Preoperative radiotherapy and local excision of rectal cancer: Long-term results of a randomised study

Abstract

Background and purpose: It is uncertain whether local control is acceptable after preoperative radiotherapy and local excision (LE). An optimal preoperative dose/fractionation schedule has not yet been established.

Material and methods: In a phase III study, patients with cT1-2N0M0 or borderline cT2/T3N0M0 < 4 cm rectal adenocarcinomas were randomised to receive either 5 × 5 Gy plus 1 × 4 Gy boost or chemoradiation: 50.4 Gy in 28 fractions plus 3 × 1.8 Gy boost and 5-fluorouracil with leucovorin bolus. LE was performed 6-8 weeks later. Patients with ypT0-1R0 disease were observed. Completion total mesorectal excision (CTME) was recommended for poor responders, i.e. ypT1R1/ypT2-3.

Results: Of 61 randomised patients, 10 were excluded leaving 51 for analysis; 29 in the short-course group and 22 in the chemoradiation group. YpT0-1R0 was observed in 66% of patients in the short-course group and in 86% in the chemoradiation group, p = 0.11. CTME was performed only in 46% of patients with ypT1R1/ypT2-3. The median follow-up was 8.7 years. Local recurrence incidences and overall survival at 10 years were respectively for the short-course group vs. the chemoradiation group 35% vs. 5%, p = 0.036 and 47% vs. 86%, p = 0.009. In total, local recurrence at 10 years was 79% for ypT1R1/T2-3 without CTME.

Conclusions: This trial suggests that in the LE setting, both local recurrence and survival are worse after short-course radiotherapy than after chemoradiation. Because of the risk of bias, a confirmatory study is desirable. Lack of CTME is associated with an unacceptably high local recurrence rate.

Keywords: Local excision; Preoperative radiotherapy; Rectal cancer.