[Comparative analysis of early diagnostic tools for breast cancer]

Mammography is the principle imaging modality used for early diagnosis of breast cancer in Western countries. It has not been well-established whether this Western diagnostic modality is adoptable for Chinese women. The aim of this study was to evaluate the respective accuracy of the common diagnostic tools for breast cancer including history-taking, physical examination, ultrasound and mammography.

Clinical presentation and investigations for consecutive patients undergoing history-taking, physical examination, ultrasound, mammography and pathological assessment at Peking Union Medical College Hospital were prospectively recorded between April 2010 and September 2011. Breast cancer high-risk factors acquired by history-taking were input into the risk assessment model established previously by Eleventh Five Year Key Programs for Science and Technology Development of China (Grant No. 2006BAI02A09) and classified into low-, medium-, high- and extremely high-risk groups. The low- and medium-risk groups were defined as test negative, while the high- and extremely high-risk groups were defined as test positive. Each mammogram and ultrasound was reported prospectively using a five-point reporting scale of the American College of Radiology (ACR) Breast Imaging Reporting and Data System (BI-RADS). Clinical data were compared with pathological findings. Sensitivity, specificity, positive predictive value (PRV), negative predictive value (NPV) and accuracy of respective diagnostic methods were calculated and compared. The patients were divided into two groups, above and below 50 years of age for subgroup analysis.

A total of 1468 patients (1475 breast lesions) constituted the study population. The median age was 44 (range 13 - 92) years. Five hundred and fifty-one patients were diagnosed as breast cancer. The median age at diagnosis was 51 years and breast cancer peaked in the age group of 40 - 60 years. The sensitivity of risk assessment model, physical examination, ultrasound and mammogram was 47.5%, 86.2%, 89.8% and 79.3%, respectively; specificity was 68.8%, 83.3%, 81.0% and 88.7%, respectively; PRV was 47.6%, 75.5%, 73.8% and 80.8%, respectively; NPV was 68.8%, 91.0%, 93.0% and 87.8%, respectively; and accuracy was 60.9%, 84.4%, 84.3% and 85.2%, respectively. Further subgroup analysis demonstrated that age is an important factor influencing the sensitivity and specificity of physical examination, ultrasound and mammography.

Ultrasound is more sensitive than mammography for early diagnosis of breast cancer in Chinese women and should be routinely used as a first-line diagnostic tool. Only a single diagnostic method is not enough sometimes and combined examination is needed for some high-risk populations.