The role of surgeon and hospital volume in optimizing adrenal surgery outcomes

The relationship between surgical volume and clinical outcomes is a well-established notion in endocrine surgery. This relationship is particularly significant in adrenal surgery, which is technically demanding and relatively rare. Evidence from recent studies underscores the importance of both surgeon and hospital volumes in optimizing patient outcomes. High-volume surgeons and centers have been shown to provide superior care and better outcomes for patients undergoing adrenalectomy. This editorial commentary reviews evidence from the United Kingdom Registry of Endocrine and Thyroid Surgery (UKRETS) and other relevant studies to advocate for the combined importance of both surgeon and center volume in achieving optimal outcomes in adrenal surgery.

The UKRETS study, which analyzed 4,464 adrenalectomies, highlights the significant impact of surgeon volume on patient outcomes. It shows that surgeons performing more than 12 adrenalectomies per year have lower complication rates, compared to those performing over 20 operations annually seeing even greater reductions in complications and shorter hospital stays (1). These results emphasize that higher surgical volumes correlate with improved proficiency and patient safety. Using logistic regression, the study adjusted for factors such as patient age, comorbidities, and adrenal lesion type to assess risk factors for complications and mortality. Linear regression models confirmed that higher surgeon volumes were linked to shorter hospital stays.

This study aligns with a broader body of research emphasizing the need for minimum volume thresholds to optimize outcomes in adrenal surgery. However, the threshold for determinizing a high-volume surgeon is still a matter of debate. For instance, Palazzo et al. reviewed that performing at least six adrenalectomies per year is associated with improved outcomes, such as fewer complications and shorter hospital stays (2). This cut-off is admitted by the European Society of Endocrine Surgeons (ESES) guidelines in 2019 (3) and those of the American Association of Endocrine Surgeons (AAES) in 2022 (4), and validated by Anderson et al.’s study. The latter used a logistic regression with restricted cubic splines and adjusted for potential confounders, such as patient comorbidities and institutional factors, to isolate the impact of surgeon volume (5).

We believe that a cut-off of six is quite low, hence the importance, in our opinion, of the UKRETS study, which suggests a more appropriate cut-off would be 12, or even 20, adrenalectomies per surgeon per year, especially for procedures involving cancer, large tumors, or bilateral adrenalectomy (1). Gray et al. also found a surgeon volume effect but couldn’t determine a single cut-off for all the studied outcomes. Yet, they concluded that ‘although a threshold of six and over may be a useful and pragmatic target, a minimum annual volume threshold of around 20 procedures per annum per surgeon… would provide greater benefits to patients’ (6).

As far as adrenocortical carcinoma (ACC) is concerned, the threshold may even be higher. Indeed, the European guidelines (7) added that for ACC, a surgeon volume of more than 20 adrenalectomies per year is preferred, given the complexity of some procedures, and the great importance of a radical surgery and tumor-free resection margins. Moreover, Park et al. found that surgeons performing more than ten adrenalectomies annually had lower rates of conversion from laparoscopic to open surgery, a common issue in complex adrenal cases, highlighting their advanced skill level and proficiency in minimally invasive techniques (8). Surgeon volume impacts not only technical execution but also the overall management of patient care. High-volume surgeons are more likely to follow evidence-based protocols, collaborate with multidisciplinary teams, and utilize advanced technologies such as minimally invasive surgery, which have been shown to reduce postoperative complications and enhance recovery.

While the surgeon’s experience is proved to be a critical factor, we believe that the hospital setting also significantly influences patient outcomes for adrenal surgery. High-volume hospitals, benefit from specialized teams, advanced infrastructure, and well-established care pathways. These factors contribute to the “center effect”, where outcomes improve due to the collective expertise and resources of the entire hospital team. This association is well established for gastrectomy, colorectal surgery, pulmonary resections and pancreatic surgery (9-11) but has been less studied in adrenal surgery.

Gray et al. referred to the usefulness of centralization at an institutional level, especially for complex cases and for open adrenal surgery, and suggested a cut-off of 30 adrenalectomies per center annually for better outcomes (6). In the Netherlands, high-volume centers demonstrated better surgical outcomes and 5-year overall survival (12). Research from German healthcare systems conducted on 17,040 cases showed that high-volume hospitals have lower complication rates and reduced in-house mortality for all types of adrenalectomies, not just those for ACC (13). Similarly, an Italian study found that hospitals performing more than 30 procedures annually—a threshold chosen arbitrarily—experience significantly lower rates of conversion to laparotomy, fewer postoperative complications and improved outcomes across various indications (14).

High-volume centers typically have dedicated multidisciplinary teams that collaborate to provide comprehensive care, ranging from preoperative evaluation to intraoperative management and postoperative follow-up (15). This facilitates the adoption of advanced surgical techniques and access to specialized resources, which could potentially result in improved patient outcomes (4,15,16).

That being said, and even though the surgeon’s effect is important, we believe that it’s better to consider the center effect, as both effects are ultimately interconnected. The evidence presented makes a compelling case for centralizing adrenal surgeries in high-volume centers with experienced surgeons. Policymakers and healthcare administrators should consider creating referral networks that direct adrenal cases to these high-volume centers, maximizing benefit from the collective expertise of multidisciplinary teams (4,13). That would also benefit surgical training. Establishing regional centers of excellence in adrenal surgery will ensure that fellows can more easily gain the necessary experience to master adrenal surgery and perform complex procedures safely and effectively (4).

Hence, the volume-outcome relationship in adrenal surgery is well-documented, emphasizing the need for both high-volume surgeons and hospitals. High-volume surgeons and centers provide structured environments that enhance patient care, reduce complications, and improve recovery. The UKRETS study, along with other research, supports increasing the accepted surgeon volume threshold from 6 to 12 adrenalectomies per year, or ideally even 20, to achieve the best outcomes. Further research should explore the center effect across a broader range of adrenal surgeries to strengthen the case for centralization. Encouraging a culture of expertise within high-volume tertiary centers and a close collaboration with primary and secondary care centers, will ensure that patients with adrenal conditions receive the highest standard of care.

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-24-383/prf

Conflicts of Interest: Both authors have completed the ICMJE uniform disclosure form (available at https://gs.amegroups.com/article/view/10.21037/gs-24-383/coif). The authors have no conflicts of interest to declare.

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