Effect of false-positive results on reattendance at breast cancer screening programmes in Spain.

Background: Mammography is the only breast screening method, we are aware of today, which is able to reduce mortality from breast cancer. Nevertheless, this procedure carries an inherent risk of false-positive screening mammogram. The association between these results and reattendance at the next scheduled screening mammogram is controversial. The aim of this study was to examine the effect of a false-positive screening mammogram and women's characteristics on reattendance in eight regional population-based breast cancer screening programmes in Spain.

Methods: This study included 1 383 032 women aged 44-67 years who were initially screened for breast cancer between 1990 and 2004. To investigate factors associated with reattendance, logistic regression models were used.

Results: The mean age of women at first screening was 53.6 years (SD = 6.1 years). Of 120 800 women with a false-positive screening mammogram, 78.3% returned for a subsequent screening mammogram compared with 81.9% of those with a negative result (P < 0.001). Multivariate analysis showed that women with a false-positive result at first screening mammogram were less likely to reattend (OR = 0.71; 95% CI 0.70-0.73) and that the likelihood was lower in those who had undergone invasive additional tests (OR = 0.56; 95% CI 0.53-0.59).

Conclusion: A false-positive screening mammogram in the first screening negatively affected attendance at the subsequent screening. The results of this study could be useful to improve the screening process and to increase women's compliance.