Efficacy of adjuvant radiotherapy for treatment of adrenocortical carcinoma: a retrospective study and an updated meta-analysis

BACKGROUND: Adrenocortical carcinoma (ACC) is a rare and highly aggressive malignancy. Surgical resection is the standard treatment for localized ACC, but the local recurrence remains high. Adjuvant radiation (ART) has been proposed as a means to reduce recurrence rates in ACC after surgery with conflicting results from nonrandomized studies. We performed a retrospective study and a meta-analysis to determine the impact of ART on survival outcomes. METHODS: A retrospective study of the adrenocortical cancer database in Peking Union Medical College was conducted. We selected postoperative ACC patients with or without ART. A meta-analysis is also performed to compare the outcomes between ART and only surgical resection in ACC patients. The obtained data were analyzed using SPSS 23.0 and Stata 15.0 statistical software. Differences between two groups were compared using the log-rank test for retrospective analysis and estimated by calculating the odds ratio (OR) and 95% confidence interval (CI) for meta-analysis. RESULTS: Of a total of 75 patients available in the database, 12 patients underwent postoperative ART and were matched one to one to patients with only surgical resection. There was no significant difference on overall survival between ART group and control group (log-rank P = 0.149). Locoregional recurrence was diagnosed in 2 of the ART group, and in 4 of the control group (P = 0.64). A total of 238 participants were selected for the meta-analysis, of which 111 and 127 patients underwent ART after surgical resection and only surgical resection, respectively. Overall survival is significantly higher in ART group, with an odds ratio (OR) of 2.41 (95% CI of 1.33, 4.38; P = 0.004). Besides, meta-analysis significantly favored ART for locoregional recurrence-free survival and disease-free survival, with an OR of 4.08 and 2.27, respectively. CONCLUSIONS: Our results show that compared to only surgical resection, ART is an effective postoperative treatment for ACC.