LAUSR

Comorbidities and advanced stage diagnosis (ASD) are both associated with poorer cancer outcomes, but the association between comorbidities and ASD is poorly understood. We summarized epidemiological evidence on the association between comorbidities and ASD of selected cancers in a systematic review and meta-analysis. We searched PubMed and Web of Science databases up to June 3rd, 2021 for studies assessing the association between comorbidities and ASD of lung, breast, colorectal, or prostate cancer. Summary odds ratios (ORs) and 95% confidence intervals (95%CIs) were calculated using random-effects models. Also, potential variations in the associations between comorbidities and ASD by cancer type were investigated using random-effects meta-regression. Thirty-seven studies were included in this review, including 8,069,397 lung, breast, colorectal, and prostate cancer patients overall. The Charlson comorbidity index score was positively associated with ASD (stages III-IV) of breast cancer but was inversely associated with ASD of lung cancer (pinteraction = 0.004). Regarding specific comorbidities, diabetes was positively associated with ASD (OR = 1.17, 95%CI = 1.09-1.26), whereas myocardial infarction was inversely associated with ASD (OR = 0.84, 95%CI = 0.75-0.95). The association between renal disease and ASD differed by cancer type (pinteraction < 0.001). A positive association was found with prostate cancer (OR = 2.02, 95%CI = 1.58-2.59) and an inverse association with colorectal cancer (OR = 0.84, 95%CI = 0.70-1.00). In summary, certain comorbidities (e.g., diabetes) may be positively associated with ASD of several cancer types. It needs to be clarified whether closer monitoring for early cancer signs or screening in these patients is reasonable, considering the problem of over-diagnosis particularly relevant in patients with short remaining life expectancy such as those with comorbidities. Also, evaluation of the cost-benefit relationship of cancer screening according to the type and severity of comorbidity (rather than summary scores) may be beneficial for personalized cancer screening in populations with chronic diseases.