Correlation in rectal cancer between clinical tumor response after neoadjuvant radiotherapy and sphincter or organ preservation: 10-year results of the Lyon R 96-02 randomized trial

Abstract

Purpose: To investigate, in rectal cancer, the benefit of a neoadjuvant radiation dose escalation with endocavitary contact radiotherapy (CXRT) in addition to external beam radiotherapy (EBRT). This article provides an update of the Lyon R96-02 Phase III trial.

Methods and materials: A total of 88 patients with T2 to T3 carcinoma of the lower rectum were randomly assigned to neoadjuvant EBRT 39 Gy in 13 fractions (43 patients) vs. the same EBRT with CXRT boost, 85 Gy in three fractions (45 patients). Median follow-up was 132 months.

Results: The 10-year cumulated rate of permanent colostomy (CRPC) was 63% in the EBRT group vs. 29% in the EBRT+CXRT group (p < 0.001). The 10-year rate of local recurrence was 15% vs. 10% (p = 0.69); 10-year disease-free survival was 54% vs. 53% (p = 0.99); and 10-year overall survival was 56% vs. 55% (p = 0.85). Data of clinical response (CR) were available for 78 patients (36 in the EBRT group and 42 in the EBRT+CXRT group): 12 patients were in complete CR (1 patient vs. 11 patients), 53 patients had a CR ≥ 50% (24 patients vs. 29 patients), and 13 patients had a CR <50% (11 patients vs. 2 patients) (p < 0.001). Of the 65 patients with CR ≥ 50%, 9 had an organ preservation procedure (meaning no rectal resection) taking advantage of major CR. The 10-year CRPC was 17% for patients with complete CR, 42% for patients with CR ≥ 50%, and 77% for patients with CR <50% (p = 0.014).

Conclusion: In cancer of the lower rectum, CXRT increases the complete CR, turning in a significantly higher rate of long-term permanent sphincter and organ preservation.