Risk of cervical cancer after completed post-treatment follow-up of cervical intraepithelial neoplasia: population based cohort study

TY - JOUR

T1 - Risk of cervical cancer after completed post-treatment follow-up of cervical intraepithelial neoplasia

T2 - population based cohort study

AU - Rebolj, Matejka

AU - Helmerhorst, Theo

AU - Habbema, Dik

AU - Looman, Caspar

AU - Boer, Rob

AU - van Rosmalen, Joost

AU - van Ballegooijen, Marjolein

PY - 2012/11/10

Y1 - 2012/11/10

N2 - Objective: To compare the risk of cervical cancer in women with histologically confirmed cervical intraepithelial neoplasia who returned to routine screening after having completed post-treatment follow-up with consecutive normal smear test results with women with a normal primary smear test result. Design: Population based cohort study using data from a nationwide pathology register. Setting: The Netherlands, 1994 to 2006. Population: 38 956 women with histologically confirmed intraepithelial neoplasia grades 1 to 3 with completed follow-up after treatment. Intervention: Routine post-treatment follow-up of cervical intraepithelial neoplasia, recommending smear tests at six, 12, and 24 months. Main outcome measure: Incidence of cervical cancer in the period from completed follow-up with negative test results after cervical intraepithelial neoplasia to the next primary test. 10-year hazard ratios were compared with periods after normal results for the primary smear test, adjusted for year in follow-up. Results: 20 cervical cancers were diagnosed during 56 956 woman years after completed follow-up of cervical intraepithelial neoplasia, whereas 1613 cervical cancers were diagnosed during 25 020 697 woman years after a normal primary smear test result. The incidence of 35.1 (95% confidence interval 21.4 to 54.2) per 100 000 woman years and 6.4 (6.1 to 6.8) per 100 000 woman years, respectively, led to an adjusted hazard ratio of 4.2 (95% confidence interval 2.7 to 6.5) for periods after completed follow-up compared with periods after normal primary smear test results. This hazard ratio was increased for all ages. No significant difference in risk of cervical cancer was observed by grade of cervical intraepithelial neoplasia. Conclusions: An excess risk of cervical cancer previously observed for women treated for cervical intraepithelial neoplasia was also observed in the subgroup of women who completed their post-treatment follow-up with three consecutive normal smear test results. The overall corrected risk of cervical cancer in these women was increased fourfold 35 cases per 100 000 woman years) compared with women with normal primary smear test results (6 per 100 000 woman years).

AB - Objective: To compare the risk of cervical cancer in women with histologically confirmed cervical intraepithelial neoplasia who returned to routine screening after having completed post-treatment follow-up with consecutive normal smear test results with women with a normal primary smear test result. Design: Population based cohort study using data from a nationwide pathology register. Setting: The Netherlands, 1994 to 2006. Population: 38 956 women with histologically confirmed intraepithelial neoplasia grades 1 to 3 with completed follow-up after treatment. Intervention: Routine post-treatment follow-up of cervical intraepithelial neoplasia, recommending smear tests at six, 12, and 24 months. Main outcome measure: Incidence of cervical cancer in the period from completed follow-up with negative test results after cervical intraepithelial neoplasia to the next primary test. 10-year hazard ratios were compared with periods after normal results for the primary smear test, adjusted for year in follow-up. Results: 20 cervical cancers were diagnosed during 56 956 woman years after completed follow-up of cervical intraepithelial neoplasia, whereas 1613 cervical cancers were diagnosed during 25 020 697 woman years after a normal primary smear test result. The incidence of 35.1 (95% confidence interval 21.4 to 54.2) per 100 000 woman years and 6.4 (6.1 to 6.8) per 100 000 woman years, respectively, led to an adjusted hazard ratio of 4.2 (95% confidence interval 2.7 to 6.5) for periods after completed follow-up compared with periods after normal primary smear test results. This hazard ratio was increased for all ages. No significant difference in risk of cervical cancer was observed by grade of cervical intraepithelial neoplasia. Conclusions: An excess risk of cervical cancer previously observed for women treated for cervical intraepithelial neoplasia was also observed in the subgroup of women who completed their post-treatment follow-up with three consecutive normal smear test results. The overall corrected risk of cervical cancer in these women was increased fourfold 35 cases per 100 000 woman years) compared with women with normal primary smear test results (6 per 100 000 woman years).

KW - Adult

KW - Cervical Intraepithelial Neoplasia

KW - Female

KW - Follow-Up Studies

KW - Humans

KW - Incidence

KW - Middle Aged

KW - Neoplasm Grading

KW - Netherlands

KW - Risk Factors

KW - Uterine Cervical Neoplasms

KW - Vaginal Smears

M3 - Journal article

C2 - 23117059

SN - 0959-8146

VL - 345

SP - e6855

JO - BMJ

JF - BMJ

ER -