The effectiveness of invitations from general practitioners in recruiting women to mammographic screening

To evaluate the effectiveness of general practitioner patient lists as a means of recruiting women to mammography screening.

This study constitutes the first part of a comparative study of two alternative recruitment strategies involving invitation of women identified from: (i) general practitioner lists; and (ii) the electoral roll.

The subjects were women aged 50-64 listed as patients of the first three private practices that agreed to collaborate with the South Australian (SA) Breast X-Ray Service to recruit by this method. These practices include five locations encompassing a spread of middle and upper class socioeconomic areas in Adelaide's southern suburbs.

In all, 1505 women who had not already attended the SA Breast X-Ray Service were sent a letter of invitation by their general practitioner to attend the Service for a screening mammogram at a specified date and time.

The primary outcome measures were eligibility status (eligible, not eligible) and attendance status (attended, cancelled appointment, failed to attend without notice).

Excluding 34 letters that were returned unopened, 10% of invitees were classified as not eligible, mostly because they had had a recent mammogram elsewhere. Of the remaining invitees, 68.6% attended, 8.4% rang to cancel the appointment and 23% failed to attend without prior notice.

This method of recruitment is viable, and it yields high participation rates close to the "Health for All Australians" target of 70% for mammography screening. Furthermore, the actual attendance rate for this population is expected to increase over time, because some of those initially classified as ineligible, or who cancelled or failed to attend, eventually will attend. The success of this method of recruitment will be measured against the relative cost and effectiveness of the electoral roll alternative, currently under investigation by the SA Breast X-Ray Service.