Predictive factors of positive circumferential resection margin after radiochemotherapy for rectal cancer: The French randomised trial ACCORD12/0405 PRODIGE 2
Mené sur 565 patients atteints d'un cancer du rectum traité par chimioradiothérapie puis résection chirurgicale, cet essai français identifie les facteurs prédictifs associés à une marge de résection circonférentielle positive
Circumferential resection margin (CRM) appears as a new powerful prognostic factor of survival after surgery for rectal cancer. We aimed to evaluate predictive factors of positive CRM following preoperative radiochemotherapy in a French trial.
Patients with rectal cancer were randomised in long course preoperative radiotherapy 45Gy plus capecitabine versus 50Gy plus capecitabine and oxaliplatin. Mesorectal excision was performed 6weeks after treatment. Impact of clinical, pathological and surgical variables on positive CRM (⩽1mm) were analysed by multivariate analysis.
Of 565 randomised patients, CRM was recorded in 390 cases and was positive in 8% (30/390). Patients with 50Gy plus capecitabine and oxaliplatin had a 6% rate of positive CRM while those treated by 45Gy plus capecitabine had a 10% rate (p=0.128). Three independent predictive factors of positive CRM were identified: abdominoperineal resection (APR) (odds ratio OR=3.24; p=0.004), vascular tumour invasion (OR=2.78; p=0.026) and poor histological response (modified Dworak 0–2) (OR=9.01; p=0.003).
Significant predictive factors of positive CRM are related to type of surgery, especially APR, and poor histological prognostic factors. Intensification of neoadjuvant radiochemotherapy does not seem to have a major role in this study.
European Journal of Cancer , résumé, 2011