Defining high-volume adrenal surgeons to improve patient outcomes

The relatively low incidence of adrenal pathology presents challenges due to the low volume of procedures performed by individual surgeons at many hospitals. Consequently, the number of adrenalectomies performed annually by each surgeon varies widely, with a median of one case per year, ranging up to 29 cases (1-3). Evidence suggests that surgeons who perform more adrenalectomies achieve better outcomes regarding complications, length of stay, and costs (1,2,4-6). However, it is unclear if there is a clinically significant volume threshold associated with improved outcomes. The incidence of complications also largely depends on the difficulty of the adrenalectomy, which can vary with the type of adrenal pathology. The American Association of Endocrine Surgeons (AAES) recommends that adrenalectomies be performed by “high-volume” surgeons (7). Definitions of high-volume range from four to seven annual adrenalectomies, with many guidelines recommending a threshold of six per year (1,2,5,7,8). However, a small proportion of adrenal surgeons are considered high-volume, with only 16% performing six or more adrenalectomies per year (4). This has prompted discussions regarding centralizing adrenal surgery to high-volume surgeons to improve patient outcomes, although the optimal volume threshold for maximizing benefits remains uncertain.

In light of these challenges and recommendations, the study by Rajan et al. aimed to evaluate the impact of surgeon volume on outcomes and to identify factors that define high-risk adrenal procedures that may benefit from being restricted to high-volume surgeons (9). Using the United Kingdom Registry of Endocrine and Thyroid Surgery (UKRETS) national database, maintained by the British Association of Endocrine and Thyroid Surgeons (BAETS), the authors identified 6,174 adrenal operations recorded from 2004 to 2021 for various indications. The results confirmed previous findings that surgeons who performed more adrenal operations per year had better patient outcomes, including fewer postoperative complications and shorter hospital stays. A minimally invasive approach was associated with decreased post-operative complications. The authors reported lower complication rates when surgeons performed above a threshold of 12 and 20 procedures per year. Length of hospital stay was also shorter for surgeons performing more than 20 procedures per year. Increased risk was noted in patients with adrenal cancer, surgeries for older patients and those who underwent bilateral adrenal surgery while there was no increased risk among patients with pheochromocytoma. The authors suggest that a volume threshold of 12 procedures per surgeon per year could define a high-volume adrenal surgeon and recommend restricting surgeries for adrenal carcinoma and bilateral adrenalectomy to higher-volume surgeons.

Many prior studies recommend a threshold of six or more adrenalectomies per year to achieve fewer complications, reduced in-hospital mortality, decreased cost of care, and shorter hospital stays (3,10,11). However, the study by Rajan et al. suggests doubling that threshold, recommending that 12 procedures per year define a high-volume adrenal surgeon. Although significant differences were only observed for cut-offs above 12 procedures, the absolute complication rates were similar for surgeons performing fewer than 6, 6–11.99, and 12–20 procedures per year (10.1%, 10.9%, and 10.4%, respectively). The complication rate was markedly lower (6.6%) for those performing more than 20 procedures annually. This lower complication rate above the 20-procedure threshold may contribute to the significant difference observed above 12 procedures. Therefore, it is more likely that there is little variation in complications until a surgeon performs more than 20 procedures per year, consistent with a previous study of adrenalectomies in a UK population (12). The authors acknowledge that the study is limited by the nature of data collection through a national registry and the proportion of missing data. Additionally, the study excluded surgeons who contributed fewer than 10 procedures during the study interval and reported a median of 12 adrenal operations per surgeon per year, much higher than the previously reported median operative volume. As a result, the findings may be biased towards surgeons with more operative experience.

The authors also identified adrenal carcinoma as a higher-risk procedure that should be restricted to higher-volume surgeons. Patients with malignant disease exhibit a higher reported conversion rate, length of stay, morbidity, and mortality (13). Thus, the results of the present study showing increased complication rates, reoperations and length of stay, taken in the context of prior literature, support restricting adrenal surgery for adrenal carcinoma to high-volume surgeons (13). This recommendation aligns with prior society guidelines from the AAES and the European Society of Endocrine Surgeons (ESES), which recommend that adrenal carcinomas be treated at high-volume multidisciplinary centers (7,10). Surgeons experienced in both open and laparoscopic techniques, particularly those at high-volume centers, should manage these cases as these may require an initial upfront approach and have a higher risk of requiring conversion to open (14). Additionally, the size of the lesion should be considered as giant adrenal tumors (those >6 cm) carry a significant risk of malignancy and increased complications (15). Rajan et al. also reports an association between adverse outcomes, hospital length of stay, and mortality among elderly patients and those undergoing bilateral adrenal surgery. Previous studies corroborate these findings, reporting higher complication rates and longer length of stay in older patients and those undergoing bilateral adrenalectomy (1,11,16). The study by Rajan et al. thus adds to the literature supporting that patient outcomes in these special patient groups may benefit from selective referral to higher volume surgeons.

In summary, there is still limited evidence to establish a definitive threshold for defining a high-volume adrenal surgeon. Rajan et al. contribute to the existing literature by highlighting that patient outcomes tend to improve with higher-volume surgeons, as evidenced by the lowest complication rates observed in surgeons performing more than 12 adrenalectomies per year. However, the majority of surgeons who perform adrenal surgery are not high-volume and may perform only one adrenal operation annually. Centralizing adrenal care to centers that perform a large volume of adrenal surgeries will likely improve outcomes at a lower cost. Additional data is still needed to determine an exact threshold where improved outcomes may be observed and to evaluate any potential barriers that centralization may pose for patients seeking access to high-volume surgeons.

Acknowledgments

Funding: None.

Footnote

Provenance and Peer Review: This article was commissioned by the editorial office, Gland Surgery. The article has undergone external peer review.

Peer Review File: Available at https://gs.amegroups.com/article/view/10.21037/gs-24-257/prf

Conflicts of Interest: Both authors have completed the ICMJE uniform disclosure form (available at https://gs.amegroups.com/article/view/10.21037/gs-24-257/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Park HS, Roman SA, Sosa JA. Outcomes from 3144 adrenalectomies in the United States: which matters more, surgeon volume or specialty? Arch Surg 2009;144:1060-7. [Crossref] [PubMed]
2. Lindeman B, Hashimoto DA, Bababekov YJ, et al. Fifteen years of adrenalectomies: impact of specialty training and operative volume. Surgery 2018;163:150-6. [Crossref] [PubMed]
3. Anderson KL Jr, Thomas SM, Adam MA, et al. Each procedure matters: threshold for surgeon volume to minimize complications and decrease cost associated with adrenalectomy. Surgery 2018;163:157-64. [Crossref] [PubMed]
4. Palazzo F, Dickinson A, Phillips B, et al. Adrenal surgery in England: better outcomes in high-volume practices. Clin Endocrinol (Oxf) 2016;85:17-20. [Crossref] [PubMed]
5. Al-Qurayshi Z, Robins R, Buell J, et al. Surgeon volume impact on outcomes and cost of adrenal surgeries. Eur J Surg Oncol 2016;42:1483-90. [Crossref] [PubMed]
6. Villar JM, Moreno P, Ortega J, et al. Results of adrenal surgery. Data of a Spanish National Survey. Langenbecks Arch Surg 2010;395:837-43. [Crossref] [PubMed]
7. Yip L, Duh QY, Wachtel H, et al. American Association of Endocrine Surgeons Guidelines for Adrenalectomy: Executive Summary. JAMA Surg 2022;157:870-7. [Crossref] [PubMed]
8. Bergamini C, Martellucci J, Tozzi F, et al. Complications in laparoscopic adrenalectomy: the value of experience. Surg Endosc 2011;25:3845-51. [Crossref] [PubMed]
9. Rajan S, Patel N, Stechman M, et al. Impact of adrenal surgeon volume on outcome: analysis of 4464 operations from the United Kingdom Registry of Endocrine and Thyroid Surgery (UKRETS). Br J Surg 2024;111:znae002. [Crossref] [PubMed]
10. Mihai R, Donatini G, Vidal O, et al. Volume-outcome correlation in adrenal surgery-an ESES consensus statement. Langenbecks Arch Surg 2019;404:795-806. [Crossref] [PubMed]
11. Kazaure HS, Sosa JA. Volume-outcome relationship in adrenal surgery: A review of existing literature. Best Pract Res Clin Endocrinol Metab 2019;33:101296. [Crossref] [PubMed]
12. Gray WK, Day J, Briggs TWR, et al. Volume-outcome relationship for adrenalectomy: analysis of an administrative dataset for the Getting It Right First Time Programme. Br J Surg 2021;108:1112-9. [Crossref] [PubMed]
13. Patel N, Egan RJ, Carter BR, et al. Outcomes of surgery for benign and malignant adrenal disease from the British Association of Endocrine and Thyroid Surgeons' national registry. Br J Surg 2019;106:1495-503. [Crossref] [PubMed]
14. Giordano A, Feroci F, Podda M, et al. Minimally invasive versus open adrenalectomy for adrenocortical carcinoma: the keys surgical factors influencing the outcomes-a collective overview. Langenbecks Arch Surg 2023;408:256. [Crossref] [PubMed]
15. Giordano A, Alemanno G, Bergamini C, et al. Laparoscopic adrenalectomy for giant adrenal tumours: Technical considerations and surgical outcome. J Minim Access Surg 2021;17:76-80. [Crossref] [PubMed]
16. Kazaure HS, Roman SA, Sosa JA. Adrenalectomy in older Americans has increased morbidity and mortality: an analysis of 6,416 patients. Ann Surg Oncol 2011;18:2714-21. [Crossref] [PubMed]