Stage IV prostate cancer: survival differences in clinical T4, nodal and metastatic disease

Purpose: In the prostate specific antigen era most prostate cancer presents at an early stage. However, a significant number of patients have advanced disease, including those with stage IV disease. Assignment to stage IV prostate cancer may occur by different modes, namely as T4N0M0 vs N1 vs M1 disease. We hypothesize that patients with clinical T4 disease have better outcomes than those with N1 or M1 disease.

Materials and methods: A total of 17 SEER registries were queried from 1995 through 2003. Multivariate and univariate analyses examined overall survival and prostate cancer specific survival across subcategories of stage IV disease while controlling for various patient and disease related characteristics.

Results: There were 615 patients with cT4N0M0 disease, 3,189 with TxN1M0 and 10,893 with TxNxM1 who met the study inclusion criteria. Survival differences were observed between cT4N0M0 and M1 cancer, between N1 and M1 disease, and were most pronounced in younger patients (age 50 years or younger), gradually narrowing with increasing patient age. Factors that demonstrated significant association with poor survival included higher tumor grade, unknown tumor grade and absence of a spouse.

Conclusions: Staging systems based on American Joint Committee on Cancer/TNM staging enables the grouping of patients into homogenous categories for treatment selection and prognostication. However, our data suggest that not all stage IV prostate cancers behave similarly. The difference in survival among locally advanced (T4), node positive and distantly metastatic stage IV prostate cancer appears to be dependent on patient age.