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Unbiased Outcome Estimates from Conservative vs. Aggressive Treatment of Early Stage Prostate Cancer from Retrospective Data: An Instrumental Variables Approach

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Final rept. 1 Oct 1998-31 Mar 2001

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Instrumental variables IV techniques were used to estimate the outcome differences between aggressive treatment and conservative management among marginal patients with early stage prostate cancer and determine what type of patients may be safely shifted from aggressive to conservative treatment. We demonstrated IV that group patients in groups that have different rates of aggressive treatment but do not differ in demographic, tumor, or co-morbidity characteristics, satisfying criteria for valid IV analyses. We demonstrated that, for a population of 100 patients, aggressive treatment of an additional 3 or 4 marginal patients would result in one more patient surviving three years. Patient characteristics and treatment patterns were contrasted across patients grouped by IV to describe the set of clinically localized prostate cancer patients at the practice margins for receiving aggressive treatment and who would benefit from increased utilization of aggressive treatments. We concluded that these are men aged 65-69 with co-morbidity and grade I tumors, aged 70-74 with no co-morbidity and grade I tumors, aged 65 to 74 with co-morbidity and with Phase IIIII tumors and age 75-84 with grade IIIII tumors regardless of co-morbidity. These patient groups coincide with theoretical predictions. Cost-effectiveness analyses and radiation vs. prostatectomy analyses will ensue.

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  • Medicine and Medical Research

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