Inflammation is associated with worse prognosis and survival in many cancers. Our aim was to investigate the associations of circulating C-reactive protein (CRP) and interleukin-6 (IL-6) concentrations with all-cause mortality in cancer patients and to determine whether any associations were specific to malignancy. Method: We used data from the British Women's Heart and Health Study, a cohort of 4,286 women aged 60 to 79 years. We investigated the associations between CRP, IL-6, and survival in

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... women with and without cancer using Cox regression and assessed the interaction between cancer status and these inflammatory markers to determine whether these associations differed according to cancer status. Results: Elevated CRP and IL-6 were associated with decreased survival in women with cancer [unadjusted hazard ratio per doubling of CRP, 1.22, 95% confidence interval (95% CI), 1.03, 1.46; and per doubling of IL-6, 1.52, 95% CI, 1.25, 1.86] and in women without cancer [CRP: 1.24 (1.12, 1.37); IL-6: 1.53 (1.35, 1.75)]. Adjustment for age, body mass index, physical activity level, socioeconomic position, HRT use, and tobacco smoking did not change these associations. After mutual adjustment, IL-6 but not CRP was independently associated with survival. We found no strong evidence that these associations differed between cancer patients and cancer-free women. Conclusions: Elevated CRP and IL-6 concentrations were similarly associated with an increased risk of death in elderly women with and without cancer. Thus, in this group, these markers are likely to be indicators of non-cancer comorbidities rather than related to the malignancy itself.