Cost-Benefit Analysis of Post-Lumpectomy Treatment in Elderly Women.

Abstract

Introduction In this era of rising cost of medical care, it is difficult to decide how to treat patients (pts). Specifically, with elderly pts who have small breast cancers (BC), there are many options. The NSABP B21 study looked at the need for breast radiotherapy (RT) after lumpectomy in node - pts with invasive BC <=1 cm, by speculation that tamoxifen (tam) might be as effective as radiotherapy (RT) in reducing in breast tumor recurrence (IBTR). Pts were randomly assigned to tam, RT/placebo or RT/tam. IBTR rates were similar in the 2 groups of pts aged >=70 who received tam or RT alone. The CALGB also looked at this question in pts >= 70 with stage 1, node -, ER+ BC by randomly assigning them to tam or tam/RT. The only difference between the 2 groups was the rate of IBTR, which was 1% in the tam/RT group and 4% in the tam group. There was no differences in mastectomy for local recurrences, distant metastases, or 5 year OS. With the addition of aromatase inhibitors (AI), the IBTR rate in this cohort would be smaller. Based on these studies, we undertook a cost-benefit analysis of RT vs tam vs AI in pts >=70 with node -, ER+, stage 1 BC.MethodsThe 3 adjuvant treatment (tx) methods considered were conventional whole breast RT (28 fractions) alone, anastrozole (1mg Qday x 5 years), & tam (20mg Qday x 5 yrs). Rates of IBTRs were extrapolated from the CALGB 5 year data as a basis, the NSABP B21 trial relative risks (9.3% RT alone vs 16.5% Tam alone), & the ATAC trial relative risks (1.5% RT+Tam vs 1.0% RT+AI). Rates of contralateral breast cancers (CBC) were similarly estimated. Costs of outpatient tx was estimated using Medicare Part B reimbursements as a surrogate. Drug costs were taken from prices from Drugstore.com. All breast failures (CBC + IBTRs) were assumed treated with mastectomy alone. Costs associated with mastectomy were estimated using Medicare Part B reimbursements for surgical costs and associated Part A inpatient prospective payments. Total cost for each tx was calculated by the formula C = FC + TC, where C= total cost, FC= failure associated cost (failure rate x mastectomy cost), and TC = tx cost.ResultsThe results for estimation of failure rates at 5 years is shown in Table 1.Table 1 IBTRCBCTotal Breast FailuresRT alone2.25%3.07%5.32%AI alone2.67%0.74%3.41%Tam Alone4.00%1.25%5.25% The cost of mastectomy was $10,037.08.The results for total cost are shown in Table 2.Table 2 Treatment CostFailure Associated CostTotal CostRT alone$11,717.70$533.97$12,251.67AI alone$18,645.14$342.26$18,987.40Tam alone$1,013.28$526.95$1,540.23 DiscussionWe consider costs of initial tx and tx of local failure. Tam alone would be the tx of choice if simply considering this total cost. However, if side effects associated with each tx is considered, then the cost for each would need to be increased accordingly. For example, in NSABP P1 trial, 3 pts died from PE on tam. If a cost were estimated for these deaths (beyond the scope of this abstract), the total cost for tam would be much higher.ConclusionsThe results from adjuvant tx after breast conserving surgery in older women with early stage BC have been excellent. In an era of steadily increasing health care costs, the cost-to-benefit ratio should be one of the factors taken into consideration when deciding tx options. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1074.