A COST-EFFECTIVENESS ANALYSIS OF THERAPEUTIC OPTIONS FOR LOW RISK PROSTATE CANCER

Purpose: The optimal therapeutic approach for low-risk clinically-localized prostate cancer (CaP) is unknown:  over 50% of screen-detected men are overtreated and treatment is associated with significant side effects (SE).  This analysis examines the cost-effectiveness of radical prostatectomy (RP), radiation therapy (IMRT), brachytherapy (BT), proton beam therapy (PBT) and active surveillance (AS) in these men.

Method: A state transition model was constructed and analyzed using Monte Carlo simulation.  Men received treatment or AS and incurred SE for 1-2 y and costs until death of CaP/other cause.  Men on AS could elect therapy or be treated at progression (both with IMRT).  The base case used 65 yo men and included therapy and patient time costs.  Transition probabilities and utilities were developed from literature review.  Sensitivity analysis on key parameters was performed.  Main outcomes were costs (2008US$) and quality-adjusted life-years (QALYs), both discounted at 3%/y, and incremental cost-effectiveness ratios (ICERs). 

Result: AS was most effective, providing 8.58 QALYs at a cost of $30422. Compared to RP, AS provided an additional 9.1 mo of QALE at an added cost of $2074 (ICER $2729/QALY).  Among initial therapies, BT was most effective and least expensive, providing an additional 3.5 mo of QALE at a cost savings of $2743 vs. RP.  IMRT and PBT were more expensive than BT, RP, or AS. 

Strategy	Cost($)	Incremental Cost($)	QALYs	Incremental QALYs	ICER
BT	25,606	-	8.11	-	-
RP	28,348	2743	7.82	-0.29	Dominated(D)
AS	30,422	2074	8.58	0.76	$2729/QALY
IMRT	37,808	7386	8.09	-0.88	D
PBT	53,828	16,020	7.96	-0.13	D

Dominated: more expensive and less effective than BT Alternative Analyses.  AS followed by BT was more effective and less expensive than any initial therapy or AS followed by IMRT.  The relative risk of CaP-specific death would have to be 0.6 for therapy vs. AS for QALE to be equal.  Sensitivity Analysis (SA).  AS was most effective on SA including probability of SE, progressive disease on AS and utilities.  If IMRT cost was reduced to <$17000 AS was more effective and less expensive than initial therapy.

Conclusion: In this model, AS is associated with higher QALE than initial therapy and carries a minimal additional cost relative to RP or BT.  AS should be strongly considered in these patients.