Diagnostic Utility of Immunohistochemical Markers in Prostate Cancer

Introduction: Prostate cancer is a multifaceted disease comprises distinct biological subtypes with varied spectrum of clinical, pathologic and molecular features with different prognostic and therapeutic implications. Over the last few decades there have been outstanding advances in prostate cancer management leading to earlier detection of disease. Prostatic cancer diagnosis is based on a combination of architectural, cytological and ancillary features. Immunohistochemistry (IHC) is a valuable adjunctive in diagnosis of minute foci of prostatic carcinoma and to differentiate it from benign mimickers & precursor lesions. Prostate cancer is now the 5th most common cancer in the world (in terms of number of new cases), and 2nd most common cancer in men. Aims of study :1) To assess the diagnostic utility of IHC markers in morphologically ambiguous prostate carcinomas 2) To assess the efficacy of P63 over HMWCK 3) To know the level of diagnostic error in reporting of Prostatic lesions on routine H&E. Materials &Methods : The Present study is a prospective study carried for a period of two years from June 2011 to May 2013 in Department of Pathology, Rangaraya medical college / Government general hospital, Kakinada. We received 310 cases of prostate biopsies in our department in the two year period. Out of the 310 cases, 40 cases were reported as suspicious of malignancy on H&E and are subjected for IHC. Results &Analysis : 40 suspicious cases were subjected for IHC. Out of 40 cases, in only 20 cases (50%) there is disparity between diagnosis on H&E and diagnosis on IHC. In 20 cases, 14 cases (35%) were underdiagnosed as benign or pre-malignant or suspicious of malignancy. These got upgraded to HGPIN or carcinoma or carcinoma with foci of HGPIN after IHC study. Remaining 6 cases (15%) are downgraded from pre-malignant lesions to benign lesions. Discussion : Our results are almost correlated with other studies. Conclusion : 1.Even though diagnosis of prostate cancer is mainly based on architectural pattern, cytological and ancillary features, Immunohistochemistry acts as a most valuable adjunctive, which significantly increases the diagnostic accuracy in prostatic carcinoma. 2.Among basal cell markers, p63 has more sensitivity and specificity than HMWCK. 3.No single marker is having 100% sensitivity or specificity in diagnosis of prostatic carcinoma. Hence combination of a Basal cell marker (p63) with AMACR is more informative in the diagnosis of prostatic carcinoma.