Palliative pelvic radiotherapy for symptomatic frail or metastatic patients with rectal adenocarcinoma: A systematic review

Locally advanced rectal cancer can cause severe symptomatic pelvic morbidity such as pain, haemorrhage or bowel obstruction for frail or metastatic patients, which are often unfit to undergo surgery or intense systemic treatment. The most frequent radiation schedule is 25 Gy/ 5f but the optimal dose is yet to determine. Our aim was to conduct a systematic review on the efficacy and toxicity of the published radiation schedules of palliative rectal cancer. Systematic literature of the Medline, Embase and Cochrane library databases were performed throughout the year 2023. Published articles on palliative external beam radiation therapy (EBRT) for locally advanced or metastatic rectal cancer reporting on symptom palliation, overall survival (OS) and quality of life (QOL) were eligible for inclusion. Thirteen studies were included, five of them were prospective studies. There were large variations in radiation schedules, associated chemotherapy and palliative care. Pooled overall symptomatic response rate was 71 %, while response rates were respectively 90 %, 85 %, and 84 % for pain, bleeding, and pelvic symptoms. Acute toxicities were mostly mild genitourinary or gastrointestinal. Short course palliative radiation for LARC for frail or metastatic patients is efficient for symptom palliation with few adverse effects. A short course EBRT with an integrated IMRT boost on the tumoral volume could be of interest.