Post-surgery recurrence more likely in right- vs left-sided colon cancer

The risk of recurrence after curative resection appears to be higher for stage II right-sided colon cancer (RCC), reports a recent study.

The study included 1,017 patients with stage I–III colon cancer who had undergone curative colectomy from August 2008 to December 2019. Outcomes included overall survival (OS) and time to recurrence (TTR), which were compared between those with left-sided (LCC) or RCC.

LCC was more common, occurring in 632 patients (mean age 65.3 years, 56.5 percent men); only 385 had RCC (mean age 67 years, 47.3 percent men). According to disease stage, 188 had stage I, 322 had stage II, and 507 had stage III colon cancer.

Over a median follow-up time of 37.8 months in RCC patients and 43.0 months in LCC comparators, multivariate analysis found a significant link between shorter TTR and RCC in stage II colon cancer (hazard ratio [HR], 2.35, 95 percent confidence interval [CI], 1.14–4.85; p=0.02).

This interaction remained significant even after propensity-score matching. In the balanced cohorts, RCC was associated with a significantly shorter TTR as compared with LCC (HR, 3.20, 95 percent CI, 1.28–8.01; p=0.01).

In contrast, OS outcomes were statistically comparable between RCC and LCC (HR, 1.19, 95 percent CI, 0.90–1.58; p=0.23).

“Sidedness is an independent risk factor for cancer recurrence in stage II colon cancer; patients with stage II RCC had shorter TTR than did those with stage II LCC,” the researchers said. “Further research is needed to evaluate the differences of sidedness by using clinicopathological and genetic factors.”