Special Feature

Quality of Care in Ovarian Cancer: What are the Metrics?

By Robert L. Coleman, MD, Professor, University of Texas; M.D. Anderson Cancer Center, Houston, is Associate Editor for OB/GYN Clinical Alert.

Dr. Coleman reports no financial relationships relevant to this field of study.

Synopsis: Hospitals with high-volume exposure to patients with ovarian cancer have been found to have better staging, debulking rates, survivorship, and lower mortality. However, variations in mortality among hospitals do not appear to be related to lower complications but rather to better ability to treat emergent complications from intervention. This metric, “failure to rescue,” is substantially lower in high-volume hospitals compared to other facilities and explains the better outcomes in these centers.

Source: Wright JD, et al. Failure to rescue as a source of variation in hospital mortality for ovarian cancer. J Clin Oncol 2012;30:3976-3982.

The association between high surgical volume and improved procedure-based outcome is ubiquitous, yet without clarity as to why the association is so prevalent. One hypothesized mechanism is that high-volume hospitals may be better at rescuing patients with complications, rather than having lower complication rates. The purpose of this report was to examine the role of complications, failure to rescue from complications, and mortality in the context of hospital volume for ovarian cancer. The Nationwide Inpatient Sample was used to identify women who underwent surgery for ovarian cancer from 1988 to 2009. Hospitals were ranked on the basis of their procedure volume. Risk-adjusted mortality, major complication rate, and “failure to rescue” rate (mortality in patients with a major complication) for each tertile were calculated. The analysis collected data from 36,624 patients treated in 1166 hospitals. The mortality rate for the cohort was 1.6%. The major complication rate was 20.4% at low-volume, 23.4% at intermediate-volume, and 24.6% at high-volume hospitals (P < 0.001). However, the rate of failure to rescue (death after a complication) was markedly higher at low-volume (8.0%) compared with high-volume hospitals (4.9%; P < 0.001). After adjusting for contributing factors, women treated at low-volume hospitals who experienced a complication were 48% more likely (odds ratio [OR], 1.48; 95% confidence interval [CI], 1.11-1.99) to die than patients with a complication at a high-volume hospital. The reduction in mortality does not appear to be the result of lower complication rates but rather a result of the ability of high-volume hospitals to rescue patients with complications.

Commentary

A decade ago, a provocative report of hospital volume and surgical morality in the United States was published in the New England Journal of Medicine.1 The report examined the outcomes of six cardiovascular and eight oncological surgical procedures in patients aged 65-99 years, over a 5-year period, with the primary endpoint being death before hospital discharge or within 30 days of the index procedure. The analysis included 2.5 million patients, mostly Medicare (CMMS) recipients, and for each of the surgical procedures, mortality was significantly better at high-volume centers vs low-volume centers. It appeared that more complex procedures — those associated with higher complication potential — saw the most improvement with the odds of death being 2- to 5-fold lower at high-volume hospitals. The authors opined that higher volume centers were more likely to have surgical specialists, more consistent postoperative care, better-staffed ICUs, and better resources for dealing with postoperative complications. They recommended that Medicare recipients between 65-99 years of age undergoing one of these procedures should seek high-volume hospitals to have their procedure performed. Although there are methodological issues about making this conclusion from the examined data, the consistency of the results within this study and those from other studies do raise the issue for regionalization of care based on metrics of successful outcome.

In ovarian cancer, similar data recently have been produced.2-6 The association is most marked when comparing outcomes in high-volume hospitals with expert gynecologic oncologists to low-volume hospitals without specialized care. The association is less dramatic when a low-volume center has a gynecologic oncologist, unless that individual also has a low volume of individual cases.3 In general, higher ovarian cancer surgical caseloads produce individuals with a broader technical skill set, improved operative proficiency, lower complication rates, and adherence to treatment guidelines. However, when looking at individual hospitals with high-volume ovarian cancer populations, complications are generally higher and patients are more likely to present with comorbidities. In addition, these facilities are more likely to be urban, in large metropolitan areas, and at teaching facilities. Yet, despite these characteristics and the more frequent performance of more radical procedures, mortality is significantly lower. The apparent paradox is the subject of the Wright et al manuscript, which investigated mortality variance in ovarian cancer patients cared for at low-, medium-, and high-volume hospitals.

As outlined in the abstract, mortality among 36,624 identified patients from 1166 hospitals was significantly reduced at high-volume centers despite having significantly higher complication rates and performing more extensive surgical resections. Their investigation into outcomes from complications experienced provided the most relevant metric describing the outcomes data: patients experiencing an operative complication in a low-volume hospital were 48% more likely (OR: 1.48, 95% CI: 1.11-1.99) to die compared to patients experiencing a complication in a high-volume hospital. This metric, also termed “failure to rescue,” increasingly has been recognized across several surgical procedures as the most important driver of operative performance. It is precisely the management of a complication, rather than the complication itself, that determines operative mortality.

The article is insightful and instructive, and raises many important questions about the quality and the delivery of health care as it relates to ovarian cancer surgery. One visceral response to data, like the analysis from the 2002 CMMS report, is that care should be regionalized based on volume, that is, to centers with low failure to rescue percentages. However, it is clear that providers and patients would likely find this unacceptable and potentially counter-productive, particularly if patients refuse triage and thus receive improvised local care. There are many potential drawbacks in the current analysis. For instance, data on physician specialty were not available, so it is unclear whether availability of subspecialty care can override the failure to rescue rate. In addition, ovarian cancer outcome depends on many factors other than surgery. Thus, overall disease-specific outcomes could be influenced by factors not examined in this report. Finally, surgical postoperative residuum is the strongest prognostic variable to survival; these data were not available to the investigators, so it is unclear if this event was balanced among the cohorts. Despite the many potential flaws in the current analysis, outcome metrics are already being compiled and analyzed and may be marketed. Further work in this arena is desperately needed to provide clarity on health care delivery metrics so that patients and providers can respond to improve outcomes.

References

  1. Birkmeyer JD, et al. Hospital volume and surgical mortality in the United States. N Engl J Med 2002;346:1128-1137.
  2. Kumpulainen S, et al. The effect of hospital operative volume, residual tumor and first-line chemotherapy on survival of ovarian cancer — a prospective nation-wide study in Finland. Gynecol Oncol 2009;115:199-203.
  3. Schrag D, et al. Associations between hospital and surgeon procedure volumes and patient outcomes after ovarian cancer resection. J Natl Cancer Inst 2006;98:163-171.
  4. Earle CC, et al. Effect of surgeon specialty on processes of care and outcomes for ovarian cancer patients. J Natl Cancer Inst 2006;98:172-180.
  5. Chan JK, et al. Influence of the gynecologic oncologist on the survival of ovarian cancer patients. Obstet Gynecol 2007;109:1342-1350.
  6. Bristow RE, et al. The National Cancer Database report on advanced-stage epithelial ovarian cancer: Impact of hospital surgical case volume on overall survival and surgical treatment paradigm. Gynecol Oncol 2010;118:262-267.