An umbrella review of meta-analyses on smoking cessation and cancer survival: a brief report.

Smoking cessation at or around the time of cancer diagnosis is associated with significant improvements in survival across multiple tumor types. This umbrella review of 12 meta-analyses demonstrates that patients who quit smoking post-diagnosis have a 15-29% reduction in mortality in lung cancer, a 20% reduction in head and neck cancers, and a 24% reduction in colorectal cancer. Suggestive benefits were also observed in breast, bladder, and gastrointestinal cancers. The strongest evidence supports the prognostic value of cessation in lung and colorectal cancers. These findings underscore the clinical importance of integrating structured tobacco cessation interventions into routine oncologic care, not only for long-term disease prevention but also to improve survival outcomes in patients already diagnosed with cancer. Despite the consistency of benefit, cessation support remains underutilized in oncology settings. Addressing this gap represents a critical and actionable step toward improving cancer prognosis with minimal toxicity and high cost-effectiveness.