Measurement in comparative effectiveness research

Follow-up of women with cervical cytological abnormalities showing atypical squamous cells of undetermined significance or low-grade squamous intraepithelial lesion: a nationwide cohort study

BACKGROUND

Atypical squamous cells of undetermined significance or low-grade squamous intraepithelial lesion in abnormal cervical cytology among young women in cervical cancer screening is an increasing health burden, and comparative effectiveness studies of different management options for such diagnoses are needed.

OBJECTIVE

The objective of the study was to compare the incidence of invasive cervical cancer, following different management options pursued after an atypical squamous cells of undetermined significance/low-grade squamous intraepithelial lesion index smear.

STUDY DESIGN

In this nationwide cohort study, we included all women aged 22-50 years and resident in Sweden 1989-2011 and with at least 1 cervical smear registered during the study period (n = 2,466,671). Follow-up of a first atypical squamous cells of undetermined significance/low-grade squamous intraepithelial lesion cytological diagnosis within 25 months was classified as repeat cytology, colposcopy/biopsy, or without further assessment. Incidence rate ratios and 95% confidence intervals of subsequent cervical cancer within 6.5 years following atypical squamous cells of undetermined significance/low-grade squamous intraepithelial lesion were estimated using Poisson regression by age group and management strategy.

RESULTS

Women managed with repeat cytology within 6 months after atypical squamous cells of undetermined significance or low-grade squamous intraepithelial lesion cytology had a similar risk of cervical cancer compared with colposcopy/biopsy (incidence rate ratio, 1.1, 95% confidence interval, 0.5-2.5, and incidence rate ratio, 2.0, 95% confidence interval, 0.6-6.5, respectively) among women aged 22-27 years. For women aged 28 years and older, women managed with repeat cytology had a higher risk for cervical cancer than women managed with colposcopy/biopsy.

CONCLUSION

Our findings suggest that women with a first cytological diagnosis of atypical squamous cells of undetermined significance/low-grade squamous intraepithelial lesion up to age 27 years may indeed be safely followed up with repeat cytology within 6 months. A large amount of colposcopies that are currently performed in this group, therefore, could safely be discontinued.

Breast cancer mortality in relation to receipt of screening mammography: a case-control study in Saskatchewan, Canada

PURPOSE

The efficacy of screening mammography in reducing breast cancer mortality continues to be controversial. In addition, few data exist on the efficacy of screening mammography in women 70 years of age or older. An organized screening mammogram program has existed in Saskatchewan since the mid-1990s. It offers mammography every 2 years to women ≥50 years of age.

METHODS

We conducted a population-based case-control study to evaluate the efficacy of screening mammography, as practiced in Saskatchewan, Canada. Cases (n = 501) were women who died of breast cancer during 1995-2008 and were at least 52 years of age at the time of their diagnosis. Controls (n = 5,009) were matched to cases on birth year and duration of healthcare coverage prior to the cases' breast cancer diagnosis date. In cases and controls, receipt of screening mammography during the several years up to and including the date of the case's diagnosis of breast cancer was ascertained from the records of the screening program.

RESULTS

Receipt of a screening mammogram in the preceding 2 years was more common among controls (53 %) than cases (37 %), OR 0.51 (95 % CI 0.42-0.62). A decreased risk was observed among women in all age groups, including those 70-79 years (OR 0.40; 95 % CI 0.27-0.60).

CONCLUSION

Our findings suggest that receipt of screening mammography among women in Saskatchewan has been associated with a decreased risk of death from breast cancer.