Radiation-associated angiosarcoma of the breast: An international multicenter analysis.

INTRODUCTION: Radiation-associated angiosarcoma (RAAS) is a rare and serious complication of breast irradiation. Due to the rarity of the condition, clinical experience is limited and publications on this topic include only retrospective studies or case reports. MATERIALS AND METHODS: All patients diagnosed with RAAS between January 2000 and December 2017 in twelve centers across the Czech Republic and Slovakia were evaluated. RESULTS: Data of 53 patients were analyzed. The median age at diagnosis was 72 (range 44-89) years. The median latency period between irradiation and diagnosis of RAAS was 78 (range 36-172) months. The median radiation dose was 57.6 (range 34-66) Gy. The whole breast radiation therapy with radiation boost to the tumor bed was the most common radiotherapy regimen. Total mastectomy due to RAAS was performed in 43 patients (81%), radical excision in 8 (15%); 2 patients were not surgically treated due to unresectable disease. Adjuvant chemotherapy followed surgical therapy of RAAS in 18 patients, 3 patients underwent adjuvant radiotherapy. The local recurrence rate of RAAS was 43% and the median time from surgery to the onset of recurrence was 7.5 months (range 3-66 months). The 3-year survival rate was 56%, the 5-year survival rate was only 33%. 46% of patients died during the follow-up period. CONCLUSION: The present data demonstrate that RAAS is a rare condition with high local recurrence rate (43%) and mortality (the 5-year survival rate was 33%.). Early diagnosis of RAAS based on biopsy is crucial for treatment with radical intent. Surgery with negative margins constitutes the most important part of the therapy; the role of adjuvant chemotherapy and radiotherapy is still unclear.

Permanent Pro-Tumorigenic Shift in Adipose Tissue-Derived Mesenchymal Stromal Cells Induced by Breast Malignancy.

During cancer progression, breast tumor cells interact with adjacent adipose tissue, which has been shown to be engaged in cancer aggressiveness. However, the tumor-directed changes in adipose tissue-resident stromal cells affected by the tumor-stroma communication are still poorly understood. The acquired changes might remain in the tissue even after tumor removal and may contribute to tumor relapse. We investigated functional properties (migratory capacity, expression and secretion profile) of mesenchymal stromal cells isolated from healthy (n = 9) and tumor-distant breast adipose tissue (n = 32). Cancer patient-derived mesenchymal stromal cells (MSCs) (MSC-CA) exhibited a significantly disarranged secretion profile and proliferation potential. Co-culture with MDA-MB-231, T47D and JIMT-1, representing different subtypes of breast cancer, was used to analyze the effect of MSCs on proliferation, invasion and tumorigenicity. The MSC-CA enhanced tumorigenicity and altered xenograft composition in immunodeficient mice. Histological analysis revealed collective cell invasion with a specific invasive front of EMT-positive tumor cells as well as invasion of cancer cells to the nerve-surrounding space. This study identifies that adipose tissue-derived mesenchymal stromal cells are primed and permanently altered by tumor presence in breast tissue and have the potential to increase tumor cell invasive ability through the activation of epithelial-to-mesenchymal transition in tumor cells.