Validation of the prognostic grouping of the seventh edition of the tumor-nodes-metastasis classification using a large-scale prospective cohort study database of prostate cancer treated with primary androgen deprivation therapy.
OBJECTIVE
In the TNM seventh edition, a prognostic grouping for prostate cancer incorporating prostate-specific antigen and Gleason score was advocated. The present study was carried out to evaluate and validate prognostic grouping in prostate cancer patients.


METHODS
The 15 259 study patients treated with primary androgen deprivation therapy were enrolled in the Japan Study Group of Prostate Cancer. Overall survival was stratified by tumor-nodes-metastasis, Gleason score and prostate-specific antigen, and extensively analyzed. The accuracy of grouping systems was evaluated by the concordance index.


RESULTS
The 5-year overall survival in prognostic grouping-I, IIA, IIB, III and IV was 90.0%, 88.3%, 84.8%, 80.6% and 57.1%, respectively. When considering subgroup stratification, the 5-year overall survival of subgroups prognostic grouping-IIA, IIB, III and IV was 80.9∼90.5%, 75.4∼91.8%, 75.7∼89.0% and 46.9∼86.2%, respectively. When prognostic grouping-IIB was subclassified into IIB1 (except IIB2) and IIB2 (T1-2b, prostate-specific antigen >20, Gleason score ≥8, and T2c, Gleason score ≥8), the 5-year overall survival of IIB2 was significantly lower than that of IIB1 (79.4% and 87.3%, P < 0.0001). Also, when prognostic grouping-IV was subclassified into IV1 (except IV2) and IV2 (M1, prostate-specific antigen >100 or Gleason score ≥8), the 5-year overall survival of prognostic grouping-IV1 was superior to that of IV2 (72.9% and 49.5%, P < 0.0001). Prognostic groupings were reclassified into modified prognostic groupings, divided into modified prognostic grouping-A (prognostic grouping-I, IIA, and IIB1), modified prognostic grouping-B (prognostic grouping-IIB2 and III), modified prognostic grouping-C (prognostic grouping-IV1) and modified prognostic grouping-D (prognostic grouping-IV2). The concordance index of prognostic grouping and modified prognostic grouping for overall survival was 0.670 and 0.685, respectively.


CONCLUSIONS
Prognostic grouping could stratify the prognosis of prostate cancer patients. However, there is considerable variation among the prognostic grouping subgroups. Thus, the use of a modified prognostic grouping for patients treated with primary androgen deprivation therapy is advisable.
Department of Urology, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.
Tomokazu
T
Kimura
Mizuki
M
Onozawa
Jun
J
Miyazaki
Koji
K
Kawai
Hiroyuki
H
Nishiyama
Shiro
S
Hinotsu
Hideyuki
H
Akaza
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000726:Androgen Antagonists / Q000627:therapeutic use*; D003953:Diagnosis-Related Groups / Q000145:classification* / Q000592:standards*; D006801:Humans; D007564:Japan / Q000453:epidemiology; D007610:Kallikreins / Q000097:blood; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011379:Prognosis; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000401:mortality* / Q000556:secondary*; D012307:Risk Factors; D016896:Treatment Outcome
D000726:Androgen Antagonists; C549870:KLK3 protein, human; D007610:Kallikreins; D017430:Prostate-Specific Antigen
neoplasms staging; primary androgen deprivation therapy; prognostic grouping; prostate; validation studies