Surgical and ablative therapies for the management of adrenal 'oligometastases' - A systematic review

Background: We systematically reviewed the literature on the use of surgery, stereotactic ablative body radiotherapy (SABR) and percutaneous catheter ablation (PCA) techniques for the treatment of adrenal metastases to develop evidence-based recommendations. Methods: A systematic review of the MEDLINE database was performed using structured search terms following PRISMA guidelines. Eligible publications were those published from 1990 to 2012, written in English, had at least five patients treated for adrenal metastasis and reported on patient clinical outcomes (local control, survival and treatment related complications/toxicity). Where possible, pooled 2-year local control and overall survival outcomes were analysed. Results: Our search strategy produced a total of 45 papers addressing the three modalities - 30 adrenalectomy, nine SABR and six PCA (818, 178 and 51 patients, respectively). There was marked heterogeneity in outcome reporting, patient selection and follow-up periods between studies. The weighted 2-year local control and overall survival for adrenalectomy were 84% and 46%, respectively, compared with 63% and 19%, respectively for the SABR cohort. Only one study of PCA with five patients analysed clinical outcomes, reporting an actuarial local control of 80% at 1 year. Treatment related complications/toxicities were inconsistently reported. Conclusion: There is insufficient evidence to determine the best local treatment modality for isolated or limited adrenal metastases from any primary tumour. Published data suggests adrenalectomy to be a reasonable treatment approach for isolated adrenal metastasis in suitable patients. SABR is a valid alternative in cases when surgery is not feasible or the operative risk is unacceptable. PCA cannot be recommended until there are more robust studies which include long-term oncological outcomes. (C) 2014 Elsevier Ltd. All rights reserved.