208 Background: From the moment cancer is suspected, patients and their caregivers may feel overwhelmed and not know where to seek help for non-medical questions. Social risks, including financial instability, housing and food insecurity can lead to poor cancer outcomes, and 39% of Kaiser Permanente (KP) cancer patients screened positive for at least one social risk. KP implemented the Cancer Support Line to provide patients and caregivers with a single point of contact to address non-medical concerns, including financial navigation, social health needs, and general cancer information. Methods: Kaiser Permanente partnered with patients, clinicians, and health plan functions supporting member services, social health, and quality to co-design and implement a phone number for cancer members in the KP Northwest market. The Cancer Support Line (‘Line’) is an inbound phone number staffed by Cancer Support Specialists (‘Specialists’), a dedicated team of health plan member services, trained in cancer support skills. Specialists use four co-designed pathways to navigate callers to resources for financial questions, social needs, and general cancer information and support. If clinically appropriate questions arise, Specialists use existing operational channels to connect patients back to their care teams. Results: During the pilot, there were 1,057 interactions with members, patients, and caregivers from March 12 th to May 17 th . Financial questions about payment assistance and insurance benefits/eligibility emerged as the highest call driver. The top call outcomes by volume are shown in the included table. A high majority of calls (94%, n=992) were addressed by the Cancer Support Specialists themselves. Post-call survey results revealed that 96% of callers (n=26) rated their call experience high when asked “How would you rate your overall call experience today?” Conclusions: Effective collaboration across KP’s project teams was a critical driver of the pilot’s success. Workflows were built with all partner teams and departments, Specialist training was designed internally with consultation from the American Cancer Society, team communications were open and consistent, call reporting was robust and adaptable. Furthermore, the Line addresses a critical gap in the cancer patient experience: navigating non-medical needs that busy care teams are unable to address on their own. Though positive, these pilot results are preliminary and focused on one KP market. To evaluate the pilot for scalability, the team will assess process metrics and outcomes on caller, frontline staff, and Specialist experience on an ongoing basis to capture the Line’s broader operational impact. Call transfer destination. Transfer Destination # of calls % No Transfer 992 93.9% KP Community Support Hub Transfer 45 4.3% Clinical Transfer 17 1.6% KP Community Support Hub + Clinic Transfer 3 0.3%