The curative potential of stereotactic radiotherapy in oligometastatic colorectal cancer: a narrative review.

Abstract

Background and objective: Oligometastatic colorectal cancer (CRC), characterised by limited metastatic disease, has traditionally been managed with surgery and chemotherapy. However, advances in stereotactic ablative radiotherapy (SABR), also known as stereotactic body radiotherapy (SBRT), have introduced the possibility of curative outcomes for selected patients with limited metastatic disease. SABR delivers high-dose, highly precise radiation with minimal toxicity, making it an attractive alternative or complement to surgery and systemic therapy. This narrative review evaluates the role of SABR in the management of oligometastatic CRC, and its application in both palliative and curative settings.

Methods: A systematic search of PubMed and Scopus databases (2014-2024) was conducted using search terms including "colorectal cancer", "oligometastatic", "SABR", "SBRT", "palliative", and "radical". Relevant meta-analyses, systematic reviews, and single- and double-arm studies were included.

Key content and findings: SABR demonstrates promising outcomes in both palliative and curative settings for oligometastatic CRC. Trials like SABR-COMET report significant improvements in overall survival (OS) and progression-free survival (PFS) with SABR, achieving a median OS of 50 months compared to 28 months with standard care. SABR is particularly effective for pulmonary metastases, achieving higher local control (LC) rates than hepatic lesions, likely due to differences in tissue radiosensitivity. Palliative SABR has been shown to delay systemic therapy and improve symptom management, with low toxicity rates, while radical SABR offers durable disease control and potential curative outcomes. Despite these benefits, evidence is limited by small cohort sizes, variable dosing regimens, and a lack of CRC-specific randomised trials.

Conclusions: SABR has emerged as a transformative treatment for oligometastatic CRC, providing significant benefits in both palliative and curative settings, although not yet outperforming traditional treatment modalities such as surgery. Future research, including ongoing phase III trials, aims to refine patient selection, optimise dosing protocols, and integrate SABR with systemic treatments to enhance outcomes. With further validation, SABR has the potential to redefine the therapeutic landscape for oligometastatic CRC, offering hope for improved survival and quality of life.