The five-year survival rate for ovarian cancer is notoriously low. Yet, data presented at the Society of Gynecologic Oncology Annual Meeting on Women's Cancer suggest that the survival rate could be dramatically improved if more women simply received the care recommended in the National Comprehensive Cancer Network (NCCN) treatment guidelines.
In the study, a retrospective analysis of 13,321 women diagnosed with ovarian cancer in California between January 1999 and December 2006, just over a third of patients received care consistent with the NCCN guidelines. Moreover, women who received care that was not adherent to guidelines had a significantly worse survival rate than those who did, regardless of whether they were diagnosed with early or late stage disease.
“This is kind of like a For Dummies book—i.e., ‘Ways to Improve Ovarian Cancer Outcomes for Dummies,’ said the study's lead author, Robert E. Bristow, MD, Director of the Division of Gynecologic Oncology at the University of California, Irvine Medical Center.
“When we look at all the research and resources being directed to developing new pharmaceuticals and chemotherapy drugs and biologic agents and tumor vaccines, we could have a more positive impact on survival that would dwarf all of those things if we could just make sure that ovarian cancer patients got to the proper people to be treated,” he told OT.
The analysis of data from the California Cancer Registry included all patients 18 years of age or older who were diagnosed with a first or only invasive epithelial cancer. Of the 15,477 patients identified, 2,156 were excluded for the purpose of the study (due to missing clinical information or ICD-O-2 codes, having non-epithelial histologic subtypes, or being diagnosed only at death or autopsy).
Of the remaining patients in the study population, the researchers found that about 54 percent received appropriate surgery for their tumor grade and stage and approximately 61 percent received appropriate chemotherapy. However, just 37 percent of patients received both appropriate surgery and appropriate chemotherapy, based on NCCN guidelines.
“Putting the whole package together only happens about one out of three times,” Bristow said.
Moreover, women who received guideline-adherent care had significantly better overall survival rates: The five-year disease-specific survival for women with early-stage disease who received guideline-adherent care was about 86 percent compared with about 81 percent for women who received non-adherent care. Similarly, women diagnosed with advanced ovarian cancer who received care according to NCCN guidelines had a five-year disease-specific survival rate of almost 35 percent compared with about 26 percent for women who did not receive such care. The differences were statistically significant in both early and advance-disease groups.
Bristow's results are disappointing but not surprising, according to Heidi Gray, MD, Associate Professor of Obstetrics and Gynecology at the University of Washington School of Medicine and a gynecologic oncologist with Seattle Cancer Care Alliance. Her group found similar rates of guideline-adherent care in an analysis of the Medicare population.
“The percentage of [Medicare] patients who get six cycles of chemotherapy and surgery is markedly low, around 40 percent,” said Gray, who chaired the session in which Bristow presented the work.
“What was very interesting about this study was that it correlated outcomes,” she told OT. “If you did not receive NCCN-guideline care you had a worse prognosis in terms of overall survival. That was a pretty sobering finding.”
She also noted that the care specified in the NCCN guidelines is not particularly detailed: “It was pretty basic care,” which makes the low rate of adherence even more alarming. “The standard guideline care, the bar isn't really high. Yes, it is a complicated surgery, but that is what most Gyn oncologists are trained to do, and six cycles of chemotherapy with a taxane or a platinum.”
When the investigators looked at patient characteristics associated with guideline-adherent care, it was found that older women were less likely to receive the specified care, as were women with higher grade or FIGO stage disease. Moreover, hospital and physician characteristics were also important predictors of adherent versus non-adherent care.
Most women (81%) received treatment at low-volume centers, which the investigators defined as hospitals that cared for fewer than 20 ovarian cancer cases a year. Conversely, high-volume centers accounted for just 2.8 percent of the hospitals in the study but 18.8 percent of patients.
Women treated at high-volume centers were more likely to receive guideline-adherent care than women treated at low-volume centers (about 51% vs. 34% for overall treatment). Low hospital volume was also associated with an eight percent increased risk of death, which was a statistically significant increase in risk.
Of the 10,464 patients for whom an operating surgeon or treating physician was identified in the database, 81 percent were treated by low-volume physicians, defined as those who treated fewer than 10 cases a year. Conversely, the high-volume physicians, who accounted for just 0.3 percent of the physicians listed, treated almost 21 percent of the patients.
As with hospital volume, physician volume was associated with the likelihood of guideline-adherent care (about 48% vs. 34.5%, respectively) and with disease-specific survival. Patients treated by low-volume physicians had an 18 percent increased risk of death.
Physician Collaboration Can Improve Care
Both Gray and Bristow say these data show that women with ovarian cancer should be treated by a specialist whenever possible, but determining exactly how to do that will take effort.
“We don't want community physicians to send every woman with an ovarian mass to a gynecologic oncologist,” Bristow said. “It's not good for continuity of care or for the ob/gyn's revenue stream. But, there are commercial tests and decision algorithms that can help decipher which women need to see a gyn oncologist.”
He also emphasized that the referral should be made prior to surgery, noting that previous studies have shown that the initial surgery is a key prognostic factor for overall survival, so getting women to a gynecologic oncologist prior to surgical resection is key. If a surgeon other than a gynecologic oncologist (who is specifically trained for this type of surgery) performs the resection, then staging information may be reduced and debulking may be less complete. Patients in that situation are starting their care “already behind the eight-ball,” Bristow said.
Gray also emphasized the importance of surgery being done by a specialist. But once that's in place, patients can often see a local oncologist and the chemotherapy care can be a collaborative effort: “The patient technically gets their chemotherapy outside my hospital or clinic, but it is overseen by me. So they are getting the standard of care or the latest regimen, or the opportunity for clinical trials.”
Gray said that during the discussion following Bristow's presentation an audience member asked how geography and the urban-versus-rural divide affected the likelihood of receiving guideline-adherent care.
The majority of low-volume hospitals were urban, Bristow answered. “So it was not that the majority of patients couldn't travel to a high-volume hospital, because it was within their same geographic region,” Gray said. “They just weren't getting referred to those centers—that is what is more disturbing.”