2011. Geographic Variation in the Treatment of Early-Stage Prostate Cancer across VA Medical Centers
C Fung, Greater Los Angeles VA Healthcare System, B Spencer, Greater Los Angeles Healthcare System, LV Rubenstein, Greater Los Angeles Healthcare System

Objectives: The proposed study asks the question, "Is there geographic variation across VA Medical Centers in the use of radiation, surgery, and "watchful waiting" in patients with early stage prostate cancer?" 

Methods: We selected demographic and clinical variables including age, race, ethnicity, class of case, grade of disease, marital status at time of diagnosis, insurance, type of treatment, stage of disease, and VISN.  We generated a variable, "geographical region," from the VISN variable. We used a nested logit model to determine the relationship between geographic region and treatment use, after adjusting for demographic and clinical variables. For the lower level, we performed logistic regression, modeling the relationship between geographic region and the potentially curative treatment options, surgery and radiation. For the upper level, we performed logistic regression, modeling the relationship between geographic regions and the treatment options, surgery/radiation and non-curative treatment ("watchful waiting”). We calculated the probability of surgery, radiation, and non-curative treatment for each geographic region.

Results: The west region appears to have higher predicted probability of surgery compared to other geographic regions and lower predicted probability of radiation compared to other geographic region. Patients in the west region have slightly lower probability of undergoing non-curative treatments such as "watchful waiting" compared to patients in other geographic regions.  In all regions except the south, patients have a higher predicted probability of receiving either surgery or radiation than non-curative treatment. 

Conclusions: Although surgery, radiation, and "watchful waiting" are all acceptable forms of treatment for early-stage prostate cancer, prior studies suggest that geographic variation exists in the use of modalities of treatment. Our results suggest that geographic variation in the care of early-stage prostate cancer also exists in the VA system. 

Impact: This study prompts us to explore the mechanisms that cause variations in practice patterns and implementation of new practices.