Abstract PO3-02-13: Breast Cancer in Very Young Adult Women At or Under the Age of 35 Years: Characteristics and Outcomes

Abstract Background: Breast cancer (BC) is the most common malignancy among women in Saudi Arabia. Noticeably, it shows a higher incidence in younger age groups than what is reported from Western countries. Age 35 years and less is an applied cut-off age for clinically defining BC in very young women (BCVY). This study describes characteristics, survival and risk of death associated factors in this rare subset of patients. Methods: A retrospective cohort study included females 18 and 35 years with histologically confirmed primary non-metastatic breast cancer from an academic hospital in Jeddah, Saudi Arabia between the years 2009-2019. Demographic data, tumor clinicopathological features, and outcomes were obtained. Survival and potential associated factors were examined. A p-value of less than 0.05 was regarded as statistically significant. Results: 204 female patients with a confirmed breast cancer diagnosis were included. The mean age at diagnosis was 31.43 ± 2.94 years. Fifty-three percent of the patients had a left-sided tumor with the majority being IDC (92%) and one-third with positive axillary lymph nodes (N+) and multifocal disease in 17%. One-quarter of the tumors showed LVI, 45% revealed associated DCIS and 26% showed tumor necrosis on histopathology examination. The presence of tumor-infiltrating lymphocytes (TILs) was reported in 23% of TNBC cases. Tubular differentiation score 3 was reported in 79.4%, nuclear pleomorphism score 3 in 79% and mitosis activity score 3 in 19% while the most reported overall grade was II in 48.5% followed by grade III in 34%. HER2-positive in 33.8 %, HR-positive in 34.3 %, TNBC in 24% and unknown in 8% of the patients. Thirty percent had a distant recurrence and 15% were deceased. The mean survival time was 4.61 years with a maximum of 6.54 years and a minimum of 3.67 years. Table 1 shows the multivariate logistic regression analysis of factors influencing the risk of death in very young patients with breast cancer. Conclusions: The current study describes the clinicopathological characteristic, survival and related factors of breast cancer in very young patients 35 years, which is considered an uncommon presentation. Large, high-grade tumors and a high frequency of HER2 and TNBC were observed in BCVY patients. Involvement of the regional lymph nodes and the development of distant recurrence were associated significantly with an increased risk of death. The presence or absence of TILs, LVI and tumor necrosis on histopathological examination did not influence the risk of recurrence or death in this cohort. Table 1. The multivariate logistic regression analysis of factors influencing the risk of death in very young patients with breast cancer. Citation Format: Atlal Abusanad, Rana Ajabnoor, Aydah Al-Awadhi, Omalkhair Abualkhair. Breast Cancer in Very Young Adult Women At or Under the Age of 35 Years: Characteristics and Outcomes 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 PO3-02-13.