Time trends and local variation in primary treatment of localized prostate cancer

Abstract

PURPOSE In the absence of high-level evidence or clinical guidelines supporting any given active treatment approach over another for localized prostate cancer, clinician and patient preferences may lead to substantial variation in treatment use. METHODS Data were analyzed from 36 clinical sites that contributed data to the Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE) registry. Distribution of primary treatment use was measured over time. Prostate cancer risk was assessed using the D'Amico risk groups and the Cancer of the Prostate Risk Assessment (CAPRA) score. Descriptive analyses were performed, and a hierarchical model was constructed that controlled for year of diagnosis, cancer risk variables, and other patient factors to estimate the proportion of variation in primary treatment selection explicable by practice site. Results Among 11,892 men analyzed, 6.8% elected surveillance, 49.9% prostatectomy, 11.6% external-beam radiation, 13.3% brachytherapy, 4.0% cryoablation, and 14.4% androgen deprivation monotherapy. Prostate cancer risk drives treatment selection, but the data suggest both overtreatment of low-risk disease and undertreatment of high-risk disease. The former trend appears to be improving over time, while the latter is worsening. Treatment varies with age, comorbidity, and socioeconomic status. However, treatment patterns vary markedly across clinical sites, and this variation is not explained by case-mix variability or known patient factors. Practice site explains a proportion of this variation ranging from 13% for androgen deprivation monotherapy to 74% for cryoablation. CONCLUSION Substantial variation exists in management of localized prostate cancer that is not explained by measurable factors. A critical need exists for high-quality comparative effectiveness research in localized prostate cancer to help guide treatment decision making.

Fig 1.

Treatment patterns by risk level. Treatment distribution at each level of risk as measured by the Cancer of the Prostate Risk Assessment (CAPRA) score is illustrated. Treatment trends by risk group were statistically significant by Mantel-Haenszel χ² test, P < .001. WW, watchful waiting/active surveillance; RP, radical prostatectomy; Brachy, brachytherapy; EBRT, external-beam radiation therapy; Cryo, cryoablation; PADT, primary androgen deprivation therapy.

Fig 2.

Treatment trends over time by risk group. Changes over time in primary treatment patterns across all practice sites, by risk groups defined by categorized Cancer of the Prostate Risk Assessment (CAPRA) scores. Trends over time for each risk group were statistically significant by Mantel-Haenszel χ² test, P < .001. WW, watchful waiting; RP, radical prostatectomy; Brachy, brachytherapy; EBRT, external-beam radiation therapy; Cryo, cryoablation; PADT, primary androgen deprivation therapy.

Fig 3.

Treatment variation among practice sites. Primary treatment distribution from 1990 to 2006 at each clinical site for patients with localized prostate cancer. Sites had at least 30 patients. Clinical sites are arranged in order of increasing average disease risk as assessed by the mean Cancer of the Prostate Risk Assessment (CAPRA) score for that site (listed on x-axis). WW, watchful waiting; RP, radical prostatectomy; Brachy, brachytherapy; EBRT, external-beam radiation therapy; Cryo, cryoablation; PADT, primary androgen deprivation therapy.