Clinical staging of prostate cancer: Reproducibility and clarification of issues

The American Joint Committee on Cancer (AJCC) staging system for prostate c ancer adopted in 1992 is based on tumor-node-metastasis (TNM) designations. It has been widely accepted for use in local and advanced disease. The pur pose of this study was to assess reproducibility of staging among observers and to help clarify staging issues. Twelve prostate cancer cases were sent to 20 physicians with special expertise in prostate cancer including eight urologists, eight radiation oncologists, and four medical oncologists. Phy sicians were asked to assign a stage based on the 1992 AJCC clinical stagin g. The most frequently reported stage assigned to each case was taken to be the consensus. Agreement was the percentage of physicians who reported tha t particular stage. Seventy-five percent of the physicians responded. The o verall agreement for assignment of T stage was 63.9%. Differences were foun d by specialty for inclusion of available information in designating a T st age. The overall agreement for N stage was 73.8%. The most common designati on was Nx regardless of availability of a computed tomography scan. The ove rall agreement for M stage was 76.6%. Without a bone scan the most common d esignation was Mr regardless of Gleason grade or prostate-specific antigen (PSA). A frequent comment was that PSA was more indicative of disease exten t than current clinical staging. The reproducibility of the 1992 clinical A JCC staging is poor even among experts in the field. This problem arises pr imarily from disagreement regarding which studies are included in assigning a stage. Some of these difficulties are addressed in the 1997 revision. Ho wever, the clinical staging does not address the true biological. significa nce of disease in many instances. (C) 2001 Wiley-Liss, Inc.