Association between incomplete neoadjuvant radiotherapy and survival for patients with locally advanced rectal cancer
Menée à partir de données portant sur 17 600 patients atteints d'un adénocarcinome rectal de stade II à III diagnostiqué entre 2006 et 2012 (âge médian : 59 ans ; 10 862 hommes), cette étude évalue, en fonction de la dose de rayonnements administrée (dose inférieure à 45.0 Gy ou comprise entre 45.0 et 50.4 Gy), l'effet d'une radiothérapie néo-adjuvante sur la survie globale à 5 ans
Importance : Failing to complete chemotherapy adversely affects survival in patients with colorectal cancer. However, the effect of incomplete delivery of neoadjuvant radiotherapy is unclear. Objective : To determine whether incomplete radiotherapy delivery is associated with worse clinical outcomes and survival. Design, Setting, and Participants : Data on 17 600 patients with stage II to III rectal adenocarcinoma from the 2006-2012 National Cancer Database who received neoadjuvant chemoradiotherapy followed by surgical resection were included. Multivariable regression methods were used to compare resection margin positivity, permanent colostomy rate, 30-day readmission, 90-day mortality, and overall survival between patients who received complete (45.0-50.4 Gy) and incomplete (<45.0 Gy) doses of radiation as preoperative therapy. Main Outcomes and Measures : The primary outcome measure was overall survival; short-term perioperative and oncologic outcomes encompassing margin positivity, permanent ostomy rate, postoperative readmission, and postoperative mortality were also assessed. Results : Among 17 600 patients included, 10 862 were men, with an overall median age of 59 years (range, 51-68 years). Of these, 874 patients (5.0%) received incomplete doses of neoadjuvant radiation. The median radiation dose received among those who did not achieve complete dosing was 34.2 Gy (interquartile range, 19.8-40.0 Gy). Female sex (adjusted odds ratio [OR] 0.69; 95% CI, 0.59-0.81; P < .001) and receiving radiotherapy at a different hospital than the one where surgery was performed (OR, 0.72; 95% CI, 0.62-0.85; P < .001) were independent predictors of failing to achieve complete dosing; private insurance status was predictive of completing radiotherapy (OR, 1.60; 95% CI, 1.16-2.21; P = .004). At 5-year follow-up, overall survival was improved among patients who received a complete course of radiotherapy (3086 [estimated survival probability, 73.2%] vs 133 [63.0%]; P < .001). After adjustment for demographic, clinical, and tumor characteristics, patients receiving a complete vs incomplete radiation dose had a similar resection margin positivity (OR, 0.99; 95% CI, 0.72-1.35; P = .92), permanent colostomy rate (OR, 0.96; 95% CI, 0.70-1.32; P = .81), 30-day readmission rate (OR, 0.92; 95% CI, 0.67-1.27; P = .62), and 90-day mortality (OR, 0.72; 95% CI, 0.33-1.54; P = .41). However, a complete radiation dose had a significantly lower risk of long-term mortality (adjusted hazard ratio, 0.70; 95% CI, 0.59-0.84; P < .001). Conclusions and Relevance : Achieving a target radiation dose of 45.0 to 50.4 Gy is associated with a survival benefit in patients with locally advanced rectal cancer. Aligning all aspects of multimodal oncology care may increase the probability of completing neoadjuvant therapy.