Abstract P6-12-13: Synchronous metastases are highly prevalent in HER2 positive inflammatory breast carcinomas evaluated by 18F-FDG PET/CT

Background: Inflammatory breast carcinomas have poor prognosis even in the absence of evident synchronous metastases. 18F-FDG PET/CT is not recommended in initial staging but could improve the sensibility of synchronous metastases detection and the management of the patients. Objective: To assess factors associated with synchronous metastases in inflammatory breast carcinomas when evaluated by 18F-FDG PET/CT. Methods: Since 2006, initial staging of locally advanced breast carcinomas in our center consisted of 18F-FDG PET/CT in addition to standard laboratory and radiological tests. We reviewed data of patients with inflammatory breast carcinomas treated from 2006 to 2013 who had an initial evaluable18F-FDG PET/CT. Fisher9s exact test and logistic model were used to assess factors associated with synchronous metastases. Overall survival was estimated with the method of Kaplan-Meier. Results: Among 353 locally advanced breast carcinomas seen at the breast disease unit, hospital Saint Louis from 04/2006 to 04/2013, we identified 40 inflammatory breast carcinomas. Initial 18F-FDG PET/CT was available for review in 32 inflammatory breast carcinomas. Median age was 57 years (range 38-78), 39% had pre-menopausal status (n = 12), clinical node involvement was found in 87.5% (n = 28). Histological features on biopsy were: ductal invasive carcinoma 91% (n = 29), SBR grade III 72% (n = 23), negative hormonal receptor 75% (n = 24), positive HER2 37.5% (n = 12), triple negative 44% (n = 14). Synchronous metastases were found in 41% of inflammatory breast carcinomas (n = 13), bone (n = 7), liver (n = 6) and mediastinum (n = 4). Synchronous metastases seemed more common in HER2 positive than in HER2 negative inflammatory breast carcinomas (58% vs 30%, p = 0.15). In multivariate analysis, no factor was associated with synchronous metastases. All patients with inflammatory breast carcinomas received neoadjuvant chemotherapy with sequential anthracycline and taxane (16 patients), dose-dense anthracycline and alkylating agent (8 patients), taxane with or without bevacizumab (7 patients) and anthracycline in 1 patient. Trastuzumab was given in all HER2 positive inflammatory breast carcinomas. Clinical response to neoadjuvant chemotherapy was complete in 16.5% (n = 5), partial in 67% (n = 20), stable or progressive in 16.5% (n = 5) and missing for 1 patient. One patient died before response assessment. Thirty patients (94%) underwent radical mastectomy with axillary node dissection. Pathologic complete response in breast and nodes was found in 27.5% (n = 8). Axillary node invasion was found in 45% (n = 13). All positive hormonal receptors patients received endocrine therapy after surgery. With a median follow-up of 33 months, 10 patients died. Median overall survival was 38.8 months (95%CI: 30.3-NA) with no difference between HER2 positive and HER2 negative patients. Conclusion: Synchronous metastases are common in inflammatory breast carcinomas especially in case of HER2 positive tumors. Complete initial staging with 18F-FDG PET/CT could be useful to detect synchronous metastases mainly in bone and liver and thus allowed to adapt further treatment. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-12-13.