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An International Multicenter Prospective Study Evaluating the Long-term Oncological Impact of Adjuvant Chemotherapy in ypN+ Rectal Cancer.

OBJECTIVE
To assess the oncological benefit of adjuvant chemotherapy (AC) in node positive (ypN+) rectal cancer following neoadjuvant chemoradiotherapy (NACRT) and radical surgery.


SUMMARY BACKGROUND DATA
The evidence for adjuvant chemotherapy (AC) following total mesorectal excision (TME) for locally advanced rectal cancer (LARC) is conflicting and the net survival benefit is debated.


METHODS
An international multicenter comparative cohort study was performed comparing oncological outcomes in tertiary rectal cancer centers from the Netherlands and France. Patients with LARC treated with NACRT followed by TME surgery and with positive lymph nodes on histological examination (ypN+) were included for analysis. Kaplan-Meier curves were generated to compare disease-free (DFS) and overall survival (OS) in AC and non-AC groups.


RESULTS
Of 1265 patients screened, a total of 239 rectal cancer patients with ypN+ disease were included. Demographic and clinical characteristics were similar in both groups. Higher systemic recurrence rates were observed in the non-AC group compared to those who received AC [32.0% (n=40) vs. 17.5% (n=11) respectively, P=0.034]. Disease free survival at one and five-years post-operatively were significantly better in the AC group (92% vs. 80% at one year; 72% vs. 51% at five years, P=0.024), while no difference in OS was observed.


CONCLUSION
In this multicenter comparative cohort study, we identified an oncological benefit of adjuvant chemotherapy in both systemic recurrence and disease-free survival in ypN+ rectal cancer patients. From this data, systemic chemotherapy continues to confer oncological benefit in locally advanced node positive rectal cancer.