This study, conducted jointly by the National Cancer Institute and the Kaiser Permanente Center for Health Research Northwest (KPCHRN) in Portland, Oregon, will lay the groundwork for a future study to identify precursors of endometrial cancer; that is, conditions that precede development of cancer of the lining of the uterus. The diagnosis of endometrial hyperplasia (a condition of abnormal proliferation of endometrial tissue) includes most precursors of endometrial cancer, as well as many benign conditions. Currently, three methods of classifying endometrial cancer precursors have been suggested based on endometrial hyperplasia findings, but it is not known which classification best predicts cancer risk.

This study will examine surgical specimens of hyperplasia and cancer from women diagnosed with endometrial cancer at least 2 years after a diagnosis of endometrial hyperplasia. Investigators will estimate the percentage of cases with different degrees of hyperplasia, and assess the subsequent cancers that developed. This will allow them to rank hyperplasia lesions according to cancer risk and identify lesions that represent the most immediate cancer precursors. They will also review patients medical charts for information related to cancer risk and treatment.

Study participants will include women enrolled in the KPCHRN who are 40 years of age or older and who were diagnosed with endometrial cancer at least 2 years after being diagnosed with endometrial hyperplasia.

Three systems have been proposed to classify endometrial carcinoma precursors, but it is currently unclear which system best predicts cancer risk and is most reproducible. The optimal surrogate endpoint for endometrial carcinoma is therefore unknown. The pathologic diagnosis of endometrial hyperplasia (EH) includes most suspected immediate precursors and many mild, highly reversible proliferations. We propose an exploratory study to assess the feasibility of investigating EH as a source of an endometrial carcinoma surrogate endpoint.

We are conducting a nested case-control study within a large, population-based health care plan. We will identify cases, defined as women who were diagnosed with EH at least one year before being diagnosed with endometrial carcinoma or severe atypical hyperplasia at hysterectomy, through a computerized search of plan databases. We will retrieve the slides from the matching biopsy and hysterectomy on which carcinoma was diagnosed. Women ages 40 or older who were plan members and received a biopsy or curettage diagnosis of EH between 1970 and 2002 will be eligible to be a case.

We will perform an initial histologic review of cases index biopsy slides to assess two types of misclassification known to affect the diagnosis of EH: a) false-negative endometrial carcinoma (i.e., prevalent carcinoma t the time of EH diagnosis) and b) false-positive EH (i.e., a benign, non-hyperplastic lesion). From cases physical records and linked computer records, we will collect data on histopathologic classification of EH lesions and subsequent carcinomas; descriptive data (e.g., patient weight, parity, and menopausal status); and a summary of relevant treatments and follow-up procedures (e.g., hormone therapy or additional clinical procedures).

We will select controls, defined as women who were diagnosed with EH but then did not develop endometrial carcinoma or undergo hysterectomy for a follow-up interval that is equivalent to the follow-up interval of the cases. Controls will be individually matched to cases on age at EH diagnosis, date of EH diagnosis, and duration of follow-up, and also counter-matched based on the original EH diagnosis. After selecting 3 controls per case, we will assemble the same data from controls: histologic review of original slides, descriptive data from medical records databases, and treatment and follow-up procedure data from linked databases.

These data will then be used to estimate the cancer risk associated with specific EH classifications, identify other patient or clinical factors that might modify those risks, explore predictors of EH, and explore molecular factors that might influence the probability of developing carcinoma after a diagnosis of EH.

• INCLUSION CRITERIA:

All women who were members of the KPNW health plan between 1970 and 2003 who were at risk of developing endometrial carcinoma will be eligible.

EXCLUSION CRITERIA:

Women will be considered ineligible if they had substantial gaps in KPNW coverage during the years between the index biopsy and diagnosis date (cases) or censoring date (controls).

NCI and KPNW will review otherwise eligible women who have coverage gaps to identify substantial gaps and determine eligibility on an individual basis.

We are conducting a nested case-control study of adenocarcinoma of the endometrium within a retrospective cohort of one large managed health care organization in the Northwest U.S. Cases, i.e., women who developed endometrial cancer after a diagnosis of endometrial hyperplasia, will be compared with women who were diagnosed with endometrial hyperplasia but did not develop cancer during an equivalent follow-up period, after controlling for relevant confounders.@@@@@@