Tissue prostate-specific antigen and androgen receptor immunoreactivity in prostate cancer biopsies before, during and after neo-adjuvant androgen deprivation followed by radiotherapy.

OBJECTIVE

The purpose of the study was to examine the immunohistochemical stainability of prostate-specific antigen (PSA) and androgen receptor (AR) in biopsies from localised prostate cancers before treatment, after androgen deprivation and after radiation therapy.

PATIENTS AND METHODS

Biopsies were taken from 16 men with prostate cancer (T1-3,Nx,M0) before the start (START) of androgen deprivation with LHRH analogue, during the following pelvic lymph node dissection (PLND), and twice after radiotherapy (POSTRAD and FINAL).

RESULTS

Malignant cells were observed in all START, PLND and POSTRAD biopsies and in 6 of 7 FINAL specimens. During androgen suppression and subsequent radiotherapy a gradual reduction in tissue immunoreactivity for PSA and AR was observed paralleled by a reduction in serum PSA. The most striking observation was the complete lack of AR stainability after combined LHRH/radiation therapy. Of the 7 patients who had a long-term follow-up after radiotherapy, 1 patient was cancer negative on biopsy and without AR and PSA stainability. Six patients with cancer-positive FINAL biopsies had regained AR stainability. Five of these latter biopsies also stained for PSA. Five of the six patients had no elevation in serum PSA.

CONCLUSION

After combined hormone/radiotherapy serum PSA is a relatively unreliable marker for the demonstration of residual cancer. This combination therapy leads to transient loss of immunohistochemically stained tissue PSA and AR in the residual cancer.