This Article  • Full text  • PDF  • Send to a friend  • Save in My Folder  • Save to citation manager  • Permissions  Citing Articles  • Contact me when this article is cited  Related Content  • Similar articles in JAMA  Topic Collections  • Men's Health  • Prostate Disease  • Oncology  • Prostate Cancer  • Diagnosis  • Alert me on articles by topic  Social Bookmarking   What's this?

	Since this article does not have an abstract, we have provided the first 150 words of the full text and any section headings.

In Reply: We are pleased that our results, with 65.2% biopsy verification, confirmed the operating characteristics of PSA reported by Dr Punglia and colleagues¹ from a study sample with 10.5% verification. While we agree that there is no evidence of violation of the mathematical requirements for applying the Begg and Greenes verification bias adjustment algorithm² at face value, we do have concerns about this.

With correct inference obtainable from a sample with nearly 90% of the true outcome missing, it is tempting to extend the algorithm of Begg and Greenes, developed initially only for a dichotomous test, to large cohorts with continuous tests from screening studies, which may have few verified samples in the lower range of test results. We are cautious about this extension for 2 reasons. First, a third requirement in Begg and Greenes is a model that accurately predicts probability of disease in the unverified cases. Second, . . . [Full Text of this Article]

Donna Pauler Ankerst, PhD; Chen Chi, MS
Fred Hutchinson Cancer Research Center
Seattle, Wash

Ian M. Thompson, MD
thompsoni@uthscsa.edu
Division of Urology
University of Texas Health Science Center
San Antonio

CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter     What's this?