Differences in Prostate Cancer Grade, Stage, and Location in Radical Prostatectomy Specimens from United States and Japan
Hiroyuki Takahashi, Jonathan I Epstein, Shin Wakui, Toshihiro Yamamoto, Bungo Furusato, Miao Zhang. Jikei University School of Medicine, Tokyo, Japan; Johns Hopkins Hospital, Baltimore, MD
Background: Although it is recognized that prostate cancer is different in Japanese and North American men, there have been few histological studies comparing prostate cancer at radical prostatectomy between the two groups in the modern era.
Design: 373 consecutive totally embedded RP cases (162 US; 211 Japan) from 2012 were reviewed. In addition to routine parameters, tumor location (peripheral zone vs. transition zone) and tumor volume was recorded. Tumor volume was calculated by 4/3Πx(L/2)x(W/2)x(H/2) which is the measurement of a scalene ellipsoid.
Results: United States men were significantly younger (mean age 58.7y) than Japanese (mean age 64.6y) (p< 0.00001). Japanese tumors were characterized by: higher grade; larger volume; more advanced stage; increased lymphovascular invasion; and more likely to originate in the transition zone. In multivariate analysis, independent predictors of high tumor volume were Gleason grade and country of origin (Japan).
|Radical Prostatectomy Findings||United States||Japan||p-value|
|Gleason Score 3+3=6||41.4%||12.3%|
|Gleason Score 3+4=7||36.4%||47.4%|
|Gleason Score 4+3=7||12.4%||19.4%|
|Gleason Score 4+4=8||4.9%||4.3%||Overall Grade Difference|
|Gleason Score 9 or 10||4.9%||16.6%||<0.00001|
|pT3a: Extra-prostatic Extension/SV &LN Negative||25.3%||50%||<0.00001|
|pT3b: Seminal Vesicle Invasion &LN Negative||3.3%||10%||<0.00001|
|Lymph Node (LN) Metastases||1.3%||7.4%||<0.00001|
|Soley TZ Location||0.6%||41.8%||<0.00001|