Metastasis to the adrenal glands: An update

Table 1 Adrenalectomy and comparative local therapy studies for adrenal metastases

Ref.	Design/setting	n (patients)	Most common primaries (number)	Approach	Key outcomes	Evidence strength
Muth et al[21]	Institutional series (1996-2007), ADX for metastasis	30	Renal cell carcinoma (9), melanoma (5), NSCLC (5), colorectal carcinoma (4), others	10 laparoscopic, 20 open	Median survival 23 months; local recurrence: Laparoscopic 1/10, open 1/20; no surgical complications	Retrospective institutional series; heterogeneous primaries; selection bias
Drake et al[22]	Retrospective cohort with comprehensive follow-up (1995-2016)	62	NSCLC (20), renal cell carcinoma (14), melanoma (8)	59/62 laparoscopic	5-year survival 37%; median survival 34 months (NSCLC 26; renal cell carcinoma 67; melanoma 30); 0 deaths ≤ 30 days, 6 complications, 2 conversions	Retrospective cohort with SEER comparison; selection bias
Vazquez et al[23]	Mayo cohort vs SEER stage-matched controls (1992–2010)	166	Kidney (60), lung (24), sarcoma (19), colon (15), pancreas (13), others	29 Laparoscopic, 46 open, 91 combined	Better OS in ADX cohort vs SEER controls at 1-3 years for sarcoma/kidney/Lung/pancreas primary tumors	Retrospective comparative cohort vs historical controls
Hwang et al[24]	2-center retrospective cohort (2004-2012)	32	Lung (11), liver (5), colon (4), kidney (4), stomach (3), pancreas (2), others	12 Laparoscopic, 20 open	No surgical complications. Recurrence rate 625%	Small retrospective two-center pilot cohort
Lütscher et al[25]	Single-center retrospective: SBRT vs ADX	41	NSCLC (26), renal cell carcinoma (4), adenocarcinoma of the gastrointestinal tract (4), small-cell lung cancer (2), others	ADX (14) vs SBRT (27)	Local control (1-year/2-year): 100%/100% surgery vs 70.0%/52.5% SBRT (P = 0.001); progression free survival (1-year/2-year): 40.2%/32.1% surgery vs 10.6%/10.6% SBRT (P = 0.223); OS (1-year/2-year): 83.3%/83.3% surgery vs 67.0%/40.2% SBRT (P = 0.031)	Selection bias acknowledged. SBRT showed less ≥ grade 2 toxicity incidence (6.5%) compared to surgery (23.5%)
Liu et al[26]	Retrospective comparative (2008-2018): RFA vs ADX	60	Hepatocellular carcinoma (31), NSCLC (8), renal cell carcinoma (8)	RFA (29) vs ADX (31)	Local tumour progression (1-year/2-year/3-year): 17.1%/30.9%/44.7% RFA vs 6.5%/6.5%/6.5% ADX (P = 0.028); OS (1-year/2-year/3-year): 85.0%/42.4%/27.8% RDA vs 93.0%/66.1%/52.3% ADX (P = 0.057)	Retrospective RFA vs adrenalectomy comparison; selection bias

ADX: Adrenalectomy; NSCLC: Non-small-cell lung cancer; OS: Overall survival; RFA: Radiofrequency ablation; SBRT: Stereotactic body radiotherapy; SEER: Surveillance, epidemiology, and end results.