OBJECTIVEto investigate the pathologic basis of the difference between clinical response and pathologic response of breast carcinoma after neoadjuvant chemotherapy.

METHODStwo hundred and nine cases of breast cancer with neoadjuvant therapy were analyzed and clinical data were collected from June, 2005 to December, 2007. All patients had core needle biopsy taken before neoadjuvant chemotherapy and were operated within 4 weeks after neoadjuvant chemotherapy. Clinical examination, X-ray of breast and/or B ultrasonography of primary breast focus were taken before and after neoadjuvant chemotherapy. Clinical responses of breast primary focus were evaluated according to RECIST (response evaluation criteria in solid tumors) version 1.1.Pathologic responses of breast primary focus were evaluated according to Miller and Payne (MP) grading system. SPSS 15.0 software was used to statistical analysis.

RESULTS(1) Clinical responses basing on clinical examination showed complete response, partial response, stable disease and progressive response, in 33, 124, 41 and 11 cases respectively. (2) Eighty-seven cases had X-ray of breast taken before and after neoadjuvant chemotherapy. Clinical response basing on X-ray, showed complete response, partial response and stable disease in 8, 42 and 37 cases respectively. (3) Pathologic responses of breast primary focus were as MP1 (14 cases), MP2 (35 cases), MP3 (106 cases), MP4 (36 cases) and MP5 (18 cases). (4) The clinical response basing on clinical examination were related to the pathologic response (χ(2) = 33.668, P = 0.001); and the clinical response basing on X-ray of breast were also related to the pathologic response (χ(2) = 22.404, P = 0.004). (5) The pathologic basis of the difference between the pathologic response and the clinical response basing on X-ray of breast were: embolism of carcinoma, mucinous carcinoma, intraductal carcinoma with ossifying-type calcification, nodular fibrosis and others.

CONCLUSIONSthe clinical response may be related to the pathologic response. The difference between the two may be caused by pathologic changes. Some benign and malignant pathologic changes may contribute to the under-estimation of clinical response over pathologic response; whereas embolism of carcinoma may contribute to the over-estimation of clinical response over pathologic response.