In this cohort study of individuals with stage IV breast cancer, incidence increased significantly overall, across ages, and for both sexes from 2010 through 2021. The percentage of individuals with stage IV vs stages I to III diagnoses also increased. Although overall survival improved, research is warranted to determine factors contributing to increased incidence, including potential changes in natural history of breast cancer, disease screening, and incidence and mortality of other conditions.

Ivermectin-benzimidazole prescribing rose rapidly following celebrity endorsement in January 2025, with disproportionate increases among male patients, white patients, residents of the U.S. South, and individuals with cancer. The elevated prescribing observed among patients with cancer is particularly concerning; individuals facing life-threatening illness may delay or forgo conventional treatments in favor of unproven therapies, potentially allowing their disease to progress.

Prescriptions for the anti-parasite medication ivermectin doubled in the months following an endorsement by a celebrity during a high-profile podcast as an off-label cancer treatment. The endorsement came on January 9, 2025, when actor Mel Gibson appeared on The Joe Rogan Experience and described three friends with stage IV cancer who he said recovered after taking ivermectin and fenbendazole.

A study conducted by researchers at University of Tsukuba revealed that individuals with higher cancer-related health literacy, perceived susceptibility to gastric cancer, and encouragement from family members or healthcare providers demonstrated stronger intentions to undergo gastric cancer screening, even during the COVID-19 pandemic. These intentions were significantly associated with subsequent screening participation. In contrast, while fear of COVID-19 increased screening intention in the short term, over time it could suppress screening behavior.