Assessing the cost-effectiveness of postmastectomy radiation therapy

To assess the cost-effectiveness of postmastectomy local-regional radiation therapy (RT) for patients with breast cancer with regard to local-regional relapse (LRR) and quality-adjusted life years (QALY).

Data from the literature are used to estimate the risk of LRR, and the impact of RT on the risk of LRR and survival. The risk of LRR is related linearly to the number of positive axillary nodes 1% rate of LRR = 10 + (4 x number of positive nodes)]. RT reduces the risk of LRR by 67%. LRRs are treated with excision or biopsy followed by RT; half being controlled locally and half receiving additional salvage surgery and chemotherapy. Absolute improvements in 10-year overall survival due to RT are assumed to vary between 1 and 12%; and accrue linearly during the initial 10-year follow-up period. Professional and technical charges are used as a surrogate for costs. Money spent and benefits recognized in future years are discounted to 1997 values using a 3% annual rate. Quality factors are used to adjust for treatment, disease, and toxicity status.

The cost per LRR prevented with the addition of routine postmastectomy RT is highly dependent upon the number of positive axillary nodes and ranges from $100,000-$200,000 for patients with 0-2 nodes, and $25,000-$75,000 for > or = 4 nodes. The cost per QALY gained at 10 years is $10,000-$110,000 for survival benefits > or = 3%.

The cost per LRR prevented decreases with increasing numbers of positive axillary nodes. There is not a sharp cutoff at the < or = 3 vs. > or = 4 lymph node number, suggesting that using this cutoff for recommending or not recommending RT following mastectomy is not economically logical. The cost per QALY of $10,000-$100,000 compares favorably to that of other accepted medical procedures. Modest changes in the quantitative assumptions do not qualitatively alter the results. Concerns regarding costs should not generally preclude the use of postmastectomy RT.