BACKGROUND AND PURPOSE: A radical resection of locally advanced rectal cancer (LARC) or recurrent rectal cancer (RRC) can be challenging. In case of increased risk of an R1 resection, intra-operative brachytherapy (IOBT) can be applied. We evaluated the clinical selection strategy for IOBT.
MATERIALS AND METHODS: Between February 2007 and May 2018, 132 LARC/RRC patients who were scheduled for surgery with IOBT standby, were evaluated. By intra-operative inspection of the resection margin and MR imaging, it was determined whether a resection was presumed to be radical. Frozen sections were taken on indication. In case of a suspected R1 resection, IOBT (1x10 Gy) was applied. Histopathologic evaluation, treatment and toxicity data were collected from medical records.
RESULTS: Tumour was resected in 122 patients. IOBT was given in 42 patients of whom 54.8% (n=23) had a histopathologically proven R1 resection. Of the 76 IOBT-omitted R0 resected patients, 17.1% (n=13) had a histopathologically proven R1 resection. In 4 IOBT-omitted patients, a clinical R1/2 resection was seen. In total, correct clinical judgement occurred in 72.6% (n=88) of patients. In LARC, 58.3% (n=14) of patients were overtreated (R0, with IOBT) and 10.9% (n=5) were undertreated (R1, without IOBT). In RRC, 26.5% (n=9) of patients were undertreated.
CONCLUSION: In total, correct clinical judgement occurred in 72.6% (n=88). However, in 26.5% (n=9) RRC patients, IOBT was unjustifiedly omitted. IOBT is accompanied by comparable and acceptable toxicity. Therefore, we recommend IOBT to all RRC patients at risk of an R1 resection as their salvage treatment.