Utility of immunohistochemistry markers in the interpretation of post-high-intensive focussed ultrasound prostate biopsy cores.

ABSTRACT

PURPOSE: To overcome the difficulties in the interpretation of postoperative tumor obtaining biopsy cores for patients who treated their prostate cancer with high-intensity focussed ultrasound (HIFU) therapy. METHODS: The H&E slides of 58 patients with residual prostate cancer after HIFU treatment were systematically reviewed. Correlation between the pathologist's findings and immunohistochemical expression of MIB-1, alpha-Methyl-Co-Racemase and 34ßE-12 staining was analyzed. RESULTS: Mean time from treatment to biopsy was 40.2 (8-208) weeks. The expert review of the H&E slides identified 40 patients with viable carcinoma in the post-HIFU biopsy cores. 18 patients were revised to necrosis-only-tumors. These biopsies were performed not later than 16 weeks after HIFU treatment (median 10.9 weeks, range 8-14). Both MIB-1 and AMACR staining displayed significant differential expression in viable carcinoma (p < 0.001) compared to necrosis tumors. Referring to viable carcinoma tissue, AMACR staining index was significantly rising, the longer treatment dated back from biopsy (p < 0.002). In this context, 34-ß-E12 stained negative through all tumor areas and positive in the majority (85%) of the surrounding non-neoplastic epithelium. CONCLUSIONS: AMACR and MIB-1 reliably differentiate viable carcinoma from a process of ongoing irreversible necrosis in early post-HIFU prostate biopsy cores and therefore proposed-in addition with 34 beta-E12-as useful markers exposing suspicious tumor foci in difficult cases.