Impact of diabetes mellitus in cancer

Diabetes mellitus and cancer are growing global health concerns with a rising prevalence and substantial associated mortality. The study aims to find impact of diabetes mellitus in cancer. A narrative review was conducted by analysing evidence from various sources, including meta-analyses, systematic reviews, retrospective studies, database analyses, and cohort studies. The review explored the complex interplay between Diabetes Mellitus and cancer, like cancer incidence, oncology outcome i.e., acute and late toxicities, treatment compliance, overall survival (OS), and quality of life (QoL). Diabetes mellitus increases the risk of developing cancer by 10%. Diabetic patients had higher infection rates [2.6%-52%, odds ratio (OR) 1.38-1.57], increased haematologic toxicity (13%-65.7%, P=0.004), and greater hospital admissions (17.2%-74.5%, OR 2.1, P< 0.001). They received significantly lower cisplatin doses (18%-33% reduction), experienced more surgical delays [adjusted OR 1.16, 95% confidence interval (CI) 1.05-1.27], higher risk of flap failure (RR=1.83, 95% CI 1.18-2.85, P=0.007) and were less likely to undergo breast reconstruction (adjusted OR 0.48-0.54, 95% CI 0.24-1.00). Diabetes mellitus decreases local control by 10-20%, increases mortality by 27-98%, and decreases OS by 18-50% across various cancers. It increases late toxicity and negatively impacts QOL with a 1.3-2.7 times higher risk of grade ≥2 genitourinary and gastrointestinal toxicity in prostate cancer, a twofold increase in grade ≥3 radiation pneumonitis in lung cancer, and a 50% higher incidence of severe peripheral neuropathy in breast cancer, leading to delayed recovery and long-term morbidity. In patients receiving cancer directed therapy, diabetes mellitus increases acute and late toxicities, decreased local control and overall survival, and have poor quality of life.