Aim: To observe the morbidities of breast cancer of 20 000 women in Liaoning province，explore risk factors of epidemiology and determine the optimal program for breast cancer screening.
Methods: Assessment in this National Health Service Breast Screening Programme (NHSBSP) was carried out by a specialist multidisciplinary team using the five approach: clinical examination, ultrasound, mammography, and, where appropriate, MRI. After confirmation of a suspicious abnormality, needle biopsy was performed. Informed patient consent was obtained.
Results: 33 cases were found breast cancer. Thus the total morbidity of breast cancer was 0.165%. Factors contributing toward increased risk of breast cancer were benign breast disease, family history of breast cancer, earlier menache (≤14 years old), irregular menstruation, shorter feeding time(≤12 months) , overweight, previous use of oral contraceptives and drinking alcohol (p value<0.05). However, women smoke or not make no significant difference in morbidity of breast cancer (p <0.01). In the 33 cases of breast cancer with histologically diagnosis, the detection rate of clinical examination, mammography and ultrasound was 48.48％（16/33）96.97％（32/33）and 75.76％（25/33） respectively. In the 33 cases, the level of diagnostic agreement between mammography and ultrasound was low(κ＝0.155). In screening high-risk women underwent breast MRI, it was statistically valuable to differentiate benign from malignant breast lesions by the values of ADC（P<0.05）or time-signal intensity curves. The sensitivities, specificity and accuracy was 90.00%（9/10），88.46%（26/29），89.74%（35/39）respectively.
Conclusions: The high morbidity of breast cancer may be related to benign breast disease, family history of breast cancer, early menache, irregular menstruation, short feeding time, overweight, previous use of oral contraceptives and drinking alcohol in Liaoning province in China. A higher diagnostic value in breast cancer screening could be achieved by using combination of clinical examination, ultrasound and mammography. MRI with DWI or time-signal intensity curves appears to play an important role in differentiation of benign and malignant breast lesions.