Reducing the Morbidity of Rectal Cancer Treatment
Mené au Canada sur 82 patients atteints d'un cancer rectal de stade II à III traité par résection chirurgicale (âge médian : 66 ans), cet essai de phase II évalue, du point de vue de la sécurité et du taux de marges de résection circonférencielles positives, la possibilité d'utiliser les critères de l'IRM pour identifier les patients présentant un pronostic favorable et ne nécessitant pas de chimioradiothérapie pré-opératoire
A complete mesorectal excision is essential for achieving optimal local tumor control in patients with locally advanced rectal cancer.1,2 Total mesorectal excision (TME) alone has been shown in large series to achieve local recurrence rates of approximately 10% and cancer-specific survival of 70%.1,3 The strongest predictors of pelvic recurrence are T stage, involved circumferential resection margin (CRM), and N stage.2 Large randomized clinical trials of neoadjuvant radiotherapy or chemoradiotherapy for locally advanced rectal cancer have demonstrated reductions in local recurrence from 12% to 25% and from 5% to 10%, respectively, and, in some trials, reduction of cancer deaths by 10%.4-6 In the Swedish rectal trial,7 cancer-specific survival improved from 62% to 72% in patients who received preoperative irradiation. In the Dutch TME trial,5 preoperative irradiation led to an improved 10-year survival rate (N = 435; 40% to 50%; P = .03) in patients with positive nodes and a negative CRM. Perhaps this was owing in part to irradiation treating the (non-TME) lateral pelvic lymph nodes. Both rectal resection and neoadjuvant treatment produce short- and long-term toxic events, and the negative effect of these 2 modalities on bowel and sexual function are significant and additive.8-10 Thus, better selection of patients for neoadjuvant therapy to reduce toxic events and avoid overtreatment is a worthwhile, but challenging, goal. One of the shortcomings of the randomized TME trials is the accuracy of clinical staging. Pelvic magnetic resonance imaging (MRI) is a possible method to more accurately separate high- and low-risk groups.
JAMA Oncology , éditorial en libre accès, 2018