Breast cancer

Breast Cancer Mortality Reduction after Initiation of a Screening Program: Consistency of Effect Estimates Obtained Using Different Approaches

Effect on breast cancer mortality of a mammography screening program initiated in 1998 was assessed. Two effect estimates were obtained for each of three groups: participants, eligible women and all women of the target age group including those with prior breast cancer diagnosis. Methods: Four approaches were used: 1) observed and projected breast cancer mortality trends for 1998-2004 were compared, 2) breast cancer mortality in the first five years of the program (1998-2003) was compared to mortality for the five years prior to program initiation (1992-1997) restricting numerators of rates to breast cancer deaths occurring among incident cases, 3) observed number of breast cancer deaths among 523,830 program participants was compared to expected number based on breast cancer incidence and survival of non-participants, 4) nested case-control study (873 cases, 8730 controls) was done within the 1,054,620 women eligible for screening. Results: A…

Équipe d'évaluation du PQDCS

Evaluation of the performance of designated screening centers of the Programme québécois de dépistage du cancer du sein (PQDCS): description of the methods

The evaluation of the Programme québécois de dépistage du cancer du sein (PQDCS) is based primarily on the analysis of performance indicators as defined in the PQDCS guidelines. Methods were initially developed to measure performance indicators at the provincial level and then in individual regions. The goal of this report is to develop an approach for the measurement and comparison of performance indicators at the screening centre level.

The indicators selected to evaluate the performance of individual centres are: the detection rate, recall rate, and number of false positives per screen detected cancer. These indicators are estimated separately for initial and subsequent screens. The percentage of in situ cancers, the percentage of small invasive cancers, and the percentage of lymph nodenegative invasive cancers were also selected. To evaluate a centre's performance, these indicator measurements were compared to the measurements for Quebec as a whole, as well as w…

Équipe d'évaluation du PQDCS

Interval cancer in women following a normal initial mammogram in the Québec Breast Cancer Screening Program in 1998-2000

Interval cancers are cancers that are diagnosed during the interval between a negative screen and the subsequent screen. The rate of interval cancers is a performance indicator in the terms of reference of the Quebec Breast Cancer Screening Program (PQDCS). The PQDCS terms of reference do not set a standard for interval cancer rates, but the Evaluation Indicators Working Group, which monitors breast cancer screening programs in Canada, has determined that the rate of interval cancers should not exceed 6 cases of invasive cancer per 10,000 person-years within 12 months of a negative screen, or 12 cases per 10,000 person-years within 24 months of a negative screen.

The primary objective of this analysis was to estimate the rate of interval cancers among women who received an initial mammography in the PQDCS in 1998-2000 and whose mammogram was interpreted as normal (including non-equivocal benign lesions). The analysis also sought to identify the characteristics of women,…

Équipe d'évaluation du PQDCS