Aims and background: To compare the impact of different modalities of general practitioner (GP) involvement, including the introduction of target payments, on the attendance rate of organized population-based screening programs for breast cancer in Italy.
Study design: The study was conducted between 1994 and 1996 in four Italian cities where mammographic screening programs are active: Caltanissetta (CL), Firenze (FI), Modena (MO) and Torino (TO). The impact on attendance rate of different invitation strategies based on active GP involvement was tested in each center. The additional effect of economic incentives was also assessed. The incentives were proportional to the level of compliance attained by each GP and weighted by the size of his eligible patients' list.
Results: In the Firenze project, an invitation signed by the GP and the project co-ordinator attained a statistically significant higher participation (difference: 4.2%, chi2 = 7.42, P = 0.006). In Caltanissetta and Torino there was a significant increase of about 7% in the response rate to the postal reminder in the groups contacted by the GPs. No difference was observed in the Modena project between the two groups.
Conclusions: The main contributions of GP involvement can be: "cleaning up" the invitation lists, especially when computerized archives with the mammographic history of the target population are not available; increasing the women's participation by signing the invitation letter, by counseling and active participation in the invitation phase; co-operating in the reminder phase by recalling women non responders at first invitation. The offer of target payment had a certain impact on the screening uptake, but not easily distinguishable from GP signature of the invitation letter; further studies of appropriate design should be planned. Organizational factors, such as availability of a list of non-responders, might be crucial in order to enhance the effect of the GPs' action.