Principal Investigator - Dejana Braithwaite, PhD
With increased longevity of the population, comorbidity plays an important role in breast cancer prognosis and treatment. However, measuring comorbidity remains one of the important unsolved problems in clinical care. We have found that the widely used generic comorbidity measure, the Charlson Comorbidity Index (CCI), omits important prognostic comorbidities for breast cancer such as hypertension. Existing comorbidity measures are suboptimal because they include conditions inconsequential for breast cancer, exclude some that are important, and apply weights to comorbidities that do not reflect true hazards. Hence, our long term objective is to optimize the measurement of comorbidity among breast cancer patients. The proposed study will be embedded within a population-based prospective multiethnic cohort study of 2,321 breast cancer survivors followed for up to 9 years to date at Kaiser Permanente Northern California, LACE (Life After Cancer Epidemiology, PI Dr. Bette Caan). The LACE study is one of only a few prospective multiethnic studies of breast cancer survivors nationwide. Its large individual size, an extensive assessment of a broad range of comorbid conditions before or at the time of breast cancer diagnosis, functional status and extensive information on tumor characteristics (size, histology, estrogen and progesterone receptor status, HER2/neu status) and treatment (surgical procedures, chemotherapy, radiotherapy, hormonal therapy) make it a unique resource. The overall goal of this project is to generate additional preliminary data for a future NIH-funded study that will develop and validate a standard comorbidity model for breast cancer as an index disease. Three specific aims are envisioned in this research proposal: (1) Determine the impact of comorbidity individually and collectively on survival. (2) Determine the contribution of functional status associated with comorbid conditions to survival. (3) Determine whether the effect of comorbidity varies according to short-term (≤5 years) versus long-term survival (>5 years).