Impact of the Quality assured Mamma Diagnostic (QuaMaDi) programme on survival of breast cancer patients

Objective: To evaluate the effect of the Quality assured Mamma Diagnostic programme (QuaMaDi) introduced in 2001 on breast cancer and mortality on a population basis. QuaMaDi provides a standardized diagnostic process for symptomatic or at risk women of all ages. The process includes independent double-reading of mammograms, additional ultrasound, and if suspicious an expert reading and assessment. We tested the hypothesis that QuaMaDi has influenced breast cancer epidemiology and survival positively. Methods: The QuaMaDi cohort of breast cancer patients, diagnosed within the programme between 2001 and 2007, was linked to the cancer registry dataset of all breast cancer cases in Schleswig-Holstein, Germany. By this record-linkage procedure participants of QuaMaDi could be marked in the cancer registry data. Overall survival rates of 3096 patients diagnosed within QuaMaDi were compared to 5417 patients diagnosed outside QuaMaDi, matched by year of diagnosis, using multivariate Cox proportional hazard models. Results: Crude hazard ratio for overall survival was HR 0.43 (95% CI 0.35-0.52) for breast cancer cases detected inside QuaMaDi versus those diagnosed outside the programme. After stepwise adjustment for age, grading, histology, treatment, and tumour stage, the survival advantage in QuaMaDi diagnosed breast cancer patients was still statistically significant (HR 0.78, 95% CI 0.64-0.96). Conclusion: Evidence is provided that the QuaMaDi programme has a beneficial impact on the first 5-year overall survival rate after breast cancer beyond a favourable tumour stage distribution. Thus, we conclude that QuaMaDi contributes to improved health care for women, who are not eligible for mammography screening.