CORRESPONDENCE Re: Annual Report to the Nation on the Status of Cancer (1973 Through 1998), Featuring Cancer With Recent Increasing Trends

read with interest the special article by Howe et al. (1). A 14.5 % annual in-crease in peritoneal cancer was observed from 1992 through 1998. Peritoneal can-cer was first described by Smerdlow (2) in 1959 and has since been referred to by various terms, including multifocal ex-tra-ovarian carcinoma, serous surface papillary carcinoma, primary carcinoma of the peritoneum, and carcinoma of the coelomic epithelium. In the early 1990s, there was an increased recognition of peritoneal cancer as a distinct entity. In 1994, the Pathology Committee of the Gynecologic Oncology Group (GOG) established a definition of peritoneal carcinoma as a tumor with 5.0 mm or less of ovarian stromal invasion. This definition has been subsequently uti-lized in all GOG studies, which are con-ducted in more than 100 major teaching institutions and hospitals in the United States. It is likely that establishing this uniform definition has shifted cases for-merly classified as ovarian cancer to peritoneal cancer. In view of the fact that ovarian carcinoma and peritoneal carcinoma are identical in histology, bi-ology, response to therapy, and progno-sis, the GOG has included both ovarian and peritoneal cancer patients in their studies since 1996. Given the changing nomenclature, studies evaluating popu-lation incidence trends in gynecologic cancers should also combine ovarian and peritoneal carcinomas.