Patrones de reducción luego de quimioterapia neoadyuvante por cáncer de mama

Introduction: there are two patterns of tumor response to neoadjuvant chemotherapy: concentric or scattered. Patients with scattered response are not good candidates for conservative surgery since its tumor microfoci can go unnoticed in the tissue around the main residual tumor. The kind of response has been identified as an ipsilateral recurrence factor after conservative surgery. Objective: the study aims to evaluate the response percentage for each pattern and sufficiency of the surgical resection margin obtained in the cases of conservative surgery. Method: the medical records of patients who underwent surgery after neoadjuvant chemotherapy between May 2004 and December 2013 were analysed. The type of chemotherapy and the histopathology reports were thoroughly analysed to determine the reponse pattern, as well as the molecular phenotypes and the degree of tumor for each case. Results: 14 out of 55 cases (25%) presented a scattered response pattern (ten of them with distant microfoci from the invasive cancer and four with distant microfoci of in situ cancer). Percentage of pathologic complete response was 15.4%. There were no significant differences in the response patterns among the different immunophenotypes or among different degrees of tumors, and neither was there a significant difference between those who received taxenes and those who did not receive it. Conclusions: one fourth of patients in our series presented a scattered reponse pattern after neoadjuvant chemotherapy. This may be a warning signal for those who advocate for conservative surgery after neoadjuvant treatment, since scattered response increases the risk of insufficient margins and ipsilateral recurrence.