Dietary fat reduction in postmenopausal women with primary breast cancer: Phase III Women's Intervention Nutrition Study (WINS)
Reviewer: Christopher Dolinsky, MD
Abramson Cancer Center of the University of Pennsylvania
Last Modified: May 18, 2005
Presenter: R.T. Chlebowski
Presenter's Affiliation: The WINS Investigators
Type of Session: Plenary
- Laboratory and retrospective research has suggested that dietary fat intake may be related to outcomes in breast cancer patients.
- The feasibility of interventions that decrease dietary fat intake in women has been demonstrated.
- Multiple studies have shown that overweight women have higher rates of breast cancer and poorer outcomes after treatment.
- The results of this trial have been heavily reported by the lay press.
Materials and Methods
- A multi-institution, phase III prospective trial randomized 2437 women with early stage resected breast cancer to two arms.
- Women were selected for this study if they reported that at least 20% of their daily calories were consumed from dietary fats.
- The experimental arm involved a series of interventions designed to decrease the patients dietary fat intake to less than 15% of their daily calories.
- This was accomplished through a series of 8 bi-weekly meetings with centrally trained nutritionists who counseled patients on lowering dietary fat intake.
- Compliance with the dietary modifications and measurement of dietary fat intake was assessed by a series of unsolicited phone calls (recalls) by trained personnel.
- 3 recalls were required for eligibility, and 2 recalls were performed each year during the study.
- Patients were encouraged to self monitor dietary fat, and group support session were available but not mandatory.
- The control arm saw nutritionists as well, but they were not counseled about dietary fat reduction.
- 40% of patients were randomized to the experimental arm, and 60% to the control arm.
- Primary endpoint was relapse free survival, and overall survival and disease free survival were secondary endpoints.
- Patients ranged in age from 48-79 years, and had histologically confirmed, resected breast cancers.
- Patients were not eligible with node negative tumors less than 1 cm, node positive tumors greater than 5 cm, or >10 positive nodes.
- Patients with ER + tumors received 5 years of tamoxifen and were allowed to receive chemotherapy, while patients with ER tumors were required to receive chemotherapy.
- Patients were stratified by nodal status, systemic adjuvant therapy, and sentinel node status.
- The trial was ended prematurely, during the 5th interim analysis, because of funding issues; however, the review board approved the current data analysis and presentation.
- Patients were well balanced in both arms according to most disease and demographic variables including: age, time from surgery, histologic subtype, nodal status, and hormone receptor status.
- The control arm contained more patients who received breast conservation therapy (p=0.004).
- Median follow-up was 60 months.
- The experimental arm was calculated to have a lower dietary fat intake than the control arm (20.3% of calories vs 29.2% of calories).
- The experimental arm had improved relapse free survival compared to the control arm (9.8% relapse vs 12.4% relapse, hazard ratio 0.76, p=0.034).
- The experimental arm had improved disease free survival compared to the control arm (hazard ratio 0.81, p=0.042)
- In an unplanned analysis, ER negative patients appeared to have a benefit to dietary fat reduction (hazard ratio 0.58, p=0.018) while ER positive patients did not (hazard ratio 0.85, p=NS).
- Overall survival was not significantly different between the 2 arms.
- The experimental arm had a significant decrease in weight compared to the control arm.
- By using an intensive program of multiple interventions, dietary fat intake can be decreased in a clinical trial setting.
- Life-style intervention involving dietary fat reduction may improve relapse free survival in breast cancer patients.
- There may be a bigger benefit to dietary fat reduction in patients with ER negative tumors.
- Further research in this area is warranted.