Comparison of self-reported adherence to cervical and breast cancer screening guidelines in relation to the researcher’s profession.

Introduction: Self-reporting is a major and, in many cases, the only feasible method to use in cancer screening research. However, its validity has been questioned and numerous studies indicate that women over-report their participation in preventive Pap-test and mammography screenings. Aim: The objective of this study was to determine whether individuals report in the same way their Pap-test and mammography screening behaviors when the interviews are conducted by researchers of different professions, in this case a social worker and a general practitioner. Methods: Two studies assessing adherence to cervical and breast cancer screening guidelines were conducted during late 2006 - early 2007 in the same 114 women in Crete, Greece. Kappa coefficient was used to measure the agreement of participants’ answers to the same questions between the two interviewers. Results: Only 32 out of 90 (35,5%) of the women replied that ‘have had at least one’ gynecological exam respectively in both studies (Kappa=0.189, p<0.001). Agreement was also weak (Kappa=0.386 and 0.235) for self-reported mammography and Pap smear tests in the last 6 years, respectively. There were no significant differences in major demographic characteristics between women who provided, or not, the same answers in both interviewers, apart from the self-reported health status (p=0.032). Conclusions: Women overestimated their self-reported adherence to cancer screening guidelines when the interviewer was a doctor once their responses were matched to those given to a social worker. The professional identities of the researchers that perform the data collection should be made explicit to make comparison across studies more accurate.