Background: Invasive breast carcinomas are composed of invasive and noninvasive components in varying proportions and sometimes the two components show different histopathological responses to chemotherapy, however there has been no study as yet comparing the pathological response to chemotherapy of invasive and noninvasive components.
Patients and methods: A consecutive series of 100 women neoadjuvant chemotherapy with doxorubicin and docetaxel every three weeks before surgery. After the chemotherapy, surgically resected specimens were studied histologically according to the criteria of the Japanese Breast Cancer Society.
Results: Five cases (5/100; 5%) were determined to show Grade 3 pathological response, and 28 cases (28/100; 28%) showed Grade 2 response. There were 6 Grade 3 (6/96; 6%) and 18 Grade 2 (18/96; 19%) invasive component cases. There were 7 Grade 3 (7/82; 9%) and 18 Grade 2 (18/82; 22%) cases showing pathological response in the noninvasive component. With regard to pathological response, there was a strong correlation between the invasive and noninvasive components (p<0.001). There was also a correlation in pathological response between the invasive component and axillary lymph nodes in individual cases (p=0.02). There was no correlation between the response of the noninvasive component and axillary lymph nodes. By multivariate analysis, the overall primary tumor response was reflected by the histological response of the invasive component in the primary breast carcinoma.
Conclusion: We suggest that the pathological response of the invasive component of breast carcinoma should be evaluated, which might provide more accurate information for prognosis and treatment decisions.