Abstract Background: Cancer patients and survivors experience distress related to physical, psychological, social and financial concerns. Individuals diagnosed with triple negative breast cancer (TNBC) may be at increased risk of distress due to the aggressive nature of the illness and high rates of recurrence. The aim of the present study was to describe how TNBC patients characterize cancer-related distress and concerns and identify factors associated with distress. Methods: Cancer Support Community’s Cancer Experience Registry® (CER) is an online research initiative examining the physical, emotional, practical, and financial impact of cancer. The CER measures cancer-related distress using CancerSupportSource™ (CSS), a 25-item validated distress screening tool in which participants rate their level of concern (0=Not at all; 4=Very seriously) across five key domains: (1) emotional well-being (EWB; 8 items, α=.91); (2) symptom burden and impact (SYM; 8 items, α=.90); (3) body image and healthy lifestyle (BHL; 4 items, α=.80); (4) healthcare team communication (HCC; 2 items, α=.74); (5) relationships and intimacy (REL; 2 items, α=.71). CSS subscale scores were calculated as the average item rating. For item analysis, the proportion indicating moderate to very serious concern was reported. From January 2015 to August 2021, a total of 195 US residents with a history of TNBC took part in the CER and completed CSS. Multiple linear regression analysis was used to estimate the relationships between CSS subscales and socio-demographic variables (age, low-income status, employment status) and clinical history (time since diagnosis, advanced or metastatic disease, and currently receiving treatment). Results: The sample was 82% Non-Hispanic White, 7% Non-Hispanic Black, 5% Hispanic, and 7% Non-Hispanic other/multiracial. 17% reported annual household income <$40K. 44% was employed full-time, 12% part-time, 18% retired, and 24% unemployed due to disability or other reason. Mean age was 53 (SD=10) years; 11% were < 40 years. 14% of participants were < 1 year of cancer diagnosis, 27% 1 to < 2 years, 34% 2 to < 5 years, and 25% ≥5 years. 41% were currently receiving treatment, and 27% were diagnosed with advanced or metastatic disease. The mean distress subscale score was highest for concerns about BHL (1.61), followed by EWB (1.29), SYM (1.27), REL (1.04), and HCC (0.83). With regard to concerns about BHL, over half were moderately to very seriously concerned with eating and nutrition (55%) and exercise (55%). Regarding EWB, the items of greatest distress were worrying about the future (53%) and worrying about family (39%). For SYM, over half (53%) were concerned about thinking clearly, and 49% were concerned about fatigue. Participants reported moderate to very serious concern about intimacy, sexual function, and/or fertility (36%) and relationships (22%). Regarding HCC, 24% reported concern related to treatment decisions, while 22% reported concern about communicating with their doctor. In multivariate analysis, time since diagnosis was inversely associated with concerns about EWB (B=-0.03, p=.030), such that distress was higher closer to diagnosis. TNBC patients with advanced or metastatic disease status had significantly higher distress related to SYM (B=0.40, p=.009) and HCC (B=0.61, p=.001). Younger age was associated with concerns about BHL (B=-0.02, p=.011) and REL (B=-0.02, p=.006). Finally, unemployment was associated with higher distress related to EWB (B=0.57, p=.001), SYM (B=0.63, p<.001), BHL (B=0.42, p=0.03), and REL (B=0.70, p<.001). Conclusions: In this sample, average levels indicated slight distress across multiple domains. Many TNBC patients reported concerns that were physical and future-oriented, highlighting critical areas of unmet need. Factors of less time since cancer diagnosis, advanced/metastatic disease, younger age, and unemployment were predictors of higher levels of distress. Citation Format: Caroline Lawrence, Erica E. Fortune, Heather Badt, Kara Doughtie, Madyson L. Popalis, Melissa F. Miller. Cancer-Related Distress and Unmet Needs Among Triple Negative Breast Cancer Patients: Findings from the Cancer Experience Registry [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-05-01.