Intraoperative radiotherapy as an immediate adjuvant treatment of rectal cancer due to limited access to external-beam radiotherapy

Sergey Potemin,Frederik Wenz,Jens Kübler,Frank Giordano,Ivan Uvarov

doi:10.1186/s13014-020-1458-y

Abstract

BackgroundNeoadjuvant external-beam radiotherapy (EBRT) with concomitant chemotherapy is the current standard-of-care for locally-advanced rectal cancer. Intraoperative radiotherapy (IORT) is to date only recommended for pelvic recurrences or incompletely resectable tumors. We here report on patients with stage II/III rectal cancer that were treated with IORT in a regional Russian university center due to limited access to EBRT.MethodsWe retrospectively analyzed data from patients that were diagnosed with locally-advanced rectal cancer and underwent surgery from December 2012 to October 2016 at a regional oncological center in Russia (Krasnodar). During this period, access to EBRT was limited due to a temporary lack of a sufficient number of EBRT facilities. Patients unable to travel to a distant radiotherapy site received IORT alone, those that could travel received neoadjuvant external beam (chemo-) radiotherapy. Factors of interest were tumor stage, tumor differentiation, resection status, surgery type and neoadjuvant or adjuvant chemotherapy. We assessed local progression-free survival (L-PFS), PFS and overall survival (OS).ResultsA total of 172 patients were included in this analysis. Of those, 92 (53.5%) were treated with IORT alone (median dose: 15 Gy [8.4–17 Gy]) and 80 (46.5%) received both neoadjuvant EBRT (median dose: 50.4 Gy [40–50.4 Gy]) and IORT (median dose: 15 Gy [15–17 Gy]). The median age was 65 years [33–82]. The median follow-up was 23 months [0–63 months]. The incidence of toxicity was low in both groups with an overall complication rate of 5.4%. Local PFS at 4 years was comparable with 59.4% in the IORT group and 65.4% in the IORT/EBRT group (p = 0.70). Similarly, there was no difference in OS or PFS (p = 0.66, p = 0.51, respectively).ConclusionsIORT is a valuable option for patients with locally-advanced rectal cancer in the absence of access to EBRT.

Highlights

Neoadjuvant external-beam radiotherapy (EBRT) with concomitant chemotherapy is the current standard-of-care for locally-advanced rectal cancer
Patient characteristics 172 patients with stage II or III rectal cancer who underwent surgical resection and Intraoperative radiotherapy (IORT) or resection and neoadjuvant EBRT and IORT between December 2012 and October 2016 were included in this analysis (Table 1)
In the IORT group primary cancer site was found to be the middle third rectum in most patients (57.6%), whereas the majority of patients (70.0%) in the IORT/EBRT group were diagnosed with lower third rectal cancer (p < 0.0001)

Summary

Introduction

Neoadjuvant external-beam radiotherapy (EBRT) with concomitant chemotherapy is the current standard-of-care for locally-advanced rectal cancer. EBRT is known to significantly improve outcome in locally advanced rectal cancer, based on the necessity of fractionated application, it requires adequate availability, infrastructure and compliance of the patients. One approach to provide radiation therapy to the tumor bed in the absence of access to EBRT is intraoperative radiotherapy (IORT). In IORT, a single dose of radiation (usually 8–20 Gy) is delivered to the region that is considered to be at risk for recurrence It allows direct visualization of the tumor bed, maximizes the biological effect of a high dose of irradiation and minimizes the risk of complications in the surrounding healthy tissues, since organs at risk can be shifted out of the radiation field or shielded during the procedure [6, 7].

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Conclusion