Page 11 - Screening for Cervical Cancer: Systematic Evidence Review

Chapter I. Introduction

I. Introduction

Background

Since introduction of cytologic screening for cervical cancer using the Papanicolaou

(Pap) test in the 1950s, the incidence of invasive cervical cancer in the United States has fallen

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more than 100%. No other cancer screening program has been more successful. This fall
occurred despite an increase in risk factors for cervical cancer, such as younger age at initiation

of sexual intercourse, more sexual partners in a lifetime, and greater prevalence of human

papilloma virus (HPV) infection and cigarette smoking.

Success in prevention reflects three factors: (1) progression from early cellular

abnormalities, termed low-grade dysplasia, through more severe dysplasia, to carcinoma in situ

and invasive cancer is generally slow, allowing time for detection; (2) associated cellular

abnormalities can be identified; and (3) effective treatment is available for premalignant lesions.

Consequently, invasive squamous cell carcinoma of the uterine cervix is a highly preventable

disease.

Introduction of screening programs in populations naïve to screening reduces cervical

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cancer rates by 60% to 90% within three years of implementation. This reduction of mortality
and morbidity with introduction of screening with the Pap test is consistent and dramatic across

populations. As a result, Pap testing is one of the few preventive interventions that has received

an “A” recommendation from the US Preventive Services Task Force (USPSTF) in the absence

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of randomized trials demonstrating effectiveness.

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