Immune-related conditions and cancer-specific mortality among older adults with cancer in the United States
Menée à partir des données 1993-2013 des registres américains des cancers et de la base Medicare portant sur 1 229 443 patients âgés atteints d'un cancer (âge : 67-99 ans), cette étude analyse l'association entre la présence de maladies liées à un dysfonctionnement du système immunitaire et la mortalité par cancer
Immunity may play a role in preventing cancer progression. We studied associations of immune-related conditions with cancer-specific mortality among older adults in the United States. We evaluated 1,229,443 patients diagnosed with 20 common cancer types (age 67-99, years 1993-2013) using Surveillance Epidemiology and End Results-Medicare data. With Medicare claims, we ascertained immune-related medical conditions diagnosed before cancer diagnosis (4 immunosuppressive conditions [n=3380 affected cases], 32 autoimmune conditions [n=155,766], 3 allergic conditions [n=101,366]). For each cancer site, we estimated adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) for cancer-specific mortality associated with each condition, applying a Bonferroni cutoff for significance (p<5.1x10-5). Bayesian meta-analysis methods were used to detect patterns across groups of conditions and cancers. We observed 21 associations with cancer-specific mortality at the Bonferroni threshold. Increased cancer-specific mortality was observed with rheumatoid arthritis for patients with melanoma (aHR 1.51, 95%CI 1.31-1.75) and breast cancer (1.24, 1.15-1.33)), and with hemolytic anemia for bladder cancer (2.54, 1.68-3.82). Significant inverse associations with cancer-specific mortality were observed for allergic rhinitis (range of aHRs: 0.84-0.94) and asthma (0.83-0.95) for cancers of the lung, breast, and prostate. Cancer-specific mortality was nominally elevated in patients with immunosuppressive conditions for 8 cancer types (aHR range:1.30-2.36; p-value range: 7.5x10-5-3.1x10-2) and was strongly associated with grouped immunosuppressive conditions using Bayesian meta-analyses methods. For older patients with several cancer types, certain immunosuppressive and autoimmune conditions were associated with increased cancer-specific mortality. In contrast, inverse associations with allergic conditions may reflect enhanced immune control of cancer.