Radical radiotherapy for metachronous oligometastasis after initial treatment of esophageal cancer

Background and purposeThis study aimed to evaluate the efficacy of radical radiotherapy and assess prognostic factors in metachronous oligometastatic esophageal cancer (MOEC) patients after initial treatment with curative-intent surgery and/or chemoradiotherapy.Materials and methodsMOEC Patients during 2009–2018 in Mianyang Central Hospital were retrospectively analyzed. Each patient had ≤5 oligometastatic lesions, and the primary lesions were controlled in this study. Patients were devided into radiotherapy (RT) and non-radiotherapy (NRT) groups. The study endpoints were overall survival (OS) and treatment toxicities.ResultsThis study included 82 patients who underwent intensity-modulated radiotherapy for MOEC. Median OS were 14 (95% confidence interval [CI], 11.0–17.0) and 7 (95% CI, 4.5–9.5) months for the RT and NRT groups, respectively (P = 0.016). Median OS were 18 (95% CI, 13.6–22.4) and 10 (95% CI, 5.1–14.9) months for lung and bone metastases, respectively (P = 0.010). Median OS were 15 (95% CI, 12.4–17.6) and 10 (95% CI, 7.6–12.4) months for interval time from initial diagnosis to metastasis ≥12 and <12 months, respectively (P = 0.026). Median OS were 16 (95% CI, 12.2–19.8) and 10 (95% CI, 5.0–15.0) months for biological effective dose (BED10) ≥ 60 Gy and BED10 < 60 Gy, respectively (P = 0.033). Cox multivariate regression analysis showed that treatment modality (RT vs. NRT) was an independent prognostic factor for MOEC patients (hazard ratio: 1.8, 95% CI: 1.1–3.0; P = 0.022). No toxic side effects greater than grade 3 were observed in all patients.ConclusionsRadiotherapy is a feasible and positive treatment for MOEC patients after initial treatment, a radical radiation dose with BED10 ≥ 60 Gy has benefits in extending survival. Radical radiotherapy should thus be considered for MOEC patients.