ABSTRACT
The incidence of prostate cancer (PCa) has risen dramatically in the past decade, probably owing to early detection programs that employ digital rectal examination, serum prostate-specific antigen, and transrectal ultrasonography.1 In developed countries, PCa is the most commonly diagnosed non-skin malignancy in males.1 It is estimated that 1 in 6 males will be diagnosed with PCa during their lifetime,
the risk of death due to metastatic PCa being 1 in 30.2 Multiple factors contribute to the development of PCa as well as to its progression to an androgen-independent state:2 dietary factors, inherited susceptibility factors, gene defects, and androgens and their receptors.3-5
Prostatic intra-epithelial neoplasia Prostatic intra-epithelial neoplasia (PIN) refers to the pre-invasive end of the continuum of cellular proliferations within the lining of prostatic ducts, ductules, and acini. Initial references to such lesions were apparently made by Orteil,6 Andrews,7 and Kastendieck and Helpap,8 but these authors did not distinguish these findings from mimics of PIN. In 1965, McNeal9 emphasized the possible premalignant nature of proliferative changes in the prostatic epithelium, but his description included a variety of findings. Twenty-one years later, McNeal and Bostwick10 described, for the first time, reproducible diagnostic criteria for the recognition of what they referred to as ‘intraductal dysplasia’, and introduced a three-grade classification system. The following year, Bostwick and Brawer11 proposed the term of prostatic intra-epithelial neoplasia as a replacement for intraductal dysplasia, and this new term was promulgated in 1989 at a workshop on prostate preneoplastic lesions sponsored by the American Cancer Society and National Cancer Institute.12 Terms such as intraductal dysplasia, severe dysplasia, large acinar atypical hyperplasia, duct-acinar dysplasia, and intraductal carcinoma are discouraged. The 1989 conference recommended compression of the PIN classification into two grades: low-grade (formerly PIN grade l) or high-grade PIN (formerly PIN grades 2 and 3) (HGPIN). The clinical significance of HGPIN was considered substantial at that time, whereas low-grade PIN was considered largely inconsequential.
