obtained from the SARDO registry and data regarding colonoscopy, surgery and staging at diagnosis (clinical or pathological as appropriate) were collected. Priority of elective colonoscopy was defined using the MSSS grading system ranging from P1 to P5. We compared delays to colonoscopy, delays to surgery and CRC staging of the pandemic period to the pre-pandemic period using one-way ANOVA, t tests and Chi-square tests as appropriate. Only delays in elective surgeries intended as first and curative treatment were analyzed. Results: 280 CRC diagnosis were made at the pre-pandemic period compared to 127 CRC diagnosis during the pandemic period. Mean diagnosis rates of the pandemic period tend to be lower (8.3 vs. 10.5 diagnosis/month, p=0.03) compared to the pre-pandemic period. 37.6% of patient in the pandemic period had a diagnosis of CRC during a hospitalization compared to 25.9% at the pre-pandemic period (p=0.048). 51.7% of elective colonoscopy leading to a diagnostic of CRC during the pandemic period did not meet required delays according to priority compared to 38.3% (p=0.049) during the pre-pandemic period. P3 colonoscopies (mostly indicated for a positive FIT and iron deficiency anemia) were the most affected (58.9 vs. 106.5 days, p˂0.001). P2 colonoscopy (indicated for suspected colorectal cancer) did not experienced an augmentation in delays (20.9 vs. 25.2 days, p=0.39). A mean of 3.5 elective curative surgeries per month were performed during the pandemic period compared to 3.4 at the pre-pandemic period (p=0.96), and mean delays for surgery were not affected (60.4 vs. 57 days, p=0.59). Stages at diagnosis did not differ (p=0.2). Most of the delayed colonoscopies led to a stage 0 or I CRC and did not lead to a higher stage at diagnosis (p=0.2). Conclusions: In our center, the COVID-19 pandemic led to overall less CRC diagnosis and increased diagnostic endoscopic delays without a higher rate of advanced stage disease. Delays for elective surgeries were quite similar once the CRC diagnostic established.