COVID-19 Lockdown May Be Associated With Higher Tumor Burden in Newly Diagnosed Patients With Metastatic Colorectal Cancer

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In a French study reported in JAMA Network Open, Thierry et al found that tumor burden (assessed as plasma circulating tumor DNA [ctDNA]) was significantly higher among patients with newly diagnosed metastatic colorectal cancer screened for a clinical trial after vs before the first COVID-19 lockdown in France.

Study Details

The study involved analysis of patients undergoing blood screening for RAS and BRAF tumor status in the phase II PANIRINOX trial comparing FOLFIRINOX (leucovorin, fluorouracil, irinotecan, and oxaliplatin) vs modified FOLFOX (fluorouracil, leucovorin, and oxaliplatin), both in combination with panitumumab. Median plasma ctDNA concentrations were compared between 40 patients who were newly diagnosed and underwent screening between November 11, 2019, and March 9, 2020—before lockdown—and 40 newly diagnosed and screened between May 14 and September 3, 2020—after lockdown. ctDNA levels were also assessed in 188 patients undergoing screening from the start of the trial in June 2017, at 30 months before lockdown.

Key Findings

Median ctDNA concentrations were 17.3 ng/mL (interquartile range [IQR] = 9.57–43.78 ng/mL) among 40 patients newly diagnosed and screened before the lockdown vs 119.2 ng/mL (IQR = 43.38–315.8 ng/mL) among 40 newly diagnosed and screened after the lockdown (P < .001). The difference amounted to a 6.9-fold increase in postlockdown vs prelockdown ctDNA levels.  

Among an additional 188 patients screened from the start of the trial, median ctDNA concentration was 13.0 ng/mL (IQR = 6.43–46.13 ng/mL).

In analysis of 135 patients in the trial, median overall survival was 14.7 months (95% confidence interval [CI] = 8.8–18.0 months) vs 20.0 months (95% CI = 14.1–32.0 months) for patients with ctDNA greater than vs equal to or lower than the median ctDNA level of 24.4 ng/mL (hazard ratio = 1.74, 95% CI = 1.2–2.6, P =.005). Among 25 patients with ctDNA > 100 ng/mL vs 110 patients with ctDNA ≤ 100 ng/mL, the hazard ratio for overall survival was 2.00 (95% CI = 1.2–3.3, P =.009). As stated by the investigators, “This finding points to the potential adverse consequences of the COVID-19 pandemic and related lockdown.”

The investigators concluded, “This cohort study found that tumor burden differed between patients who received a metastatic colorectal cancer diagnosis before vs after the first COVID-19 lockdown in France. The findings of this study suggest that colorectal cancer is a major area for intervention to minimize pandemic-associated delays in screening, diagnosis, and treatment.”

Alain R. Thierry, PhD, of the Institut de Recherche en Cancérologie de Montpellier, Université de Montpellier, is the corresponding author for the JAMA Network Open article.

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