Efficacy of Radiotherapy In Oligometastatic Esophageal Squamous Cell Cancer Patients: New Evidence From A Retrospective Study

Abstract

The growing evidence suggests the survival outcomes of radiotherapy (RT) for metastatic esophageal squamous cell cancer (ESCC) patients. Compared to polymetastatic ESCC, oligometastatic ESCC has favorable prognosis due to its indolent property, and was more likely to get clinical benefit from RT. The purpose of the present study was to characterize survival outcomes associated with primary tumor- and metastases- directed RT (MDRT and PTDRT) in newly diagnosed oligometastatic esophageal cancer. Newly diagnosed oligometastatic ESCC patients, defined as the presence of 1-5 metastases and 1-3 lesions, were included in this study. Characteristic of patients were compared with c2 test. Overall survival (OS) and progression-free survival (PFS) after treatment with CT (chemotherapy) alone and CT+RT were compared by using Cox proportional hazards models and survival analysis. Further analysis was performed to compared the efficacy of CT+PTDRT, CT+MDRT or CT+PTDRT+MDRT among patients receiving CT+RT. A total of 239 oligometastatic ESCC patients were enrolled in this study, including 76 patients treated with CT alone and 163 patients treated with CT + RT (CT+PTDRT, n = 28; CT+MDRT, n = 7; CT+PTDRT+MDRT, n = 128). There was no significant difference between the groups with respect to age, sex, ECOG performance, smoking status, esophageal fistula and location. Patients receiving CT plus RT were associated with improved PFS (9.5 vs 3.8 months, P<0.001) and OS (21.3 vs 12.7 months, P<0.001) compared to CT alone. Compared to CT+PTDRT+MDRT, CT+PTDRT (9.8 vs 7.9 months, P = 0.066) and CT+MDRT (9.8 vs 7.1 months, P = 0.026) were associated with inferior PFS. On multivariable analysis, CT+PTDRT+MDRT, no smoking history and no fistula were associated with improved PFS. Additionally, there was no significance difference on OS between patients receiving CT+PTDRT+MDRT, CT+PTDRT and CT+MDRT (21.3 vs 20.3 vs 20.1 months, P = 0.29). CT plus RT improved PFS and OS in ESCC patients with oligometastases, and CT+PTDRT+MDRT resulted in the most favorable PFS suggesting the important role of aggressive local treatment.