Participation behaviour following a false positive test in the Copenhagen mammography screening programme.
BACKGROUND
There is an ongoing debate concerning possible disadvantages of mammography screening, one being the consequence of receiving a false positive test-result. It is argued that receiving a false positive answer may have short- and/or long-term adverse psychological effects on women, but results from different studies are conflicting. We tested if there was a difference in continued participation behaviour between the group of women who have been subject to a false positive result and those who have not.


METHODS
The study used the registers from the first six invitation rounds of the mammography screening programme in Copenhagen (1991-2003). We estimated the relative risk of not participating in the subsequent screening round for women with a false positive test using women with a negative test as baseline. As outcome measure odds ratios (OR) with 95% confidence intervals (CI) were used.


RESULTS
There was no significant difference in participation in the subsequent round between women with a false positive test and women with a negative test. The proportion of screens resulting in false positive answers, both after assessment and after surgery, decreased from 5.54% in Round 1 to 1.79% in Round 5. Participation in the subsequent screening round was well above 80% in all five screening rounds.


CONCLUSIONS
Our results showed that women experiencing a false positive test at mammography screening participated in the subsequent screening round to the same extent as did women experiencing a negative screening test, regardless of whether the false positive statement was given following assessment or following surgery. The benign to malignant biopsy ratio, comparing the type B false positives to the true positives, was by the fifth round well below the desirable level of </=1:4, recommended by the European guidelines. Other possible adverse effects should be further investigated.
Andersen
Sune Bangsbøll
SB
Department of Epidemiology, Institute of Public Health, University of Copenhagen, Denmark.
Vejborg
Ilse
I
von Euler-Chelpin
My
M
D000368:Aged; D044963:Biopsy, Fine-Needle; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000523:psychology*; D003718:Denmark; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008327:Mammography / Q000523:psychology*; D008403:Mass Screening / Q000379:methods / Q000523:psychology; D008875:Middle Aged; D010342:Patient Acceptance of Health Care / Q000523:psychology*