Cumulative risk of cancer detection in breast cancer screening by protocol strategy.

BACKGROUND: There is little information on the individual risk of screen-detected cancer in women over successive participations. This study aimed to estimate the 10-year cumulative breast cancer detection risk (ductal carcinoma in situ and invasive carcinoma) in a population-based breast cancer screening program according to distinct protocol strategies. A further aim was to determine which strategies maximized the cancer detection risk and how this risk was affected by the radiologic protocol variables. METHODS: Data were drawn from a retrospective cohort of women from nine population-based screening programs in Spain from 1990 to 2006. We used logistic regression with discrete intervals to estimate the cumulative detection risk at 10 years of follow-up according to radiologic variables and protocol strategies. RESULTS: In women starting screening at the age of 45-59 years, the cumulative risk of screen-detected cancer at 10 years ranged from 11.11 to 16.71 per 1,000 participants according to the protocol strategy. The cumulative detection risk for overall cancer and invasive cancer was the highest with strategies using digital mammography, double reading, and two projections (16.71 and 12.07 ‰, respectively). For ductal carcinoma in situ, cumulative detection risk was the highest with strategies using screen-film, double reading, and two projections (2.32 ‰). The risk was the lowest with strategies using screen-film mammography, single reading, and two projections. CONCLUSIONS: This study found that at least eleven cancers are detected per 1,000 women screened in the first 10 years of follow-up. Enhanced knowledge of the variability in cumulative risk of screen-detected cancer could improve protocol strategies.

Effect of protocol-related variables and women's characteristics on the cumulative false-positive risk in breast cancer screening.

BACKGROUND: Reducing the false-positive risk in breast cancer screening is important. We examined how the screening-protocol and women's characteristics affect the cumulative false-positive risk. METHODS: This is a retrospective cohort study of 1,565,364 women aged 45-69 years who underwent 4,739,498 screening mammograms from 1990 to 2006. Multilevel discrete hazard models were used to estimate the cumulative false-positive risk over 10 sequential mammograms under different risk scenarios. RESULTS: The factors affecting the false-positive risk for any procedure and for invasive procedures were double mammogram reading [odds ratio (OR)=2.06 and 4.44, respectively], two mammographic views (OR=0.77 and 1.56, respectively), digital mammography (OR=0.83 for invasive procedures), premenopausal status (OR=1.31 and 1.22, respectively), use of hormone replacement therapy (OR=1.03 and 0.84, respectively), previous invasive procedures (OR=1.52 and 2.00, respectively), and a familial history of breast cancer (OR=1.18 and 1.21, respectively). The cumulative false-positive risk for women who started screening at age 50-51 was 20.39% [95% confidence interval (CI) 20.02-20.76], ranging from 51.43% to 7.47% in the highest and lowest risk profiles, respectively. The cumulative risk for invasive procedures was 1.76% (95% CI 1.66-1.87), ranging from 12.02% to 1.58%. CONCLUSIONS: The cumulative false-positive risk varied widely depending on the factors studied. These findings are relevant to provide women with accurate information and to improve the effectiveness of screening programs.

Effect of false-positives and women's characteristics on long-term adherence to breast cancer screening.

False-positive results may influence adherence to mammography screening. The effectiveness of breast cancer screening is closely related to adequate adherence among the target population. The objective of this study was to evaluate how false-positives and women's characteristics affect the likelihood of reattendance at routine breast cancer screening in a sequence of routine screening invitations. We performed a retrospective cohort study of 1,371,218 women aged 45-69 years, eligible for the next routine screening, who underwent 4,545,346 screening mammograms from 1990 to 2006. We estimated the likelihood of attendance at seven sequential screening mammograms. Multilevel discrete time hazard models were used to estimate the effect of false-positive results on reattendance, and the odds ratios (OR) of non-attendance for the women's personal characteristics studied. The overall reattendance rate at the second screening was 81.7% while at the seventh screening was 95.6%. At the second screening invitation reattendance among women with and without a false-positive mammogram was 79.3 vs. 85.3%, respectively. At the fourth and seventh screenings, these percentages were 86.3 vs. 89.9% and 94.6 vs. 96.0%, respectively. The study variables associated with a higher risk of failing to participate in subsequent screenings were oldest age (OR = 8.48; 95% CI: 8.31-8.65), not attending their first screening invitation (OR = 1.12; 95% CI: 1.11-1.14), and previous invasive procedures (OR = 1.09; 95% CI: 1.07-1.10). The risk of non-attendance was lower in women with a familial history of breast cancer (OR = 0.97; 95% CI: 0.96-0.99), and those using hormone replacement therapy (OR = 0.96; 95% CI: 0.94-0.97). In conclusion, reattendance was lower in women with false-positive mammograms than in those with negative results, although this difference decreased with the number of completed screening participations, suggesting that abnormal results in earlier screenings more strongly influence behavior. These findings may be useful in providing women with accurate information and in improving the effectiveness of screening programs.

Cancer screening in Spain.

OBJECTIVE: To describe the current status of breast, colorectal and cervical cancer screening in Spain. METHODOLOGY: The situation was analysed on the basis of data drawn from surveys conducted in each autonomous region (Comunidad Autónoma). RESULTS: Currently, breast cancer screening coverage is 100%. In 2007, overall participation was 67.0% with an adherence of 91.2%. The detection rate was 3.4 per thousand, 15.1% intraductal and 30% invasive <1 cm in diameter, with 65% showing axilary node negative. Colorectal cancer screening had been implemented in six regions (4.5% of the target population). Participation ranged from 17.2% to 42.3%, with positive test percentages ranging from 1.7 per thousand (guaiac) to 9.5% (immunological). The invasive cancer detection rate was 1.7 per thousand (guaiac) and 3.4 per thousand (immunological). In most cases, cervical cancer screening was undertaken opportunistically, with an estimated coverage of 69.0%. CONCLUSIONS: In Spain, cancer screening is being conducted in accordance with national and international recommendations. The fact that screening programmes are operated as a network has led to a high degree of consensus as to the methodology and information systems to be used to enable joint evaluation.

[Analysis of the management of the vaccination campaign in 1996-1997 against meningococcus C in Galicia]. / Análisis de la gestión de la campaña de vacunación 1996-1997 frente al meningococo C en Galicia.

This paper describes the process to design and plan a vaccination campaign against group C N. Meningitidis developed in the Autonomous Community of Galicia between December 9, 1996 and January 31, 1997. We also analyse the results of this process in terms of management results, vaccine coverage and preliminary estimates of effectiveness. A Work group was established, made up of professionals in charge of different intervention areas. A person was designated in charge of the whole campaign and a follow-up and information system was created. The work plan consisted of daily meetings for follow-up, co-ordination and task distribution; and periodical meetings with primary health care and peripheral public health coordinators. Strategies of implantation--in order to make sure the campaign accessibility and acceptability; of budget and of communication with health workers, inhabitants and mass media were developed. Up to 100 tasks were identified to develop the technical information and logistic activities: mailings, meetings, leaflets, ...; purchasing of 584.980 doses of vaccine, supplying to 715 vaccination points (1040 deliveries); problem solving and intervention recording. A vaccination coverage of 85% was achieved, with notification of 8 adverse reactions and 6 errors in the administration of the vaccine (34 children affected). The strategy chosen for the design and planning of the campaign has proven to be effective and valid and sufficient to achieve the final goals, in due time and without problems of misinformation, shortage of vaccine or lack of participation of professionals or people. Mistakes due to incorrect administration of the vaccine, management problems, rupture of the cold chain or recording failures were minimal and accidental.

Breast cancer detection risk in screening mammography after a false-positive result.

BACKGROUND: False-positives are a major concern in breast cancer screening. However, false-positives have been little evaluated as a prognostic factor for cancer detection. Our aim was to evaluate the association of false-positive results with the cancer detection risk in subsequent screening participations over a 17-year period. METHODS: This is a retrospective cohort study of 762,506 women aged 45-69 years, with at least two screening participations, who underwent 2,594,146 screening mammograms from 1990 to 2006. Multilevel discrete-time hazard models were used to estimate the adjusted odds ratios (OR) of breast cancer detection in subsequent screening participations in women with false-positive results. RESULTS: False-positives involving a fine-needle aspiration cytology or a biopsy had a higher cancer detection risk than those involving additional imaging procedures alone (OR = 2.69; 95%CI: 2.28-3.16 and OR = 1.81; 95%CI: 1.70-1.94, respectively). The risk of cancer detection increased substantially if women with cytology or biopsy had a familial history of breast cancer (OR = 4.64; 95%CI: 3.23-6.66). Other factors associated with an increased cancer detection risk were age 65-69 years (OR = 1.84; 95%CI: 1.67-2.03), non-attendance at the previous screening invitation (OR = 1.26; 95%CI: 1.11-1.43), and having undergone a previous benign biopsy outside the screening program (OR = 1.24; 95%CI: 1.13-1.35). CONCLUSION: Women with a false-positive test have an increased risk of cancer detection in subsequent screening participations, especially those with a false-positive result involving cytology or biopsy. Understanding the factors behind this association could provide valuable information to increase the effectiveness of breast cancer screening.