Conformal Radiation Therapy or Stereotactic Body Radiation Therapy: Institutional Experience in the Management of Colorectal Liver Metastases by Radiation Therapy

Abstract

Aim:Radiation therapy has been proven “safe and effective” in the management of colorectal cancer liver metastases, especially for oligometastases. However, to date, there is no consensus on optimal prescribed doses or dose fraction schemes. The current study was conducted to investigate the effectiveness and safety of 2 different radiation therapy methods, conventional conformal radiation therapy and stereotactic body radiation therapy, in the treatment of limited colorectal cancer liver metastases.Methods:From December 2011 to December 2016, twenty-six patients with colorectal cancer having postoperative liver metastases (≤3) who were being treated with radiation therapy, either conventional conformal radiation therapy (50 Gy in 25 fractions) or stereotactic body radiation therapy (50 Gy in 10 fractions), were selected for this study. Overall survival and local control survival were analyzed by log-rank and Cox regression methods.Results:Radiation therapy delivered to each of the 26 patients with a total of 50 liver lesions. Conformal radiation therapy was delivered to 32 lesions in a total of 15 patients. Stereotactic body radiation therapy was delivered to 18 lesions in a total of 11 patients. Median follow-up was 13 months. Three-year overall survival and local control survival were 0% and 38.5%, 20.5%, and 53.0%, respectively, for the conformal radiation therapy and stereotactic body radiation therapy groups. The slightly better overall survival and local control survival in the stereotactic body radiation therapy group in comparison to the conformal radiation therapy group (P = .323 and .297) is insignificant. There were no differences in grade 3 hepatic toxicity between the 2 groups. Eastern Cooperative Oncology Group performance status and the number of liver lesions were significant prognostic factors in both univariate and multivariate analyses.Conclusions:Noninvasive radiation therapy provides satisfactory survival benefit for limited colorectal cancer liver metastases without intolerable toxicity and is therefore especially suitable for those elderly patients with poor performance status. Furthermore, stereotactic body radiation therapy with a higher biological equivalent dose and an abbreviated course of treatment has been shown to provide a better outcome than conventional conformal radiation therapy.