Abstract
To determine the preliminary effectiveness of breast cancer screening among Chinese females, 1226714 women aged 35-69 years first received clinical breast examinations. Urban women with suspected cancer received mammography followed by breast ultrasound (BUS), while rural suspected women underwent BUS followed by mammography. After one-year follow-up, 223 and 431 breast cancers were detected among urban and rural women (respectively), with overall detection rates of 0.56/1000 and 0.52/1000. Higher detection rates were significantly associated with older age at screening for both urban and rural women; additionally, urban women were at significantly higher risk if they had no job, no insurance, or were obese; additional risk factors specific to rural women included Han nationality, higher income, being unmarried, and having a family history of cancer (all P values < 0.05). Among screening-detected breast cancers in urban vs. rural women, 46.2% and 38.8% (respectively) were early stage, 62.5% and 66.3% were ≤2 centimeters, 38.0% and 47.3% included lymph-node involvement, and 14.0% and 6.0% were identified as carcinoma in situ. All abovementioned cancer characteristics were significantly better than clinic-detected cancers (all P values < 0.001). In conclusion, several important differences were found between urban and rural women in screening effectiveness and patterns of cancer distribution.