PCN14: CHOICE OF LOCALIZED BREAST CANCER TREATMENTS IN A MEDICARE POPULATION: A COMPARISON OF OUTCOMES AND COSTS

Abstract

OBJECTIVES: In this study we compared outcomes and costs between three treatments options (mastectomy (MRM), breast conservation surgery with radiation (BCSRT), and breast conservation surgery only (BCSO)) for elderly women with localized breast cancer. METHODS: The sample was a national random sample from Medicare claims of 2,821 elderly women treated between 1992 to 1994 for localized breast cancer. Data on patient preferences were collected in patient interviews conducted in 1997. The outcomes studied were 5-year survival, Quality Adjusted Life Years (QALY), total costs and cost/QALY. For each outcome we used univariate, multivariate and instrumental variable analysis to compare the differences between treatments. The instrumental variables used were geographic region, and distance to nearest radiation facility. RESULTS: There were 1813 patients who received MRM, 704 who received BCSRT, and 304 who received BCSO. The multivariate analysis showed significantly higher survival for BCSRT relative to MRM (4.21 vs. 4.13) and significantly higher QALYs (3.50 vs. 3.45), but the IV analysis found an insignificant difference opposite in sign. Costs were significantly higher for BCSRT relative to MRM ($54,073 vs. $37,327 in multivariate analysis). The cost-effectiveness ratio of BCSRT relative to MRM is $334,920/QALY (CI:$80,000 to NW) per QALY using multivariate estimates and dominated using IV estimates. CONCLUSION: Survival and QALYs are statistically higher in traditional analyses of the BCSRT group relative to MRM, but the IV analysis suggests an upward bias due to the selection of healthier patients into BCSRT. This finding is consistent with previous studies. Costs are unequivocally higher in the BCSRT group suggesting BCSRT is not a cost-effective option relative to MRM. Supplemental analyses suggests that the presence of choice between MRM and BCSRT raises the quality of life for all elderly women independent of the choice that is made. Thus, choice is costly but valuable.