The long-term outcomes and prognostic factors about locally advanced right colon cancer: a retrospective cohort study

The first case of treatment with en bloc right hemicolectomy with pancreatoduodenectomy (RHCPD) for locally advanced right-sided colon cancer (LARCC) invading the pancreas, duodenum, or other organs, was reported in 1953 by Van Prohaska. Right-sided colon cancers invading the pancreas and duodenum are rare. Surgery can be technically challenging, with unclear oncologic consequences, hence there are few reports on the clinical outcomes and factors associated with survival in this patient cohort. The need for neoadjuvant chemotherapy in patients with LARCC is controversial, and the long-term survival of these patients as well as the preferred treatment regimen needs to be explored. This paper reports our experience in right hemicolectomy with en bloc resection for LARCC. We conducted this study to analyze the clinical features and surgical outcomes of LARCC.

A retrospective study was performed using a database of all patients who underwent RHCPD due to the tumour directly invading the duodenum and/or pancreas in a 19-year period [2003-2022]. We included patients whose primary tumor site was the right hemicolon and who had undergone a negative tumor resection margin (R0) resection. In addition, the adhesions between the colon and other organs in these patients were malignant adhesions. The primary outcome was the overall survival after surgery. The secondary endpoints of the study included 30-day postoperative mortality, postoperative complications, prognostic factors, and tumour genetics. All patients were followed up with postoperative imaging at an interval of 3 months for the first 3 years and at an interval of 6 months for the next 2 years, and annual follow-up thereafter. Survival was estimated using Kaplan-Meier analysis. Variables with P values <0.05 in univariate analysis were entered into multivariate Cox proportional risk regression to identify independent predictors of survival.

There were 47 patients (23 males and 24 females) who underwent en bloc resection for LARCC. The median age of the patients was 61 years (range, 38-80 years). R0 resection was achieved in all cases. The overall complication rate was 27.7% (n=13). Two patients died within 30 days of surgery. The overall survival was 80.9%, 63.5%, and 51.7% at 1, 3, and 5 years, respectively. Univariate survival analysis identified pancreatic invasion, regional lymph node positivity, more than two organs invaded, and no neoadjuvant treatment as predictors of poor survival (log-rank P<0.05). Multivariate analysis showed that regional lymph node positivity [95% confidence interval (CI): 1.145-7.736; P=0.025] and more than two organs invaded (95% CI: 1.321-26.981; P=0.020) were predictors of poor survival.

Relatively optimistic clinical outcomes from en bloc resection were demonstrated for patients with LARCC. For LARCC patients, en bloc resection can be carefully considered.