Morris, Arden M.

ImportanceCancer imposes a substantial economic burden on patients that may be worse in patients with higher-stage disease due to the need for more therapy.ObjectiveTo investigate the out-of-pocket costs (OOPCs) attributable to the initial treatment of common cancers among privately insured individuals diagnosed at different stages.Design, Setting, and ParticipantsThis retrospective cohort study used administrative claims data of a large national insurer in the US linked to the Surveillance, Epidemiology, and End Results (SEER) cancer registry to compare OOPCs of individuals diagnosed with breast, colorectal, and lung cancer at different stages with OOPCs of similar individuals without cancer using difference-in-differences methods. Individuals living in the US between 2008 and 2022, aged younger than 65 years, insured through a large national private health insurer, and with 6 or more months of continuous enrollment were included. Data were analyzed from June 2024 through February 2025.ExposureThe presence or absence of an incident cancer diagnosis and disease stage from the SEER registry diagnosed from 2008 to 2019.Main Outcomes and MeasuresThe primary outcome was OOPCs among individuals with breast, colorectal, and lung cancer diagnosed at different disease stages compared with those with no cancer diagnosis.ResultsThe cohort consisted of 46 158 patients (mean [SD] age at diagnosis, 46 [12] years; 30 733 female [66.6%]; 2543 Asian [5.5%], 4114 Black [8.9%], 3590 Hispanic [7.8%], and 31 099 White [67.4%]), including 19 656 patients with cancer and 26 502 patients without cancer in the control group. Among patients with cancer, 14 581 patients had breast cancer, 2842 patients had colorectal cancer, and 2233 patients had lung cancer. An incident cancer diagnosis was associated with a mean increase in OOPCs of $592.53 per month (95% CI, $528.01-$627.04 per month) for the 6 months after the diagnosis. Cost monotonically increased with stage at diagnosis (mean OOPC increase range, $462.01 per month [95% CI, $417.92-$506.11 per month] for stage 0 to $719.97 per month [95% CI, $626.11-$813.83 per month] for stage 4).Conclusions and RelevanceIn this study of individuals with private insurance, patients faced high OOPCs after an incident diagnosis of cancer, with patients with more advanced cancer having the highest OOPCs. Further research is needed to determine the clinical and financial effects of increased OOPCs for patients with cancer.