JRSBRT 9.3, p. 237-243

Evaluating the efficacy of stereotactic radiotherapy for metastatic colorectal cancer: A retrospective review of clinical outcomes
Beini Chen, Justin Smith, Revadhi Chelvarajah, Alexandra Knesl, Parushka Moodley, David Pryor, Mark B Pinkham, G Tao Mai, Howard Y Liu and Yoo Young Lee

Background: Despite advances in systemic therapy, survival in metastatic colorectal cancer (mCRC) remains poor. The utility of stereotactic body radiotherapy (SBRT) and stereotactic radiosurgery (SRS), allowing dose escalation to achieve improved local control has risen in the treatment of mCRC. However, local control (LC) and overall survival (OS) varies widely between studies, and prognostic factors are not well defined.

Methods: We retrospectively assessed LC and OS in patients with mCRC treated with SBRT/SRS between 2014 and 2022.

Results: 124 Patients were treated during the study period. Median follow up was 16.4 months (0.2–93.1 months). There were 310 lesions treated with 53% located in the brain, 22% lung, 16% liver, 4% bone, 4% nodal and 1% other. Biologically effective dose (BED10) ranged from 33.6 to 151.2 Gy.

LC was 75% (95% CI 67–81%) at 1 year and 65% (95%CI 56–73%) 2 years. On multivariable analysis (MVA), older age (HR 1.04, p = 0.001) and tumour volume >2.5 cc (HR 3.13, p < 0.001) were associated with worse LC.

OS from first course of SBRT/SRS was 68% at 1 year (95%CI 58–76%), and 48% at 2 years (95%CI 38–58%). On MVA, ≥2 or more lines of systemic therapy (HR 3.04, p < 0.001) and brain metastases (HR 4.24, p = 0.001) were associated with shorter OS. Living long enough to receive ≥2 courses of SBRT/SRS (HR 0.20, p = 0.004) was associated with longer OS.

Conclusion: This study demonstrates that SBRT and SRS offer effective local control, and LC is associated with tumour volume.

Keywords: radiotherapy, radiosurgery, colorectal neoplasms, neoplasm metastasis

Includes supplement

After payment has been processed for your order of a digital copy (PDF) of this article, you will see a download link on your completed order page and also receive an email containing a download link. The links, which will enable you to download one copy of the article, will expire after 24 hours.