Effects of radiotherapy, chemotherapy, and chemoradiotherapy on survival outcomes in patients with gallbladder carcinoma: a real population-based study.

Background: The clinical value of radiotherapy or chemotherapy in gallbladder carcinoma (GBC) remains controversial, especially for GBCs at different stages. Therefore, this study analyzed the effects of radiotherapy, chemotherapy, and concurrent chemoradiotherapy on overall survival (OS) and cancer-specific survival (CSS) in patients with different stages of GBC based on data from the Surveillance, Epidemiology, and End Results (SEER) database.

Methods: Data on patients diagnosed with GBC from January 1, 2010 to December 31, 2017 were collected from the SEER database, and those involved patients were divided into the following groups according to their treatment regimens: non-therapy group, radiotherapy alone group, chemotherapy alone group, and concurrent chemoradiotherapy group. After adjusting for factors related to demographics, the tumor, and the procedure, Cox regression was performed to analyze the effect of radiotherapy, chemotherapy, and chemoradiotherapy on OS. The relationships between these three therapies and CSS were assessed using the competing risk model.

Results: This study included 6,275 GBC patients, among whom 3,444 received no therapy, 152 received radiotherapy alone, 1,913 received chemotherapy alone, and 766 received chemoradiotherapy. Of these patients, there were 4,886 (77.86%) all-cause death cases and 4,379 (69.78%) cancer-specific death cases. The multivariate analysis showed that radiotherapy [hazard ratio (HR) =0.700, 95% confidence interval (CI): 0.581, 0.844], chemotherapy (HR =0.500, 95% CI: 0.465, 0.538), and chemoradiotherapy (HR =0.486, 95% CI: 0.439, 0.538) significantly improved OS in all patients (all P<0.001); for stage III and IV GBC patients, radiotherapy, chemotherapy, and chemoradiotherapy significantly improved OS (all P<0.001). Regarding CSS, the competing risk model showed that chemotherapy (HR =0.589, 95% CI: 0.540, 0.635] and chemoradiotherapy (HR =0.577, 95% CI: 0.523, 0.636) improved CSS in all patients (both P<0.001); for patients with stage III GBC, radiotherapy, chemotherapy, and chemoradiotherapy significantly improved CSS (P=0.02, <0.001, <0.001, respectively); and for patients with stage IV GBC, chemotherapy and chemoradiotherapy significantly improved CSS (both P<0.001). The subgroup analyses based on different pathological types showed similar patterns in the effects of radiotherapy, chemotherapy, and chemoradiotherapy on OS and CSS.

Conclusions: Our study shows that advanced gallbladder cancer patients receiving radiotherapy, chemotherapy, or chemoradiotherapy can significantly improve their OS and CSS. Therefore, it is recommended that advanced patients routinely include radiotherapy, chemotherapy, or chemoradiotherapy in comprehensive treatment to improve survival rates. However, for early-stage gallbladder cancer, the improvement effects of radiotherapy, chemotherapy, or chemoradiotherapy on OS and CSS are limited, and the decision to perform radiotherapy or chemotherapy should be individualized based on the patient's specific conditions, such as the pathological type, grade, and lymph node metastasis of the tumor.