The relationship between diabetes and colorectal cancer prognosis: A meta-analysis based on the cohort studies

Abstract

IntroductionThough a meta-analysis reported the effect of diabetes on colorectal prognosis in 2013, a series of large-scale long-term cohort studies has comprehensively reported the outcome effect estimates on the relationship between diabetes and colorectal prognosis, and their results were still consistent.MethodsWe carried out an extensive search strategy in multiple databases and conducted a meta-analysis on the effect of diabetes on colorectal prognosis, based on the included 36 cohort studies, which contained 2,299,012 subjects. In order to collect more data, besides conventional methods, we used the professional software to extract survival data from the Kaplan-Meier curves, and analyzed both the 5-year survival rate and survival risk in overall survival, cancer-specific survival, cardiovascular disease—specific survival, disease-free survival, and recurrence-free survival, to comprehensively reflect the effect of diabetes on colorectal prognosis.ResultsThe results found that compared to patients without diabetes, patients with diabetes will have a 5-year shorter survival in colorectal, colon and rectal cancer, with a 18%, 19% and 16% decreased in overall survival respectively. We also found similar results in cancer-specific survival, cardiovascular disease—specific survival, disease-free survival, and recurrence-free survival, but not all these results were significant. We performed the subgroup analysis and sensitivity analysis to find the source of heterogeneity. Their results were similar to the overall results.ConclusionsOur meta-analysis suggested that diabetes had a negative effect on colorectal cancer in overall survival. More studies are still needed to confirm the relationship between diabetes and colorectal prognosis in cancer-specific survival, cardiovascular disease—specific survival, disease-free survival, and recurrence-free survival.

Impact of Metformin Use and Diabetic Status During Adjuvant Fluoropyrimidine-Oxaliplatin Chemotherapy on the Outcome of Patients with Resected Colon Cancer: A TOSCA Study Subanalysis

“…We also failed to demonstrate an association between diabetes mellitus and RFS or OS. This result contradicts the findings of recent meta‐analyses of observational studies, which demonstrated an increased risk of death in patients with versus without diabetes with resected CRC . However, our study was not powered to test the hypothesis of reduced OS or RFS in patients with diabetes.…”

HbA1c showed a positive association with carcinoembryonic antigen (CEA) level in only diabetes, not prediabetic or normal individuals

“…10 Furthermore, compared to non-diabetic subjects, diabetic patients are at increased risk of colorectal cancer 11 and show a lower 5-year overall survival rate when diagnosed with colorectal cancer, as demonstrated in a meta-analysis. 12 Several studies have investigated the relationship between CEA levels and diabetes. 9,13,14 However, no studies have performed comprehensive medical checkups and screening, including endoscopic examinations, imaging studies, and wide-ranging blood tests including tumor markers and glycated hemoglobin, to rule out malignancy or other benign conditions that might affect CEA levels, as done in our health screening center, the Seoul National University Hospital (SNUH) Healthcare System Gangnam Center.…”

“…An estimated 285 million people worldwide had diabetes mellitus in 2010, and the number of people with diabetes will rise to 439 million by 2030, representing 7.7% of the total adult population of the world aged 20‐79 years . Furthermore, compared to non‐diabetic subjects, diabetic patients are at increased risk of colorectal cancer and show a lower 5‐year overall survival rate when diagnosed with colorectal cancer, as demonstrated in a meta‐analysis …”

Molecular evidence of field cancerization initiated by diabetes in colon cancer patients

“…The association between type 2 diabetes mellitus (T2DM) and colon cancer (CC) has been extensively discussed (González et al ., ). While several cohort studies and meta‐analyses have reported an increased risk for CC development in T2DM patients (Larsson et al ., ; Sun and Yu, ) as well as a higher short‐ and long‐term mortality (Croft et al ., ; Zhu et al ., ), others identified biases produced by the size and origin of the populations studied (de Jong et al ., ; Tsilidis et al ., ). Our own experience using a highly homogeneous Spanish cohort indicated that even if there is a higher risk of cancer development, the effect of diabetes does not entail a worse outcome once the tumor has developed (Prieto et al ., ).…”