Screening Outcomes in Older US Women Undergoing Multiple Mammograms in Community Practice: Does Interval, Age or Comorbidity Score Affect Tumor Characteristics or False Positive Rates?
A partir de données portant sur 2 993 femmes atteintes d'un cancer du sein et 137 949 femmes sans cancer du sein, ayant subi une mammographie entre 1999 et 2006 (âge compris entre 66 et 89 ans), cette étude américaine compare, du point de vue du risque de cancer en fonction du stade et du point de vue du risque d'une mammographie faussement positive, l'intérêt d'un dépistage annuel ou biennal
Background Uncertainty exists about the appropriate use of screening mammography among older women because comorbid illnesses may diminish the benefit of screening. We examined the risk of adverse tumor characteristics and false positive rates according to screening interval, age, and comorbidity.
Methods From January 1999 to December 2006, data were collected prospectively on 2993 older women with breast cancer and 137 949 older women without breast cancer who underwent mammography at facilities that participated in a data linkage between the Breast Cancer Surveillance Consortium and Medicare claims. Women were aged 66 to 89 years at study entry to allow for measurement of 1 year of preexisting illnesses. We used logistic regression analyses to calculate the odds of advanced (IIb, III, IV) stage, large (>20 millimeters) tumors, and 10-year cumulative probability of false-positive mammography by screening frequency (1 vs 2 years), age, and comorbidity score. The comorbidity score was derived using the Klabunde approximation of the Charlson score. All statistical tests were two-sided.
Results Adverse tumor characteristics did not differ statistically significantly by comorbidity, age, or interval. Cumulative probability of a false-positive mammography result was higher among annual screeners than biennial screeners irrespective of comorbidity: 48.0% (95% confidence interval [CI] = 46.1% to 49.9%) of annual screeners aged 66 to 74 years had a false-positive result compared with 29.0% (95% CI = 28.1% to 29.9%) of biennial screeners.
Conclusion Women aged 66 to 89 years who undergo biennial screening mammography have similar risk of advanced-stage disease and lower cumulative risk of a false-positive recommendation than annual screeners, regardless of comorbidity.
Journal of the National Cancer Institute , résumé, 2013