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Nevin Manimala Statistics

Chemotherapy and age stratified survival outcomes in colorectal cancer based on a population analysis from the surveillance epidemiology and end results program 2010 to 2020

Discov Oncol. 2025 Nov 24;16(1):2155. doi: 10.1007/s12672-025-04009-6.

ABSTRACT

BACKGROUND: The role of chemotherapy in colorectal cancer (CRC) treatment, particularly in elderly and very young patients, remains controversial. This study aims to evaluate the survival benefits of chemotherapy across different age groups in CRC patients using real-world data.

METHODS: We conducted a prospective cohort study using data from the SEER database from 2010 to 2020. A total of 256,320 CRC patients were included in the final analysis. Chemotherapy status (yes/no) was the primary exposure. Outcomes included overall survival (OS), cause-specific survival, and cumulative incidence of cancer- and non-cancer-specific deaths. Statistical analyses involved multivariable Cox proportional hazards models, and competing risks models, adjusted for key demographic and clinical covariates.

RESULTS: Chemotherapy significantly improved OS in patients aged 45 years and older, with the most substantial benefit in those aged 75-84 years (hazard ratios [HR] = 0.54, 95% confidence interval [CI] = 0.52-0.56) and ≥ 85 years (HR = 0.60, 95% CI = 0.57-0.64). Patients younger than 45 years did not show a significant survival benefit (HR = 1.02, 95% CI = 0.93-1.12). Survival benefit was consistent across tumor locations and most pronounced in stage III (HR = 0.40) and stage IV (HR = 0.39) disease. Competing risks models confirmed reduced cancer-specific mortality in older age groups. Sensitivity analyses excluding early deaths further validated the robustness of these findings.

CONCLUSION: Chemotherapy conferred a survival benefit in patients aged ≥ 45 years, including the very elderly, when selection was based on functional status rather than age alone, whereas no clear benefit emerged in younger patients. This association persisted after multivariable adjustment and across stage-stratified and sensitivity analyses. Given SEER’s lack of regimen, timing, comorbidity, and targeted-therapy detail, cautious interpretation is warranted.

PMID:41284200 | DOI:10.1007/s12672-025-04009-6

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