The Volume-Outcome Relationship in Retroperitoneal Soft Tissue Sarcoma: Evidence of Improved Short- and Long-Term Outcomes at High-Volume Institutions

Abstract

Background We sought to study the association between RPS case volume and outcomes. Although a relationship has been demonstrated between case volume and patient outcomes in some cancers, such a relationship has not been established for retroperitoneal sarcomas (RPSs). Study Design The National Cancer Database (NCDB) was queried for patients undergoing treatment for primary RPS diagnosed between 2004 and 2013. Mean annual patient volume for RPS resection was calculated for all hospitals and divided into low volume (<5 cases/year), medium volume (5–10 cases/year), and high volume (>10 cases/year). Risk-adjusted regression analyses were performed to identify predictors of 30-day surgical mortality, R0 margin status, and overall survival (OS). Results Our study population consisted of 5,407 patients with a median age of 61 years, of whom 47% were male and 3,803 (70%) underwent surgical resection. Absolute 30-day surgical mortality and R0 margin rate following surgery for low-, medium-, and high-volume institutions were 2.4%, 1.3%, and 0.5% (p=0.027) and 68%, 65%, and 82%, (p < 0.001), respectively. Five-year overall survival rates for low, medium, and high-volume institutions were 56%, 57%, and 66%, respectively (p < 0.001). Patients treated at low-volume institutions had a significantly higher risk of 30-day mortality (adjusted OR = 4.66, 95% CI 2.26–9.63) and long-term mortality (adjusted HR = 1.56, 95% CI 1.16–2.11) compared to high-volume institutions. Conclusion We demonstrate the existence of a hospital sarcoma service line volume-oncologic outcome relationship for RPS at the national level and provide benchmark data for cancer care delivery systems and policy makers.

Identifying the Minimum Volume Threshold for Retroperitoneal Soft Tissue Sarcoma Resection: Merging National Data with Consensus Expert Opinion

“…In response to this call, several investigators have demonstrated a strong relationship between hospital volume and favorable RPS operative outcomes. [11][12][13][14] Further, 2 recent French analyses assessing quality of sarcoma care delivered in a regionalized system uncovered improved outcomes in patients attending designated "reference" centers for sarcoma, which use at minimum, multidisciplinary tumor boards and 2 pathologist reviews of histologic specimens. 15,16 Despite the call for regionalization of RPS surgery in the United States and its supportive evidence, this trend lags significantly behind other regionalized complex surgical cancers, such as pancreatic.…”

A sommelier to guide wine selection and a specialist to manage the sarcoma patient: Barriers to referral and definition of a sarcoma specialist

“…However, retroperitoneal sarcomas (RPS) are among the largest tumors in the human body and in addition to their large size, their proximity to critical organs and major vessels makes surgery very challenging. As expected, multiple studies to date have demonstrated that outcomes for RPS patients are clearly better when they are managed by specialists vs nonspecialists 3–5 …”

“…In conclusion, just as sommeliers have an important, very specific role in the dining experience for a restaurant patron, sarcoma specialists are critical for the patient with this rare and challenging cancer. Institutional thresholds for high case volume (eg, for RPS, >10 per year) have been proposed and deserve further study 3,4 ; but in reality, many sarcoma specialists as defined above would far exceed these numbers. Referral to a sarcoma specialist has the additional benefit of centralizing research efforts and facilitating enrollment into therapeutic clinical trials.…”

“…As expected, multiple studies to date have demonstrated that outcomes for RPS patients are clearly better when they are managed by specialists vs nonspecialists. [3][4][5] What is remarkable however is that in the United States, recent data from the National Cancer Database shows that every year since 1998, only approximately 10% of RPS patients undergo surgery at high volume hospitals. 4 The overwhelming majority of patients with this complex, challenging cancer are being treated at hospitals who manage fewer than 10 cases per year or less than one a month.…”

Morbidity, mortality and temporal trends in the surgical management of retroperitoneal sarcoma: An ACS‐NSQIP follow up analysis

“…However, it is also possible that the lack of change reflects a lack of referrals to specialized centers. The etiology of the static rate of MVR warrants attention in future studies as this may be a target for increasing both MVR rates and referrals to specialized sarcoma centers with the goal of improving both postoperative morbidity and mortality as well as oncologic outcomes …”