Use and spending on antineoplastic therapy for Medicare beneficiaries with cancer.

Background: Oral antineoplastic drugs, not generally covered by Medicare Part B, have assumed an increasingly important role in cancer treatment. Objective: We examined use and spending on infused/injected (Part B covered) and non-Part B antineoplastic agents in a Medicare beneficiary population with cancer, and the effect of supplemental insurance. Research Design: This retrospective, observational study used pooled 1997-2007 data from the Medicare Current Beneficiary Survey, linked to Medicare claims. Logistic regression models identified factors associated with antineoplastic use. Generalized linear models were used to estimate spending among antineoplastic users. Population studied: A total of 1836 Medicare beneficiaries with newly diagnosed cancer were selected based on the presence of claims-based diagnoses after a 12-month washout period. Results: Five hundred fifty-nine (31.0%) Medicare beneficiaries received antineoplastic therapy; 395 (21.3%) used Part B, 253 (14.6%) used non-Part B antineoplastics. Spending per user was $7841 (any), $10,364 (Part B), and $1535 for non-Part B antineoplastics. Supplemental insurance was associated with antineoplastic use. Primary cancer site and age were key predictors of spending among users. Spending on non-Part B antineoplastics increased during 2006-2007 relative to 2004-2005 but time trends were not significant in multivariate analysis. Conclusions: Antineoplastic therapy use by Medicare beneficiaries is sensitive to the presence but not type of supplemental insurance. Non-Part B therapy was used by a relatively large proportion of beneficiaries with cancer receiving therapy, although spending was less than for Part B therapy. Monitoring the role of supplemental insurance, and particularly the role of Medicare Part D is a critical area for ongoing research.