Definition of castration-resistant prostate cancer.
Castrate serum levels of testosterone (testosterone <50 ng/dl or <1.7 nmol/l).
Three consecutive rises of prostate-specific antigen (PSA), 1 week apart, resulting in 2.5% increases over the nadir, with a PSA >2.
PSA progression either antiandrogen withdrawal for at least 4 weeks for flutamide and 6 weeks for bicalutamide or secondary hormonal manipulation.
Progression or appearance of two or more lesions on bone scan or soft tissue lesions using Response Evaluation Criteria in Solid Tumors (RECIST) and with nodes >2 cm in diameter.
RECIST criteria are inadequate for measuring response in PCa, while bone scans, in particular, are suboptimal in distinguishing response to therapy and tumor progression. For this reason, The Prostate Cancer Clinical Trials Working Group has defined radiological progression as the development of two or more lesions on bone scan compared with prior scan and requires additional confirmation on a subsequent scan .