Clinical Complete Response in Patients with Rectal Adenocarcinoma Treated with Short-Course Radiation Therapy and Nonoperative Management
Menée auprès de 90 patients atteints d'un adénocarcinome rectal de stade I-III (durée médiane de suivi : 30,1 mois), cette étude évalue l'efficacité, du point de vue de la survie sans récidive locale, d'un traitement préservant le rectum comportant une radiothérapie de courte durée puis une chimiothérapie de consolidation
Purpose: This study aimed to determine the clinical efficacy and safety of nonoperative management (NOM) for patients with rectal cancer with a clinical complete response (cCR) after short-course radiation therapy (SCRT) and consolidation chemotherapy. Methods and Materials: Patients with Stage I-III rectal adenocarcinoma underwent SCRT followed by consolidation chemotherapy between 01/2018 and 05/2019 (n=90). Clinical response was assessed by digital rectal examination, pelvic magnetic resonance imaging (MRI), and endoscopy. Of the patients with an evaluable initial response, those with a cCR (n=43) underwent NOM and those with a non-cCR (n=43) underwent surgery. The clinical endpoints included local regrowth-free survival (LRFS), regional control (RC), distant metastasis-free survival (DMFS), disease-free survival (DFS), and overall survival (OS). Results: Compared to patients with an initial cCR, patients initial non-cCR had more advanced T and N stage (p=0.05), larger primary tumors (p=0.002), and more circumferential resection margin involvement on diagnostic MR (p=0.009). With a median follow-up of 30.1 months, the persistent cCR rate was 79% (30/38) in the NOM cohort. The 2-year LRFS was 81% (95% CI: 70-94%) in the initial cCR group, and all the patients with local regrowth were successfully salvaged. Compared to those with a non-cCR, patients with a cCR had improved 2-year RC (98% [95% CI: 93-100%] vs. 74% [95% CI: 61-88%], p < 0.01), DMFS (100% [95% CI: 100-100%] vs. 80% [95% CI: 69-94%], p < 0.01), DFS (98% [95% CI: 93-100%] vs. 71% [95% CI: 59-87%], p < 0.01), and OS (100% [95% CI: 100-100%] vs. 88% [95% CI: 79-98%], p=0.02). No late grade 3+ gastrointestinal or genitourinary toxicities were observed in the patients who underwent continued NOM. Conclusions: SCRT followed by consolidation chemotherapy may be a feasible organ preservation strategy in rectal cancer. Additional prospective studies are necessary to evaluate the safety and efficacy of this approach.
International Journal of Radiation Oncology, Biology, Physics 2021