The first study to compare survival between women with breast cancer whose treatment was based on consensus guidelines and those whose treatment was not shows that adhering to established guidelines improves survival and reduces the risk of recurrence.
The study retrospectively examined whether the systemic therapy prescribed after surgery for women with early-stage breast cancer was consistent with treatment guidelines established for at the time. Systemic therapy includes chemotherapy and hormonal therapy and is designed to reach cancer cells that may have spread beyond the original tumor site.The study and an accompanying editorial will be published online August 2 in the Journal of Clinical Oncology (JCO) at www.jco.org.
Using medical records from Canada’s national health care system, Dr. Hébert-Croteau and her colleagues compared survival between 1,002 women with early breast cancer whose systemic treatment was delivered according to guidelines developed at the 1992 St-Gallen conference in Switzerland, and 380 women whose treatment differed from those guidelines. The study also included 159 women whose guideline adherence was unknown. The women were diagnosed between 1988 and 1994 with invasive breast cancer that had not spread to nearby lymph nodes.
Developed by consensus with input from oncologists in Europe and North America, the St-Gallen guidelines continue to be updated regularly and are considered among the best guidelines available. The guidelines stipulate whether a woman with node-negative breast cancer should, after surgery, receive tamoxifen, chemotherapy, neither (as is the case for women at low risk of recurrence), or both, depending on her risk.
Researchers found that overall survival at 7 years was better among women whose systemic treatment complied with guidelines, especially for those at moderate risk of recurrence.Among those patients with moderate risk of recurrence, the 7-year survival was 88% for women who received treatment consistent with guideline recommendations vs. 79% among those whose therapy did not.
In addition, more women whose treatment differed from treatment guidelines experienced recurrence by 7 years than those whose therapy adhered to the guidelines.For those at moderate and high risk of recurrence, the recurrence rate at 7 years was 36% and 42% respectively when treatment did follow guidelines, versus 17% and 36% when treatment followed guidelines.
“Women treated for node-negative breast cancer according to consensus recommendations for systemic therapy experience a significant improvement in survival at 7 years,” said Nicole Hébert-Croteau, MD, PhD, Physician-Epidemiologist at the Quebec National Institute of Public Health and lead author of the study. “Our associations support the current movement for developing, updating, and disseminating such recommendations.”
Underuse of systemic therapy exists to some degree –at any cancer center – due to the complex nature of cancer care.For example, when a patient’s baseline prognosis is good, a physician may elect not to prescribe systemic therapy in efforts to avoid toxic side effects.Dr. Hébert-Croteau noted that patients may also have other medical problems that might influence the treatment recommendation.
An accompanying editorial by Rebecca A. Silliman, MD, PhD, of Boston University Medical Center notes that translating clinical guidelines into practice is often a slow and complex process.She suggests that interventions that use small-group, case-based approaches that incorporate role-playing and discussion are needed to change provider behaviors.
“Although evidence-based guidelines are a necessary beginning, they are not sufficient in and of themselves to change practice,” Dr. Silliman said.“What is required is a much more comprehensive approach that incorporates not only knowledge, but also builds skills and affects attitudes.”
Dr. Silliman noted that the results of this study should be interpreted with caution, since they pertain to medical care that was delivered more than a decade ago.