Cohort study of colorectal cancer treatment delay thresholds and metastasis risk

Timely treatment in colorectal cancer (CRC) may influence the disease course and outcomes. Optimal delay thresholds are uncertain. A retrospective cohort study, using deidentified administrative claims from Optum’s Clinformatics Data Mart, evaluated the association between time-to-treatment initiation (TTI) and 3-year metastasis risk in patients with newly diagnosed nonmetastatic CRC undergoing curative-intent surgery. Eligible individuals were adults aged 40 years or older with incident nonmetastatic CRC diagnosed during 2017 through 2021. Among 11 927 patients (mean age 70.7 years; SD 10.8; 50.4% women), 1438 (12.1%) developed metastasis over 3 years. Longer TTIs were associated with higher metastasis risk, varying by treatment pathway. For surgery plus adjuvant therapy, TTIs of 4 tot 34 days (sHR 1.27; 95% CI 1.04-1.55) and 47 days or longer (1.55; 1.08-2.23) were significantly associated with increased risk versus zero to 3 days. For surgery followed by radiation, delays of 223 days or longer showed higher risk (sHR 2.00; 95% CI 0.95-4.25) than TTI up to 22 days, although this result was not significant. For neoadjuvant therapy plus surgery, TTI of 68 days or longer were associated with higher risk (sHR 2.66; 95% CI 1.02-6.94) than TTI up to 67 days. For patients receiving trimodality therapy, there was no association between TTI and risk of metastasis. The authors conclude that in this cohort study, treatment delays were associated with higher, pathway-specific metastasis risk.