Characteristics of Mammary Paget’s Disease in China: a National-wide Multicenter Retrospective Study During 1999-2008

The aim of this study was to detail characteristics of mammary Paget’s disease (PD) representing thewhole population in China. A total of 4211 female breast cancer inpatients at seven tertiary hospitals fromseven representative geographical regions of China were collected randomly during 1999 to 2008. Data fordemography, risk factors, diagnostic imaging test, physical examination and pathologic characters were surveyedand biomarker status was tested by immunohistochemistry. The differences of demography and risk factorsbetween PD with breast cancer and other lesions were compared using Chi-square test or t-test, with attentionto physical examination and pathological characters. The percentage of PD was 1.6% (68/4211) in all breastcancers. The mean age at diagnosis was 48.1, and 63.2% (43/68) patients were premenopausal. There is nodifference in demography and risk factors between PD with breast cancer and other breast cancer (P > 0.05).The main pattern of PD in physical exam and pathologic pattern were patients presenting with a palpablemass in breast (65/68, 95.6%) and PD with underlying invasive cancer (82.4%, 56/68) respectively. The rate ofmultifocal disease was 7.4% (5/68). PD with invasive breast cancer showed larger tumor size, more multifocaldisease, lower ER and PR expression and higher HER2 overexpression than those in other invasive breastcancer (P < 0.05). These results suggested that PD in China is a concomitant disease of breast cancer, and thatPD with underlying invasive cancer has more multiple foci and more aggressive behavior compared with otherbreast invasive cancer. We address the urgent needs for establishing diagnostic and therapeutic guidelines formammary PD in China.