Over the course of the past quarter century, an increasing number of observational studies have been published investigating how surgeon and hospital experience can influence the outcomes of patients undergoing complex surgeries. Early studies suggested a strong volume–outcome relationship in a variety of procedures, such as pancreaticoduodenectomy, lung resection, and esophagectomy.1–3
A major rationale for this association is that surgeons who perform the same type of procedure frequently are likely to be specialists who focus their energy on just a limited number of procedures and who can continuously hone their technique over time. As more advanced and minimally invasive techniques develop, such as video-assisted and robotic-assisted thoracoscopic surgery, there is a steep learning curve that can potentially be overcome by performing a high number of similar cases.4–5 Similarly, facilities that commonly perform a specific procedure may be more likely to have anesthesiologists, intensivists, nurses, technicians, and other team members who are intimately familiar with the nuances of the surgery and can provide optimal care before, during, and after the surgery.
Given that most individual papers focus on a single procedure or disease site, and since the methodologies used are quite heterogeneous, Zaorsky et al,6 in their article titled “Impact of Facility Surgical Volume on Survival in Patients With Cancer” elsewhere in this issue, should be commended for their efforts to apply a single set of methodologies across the spectrum of disease sites while using more contemporary data. The authors stratified facilities in quartiles of annual surgical case volume. When comparing the highest versus the lowest quartile, a statistically significant difference in overall survival was noted in each of the 13 disease sites analyzed, although the magnitude of difference varied widely. Given the large numbers of patients analyzed, the clinical significance of the small absolute survival differences in disease sites like thyroid and uterine cancers may be almost negligible. However, for brain, pancreatic, and esophageal cancers, the survival differences based on case volume are difficult to ignore.
As with observational studies in general, the causality of this association can certainly be questioned. Despite robust methodological rigor, unmeasurable patient characteristics could potentially confound these relationships, especially in large registries like the National Cancer Database. For example, patients who select high-volume surgeons or centers may be more likely to have the capability or willingness to travel long distances to their preferred provider for both the surgery of interest as well as other aspects of their health. These patients may generally have more favorable social determinants of health that are not fully captured by the database, such as improved access to food, housing, and other aspects of healthy lifestyles that may make them more likely to have superior outcomes following the procedure.7 In addition, high-volume surgeons and facilities may be more likely to operate at centers that generally offer more comprehensive oncologic care, including access to clinical trials and multidisciplinary experts in radiation oncology, medical oncology, pathology, radiology, and internal medicine subspecialties, potentially influencing overall survival in a manner that is independent of the institution’s case volume of the particular surgery of interest.
Even if we were to assume that there is in fact a causal association between surgical case volume and patient outcomes, it is challenging to differentiate whether the individual surgeon or the facility where the surgery takes place is more impactful. In other words, is it more beneficial to undergo surgery performed by a single experienced surgeon who operates at multiple facilities that are each considered low-volume, or at a center where a procedure is performed frequently by multiple surgeons who each do not do it often? The National Cancer Database is unable to identify individual surgeons and therefore cannot assess the impact of individual surgeon volume on outcomes. Other surgical databases, such as the National (Nationwide) Inpatient Sample of the Healthcare Cost and Utilization Project record, separate surgeon and facility identification numbers, but these data only reflect the case volume of a surgeon or facility in a given year rather than the cumulative volume over the course of their careers or histories. Would a surgeon who is 1 year into practice but performs 100 surgeries that year be necessarily more competent than another who has performed 40 surgeries per year for the past 30 years? Furthermore, surgical volume must be differentiated from surgical specialty, because different specialties may approach the same problem from a different perspective due to the other procedures that the surgeons have learned to perform.8 Finally, personal characteristics of an individual surgeon regarding clinical judgment, attention to detail, attitude, and technical skill are impossible to accurately measure.
Now that these associations have been described in detail, how can we implement changes that will lead to meaningful improvements in cancer surgery outcomes? In 2007, the Canadian province of Ontario operationalized the concept of regionalization for thoracic cancer surgery in an attempt to achieve this goal.9 This has since expanded to surgery for hepatobiliary, head and neck, and gynecologic cancers. Regionalization occurred through the designation of a certain subset of centers that are directed to perform the vast majority of these types of surgeries through a process of financial incentivization and penalties. These designated facilities were selected based largely on volume as well as available resources. Initial outcomes of this approach for thoracic surgery were reported in 2017.10 Although the proportion of provincial lung cancer operations at designated hospitals increased substantially from approximately 70% in 2004 to 90% in 2012, there was no clear decline in overall operative mortality beyond what would be expected based on preexisting trends. However, there was an apparent benefit for patients aged ≥70 years, as well as an overall improvement in length of hospital stay. It is certainly possible that any potential gains due to regionalization were masked by the fact that most patients were already receiving their surgical care at high-volume facilities before the reorganization. With longer follow-up and a focus on the highest-risk populations, a survival benefit may emerge.
Although Ontario’s single-payer healthcare system can enforce compliance with regionalization, the United States has a very different system that may not easily allow a vast reorganization of services. Furthermore, such regionalization may not be desirable in the United States, where widening sociodemographic disparities in access to high-quality healthcare would be cause for serious concern.7 In the United States, patient convenience is highly valued, and long travel distances may discourage timely cancer treatment more so than in other developed nations with a wider social safety net.
Despite the large amount of research in this arena, there is still substantial work to be done. Avenues worth exploring may include (1) leveling the playing field by improving the education and training of lower-volume surgeons and centers, potentially through a renewable credentialing process; (2) enforcing financial incentives for regionalization of certain procedures through the Centers for Medicare & Medicaid Services, with hopes that private insurance companies will also follow; (3) creating and disseminating quality and volume metrics that are publicly available, allowing market forces to direct patient flow toward higher-volume and higher-rated physicians and centers; and (4) funding initiatives to improve access to higher-volume facilities, especially for patients who are more socioeconomically disadvantaged and have to travel further distances. More research is also needed in assessing the value of case volume in nonsurgical cancer treatments, such as radiation therapy, interventional ablation, and systemic therapy.
We are fortunate to have already developed highly effective and curative surgical treatments for patients with many types of localized cancers. However, improving the consistent delivery of this high-quality oncologic care will require both creativity and persistence.
Sosa JA, Bowman HM, Gordon TA, et al. Importance of hospital volume in the overall management of pancreatic cancer. Ann Surg 1998;228:429–438.
Bach PB, Cramer LD, Schrag D, et al. The influence of hospital volume on survival after resection for lung cancer. N Engl J Med 2001;345:181–188.
Birkmeyer JD, Stukel TA, Siewers AE, et al. Surgeon volume and operative mortality in the United States. N Engl J Med 2003;349:2117–2127.
Park HS, Detterbeck FC, Boffa DJ, Kim AW. Impact of hospital volume of thoracoscopic lobectomy on primary lung cancer outcomes. Ann Thorac Surg 2012;93:372–379.
Stoltzfus KC, Shen B, Tchelebi L, et al. Impact of facility surgical volume on survival in patients with cancer. J Natl Compr Canc Netw 2021;19:495–503.
Liu JH, Zingmond DS, McGory ML, et al. Disparities in the utilization of high-volume hospitals for complex surgery. JAMA 2006;296:1973–1980.
Park HS, Roman SA, Sosa JA. Outcomes from 3144 adrenalectomies in the United States: which matters more, surgeon volume or specialty? Arch Surg 2009;144:1060–1067.
Darling GE. Regionalization in thoracic surgery: the importance of the team [published online July 18, 2020 ]. J Thorac Cardiovasc Surg, doi:
Bendzsak AM, Baxter NN, Darling GE, et al. Regionalization and outcomes of lung cancer surgery in Ontario, Canada. J Clin Oncol 2017;35:2772–2780.