Adjuvant radiochemotherapy in high-risk rectal cancer results of a prospective non-randomized study.

Abstract

In 1990 the National Institutes of Health Consensus Conference recommended adjuvant combined therapy for patients with radically resected rectal cancer at high risk for relapse (ie, stage II-III). The purpose of our prospective non-randomized study was to verify the feasibility and effectiveness of postoperative radiochemotherapy in terms of improvement in disease-free and overall survival in this patient subgroup. From January 1990 to October 1998, 191 consecutive patients with radically resected stage II-III rectal cancer were treated. A total of 159 patients with a 24-month follow-up were assessable for toxicity and survival. Anterior resection was performed in 129 (81%) and abdomino-perineal resection in 30 (19%) patients. Fifty-four (34%) stage II and 105 (66%) stage III patients entered the study. Within 45-60 days of surgery, all patients received 5-fluorouracil chemotherapy at the dose of 500 mg/m2 as an i.v. bolus on days 1-5, every 4 weeks, for 6 cycles. Chemotherapy cycles III and IV were administered at the same daily dose on radiotherapy days 1-3 and 29-31. Radiotherapy consisted of 45 Gy/25 fractions plus a boost dose of 5.4 Gy. After a median follow-up of 57 months (range, 25-123), overall recurrent disease was reported in 58 (36%) patients: local, systemic, and both local and systemic relapses in 12 (8%), 37 (23%) and 9 (6%) cases, respectively. According to local extension, recurrence rates were 15% and 48% in stage II and III, respectively. Five-year overall and disease-free survival were 71% and 66%, respectively. Overall survival was 87% in stage II and 62% in stage III patients, and disease-free survival was 84% and 56% in stage II and III disease, respectively. According to univariate and multivariate analyses, significant prognostic factors for better tumor control were: stage (II vs III, P <0.001), the number of involved nodes (< or = 3 vs > 3, P <0.0001), and no extracapsular node invasion (P <0.0001). The recommended dose of the combined radiochemotherapy regimen was generally well tolerated. The incidence of any > or = grade 3 acute toxicity (according to the WHO scale) was 13% diarrhea, 11% proctitis, 5% perineal dermatitis and 4% myelosuppression. Four (3%) patients had radiotherapy-related severe late toxicity which required surgery. The study provided recurrence rates and survival similar to other adjuvant radiochemotherapy regimens published in the literature. However, in view of the low 5-year survival rate recorded in stage III patients, a different approach should be investigated.