Curative-intent radiotherapy in patients with oligometastatic lesions from colorectal cancer: A single-center study

The purpose of the present study was to investigate the efficacy and safety of radiotherapy for patients with oligometastases from colorectal cancer (CRC).This was a retrospective cross-sectional study. Patients with liver and/or lung oligometastatic lesions from CRC treated with curative-intent radiotherapy in West China Hospital, Sichuan University, between 2009 and 2013 were included. Radiotherapy modality included 3-dimensional conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), and stereotactic body radiation therapy (SBRT); simultaneous chemotherapies along with radiotherapy of metastasis were allowed. Overall survival (OS) and progression-free survival (PFS) were calculated using the Kaplan-Meier method. Local control (LC) rates, toxicities, and factors of prognostic significance were also assessed.A total of 40 CRC patients with 57 liver and/or lung oligometastatic lesions were included. Most of the patients (95%) had received at least 1 line of previous systemic chemotherapy. Among them, 19 patients with 26 lesions received 3D-CRT with a median dose of 51.5 Gy in 16.1 fractions, 7 patients with 11 lesions received IMRT with a median dose of 49.3 Gy in 10.4 fractions, and 14 patients with 20 lesions received SBRT with a median dose of 56.4 Gy in 6.7 fractions, respectively. The median follow-up time was 34 months (range, 9-86 months). Median OS and PFS for patients were 30.0 months [95% confidence interval (95% CI), 21.3-38.7] and 11.0 months (95% CI, 9-13), respectively. One, 3, and 5 years' LC rates for metastasis were 63.2%, 24.6%, and 16.9%, respectively. In subgroup analysis, patients with metachronous metastases had longer OS (median, 41.0 months; 95% CI, 33.3-48.7) than patients with synchronous lesions (median, 17.0 months; 95% CI, 7.4-26.6, P = .001). All patients tolerated the radiation treatment well, and there was no treatment-related death. Multivariate analysis showed that number of metastasis lesions and simultaneous liver and lung metastases were potential survival predictors.The study demonstrated that curative radiotherapy might be a tolerable and potential alternative for the treatment of patients with liver and/or lung oligometastases from CRC, and patients with metachronous lesions might have better survival than those with synchronous lesions when treated with curative-intent radiotherapy.