Daniel C. Danila, Johann S. de Bono, Mateus Crespo, David Olmos, Ines Figueiredo, Kurt Baeten, George Seed, Robert T. McCormack, Arturo Molina, Susana Miranda, Thian Kheoh, Howard I. Scher, Penny Flohr, Diletta Bianchini, Leon W.M.M. Terstappen, David Lorente, Joaquin Mateo, Martin Fleisher, [Lorente, David] Royal Marsden NHS Fdn Trust, Prostate Canc Targeted Therapy Grp, Sutton, Surrey, England, [Mateo, Joaquin] Royal Marsden NHS Fdn Trust, Prostate Canc Targeted Therapy Grp, Sutton, Surrey, England, [Bianchini, Diletta] Royal Marsden NHS Fdn Trust, Prostate Canc Targeted Therapy Grp, Sutton, Surrey, England, [Seed, George] Royal Marsden NHS Fdn Trust, Prostate Canc Targeted Therapy Grp, Sutton, Surrey, England, [Flohr, Penny] Royal Marsden NHS Fdn Trust, Prostate Canc Targeted Therapy Grp, Sutton, Surrey, England, [Crespo, Mateus] Royal Marsden NHS Fdn Trust, Prostate Canc Targeted Therapy Grp, Sutton, Surrey, England, [Figueiredo, Ines] Royal Marsden NHS Fdn Trust, Prostate Canc Targeted Therapy Grp, Sutton, Surrey, England, [Miranda, Susana] Royal Marsden NHS Fdn Trust, Prostate Canc Targeted Therapy Grp, Sutton, Surrey, England, [de Bono, Johann S.] Royal Marsden NHS Fdn Trust, Prostate Canc Targeted Therapy Grp, Sutton, Surrey, England, [Lorente, David] Inst Canc Res, Sutton, Surrey, England, [Mateo, Joaquin] Inst Canc Res, Sutton, Surrey, England, [Bianchini, Diletta] Inst Canc Res, Sutton, Surrey, England, [Seed, George] Inst Canc Res, Sutton, Surrey, England, [Flohr, Penny] Inst Canc Res, Sutton, Surrey, England, [Crespo, Mateus] Inst Canc Res, Sutton, Surrey, England, [Figueiredo, Ines] Inst Canc Res, Sutton, Surrey, England, [Miranda, Susana] Inst Canc Res, Sutton, Surrey, England, [de Bono, Johann S.] Inst Canc Res, Sutton, Surrey, England, [Olmos, David] Spanish Natl Canc Res Ctr CNIO, Prostate Canc Clin Res Unit, Madrid, Spain, [Fleisher, Martin] Mem Sloan Kettering Canc Ctr, 1275 York Ave, New York, NY 10021 USA, [Danila, Daniel C.] Mem Sloan Kettering Canc Ctr, 1275 York Ave, New York, NY 10021 USA, [Scher, Howard I.] Mem Sloan Kettering Canc Ctr, 1275 York Ave, New York, NY 10021 USA, [Baeten, Kurt] Janssen Diagnost, Med Affairs, Beerse, Belgium, [Molina, Arturo] Janssen Res & Dev, Menlo Pk, CA USA, [McCormack, Robert] Janssen Res & Dev, Menlo Pk, CA USA, [Kheoh, Thian] Janssen Res & Dev, La Jolla, CA USA, [Terstappen, Leon W. M. M.] Univ Twente, MIRA Res Inst Biomed Technol & Tech Med, Twente, Netherlands, [Lorente, David] Hosp Univ La Fe, Med Oncol Serv, Valencia, Spain, [Olmos, David] Hosp Univ Virgen de la Victoria, CNIO IBIMA Genitourinary Canc Unit, Dept Med Oncol, Malaga, Spain, [Olmos, David] Hosp Univ Reg Malaga, CNIO IBIMA Genitourinary Canc Unit, Dept Med Oncol, Malaga, Spain, Movember/Prostate Cancer UK Centre of Excellence Program grant, FP7 EU grant, Medical Research Council, MRC, NATIONAL CANCER INSTITUTE, Medical Cell Biophysics, and Faculty of Science and Technology
Background: Treatment response biomarkers are urgently needed for castration-resistant prostate cancer (CRPC). Baseline and post-treatment circulating tumor cell (CTC) counts of >= 5 cells/7.5 ml are associated with poor CRPC outcome.Objective: To determine the value of a >= 30% CTC decline as a treatment response indicator.Design, setting, and participants: We identified patients with a baseline CTC count >= 5 cells/7.5 ml and evaluable post-treatment CTC counts in two prospective trials.Intervention: Patients were treated in the COU-AA-301 (abiraterone after chemotherapy) and IMMC-38 (chemotherapy) trials.Outcome measures and statistical analysis: The association between a >= 30% CTC decline after treatment and survival was evaluated using univariable and multivariable Cox regression models at three landmark time points (4, 8, and 12 wk). Model performance was evaluated by calculating the area under the receiver operating characteristic curve (AUC) and c-indices.Results: Overall 486 patients (122 in IMMC-38 and 364 in COU-AA-301) had a CTC count >= 5 cells/7.5 ml at baseline, with 440, 380, and 351 patients evaluable at 4, 8, and 12 wk, respectively. A 30% CTC decline was associated with increased survival at 4 wk (hazard ratio [HR] 0.45, 95% confidence interval [CI] 0.36-0.56; p = 5 cells/7.5 ml are associated with poor CRPC outcome.Objective: To determine the value of a >= 30% CTC decline as a treatment response indicator.Design, setting, and participants: We identified patients with a baseline CTC count >= 5 cells/7.5 ml and evaluable post-treatment CTC counts in two prospective trials.Intervention: Patients were treated in the COU-AA-301 (abiraterone after chemotherapy) and IMMC-38 (chemotherapy) trials.Outcome measures and statistical analysis: The association between a >= 30% CTC decline after treatment and survival was evaluated using univariable and multivariable Cox regression models at three landmark time points (4, 8, and 12 wk). Model performance was evaluated by calculating the area under the receiver operating characteristic curve (AUC) and c-indices.Results: Overall 486 patients (122 in IMMC-38 and 364 in COU-AA-301) had a CTC count >= 5 cells/7.5 ml at baseline, with 440, 380, and 351 patients evaluable at 4, 8, and 12 wk, respectively. A 30% CTC decline was associated with increased survival at 4 wk (hazard ratio [HR] 0.45, 95% confidence interval [CI] 0.36-0.56; p = 30% CTC decline as a treatment response indicator.Design, setting, and participants: We identified patients with a baseline CTC count >= 5 cells/7.5 ml and evaluable post-treatment CTC counts in two prospective trials.Intervention: Patients were treated in the COU-AA-301 (abiraterone after chemotherapy) and IMMC-38 (chemotherapy) trials.Outcome measures and statistical analysis: The association between a >= 30% CTC decline after treatment and survival was evaluated using univariable and multivariable Cox regression models at three landmark time points (4, 8, and 12 wk). Model performance was evaluated by calculating the area under the receiver operating characteristic curve (AUC) and c-indices.Results: Overall 486 patients (122 in IMMC-38 and 364 in COU-AA-301) had a CTC count >= 5 cells/7.5 ml at baseline, with 440, 380, and 351 patients evaluable at 4, 8, and 12 wk, respectively. A 30% CTC decline was associated with increased survival at 4 wk (hazard ratio [HR] 0.45, 95% confidence interval [CI] 0.36-0.56; p = 5 cells/7.5 ml and evaluable post-treatment CTC counts in two prospective trials.Intervention: Patients were treated in the COU-AA-301 (abiraterone after chemotherapy) and IMMC-38 (chemotherapy) trials.Outcome measures and statistical analysis: The association between a >= 30% CTC decline after treatment and survival was evaluated using univariable and multivariable Cox regression models at three landmark time points (4, 8, and 12 wk). Model performance was evaluated by calculating the area under the receiver operating characteristic curve (AUC) and c-indices.Results: Overall 486 patients (122 in IMMC-38 and 364 in COU-AA-301) had a CTC count >= 5 cells/7.5 ml at baseline, with 440, 380, and 351 patients evaluable at 4, 8, and 12 wk, respectively. A 30% CTC decline was associated with increased survival at 4 wk (hazard ratio [HR] 0.45, 95% confidence interval [CI] 0.36-0.56; p = 30% CTC decline after treatment and survival was evaluated using univariable and multivariable Cox regression models at three landmark time points (4, 8, and 12 wk). Model performance was evaluated by calculating the area under the receiver operating characteristic curve (AUC) and c-indices.Results: Overall 486 patients (122 in IMMC-38 and 364 in COU-AA-301) had a CTC count >= 5 cells/7.5 ml at baseline, with 440, 380, and 351 patients evaluable at 4, 8, and 12 wk, respectively. A 30% CTC decline was associated with increased survival at 4 wk (hazard ratio [HR] 0.45, 95% confidence interval [CI] 0.36-0.56; p = 5 cells/7.5 ml at baseline, with 440, 380, and 351 patients evaluable at 4, 8, and 12 wk, respectively. A 30% CTC decline was associated with increased survival at 4 wk (hazard ratio [HR] 0.45, 95% confidence interval [CI] 0.36-0.56; p = 5 cells/7.5 ml and a 30% CTC decline had similar overall survival in both arms.Conclusions: A 30% CTC decline after treatment from an initial count >= 5 cells/7.5 ml is independently associated with CRPC overall survival following abiraterone and chemotherapy, improving the performance of a multivariable model as early as 4 wk after treatment. This potential surrogate must now be prospectively evaluated.Patient summary: Circulating tumor cells (CTCs) are cancer cells that can be detected in the blood of prostate cancer patients. We analyzed changes in CTCs after treatment with abiraterone and chemotherapy in two large clinical trials, and found that patients who have a decline in CTC count have a better survival outcome. (C) 2016 European Association of Urology. Published by Elsevier B.V.