The choice of adjuvant radiotherapy in adrenocortical carcinoma patients after radical adrenalectomy: a population-based analysis

PURPOSE: This study aimed to more accurately screen the adrenocortical carcinoma(ACC) patients who would benefit from adjuvant radiotherapy after radical adrenalectomy. METHODS: The clinicopathological data from 2000 to 2018 were downloaded from the SEER database. All patients were divided into two groups: surgery alone and surgery followed by radiotherapy. A propensity score-matched(PSM) pair analysis was performed to reduce potential selection bias. The Chi-square test examined differences between groups. Univariate and multivariate analyses were applied to identify prognostic factors affecting patient survival. Kaplan-Meier analysis estimated the two groups' overall survival (OS). RESULTS: 636 ACC patients who underwent radical adrenalectomy were enrolled. Among them, 95 patients (14.94%) had undergone adjuvant radiotherapy, whereas 541 (85.06%) received surgery only. After PSM, 89 received adjuvant radiotherapy, and 89 received surgery alone. Before PSM, the patients did not benefit from adjuvant radiotherapy, while the OS of the adjuvant radiotherapy group was better than that of surgery alone after PSM(P = 0.028). Univariate Cox regression analysis showed that radiotherapy, sex, tumor size, disease stage, grade, and lymph node status were correlated with OS. Multivariable Cox regression analysis demonstrated that age, disease stage, lymph node status, and adjuvant radiotherapy influenced overall survival. Patients were risk-stratified based on known high-risk features for relapse or death; the adjuvant radiotherapy was significantly associated with more prolonged survival(P = 0.031) in the high-risk group but not the low-risk group. CONCLUSION: Our study shows that ACC patients after radical adrenalectomy could benefit from adjuvant radiotherapy, especially in high-risk patients. So, we can take ACC patients after radical adrenalectomy and with more high-risk features(risk factor ≥ 2) as a potential beneficiary of adjuvant radiotherapy.