Modern Techniques in Re-Irradiation for Locally Recurrent Rectal Cancer: A Systematic Review

SIMPLE SUMMARY: Re-irradiation of locally recurrent rectal cancer presents challenges in terms of treatment options and outcomes. By conducting a systematic review focused on new technologies such as carbon ion radiotherapy, intensity-modulated photon radiotherapy, and stereotactic radiotherapy, we aimed to determine whether the new techniques have led to improvements in both outcomes and toxicities to enable clinicians and researchers to make informed decisions about incorporating new technologies into clinical practice and to identify avenues for further research. ABSTRACT: Background: Radiotherapy (RT) plays an important role in the treatment of patients with previously irradiated locally recurrent rectal cancer (LRRC). Over the years, numerous technologies and different types of RT have emerged. The aim of our systematic literature review was to determine whether the new techniques have led to improvements in both outcomes and toxicities. Methods: A computerized search was performed by MEDLINE and the Cochrane database. The studies reported data from patients treated with carbon ion radiotherapy (CIRT), intensity-modulated photon radiotherapy (IMRT), and stereotactic radiotherapy (SBRT). Results: Seven publications of the 126 titles/abstracts that emerged from our search met the inclusion criteria and presented outcomes of 230 patients. OS was reported with rates of 90.0% and 73.0% at 1 and 2 years, respectively; LC was 89.0% and 71.6% at 1 and 2 years after re-RT, respectively. Toxicity data vary widely, with emphasis on acute and chronic gastrointestinal and urogenital toxicity, even with modern techniques. Conclusion: data on toxicity and outcomes of re-RT for LRRC with new technologies are promising compared with 3D techniques. Comparative studies are needed to define the best technique, also in relation to the site of recurrence.