Recent trends in utilization of outpatient medical oncology services.

11101 Background: Health systems face escalating demand from rising cancer incidence and treatment complexity. Effective health human resource planning is critical to accommodate these trends. Limited data are available on longitudinal utilization of medical oncology services, especially volumes and complexity of care. We sought to characterize real-world longitudinal utilization of outpatient medical oncology services across common solid tumors to inform workforce planning and policy. Methods: We conducted a retrospective, population-based retrospective cohort study using linked administrative health data from Ontario, Canada. Adults diagnosed between 2015 and 2022 with lung, colon, rectal, pancreatic, breast, melanoma, or prostate cancer were identified through the Ontario Cancer Registry. Medical oncology consultations, clinic visits, and systemic treatment encounters were captured from the provincial Activity Level Reporting database. Primary outcomes included consultation and systemic therapy initiation trend, and mean clinic and treatment visits during the first year following medical oncology consultation. Results: The cohort consisted of 332,604 patients (median age 68 years; 48.7% male), with new cases increasing from 39,688 in 2015 to 45,011 in 2022. Medical oncology consultation and systemic treatment initiation were encountered by 57.8% (range: 17.2% prostate to 92.8% breast) and 71.2% respectively (range: 45.1% melanoma to 82.8% breast). The proportion of patients with medical oncology consultation increased appreciably for pancreatic (59.8% to 79.0%), colon (55.8% to 60.2%), rectal (64.4% to 69.6%), and lung cancers (57.3% to 61.4%), with resultant growth in consultation volumes except for melanoma, colon and lung cancers. Total clinic visits increased from 131,950 in 2015 to 174,630 in 2022. Mean clinic visits per patient increased significantly for all cancers except prostate (p < 0.001), with the greatest increase observed in melanoma (+0.33 visits/year). Systemic therapy exposure increased across most cancers, most notably melanoma (25.7% to 47.2%) and prostate cancer (61.2% to 73.9%). Total systemic treatment visits increased from 129,380 in 2015 to 165,149 in 2022 with total and mean per patient trends exhibiting mixed, disease-specific patterns. Conclusions: Outpatient medical oncology service utilization per patient has expanded substantially over time, driven by rising volumes of consultations, systemic therapy and clinic visits. Taken with the rising complexity of care, these data suggest that consultation-based workload metrics likely underestimate service demand. Workforce planning models should incorporate follow-up care, treatment monitoring, and disease-specific trajectories to ensure sustainable, high-quality oncology care delivery.