Abstract PO1-20-08: Primary breast implant-associated squamous cell carcinoma with subsequent TEMPUS testing and failure of immunotherapy

Abstract

Abstract Primary squamous cell carcinoma of the breast is a rare entity, and there are a limited number of cases in the literature describing squamous cell carcinoma arising from breast implants. It has been hypothesized that these implant-associated cancers may arise from epithelialization of the implant capsule followed by chronic inflammation. None of the cases in the literature were treated with immunotherapy. We present a case of an aggressive, primary sarcomatoid squamous cell carcinoma of the breast arising from a breast implant that was treated unsuccessfully with simultaneous chemotherapy and immunotherapy following TEMPUS testing. Introduction: Breast augmentation is the most common plastic surgery procedure performed worldwide, with more than 300,000 done in the United States every year. While breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is extensively discussed in recent literature, other breast implant-associated cancers are rarer and less studied. Breast implant-associated squamous cell carcinoma (BIA-SCC) specifically is an extremely rare complication of breast augmentation and no guidelines for treatment exist. The American Society of Plastic Surgeons (ASPS) released a statement on BIA-SCC on 9/2022 following a safety communication from the FDA, and it is recommended health care providers submit case reports of BIA-SCC to a patient registry. Case study: We present the case of a female patient who underwent bilateral breast augmentation in 2006 with Mcghan textured, pre-pectoral, areolar saline implants. In 2022, she presented with swelling and a lump in her breast and underwent bilateral breast implant removal with capsulectomy. Pathology showed triple negative sarcomatoid squamous cell carcinoma of the right breast capsule. TEMPUS testing on the breast biopsy revealed a PIK3CA mutation and PD-L1 negative status. Her case was discussed with a multi-disciplinary team including plastic surgery, multiple oncologists, and radiation oncology and her clinical picture was determined to be most consistent with BIA-SCC. Based on the KEYNOTE-522 study, she was determined to be a candidate for neoadjuvant therapy with pembrolizumab and chemotherapy as she was newly diagnosed, previously untreated, nonmetastatic, and had a triple negative tumor. She received two cycles of carboplatin, paclitaxel, and pembrolizumab but unfortunately rapidly progressed with chest wall extension, multiple new pulmonary nodules, worsening lymphadenopathy, right ventricular tumor thrombus, and new malignant pleural effusion and was transitioned to hospice. Discussion: Seven cases of BIA-SCC, one case of squamous cell carcinoma (SCC) after liquid silicone injection augmentation, one case of squamous metaplasia on the breast implant capsule, and one case of epithelization of the breast implant capsule have been previously described in the literature (Table 1). None of the available cases of BIA-SCC report TEMPUS testing, and none of the patients were treated with immunotherapy. The origin of BIA-SCC is unclear, but several theories have been described including chronic inflammation leading to conversion of epithelial tissue on the capsule to SCC. It is unknown how the breast implant capsule might become epithelialized to begin with – introduction of epithelium intraoperatively during augmentation, rupture of epidermal cysts, existence of epithelium in the area from a childhood injury or from birth, or epithelization from chronic shear forces from the augmentation or leakage of the implant are all possibilities. With the ongoing data gathering through the FDA patient registry, we will continue to learn more about these rare cancers and potentially get further insight into their origins. Table 1 An overview of cases of BIA-SCC in the literature Citation Format: Emily Podany, Katherine Clifton. Primary breast implant-associated squamous cell carcinoma with subsequent TEMPUS testing and failure of immunotherapy [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-20-08.