Prognostic factors after adrenalectomy for adrenal metastasis

Purpose: Very few studies have sought prognostic factors after adrenalectomy for metastasis. The aim of this study was to assess prognostic factors for oncological outcomes after adrenalectomy for adrenal metastasis.

Methods: All adrenalectomies for metastases performed in seven centers between 2006 and 2016 were included in a retrospective study. Recurrence-free survival (RFS) and cancer-specific survival (CSS) were estimated using the Kaplan-Meier method. Prognostic factors for CSS and RFS were sought by Cox regression analyses.

Results: 106 patients were included. The primary tumors were mostly renal (47.7%) and pulmonary (32.3%). RFS and CSS estimated rates at 5 years were 20.7% and 63.7%, respectively. In univariate analysis, tumor size (HR 3.83; p = 0.04) and the metastasis timing (synchronous vs. metachronous; HR 0.47; p = 0.02) were associated with RFS. In multivariate analysis, tumor size (HR 8.28; p = 0.01) and metastasis timing (HR 18.60; p = 0.002) were significant factors for RFS. In univariate analysis, the renal origin of the primary tumor (HR 0.1; p < 0.001) and the disease-free interval (DFI; HR 0.12; p = 0.02) were associated with better CSS, positive surgical margins with poorer CSS (HR 3.4; p = 0.01). In multivariate analysis, the renal origin of the primary tumor vs. pulmonary (HR 0.13; p = 0.03) and vs. other origins (HR 0.10; p = 00.4) and the DFI (HR 0.01; p = 0.009) were prognostic factors for CSS.

Conclusion: In this study, tumor size and synchronous occurrence of the adrenal metastasis were associated with poorer RFS. Renal origin of the primary tumor and longer DFI were associated with better CSS. These prognostic factors might help for treatment decision in the management of adrenal metastasis.