MP48-15 EVALUATION OF POTENTIAL BIAS IN RISK FACTOR ASSESSMENT IN THE CANARY PROSTATE ACTIVE SURVEILLANCE STUDY (PASS) (2019)

You have accessJournal of UrologyProstate Cancer: Localized: Active Surveillance I (MP48)1 Apr 2019MP48-15 EVALUATION OF POTENTIAL BIAS IN RISK FACTOR ASSESSMENT IN THE CANARY PROSTATE ACTIVE SURVEILLANCE STUDY (PASS) Lisa Newcomb*, Yingye Zheng, Anna Faino, Jeannette Schenk, James Brooks, Matthew Cooperberg, Atreya Dash, Martin Gleave, Michael Liss, Frances Martin, Todd Morgan, Peter Nelson, Andrew Wagner, Ian Thompson, and Daniel Lin Lisa Newcomb*Lisa Newcomb* More articles by this author , Yingye ZhengYingye Zheng More articles by this author , Anna FainoAnna Faino More articles by this author , Jeannette SchenkJeannette Schenk More articles by this author , James BrooksJames Brooks More articles by this author , Matthew CooperbergMatthew Cooperberg More articles by this author , Atreya DashAtreya Dash More articles by this author , Martin GleaveMartin Gleave More articles by this author , Michael LissMichael Liss More articles by this author , Frances MartinFrances Martin More articles by this author , Todd MorganTodd Morgan More articles by this author , Peter NelsonPeter Nelson More articles by this author , Andrew WagnerAndrew Wagner More articles by this author , Ian ThompsonIan Thompson More articles by this author , and Daniel LinDaniel Lin More articles by this author View All Author Informationhttps://doi.org/10.1097/01.JU.0000556449.83860.b5AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVES: In active surveillance (AS), disease progression as defined by pathology can only be ascertained at follow-up biopsy. However, clinical factors could also influence the timing of biopsy. We evaluated the impact of potential ascertainment bias in in a well-established prospective AS cohort. METHODS: Data were from the multicenter Canary PASS, in which protocol-directed biopsies are performed 6-12 months and 24 months from diagnosis, and then every 2 years, and PSA is measured every 3 months. To evaluate potential bias, we first defined windows, or date ranges, for on-time (compliant) surveillance biopsies. To determine whether factors were associated with the interval of surveillance biopsy, biopsy timing (on-time, early, or late) was regressed on clinical and prior biopsy variables using multinomial regression models. Probabilities for participants having all on-time biopsies were derived from the models. We reanalyzed a published study evaluating the association of PSA kinetics (PSAk) with biopsy reclassification using Cox proportional hazards modeling. Model coefficients were compared in the full cohort and subsets of compliant participants both with and without weighting for the propensity for compliance. RESULTS: In 851 men with 1750 biopsies, 78% of surveillance biopsies were on-time, 11% were early and 11% were late. 805 men had at least one surveillance biopsy on time, and 562 had all surveillance biopsies on time. After adjustment for prostate size, time since diagnosis, cores with cancer and prior negative biopsies, PSAk was associated with biopsy reclassification (HR=1.61 (95% CI: 1.25-2.09) in the full cohort, but was also found to be associated with biopsy timing. In multivariable models of PSAk in participants with all biopsies on time, both without and with the propensity adjustment, PSAk was still associated with reclassification [HR=2.09 (95% CI: 1.45-3.02) and HR=2.17 (95% CI: 1.45-2.93), respectively]. CONCLUSIONS: In the Canary PASS cohort, compliance to the protocol-directed biopsy schedule was high. Applying propensity weights to account for potential ascertainment bias, we demonstrated that despite its association with biopsy timing, PSA kinetics remains independently associated with reclassification. We recommend that studies evaluating risk factors in AS should consider potential ascertainment bias and utilize methods to evaluate how this bias can influence endpoint ascertainment. Source of Funding: Canary Foundation DoD W81XWH1410595 Seattle, WA; Stanford, CA; San Francisco, CA; Seattle, WA; Vancouver, Canada; San Antonio, TX; Virginia Beach, VA; Ann Arbor, MI; Seattle, WA; Boston, MA; San Antonio, TX; Seattle, WA© 2019 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 201Issue Supplement 4April 2019Page: e703-e703 Advertisement Copyright & Permissions© 2019 by American Urological Association Education and Research, Inc.MetricsAuthor Information Lisa Newcomb* More articles by this author Yingye Zheng More articles by this author Anna Faino More articles by this author Jeannette Schenk More articles by this author James Brooks More articles by this author Matthew Cooperberg More articles by this author Atreya Dash More articles by this author Martin Gleave More articles by this author Michael Liss More articles by this author Frances Martin More articles by this author Todd Morgan More articles by this author Peter Nelson More articles by this author Andrew Wagner More articles by this author Ian Thompson More articles by this author Daniel Lin More articles by this author Expand All Advertisement PDF downloadLoading ...