Determination of prognosis in patients with prostate cancer treated with radical prostatectomy: prognostic value of CD44v6 score.

A third of the patients treated with radical prostatectomy experience progression even when tumors are confined pathologically to the prostate. CD44 may be a promising prognostic marker for determining malignant potential. However, there has not been a standard scoring system because of its heterogeneous staining pattern. Thus, we developed an objective scoring system to evaluate reliably CD44v6 (Bender Medsystems, Vienna, Austria) as a prognostic marker for prostate cancer. A total of 22 patients with metastatic stage pT3bN0M0 or any pTN1M0 disease and 18 with nonmetastatic disease less than stage pT3bN0M0 were selected from a well examined group of 114 who underwent radical retropubic prostatectomy. Mean followup was 33 months (range 4 to 78). A combined CD44v6 score was determined by adding the scores of the primary and secondary areas. CD44v6 expression in terms of the CD44v6 score in primary and metastatic tissues was examined. The relationships of CD44v6 expression with pathological stage, progression and PSA-free survival were also evaluated. The prognostic value of the CD44v6 score for progression was analyzed by multivariate analysis. Progression in the metastatic group was significantly higher than in the nonmetastatic group (p <0.0001). CD44v6 expression of the primary tumors differed significantly in the 2 groups (p = 0.014). The CD44v6 score in primary tumor tissues inversely correlated with pathological stage (p = 0.004) and progression (p = 0.035), and positively correlated with PSA-free survival (p = 0.041). Furthermore, patients in the nonmetastatic group with a CD44v6 score of greater than 75 (cutoff value) had a significantly better prognosis (log rank test p = 0.0022), while those with a CD44v6 score of less than 75 had a prognosis similar to those in the metastatic group. On multivariate analysis pathological stage and surgical margin positivity were independent factors for progression but the CD44v6 score was not. According to our results the suggested CD44v6 score system is useful. A CD44v6 score of less than 75 may be a predictor of poor prognosis in the nonmetastatic group and this property may have potential application for planning adjuvant therapy.