Dossa F, et al. - Researchers investigated the possible benefit of adjuvant chemotherapy in patients with locally advanced rectal cancer who achieve pathological complete response (pCR) after neoadjuvant chemoradiation therapy and resection. Improved overall survival was seen with the administration of adjuvant chemotherapy in these patients. This was specifically seen in patients with pretreatment node-positive disease.

Methods

• In this retrospective propensity score–matched cohort study, the National Cancer Database from 2006 through 2012 was used to identify patients with locally advanced rectal cancer.
• Patients with nonmetastatic invasive rectal cancer who achieved pCR after neoadjuvant chemoradiation therapy and resection were selected.
• Those who received adjuvant chemotherapy were matched to those who did not receive adjuvant treatment in a 1:1 ratio.
• Effect modification by pretreatment nodal status was determined by separately matching subgroups of patients with node-positive disease before treatment and node-negative disease before treatment.
• Kaplan-Meier survival methods and Cox proportional hazards models were used to compare overall survival between groups.

Results

• A total of 2,455 patients (mean age, 59.5 years; 59.8% men) with rectal cancer with pCR after neoadjuvant chemoradiation therapy and resection were selected.
• A total of 667 patients with pCR who received adjuvant chemotherapy and at least 8 weeks of follow-up after surgery were matched to patients with pCR who did not receive adjuvant treatment.
• A median follow-up of 3.1 years (interquartile range, 1.94-4.40 years) revealed better overall survival in patients treated with adjuvant chemotherapy relative to those who did not receive adjuvant treatment (hazard ratio, 0.44; 95% CI, 0.28-0.70).
• Stratification by pretreatment nodal status showed improved overall survival with adjuvant chemotherapy in only those patients who had pretreatment node-positive disease (hazard ratio, 0.24; 95% CI, 0.10-0.58).