title: Screening interval and risk of invasive squamous cell cervical cancer.
abstract: To compare the risks of developing invasive squamous cell cervical cancer associated with screening intervals of 1, 2, and 3 years after a negative cervical smear. We conducted a matched case-control study of invasive squamous cell cervical cancer patients (n = 482) diagnosed between 1983 and 1995 among long-term members of a large health maintenance organization. Controls were matched for age, length of membership, and race (n = 934). Screening interval was time between the last negative cervical smear and the case diagnosis date. The main outcome measure was the relative odds of invasive disease associated with 1-year, 2-year, and 3-year intervals. The odds ratio for a 2-year versus a 1-year interval was 1.72 (95% confidence interval 1.12, 2.64, P =.013) and for a 3-year versus a 1-year interval was 2.06 (95% confidence interval 1.21, 3.50, P =.007). The odds ratio for a 3-year versus a 2-year interval was 1.20 (95% confidence interval 0.65, 2.21, P =.561). Controlling for ever having had an abnormal cervical smear or a previous consecutive negative smear did not substantially change these results. In this large health plan, the relative risks of invasive squamous cell cervical cancer were significantly greater for 2-year and 3-year cervical cancer screening intervals compared with a 1-year interval, but not for a 3-year interval compared with a 2-year interval. Our findings need to be placed in the context of the low absolute risks of developing invasive cervical cancer during the first 3 years after a negative cervical smear before making policy recommendation.
authors.affiliation: Department of Quality and Utilization, Kaiser Permanente Medical Care Program, Oakland, California 94553, USA. mariegmiller@saber.net
authors.forename: Marie Grisham
authors.initials: MG
authors.lastname: Miller
authors.forename: Hai-Yen
authors.initials: HY
authors.lastname: Sung
authors.forename: George F
authors.initials: GF
authors.lastname: Sawaya
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Kearney
authors.forename: Walter
authors.initials: W
authors.lastname: Kinney
authors.forename: Robert A
authors.initials: RA
authors.lastname: Hiatt
mesh_terms: D000328:Adult; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008403:Mass Screening / Q000706:statistics & numerical data*; D008875:Middle Aged; D016017:Odds Ratio; D011237:Predictive Value of Tests; D013997:Time Factors; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis*; D014626:Vaginal Smears / Q000706:statistics & numerical data*