Abstract PO2-28-04: Pregnancy-associated relapse of triple-negative breast cancer

Introduction: Pregnancy Triple-negative breast cancer(TNMC) is the absence of ER PR and HER2 receptor expression. It constitutes about 15-20% of all breast cancers and is known to be the aggressive form with a high relapse rate (1). Interestingly, it usually affects women aged < 40 and has a low survival rate in African-American females. This case is a typical presentation of a 38-year-old young woman with PMH of T2NO right triple-negative breast cancer diagnosed in 2017 s/p right mastectomy with sentinel LN biopsy, received immunotherapy and chemotherapy, has been cancer-free for two years, and developed metastatic cancer during her pregnancy. In this case, we understand the diagnostic and therapeutic challenges of TNBC during pregnancy. Case: A 38-year-old African American woman, G0, T2NO triple negative invasive ductal carcinoma, underwent a right breast mastectomy and sentinel LN biopsy. She received treatment with (Anti-PD-L1 Antibody) concomitant with weekly paclitaxel and Doxorubicin/Cyclophosphamide (AC) chemotherapy. However, she had a residual 4cm tumor for which she was treated with adjuvant therapy with capecitabine for six months. A repeat Mammogram in 2019 showed no evidence of malignancy. In 2021, the patient was G2P2L1, admitted to the hospital after having a seizure. CT reported cystic/necrotic left parietal lesion mass effect with 8mm right-sided midline shift with metastasis to lungs and abdominal wall. She underwent L parietal craniectomy with resection of the tumor. At 32 weeks of gestation , chemotherapy with carboplatin and paclitaxel was given after her C-section and Gamma knife radiosurgery for metastatic lesions. She developed super refractory seizures, was induced into a coma with therapeutically anesthetic agents, and passed eventually. Discussion: Little literature exists on pregnancy-associated relapse of triple-negative breast cancer and its deterioration. Our patient was in remission for two years and was diagnosed with metastatic cancer during her second pregnancy. John et al., (2018) discussed an interesting association between breastfeeding, parity, and occurrence of TNBC, that there is a two-fold increased risk of developing TNBC with high parity(3 full-term pregnancies) and short-term breastfeeding (< 12 months) (2). Studies have also shown that cancers during or postpartum pregnancy are aggressive with more tumor burden and metastasize to the lungs, liver, and brain, which is consistent with our patient. (3) Conclusion: Pregnancy-associated breast cancer is diagnostically and therapeutically challenging during or in the postpartum period and with a high propensity of the triple-negative type. It requires a multidisciplinary team approach, awareness in the African American population, clinical suspicion of breast mass during pregnancy warrants imaging, and prolonged breastfeeding postpartum. Diagnosis is usually delayed due to pregnancy, and more research is needed on the diagnostic modalities during pregnancy for early treatment initiation. References Almansour NM. Triple-Negative Breast Cancer: A Brief Review About Epidemiology, Risk Factors, Signaling Pathways, Treatment and Role of Artificial Intelligence. Front Mol Biosci. 2022 Jan 25;9:836417. doi: 10.3389/fmolb.2022.836417. PMID: 35145999; PMCID: PMC8824427. John EM, Hines LM, Phipps AI, et al. Reproductive history, breast-feeding and risk of triple-negative breast cancer: The Breast Cancer Etiology in Minorities (BEM) study. International Journal of Cancer. 2018;142(11):2273. doi:10.1002/ijc.31258 Amant F, Deckers S, Van Calsteren K, Loibl S, Halaska M, Brepoels L, et al. Breast cancer in pregnancy: recommendations of an international consensus meeting. Eur J Cancer (2010) 46(18):3158–68. 10.1016/j.ejca.2010.09.010 Citation Format: Vaidarshi Abbagoni. Pregnancy-associated relapse of triple-negative breast cancer [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 PO2-28-04.