Spotlight on COVID-19 and GI cancers

Recent international studies found that the COVID-19 pandemic may be associated with fewer new diagnoses of gastric cancer and colorectal cancer (CRC), as well as increased tumor burden in patients with newly diagnosed metastatic CRC.

Recent studies looked at the effects of the COVID-19 pandemic on diagnoses of GI cancers and the tumor burden of patients with newly diagnosed metastatic colorectal cancer (CRC) and offered a framework that may help reduce time to CRC diagnosis.

The first study found that there may have been fewer cases of screening-detected GI cancer and that CRC may have been diagnosed at more advanced stages during the COVID-19 pandemic. Researchers retrospectively looked at patients who were diagnosed with GI cancer (i.e., esophageal, gastric, colorectal, pancreatic, liver, and biliary tract cancers) between January 2016 and December 2020 at two tertiary hospitals in Japan. They defined the pre-COVID-19 period as January 2017 to February 2020 and the COVID-19 period as March to December 2020. The main outcome was the monthly number of patients with newly diagnosed cancer, who were classified by stage and compared. Results were published Sept. 21 by JAMA Network Open.

A total of 5,167 patients were included, 4,218 (mean age, 71.3 years; 67.0% men) in the pre-COVID-19 period and 949 (mean age, 71.8 years; 64.0% men) in the COVID-19 period. The mean number of patients with newly diagnosed gastric cancer decreased from 30.63 patients per month before COVID-19 to 22.40 patients per month during the pandemic (change, −26.87%; P<0.001), and new diagnoses of CRC also decreased from 41.61 to 36.00 patients per month (change, −13.47%; P=0.03). There were also significant decreases in the mean number of cases of stage I gastric cancer during the study period (21.55 vs. 13.90 cases per month; change, −35.51%; P<0.001), stage 0 CRC (10.58 vs. 7.10 cases per month; change, −32.89%; P=0.008), stage I CRC (10.16 vs. 6.70 cases per month; change, −34.04%; P=0.003), and stage II CRC (7.42 vs. 4.80 cases per month; change, −35.32%; P=0.01). There was a significant increase in the number of cases per month of stage III CRC (7.18 vs. 12.10 cases per month; change, 68.42%; P<0.001). No significant increases were observed for esophageal, gastric, pancreatic, liver, or biliary tract cancers. The study was limited by its retrospective design and the fact that data were collected from only two Japanese hospitals through the end of 2020, the authors noted.

“Given the ongoing nature of the COVID-19 pandemic, it … is important to ensure that patients undergo necessary screening and surveillance without waiting for the pandemic to end, especially patients who require colonoscopy to potentially detect colorectal cancer,” they wrote. “Moreover, given the speed of cancer progression, it is possible that the negative effects of the COVID-19 pandemic may become more pronounced over time, and further research is needed to better evaluate this issue.”

Another study, published by JAMA Network Open on Sept. 8, focused on how the COVID-19 lockdown affected the tumor burden of patients with newly diagnosed metastatic CRC in particular. Researchers looked at a cohort of 80 newly diagnosed patients who participated in a phase II randomized trial, received care at one of 18 clinical centers in France, and were recruited before or after the lockdown was enacted in the spring of 2020. The researchers used circulating tumor DNA (ctDNA) analysis to identify their RAS and BRAF tumor status and evaluated tumor burden by the total plasma ctDNA concentration. They compared the median ctDNA concentration in patients screened before (Nov. 11, 2019, to March 9, 2020) versus after (May 14 to Sept. 3, 2020) lockdown and in patients who were included from the start of the trial.

Of 80 patients (median age, 62 years; 60% men) included in the analysis, 40 underwent screening before and 40 others underwent screening after the first COVID-19 lockdown in France. The median ctDNA concentration was statistically higher in patients who were newly diagnosed after lockdown compared with those who were diagnosed before lockdown (119.2 ng/mL vs. 17.3 ng/mL; P<0.001). Those with metastatic CRC and high ctDNA concentration had lower median survival compared with those who had lower ctDNA concentration (14.7 [95% CI, 8.8 to 18.0] months vs. 20.0 [95% CI, 14.1 to 32.0] months). The study was exploratory and could not draw a direct association between tumor burden and the distinct delays in care for newly diagnosed patients enrolled in the trial, the authors noted. “The findings of this study suggest that CRC is a major area for intervention to minimize the clinical implications of a pandemic-associated diagnostic delay,” they concluded.

The third and final study focused on this challenge by offering a framework for analyzing barriers to CRC diagnosis during the pandemic and generating evidence to support health system changes aimed at reducing time to diagnosis. Researchers in Canada retrospectively looked at CRC cases from the Alberta Cancer Registry for the prepandemic (Jan. 1, 2016, to March 4, 2020) and intrapandemic (March 5 to July 1, 2020) periods and obtained data on diagnostic milestones in the year prior to CRC diagnosis from administrative health data. They identified CRC diagnostic pathways, measured diagnostic intervals, and used CRC diagnoses made during hospitalization as a proxy for severe disease at presentation. They estimated the adjusted relative risk (RR) and a 95% CI for the effect of the pandemic on the risk of hospital-based diagnoses. Results were published online on Aug. 28 by the International Journal of Environmental Research and Public Health.

During the study period, 8,254 patients in Alberta were diagnosed with CRC. During the pandemic, diagnosis through symptomatic screening decreased by 6.5%. The adjusted RR for hospital-based diagnoses during COVID-19 versus before COVID-19 was 1.24 (95% CI, 1.03 to 1.49), and colonoscopies were identified as the main bottleneck for CRC diagnoses. The researchers suggested that to clear the backlog before progression is expected, health systems should target high-risk subgroups to double the colonoscopy yield for CRC diagnosis and increase monthly colonoscopy volumes by 140% for a period of three months. “Given the substantial changes required in both the procedure capacity and patient triaging to increase the CRC diagnosis yield from colonoscopies, it is unlikely that a surge in CRC diagnoses will occur over the coming months,” they concluded, adding that they have shared these findings with administrators in Alberta's health system to aid in decision making.