Endometrial Intraepithelial Neoplasia

The American College of Obstetricians and Gynecologists

WOMEN’S HEALTH CARE PHYSICIANS

COMMITTEE OPINION

Number 631 • May 2015

Committee on Gynecologic Practice

Society of Gynecologic Oncology

This document reflects emerging clinical and scientific advances as of the date issued and is subject to change. The information should not be construed as dictating an exclusive course of treatment or procedure to be followed.

Endometrial Intraepithelial Neoplasia

ABSTRACT: Endometrial hyperplasia is of clinical significance because it is often a precursor lesion to adeno­carcinoma of the endometrium. Making the distinction between hyperplasia and true precancerous lesions or true neoplasia has significant clinical effect because their differing cancer risks must be matched with an appropriate intervention to avoid undertreatment or overtreatment. Pathologic diagnosis of premalignant lesions should use criteria and terminology that clearly distinguish between clinicopathologic entities that are managed differently. At present, the endometrial intraepithelial neoplasia schema is tailored most closely to this objective, incorporating modified pathologic criteria based upon evidence that has become available since the creation of the more widely used 1994 four-class World Health Organization schema (in which atypical hyperplasia is equated with precancer­ous behavior). The accuracy of dilation and curettage compared with endometrial suction curette in diagnosing precancer and excluding concurrent carcinoma is unclear. Hysteroscopy with directed biopsy is more sensitive than dilation and curettage in the diagnosis of uterine lesions. When clinically appropriate, total hysterectomy for endometrial intraepithelial neoplasia provides definitive assessment of a possible concurrent carcinoma and effectively treats premalignant lesions. Systemic or local progestin therapy is an unproven but commonly used alternative to hysterectomy that may be appropriate for women who are poor surgical candidates or who desire to retain fertility.

Conclusions and Recommendations

Sensitive and accurate diagnosis of true premalignant endometrial lesions can reduce the likelihood of devel­oping invasive endometrial cancer. Based on avail­able data and expert opinion, the American College of Obstetricians and Gynecologists and the Society of Gynecologic Oncology make the following consensus recommendations:

• The endometrial intraepithelial neoplasia schema seems to be preferable to the 1994 four-class World Health Organization (WHO94) schema. Pathologic diagnosis of premalignant lesions should use criteria and terminology that clearly distinguish between clinicopathologic entities that are managed differ­ently. At present, the endometrial intraepithelial neoplasia schema is tailored most closely to this objective, incorporating modified pathologic criteria based upon evidence that has become available since the creation of the more widely used WHO94 schema (in which atypical hyperplasia is equated with pre­cancerous behavior). The preferred terminology is “endometrial intraepithelial neoplasia” (rather than “atypical endometrial hyperplasia”).
• Regarding tissue sampling, hysteroscopy, while not required, is recommended with directed dilation and curettage (D&C) to include any discrete lesions as well as the background endometrium. This will provide the best opportunity to confirm the diag­nosis of a true premalignant endometrial lesion and exclude anassociated endometrial carcinoma. When clinically appropriate, total hysterectomy for endo­metrial intraepithelial neoplasia provides definitive assessment of a possible concurrent carcinoma and effectively treats premalignant lesions.

2 Committee Opinion No. 631

Supracervical hysterectomy, morcellation, and endo­metrial ablation are unacceptable for treatment of endometrial intraepithelial neoplasia.

Systemic or local progestin therapy is an unproven but commonly used alternative to hysterectomy that may be appropriate for women who are poor surgical candidates or who desire to retain fertility.

Posthormonal treatment surveillance after nonsurgi­cal management of endometrial intraepithelial neo­plasia may include serial endometrial sampling every 3–6 months, but the appropriate frequency has not yet been determined. precancerous behavior).

*Previously known as atypical endometrial hyperplasia.

Data from Baak JP, Mutter GL, Robboy S, van Diest PJ, Uyterlinde AM, Orbo A, et al. The molecular genetics and morphometry-based endometrial intraepithelial neoplasia classification system predicts disease progression in endometrial hyperplasia more accurately than the 1994 World Health Organization classification system. Cancer 2005;103:2304–12 and Mutter GL. Endometrial intraepithelial neoplasia (EIN): will it bring order to chaos? The Endometrial Collaborative Group. Gynecol Oncol 2000;76:287–90.

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