Neoplasia Intraepitelial Cervical

Gynecologic Cancer Prevention
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CERVICAL INTRAEPITHELIAL NEOPLASIA AND CERVICAL CANCER

Obstetrics and Gynecology Clinics
Volume 23 • Number 2 • June 1996
Copyright © 1996 W. B. Saunders Company

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Mitchell Morris MD
Guillermo Tortolero-Luna MD, PhD
Anais Malpica MD
Vicki V. Baker MD
Elise Cook MD
Ellen Johnson MS
Michele Follen Mitchell MD, MS
This work wassupported by National Cancer Institute Contracts CA-25433A and CA-25433B, the Business and Professional Women's Association, and the University Cancer Foundation.
From the Departments of Gynecologic Oncology (MM, GT-L, MFM), and Pathology (AM), The University of Texas M. D. Anderson Cancer Center; the Women's Health Care Center of Houston (EC), Houston, Texas; the Department of Obstetrics andGynecology, Division of Gynecologic Oncology, The University of Michigan Medical Center (VVB); and the Department of Health Services Management and Policy, University of Michigan School of Public Health (EJ), Ann Arbor, Michigan
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Address reprint requests to
Michele Follen Mitchell, MD, MS
Department of Gynecologic Oncology, Box 67
The University of Texas M. D. Anderson Cancer Center
1515Holcombe Boulevard
Houston, TX 77030
Cervical intraepithelial neoplasia (CIN) and cervical cancer remain important health problems for women worldwide, with high morbidity of treatment and mortality for advanced lesions. To give a complete picture of why, whom, and how we can screen for CIN and cervical cancer, in this article we describe the nature of these diseases, epidemiologic factors, how thediseases are evaluated and treated, and how they can be detected by examination and by molecular methods. We then summarize the current and future armamentarium for preventing cervical cancer from developing, including chemoprevention.

DEFINITIONS

Cervical Intraepithelial Neoplasia

Cervical intraepithelial neoplasia is defined as "the spectrum of intraepithelial changes beginning as witha generally well-differentiated
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neoplasm, traditionally classified as mild dysplasia, and ending with invasive carcinoma." [62] These changes, confined to the squamous epithelium above the basement membrane, include nuclear pleomorphism, loss of polarity, abnormal mitoses, and loss of differentiation as cells progress from the basement membrane to the surface epithelium. [62]Richart [173] coined the term cervical intraepithelial neoplasia and in the 1960s devised a grading system for CIN in which lesions are classified from grades 1 to 3 based on the percentage of cells from the basement membrane to the surface that are undifferentiated. When one third or less of the distance from the basement membrane to the surface is involved, the lesions are called grade 1 (CIN 1);when more than one third but less than or equal to two thirds is involved, grade 2 (CIN 2); and when more than two thirds is involved, grade3 (CIN 3). Full-thickness involvement in the past was called carcinoma in situ (CIS) and is now often called grade 3.
A new classification is now being applied to these lesions. In 1988 the National Cancer Institute convened a panel to address the issue of theclassification of Papanicolaou (Pap) smears. [141] The panel's goal was to define a uniform terminology for smear reading, standards for the adequacy of the smear, and guidelines for typing the results of the smear to the clinical management of the patient. The resulting Bethesda classification has the underlying philosophy that it is difficult to distinguish between lesions caused by humanpapillomavirus (HPV) and CIN 1; so the two types are combined into one category called low-grade squamous intraepithelial lesions (LGSIL). Similarly, CIN 2 and 3 lesions are placed in a category called high-grade squamous intraepithelial lesions (HGSIL). Lesions that contain cells with abnormal nuclear characteristics but without changes suggestive of koilocytotic atypia or CIN 1 are classified as...