FOLLOW-UP PROSTATE-CANCER TREATMENTS AFTER RADICAL PROSTATECTOMY - A POPULATION-BASED STUDY

Background: Radical prostatectomy is one of the most commonly used cur ative procedures for the treatment of localized prostate cancer. The p robability that a patient will undergo additional cancer therapy after this procedure is largely unknown. Purpose: The objective was to dete rmine the likelihood of additional cancer therapy after radical prosta tectomy. Methods: Data for this study were derived from a linked datas et that combined information from the Surveillance, Epidemiology, and End Results Program and Medicare hospital and physician claims. Record s were included in this study if patient histories met the following c riteria: (a) residing in Connecticut, Washington (Seattle-Puget Sound) , or Georgia (Metropolitan Atlanta); (b) having been diagnosed with pr ostate cancer during the period from January 1, 1985, through December 31, 1991; (c) undergoing radical prostatectomy by December 31, 1992; and (d) having no evidence of other types of cancer. Patients were con sidered to have had additional cancer therapy if they had had radiatio n therapy, orchiectomy, and/or androgen-deprivation therapy by injecti on after radical prostatectomy. The interval between the initial treat ment and any follow-up treatment was calculated from the date of radic al prostatectomy to the Ist day of the follow-up cancer therapy. All p resented probabilities are based on Kaplan-Meier estimates. Results: T he study population consisted of 3494 Medicare patients, 3173 of whom underwent radical prostatectomy within 3 months of prostate cancer dia gnosis. Although radical prostatectomy is often reserved for localized cancer, less than 60% (1934) of patients whose records were included in this study had organ-confined disease, according to final surgical pathology. Overall, the 5-year cumulative incidence of having any addi tional cancer treatment after radical prostatectomy reached 34.9% (95% confidence interval [CI] = 31.5% -38.5%). For patients with pathologi cally organ-confined cancer, the 5-year cumulative incidence was 24.3% (95% CI = 20.0%-29.3%) overall and ranged from 15.6% (95% CI = 9.7%-2 4.5%) for well-differentiated cancer (Gleason scores 2-4) to 41.5% (95 % CI = 27.9%-58.4%) for poorly differentiated cancer (Gleason scores 8 -10). The corresponding figures for pathologically regional cancer wer e 22.7% (95% CI = 12.9%-40.5%) and 68.1% (95% CI = 58.7%-77.1%). Concl usion: Further treatment of prostate cancer was done in about one thir d of patients who had had a radical prostatectomy with curative intent and in about one quarter of patients who were found to have organ-con fined disease. Implications: Given the common requirement for follow-u p cancer treatments after radical prostatectomy and the uncertainties about the effectiveness of the various follow-up treatment strategies, further investigation of these treatments is warranted.