PAOB is a rare malignant tumor that arises from endothelial cells. The efficacy of adjuvant radiotherapy remains uncertain. Some studies have reported significant differences in radiotherapy's ability to improve survival, others have not. Thus, we conducted this study to evaluate the effect of radiotherapy on overall survival (OS) and cancer-specific survival (CSS) in patients with PAOB without distant metastasis.
Data were obtained from the Surveillance, Epidemiology, and End Results (SEER) database between 2000 and 2019. Patients with a previous history of cancer or concurrent malignancies and with distant metastasis were excluded. Two groups were formed based on radiotherapy exposure: radiotherapy and non-radiotherapy. The clinicopathological features of each group were compared using chi-square tests. Kaplan-Meier estimator, log-rank tests, and cox proportional hazard regression were used to identify prognostic factors over OS and CSS.
In a study of 286 patients, 101 (35.3%) were exposed to radiotherapy while 185 (64.7%) were not. Most patients were aged 45 years or above (59.1%) and with the dominant race being white (n = 226). 54.5% had a tumor size of 50 mm or greater, with an average tumor size of 50.2 mm. Primary surgical resection was performed on 95.1% of patients and 34.6% had undergone chemotherapy. The non-radiotherapy group had better survival outcomes, with 5-year OS and CSS rates of 62% and 53.9%, respectively, compared to 42% for both in the radiotherapy group. Tumor size greater than 5 cm was identified as a poor prognostic factor for both OS and CSS, while chemotherapy was found to be a better prognostic factor for both. Age greater than 45 years was identified as a poor prognostic factor only for CSS. Interestingly, the use of radiotherapy did not result in improved OS and CSS (HR=0.91, 95%CI: 0.61-1.36 and HR=0.99, 95% CI: 0.64-1.54, respectively).
The results of the study indicated that radiotherapy may not improve survival outcomes in patients with PAOB. This study was the first of its kind to investigate PAOB without distant metastasis using a large sample size. Further randomized clinical trials are needed to confirm the efficacy of radiotherapy in PAOB treatment.
The authors.
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All authors have declared no conflicts of interest.