Immunohistochemical study of chromogranin A in Stage D2 prostate cancer

To study the clinical and pathologic factors that affect the time to recurrence after hormonal therapy in patients with Stage D2 prostate cancer and to determine whether cells positive for chromogranin A (CgA) in tissue biopsied at diagnosis is a useful marker for predicting the duration to recurrence after hormonal therapy.

A total of 50 patients diagnosed with Stage D2 prostate cancer at our institution from January 1998 to December 2001 were studied. The needle prostate biopsy specimens obtained at diagnosis were stained by immunohistochemistry using the labeled streptavidin biotin method, and the results were considered positive if CgA-positive cells constituted 10% or more of the tumor area.

No significant differences were found between patients on the basis of the time to recurrence of less than 2 years versus 2 years or more with respect to prostate-specific antigen level, patient age, Gleason score, or extent-of-disease grade. Of the 50 patients, 11 (22.0%) had positive cell staining for CgA. No significant differences were found between the CgA-positive group and the CgA-negative group in age, prostate-specific antigen level, Gleason score, extent-of-disease grade, T stage, or N stage. The rate of freedom from recurrence after 2 years as analyzed by the Kaplan-Meier method was 18.2% for the CgA-positive group and 47.4% for the CgA-negative group, and the CgA-positive group had a significantly shorter time to recurrence (P < 0.0122).

The results of our study have shown that patients with overexpression of CgA-positive cells in the prostate have a significantly shorter time to recurrence after hormonal therapy than patients with CgA-negative cells; thus, CgA expression may be a useful marker predictive of the time to recurrence.