The Slow Adoption of Neoadjuvant Treatment for Clinical T4b Colon Cancer: A National Cancer Database Analysis.

Abstract

Background: Emerging data support the use of neoadjuvant treatment (NAT), particularly immunotherapy in microsatellite instability-high (MSI-H) tumors. We evaluate national trends in NAT utilization for clinical T4b colon cancers and its association with overall survival, with a focus on MSI-H tumors.

Methods: We conducted a retrospective cohort study using the National Cancer Database (2010-2022) evaluating patients with non-metastatic clinical T4b colonic adenocarcinoma who underwent colectomy. The primary outcome measures were trends in NAT utilization and overall survival.

Results: Among 8862 patients with clinical T4b colon cancer, NAT utilization increased over time, peaking at 28% in the most recent quartile. NAT recipients were more likely younger, healthier, and to be treated at academic centers. NAT was associated with higher R0 resection rates (83% vs 77%, p < 0.001) and significantly longer mean overall survival (105 vs 80 months, p < 0.001). Among MSI-H patients (11% of the cohort), 15% received NAT. Immunotherapy use increased steadily, surpassing chemotherapy in 2022. Patients receiving neoadjuvant immunotherapy +/- chemotherapy demonstrated superior survival to chemotherapy alone (106 vs 85 months, p < 0.001).

Conclusions: Neoadjuvant therapy use has increased nationally, with a notable rise in immunotherapy for MSI-H tumors. Neoadjuvant treatment, particularly immunotherapy, is associated with significant overall survival benefit.