Is Adjuvant Chemotherapy Necessary for Obstructing Stage II Colon Cancer? Results From a Propensity Score Analysis of the French Surgical Association Database

<jats:sec> <jats:title>Objective:</jats:title> <jats:p>The aim of this study was to compare the survival of patients with stage II obstructing colon cancer (OCC) who had adjuvant chemotherapy with those who did not.</jats:p> </jats:sec> <jats:sec> <jats:title>Summary Background Data:</jats:title> <jats:p>The need for adjuvant chemotherapy in stage II colon cancer is still debated.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods:</jats:title> <jats:p>All consecutive patients treated for a stage II OCC in a curative intent (with primary tumor resection) between January 2000 and December 2015 were included in this retrospective, multicenter cohort study which included a propensity score analysis using an odds of treatment weighting (Average Treatment effect on the Treated, ATT). The endpoint was the comparison between the 2 groups for overall survival (OS) and disease-free survival (DFS) according to whether or not patients received adjuvant chemotherapy.</jats:p> </jats:sec> <jats:sec> <jats:title>Results:</jats:title> <jats:p>During the study period, 504 patients underwent a curative colectomy for a stage II OCC. Among these patients, 179 (35.5%) had adjuvant chemotherapy and 325 (64.5%) had no adjuvant treatment. Among the 179 patients who received adjuvant chemotherapy, 108 patients (60%) received oxaliplatin based regimen and 99 patients (55%) completed all scheduled cycles. At multivariate analysis, after weighting by the odds (ATT analysis) and adjustment, adjuvant chemotherapy after resection of a stage II OCC was associated with improvements in OS [hazard ratio (HR) = 0.42 (0.17–0.99), <jats:italic toggle="yes">P</jats:italic> = 0.0498] and DFS [HR = 0.57 (0.37–0.88), <jats:italic toggle="yes">P</jats:italic> = 0.0116].</jats:p> </jats:sec> <jats:sec> <jats:title>Conclusion:</jats:title> <jats:p>This study suggests that adjuvant chemotherapy after curative resection of stage II OCC may improve oncological outcomes.</jats:p> </jats:sec>