Biomarker Testing Approaches, Treatment Selection, and Cost of Care Among Adults With Advanced Cancer.

Importance: Clinical guidelines recommend biomarker testing to identify patients eligible for targeted therapy. However, evidence suggests that biomarker testing rates are below guideline recommendations, which has been associated with worsened clinical outcomes, including overall survival. Objectives: To identify patients with newly diagnosed advanced cancer receiving comprehensive genomic profiling (CGP), non-CGP, or no biomarker testing and to explore the change in rates of testing over time and compare targeted therapy rates and health care costs during first-line therapy. Design, Setting, and Participants: This retrospective cohort study used the deidentified Optum Labs Data Warehouse, a claims database of longitudinal health information on commercial health plan and Medicare Advantage enrollees, to identify patients diagnosed with advanced cancer between January 1, 2018, and January 1, 2022. The study included 26 311 adults with newly diagnosed advanced cancer (breast, colorectal, gastric, non-small cell lung, ovarian, and pancreatic) and continuous enrollment in a commercial or Medicare Advantage health plan for 12 months before and 6 months after their first advanced cancer diagnosis. Data were analyzed between February 1, 2023, and March 31, 2024. Exposure: Biomarker testing. Main Outcomes and Measures: Evidence of biomarker testing, the receipt of targeted therapy during first-line therapy, and per-patient, per-month (PPPM) costs during first-line therapy. Results: Among 26 311 patients (mean [SD] age, 68 [11] years; 62% female; 70% Medicare Advantage enrollees), molecular testing rates were suboptimal (35% had evidence of molecular testing), but testing rates increased across time for most cancer types (from 32% in 2018 to 39% in 2021-2022). Patients with non-small cell lung cancer and colorectal cancer with CGP testing were more likely to receive targeted therapy (odds ratio [OR], 1.57; 95% CI, 1.31-1.90; P < .001) compared with patients who received non-CGP testing (OR, 2.34; 95% CI, 1.58-3.47; P < .001). Costs among patients with CGP testing were not statistically different from those with non-CGP testing (cost ratios of 1.03; 95% CI, 0.91-1.17 [P = .63] for breast cancer, 0.98; 95% CI, 0.89-1.09 [P = .71] for colorectal cancer, 1.10; 95% CI, 0.87-1.40 [P = .42] for gastric cancer, 1.06; 95% CI, 1.00-1.13 [P = .054] for non-small cell lung, 0.94; 95% CI, 0.76-1.15 [P = .55] for ovarian cancer, and 1.00; 95% CI, 0.83-1.21 [P = .98] for pancreatic cancer). Conclusions and Relevance: In this cohort study, although increasing over time, biomarker testing rates were suboptimal despite guideline recommendations and increasing insurance coverage for testing. Given the potential benefits of CGP testing, such as increasing rates of targeted therapy without increased treatment-related costs, increasing CGP testing may improve outcomes.