The role of intra‐operative radiotherapy in advanced rectal cancer: a meta‐analysis

Background Patients with locally advanced and locally recurrent rectal cancer (LARC/LRRC) experience higher rates of local recurrence (LR) and poorer overall survival despite improved neoadjuvant treatment regimens and radical surgical procedures. Intraoperative radiotherapy (IORT) has been suggested as an adjunctive tool in the surgical management of these challenging cases. However, clear evidence regarding oncological benefit is sparse. This review sought to update the evidence in the era of standardised neoadjuvant radiotherapy administration. Methods A systematic review of patients who received IORT as part of multimodality treatment for advanced rectal cancer from 2000 to 2020 and an analysis of IORT and surgery/EBRT groups was performed. The primary endpoint was the rate of LR between the two groups. Results Seven papers met the predefined criteria. LR was reduced by the addition of IORT when compared with the surgery/external beam radiotherapy alone group (14.7% vs 21.4%; OR 0.55, 95% CI 0.27- 1.14; p=0.11). There was no increase in reported genitourinary morbidity, wound issues, pelvic collections or anastomotic leak in those patients receiving IORT. Notably, there was no survival difference between the two groups. Conclusion The addition of IORT to contemporary treatment strategies in the management of patients with LARC/LRRC is associated with a lower rate of locoregional recurrence, without increased morbidity. However, this marks a highly selective group of patients, with heterogeneity regarding indications, prior neoadjuvant treatments and/or IORT dosing.