Purpose: To assess the cost-effectiveness of radiation therapy (RT) in patients with ductal carcinoma in situ (DCIS) after breast-conserving surgery (BCS).
Methods and materials: A Markov model was constructed for a theoretical cohort of 55-year-old women with DCIS over a life-time horizon. Probability estimates for local noninvasive (N-INV), local invasive (INV), and distant recurrences were obtained from National Surgical Adjuvant Breast and Bowel Project (NSABP) B-17. Utilities for eight nonmetastatic health states were collected from both healthy women and DCIS patients. Direct medical (2002 Medicare fee schedule) and nonmedical costs (time and transportation) of RT were ascertained.
Results: For BCS + RT vs. BCS alone, the estimated N-INV and INV rates at 12 years were 9% and 8% vs. 16% and 18%, respectively. The incremental cost of adding RT was 3300 US dollars despite an initial RT cost of 8700 US dollars due to higher local recurrence-related salvage costs incurred with the BCS alone strategy. An increase of 0.09 quality-adjusted life-years (QALYs) primarily reflected the lower risk of INV with RT, resulting in an incremental cost-effectiveness ratio (ICER) of 36,700 US dollars/QALY. Sensitivity analyses revealed the ICER to be affected by baseline probability of a local recurrence, relative efficacy of RT in preventing INV, negative impact of an INV on quality of life, and cost of initial RT. Cost of salvage BCS + RT and source of utilities (healthy women vs. DCIS patients) influenced the ICER albeit to a lesser degree.
Conclusions: Addition of RT following BCS for patients with DCIS should not be withheld because of concerns regarding its cost-effectiveness.