Low-kilovolt x-ray intraoperative radiotherapy for pT3 locally advanced colon cancer: a single-institution retrospective analysis

Li Ma,Xinwei Li,Hong Chen,Heliang Yin,Li Dong,Dongmei Wei,David L Schwartz,Changying Ma,Lin Lin,Weikuan Gu,Yan Jiao,Junhao Qiang,Jinglin Cui,Ankur M Sharma

doi:10.1186/s12957-020-01903-x

Abstract

BackgroundPatients with locally advanced colon cancer (LACC) treated with surgery had a high risk of local recurrence. The outcomes can vary significantly among patients with pT3 disease. This study was undertaken to assess whether low-kilovolt (kV) x-ray intraoperative radiotherapy (IORT) can achieve promising results compared with electron beam IORT (IOERT) and whether specific subgroups of patients with pT3 colon cancer may benefit from low-kV x-ray IORT.MethodsWe retrospectively reviewed 44 patients with pT3 LACC treated with low-kV x-ray IORT. Clinicopathologic characteristics were analyzed to identify patients that could potentially benefit from low-kV x-ray IORT. The Kaplan-Meier survival analysis was used to assess overall survival (OS) and progression-free survival (PFS). Correlation analysis was used to discover the association of multiple factors to the results of treatment represented by the values of OS and PFS.ResultsThe median follow-up of patients was 20.5 months (range, 6.1–38.8 months). At the time of analysis, 38 (86%) were alive and 6 (14%) had died of their disease. The 3-year Kaplan-Meier of PFS and OS for the entire cohort was 82.8% and 82.1%, respectively. At median follow-up, no in-field failure within the low-kV x-ray IORT field had occurred. Locoregional and distant failure had occurred in 2 (5%) patients each. The rate of perioperative 30-day mortality was 0%, and the morbidity rate was 11%. Five patients experienced 7 complications, including 4 early complications (30 days) and three late complications (> 30 days) leading early and late morbidity rates of 9% and 7%, respectively.ConclusionPatients with LACC who had undergone an additional low-kV x-ray IORT can achieve encouraging locoregional control, PFS, OS, and distant control without an increase in short-term or long-term complications. Low-kV x-ray IORT can be considered as part of management in pT3 LACC.

Highlights

Patients with locally advanced colon cancer (LACC) treated with surgery had a high risk of local recurrence
We aim to evaluate whether low-kV x-ray intraoperative radiotherapy (IORT) can benefit pT3 patients not being inferior to the electron Electron beam intraoperative radiotherapy (IOERT)
Our results suggest that patients treated with low-kV x-ray IORT had encouraging progression-free survival (PFS) and overall survival (OS) and without an increase in short-term or long-term complications in comparison to previous multimodality studies, whose acute complications were not more than 10% and long-term morbidities were between 37 and 53% [22]

Summary

Introduction

Patients with locally advanced colon cancer (LACC) treated with surgery had a high risk of local recurrence. Most colon cancer patients were sufficiently treated surgically with or without adjuvant systemic therapy. 70 to 90% of all patients who had colorectal cancer undergo surgical resection with curative intent, the 5-year recurrence rate was 12% and 33% in stage II and III patients, respectively [3, 4]. Multivariable analysis indicated that disease stage II and III were independent predictors of locoregional recurrence (LR). The recurrence or metastasis leads to a clinical and therapeutic challenge associated with a poor prognosis. It is worth exploring how local control could be improved beyond standard care of colon cancer

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