Approximately 10-20% of women with ductal carcinoma in situ (DCIS) will have recurrent breast cancer, either in situ or invasive, within 5 years of their initial diagnosis. While every year in the US more than 47,000 women are diagnosed with DCIS, our ability to accurately predict which patients are most likely to have a recurrence is quite poor. Consequently, treatment decisions are difficult and up to 40% of DCIS patients will have a mastectomy. Investigators at three CRN sites are therefore conducting a study to identify clinical and pathologic factors that could be used to accurately identify DCIS patients at high and low risk of a recurrence.
The study population will come from the memberships of three CRN sites. DCIS patients diagnosed between 1990 and 2001 and treated with breast-conserving surgery will be identified (N=3,700) and followed for recurrence. Diagnostic slides from patients with a recurrence (N=490) and from matched controls will be retrieved and reviewed by an expert DCIS pathologist. One control will be selected for each recurrence (case), matched on health plan, calendar year of the initial diagnosis, age, and follow-up time. Pathology review will be conducted on the slides from the initial and recurrent tumors of cases and from the initial tumors of controls. Data on clinical factors will also be obtained. The study aims are to:
- Estimate and compare the risk of recurrence associated with tumor markers and several pathologic features of the index DCIS, and compare features of the index DCIS to those in recurrent lesions;
- Estimate and compare the risk of recurrence associated with several clinical factors, such as age, menopausal status, obesity, and family history of breast cancer; and
- Evaluate the relation between clinical and pathologic factors, and determine which combination of these factors best identifies subgroups of women at very high and low risk of recurrence.
- Evaluate practice variation in DCIS treatment in relation to disease, patient, provider and institutional factors to identify aspects of quality of care that may influence recurrence.
This is the largest and most comprehensive study to date on prognostic factors for DCIS. Results will provide information on the natural history of this heterogeneous group of lesions, and in the future may help in the development of individually tailored treatment strategies for patients with DCIS.
Project Status: This study was funded as part of the CRN Competing Continuation (Ed Wagner, PI). The project began March 1, 2003. The project leader is Laurel Habel, PhD, of the Kaiser Permanente Northern California Division of Research.