The epidemiological profile of women with an interval cancer in the DOM screening programme.

Risk factors for breast cancer were compared in 107 women with interval breast cancer (cancers occurring within 2 years after a negative screen) and 258 women with breast cancer detected at 1st screening. All women (aged 40-67) were screened in the DOM project (the Utrecht programme for the early detection of breast cancer). Women with an interval cancer reported more often a history of benign breast disease (OR 4.66, 95% C.I. 2.08-10.41) and an artificial menopause (OR 4.07; 95% C.I. 1.74-9.55) than women with a screen detected cancer. Women with an interval cancer were taller than women with a screen detected cancer; this was seen most clearly in women with an artificial menopause (chi 2 for trend = 5.88; p = 0.02) and to a lesser extent in premenopausal women (chi 2 for trend = 1.70; p = 0.19). Premenopausal women with an interval cancer were heavier than women with a screen detected cancer (chi 2 for trend = 4.66; p = 0.03); whereas natural postmenopausal women with an interval cancer were leaner than women with a screen detected cancer (chi 2 for trend = 1.57; p = 0.21). All analyses were done while correcting for age and selected other risk factors for breast cancer. These results suggest that the epidemiological profile of pre- and post-menopausal women with an interval cancer differs from that of women with a screen detected cancer, which might imply a different natural history of these two types of breast tumours.