All surgically treated patients with LARC treated in a tertiary聽referral center between 1996 and 2012 were analyzed retrospectively. The聽outcome in patients treated with IORT with a clear but narrow CRM (鈮?聽mm) or a microscopically involved CRM was compared with the outcome in patients who were not treated with IORT.
A total of 409 patients underwent resection of LARC, and 95 patients (23%) had a CRM聽鈮ぢ?聽mm. Four patients were excluded from further analysis because of a macroscopically involved resection margin. In 43 patients with clear but narrow CRMs, there was no difference in the cumulative 5-year local recurrence-free survival of patients treated with (n=21) or without (n=22) IORT (70% vs 79%, P=.63). In 48 patients with a microscopically involved CRM, there was a significant difference in the cumulative 5-year local recurrence-free survival in favor of the patients treated with IORT (n=31) compared with patients treated without IORT (n=17) (84 vs 41%, P=.01). Multivariable analysis confirmed that IORT was independently associated with a decreased local recurrence rate (hazard ratio 0.24, 95% confidence interval 0.07-0.86). There was no significant difference in complication rate of patients treated with or without IORT (65% vs 52%, P=.18)
The current study suggests that IORT reduces local recurrence rates in patients with LARC with a microscopically involved CRM.