The study, led by Dr. Suping Ling of the Leicester Real World Evidence Unit, Leicester Diabetes Research Centre, University of Leicester and London School of Hygiene & Tropical Medicine, UK, also found that breast cancer death rates increased by 4.1% per year in older women. young people with type 2 diabetes during the 20-year study period 1998-2018. This is one of the reasons why the authors suggest that breast cancer screening should be extended to younger women with T2DM.
A growing body of epidemiological evidence has shown that individuals with type 2 diabetes are at an increased risk of cancer incidence and mortality from certain types of cancer. This is thought to be due to prolonged exposure to the effects of high blood sugar and insulin levels, insulin resistance, and chronic inflammation. There is strong evidence to suggest that there is a causal relationship between type 2 diabetes and pancreatic, liver and endometrial cancer. Although previous studies have focused on inequalities in cardiovascular outcomes among people with type 2 diabetes, little is known about whether similar inequalities exist in cancer death rates.
The authors of this study used a cohort of individuals aged 35 years and older who had recently diagnosed type 2 diabetes in the Clinical Practice Research Datalink, a UK general practice database, over a 20-year period between 1 January 1998 and November 30, 2018. They analyzed trends in all-cause, all-cancer, and cancer-specific mortality rates by age, sex, ethnicity, socioeconomic status, obesity, and smoking status. They also estimated standardized death rates by comparing death rates in people with type 2 diabetes with the general population.
The study included 137,804 individuals with newly diagnosed type 2 diabetes with a median follow-up of 8.4 years. The authors found that all-cause death rates declined at all ages between 1998 and 2018; cancer (all cancers combined except non-melanoma skin cancer) mortality rates also decreased for people age 55 (by 1.4% per year) and age 65 (by 0.2% per year), but increased for people 75 years old (at 1.2% per year) and 85 years old (at 1.6% per year). The authors say that the decrease in cardiovascular mortality observed in older age groups, due to successful cardiovascular prevention and treatment in recent decades, means that people live longer now and are more likely to experience other conditions and therefore die from other causes (including cancer). However, diabetes screening, better management of diabetes and its complications, early detection of cancer, and improved cancer treatments appear to have benefited young people with T2DM as much as the general population.
There were also greater ‘mean annual percentage changes’ (AAPC – the average percentage increase/decrease per year) in cancer mortality in women (1.5%) compared to men (1.0%), although women had lower cancer mortality during the study period. Biological factors, health-seeking behaviors, and lifestyle factors such as smoking and obesity differ between men and women, but the relative contribution of each to cancer mortality is not known. The less deprived/wealthier group also had a higher AAPC (1.5%) than the poorer/neediest (1.0%) – leading to an ever-shrinking but persistent gap by socioeconomic status. (see table 3)
Other key findings included higher AAPC cancer mortality for morbidly obese people (5.8%) versus people in other weight categories (all under 1.0%) and also higher AAPC cancer mortality for white people (2.4 %) compared to an average annual percentage drop of 3.4% among nonwhite ethnicities combined. The difference in cancer mortality between smokers and non-smokers also widened, with smokers having an AAPC cancer mortality increase of 3.4%, while for non-smokers the AAPC dropped by 1.4%. The authors suggest that current health policies and frameworks may benefit never-smokers more than current smokers – and that personalized interventions for smokers, such as specific screening programs, may help address rising cancer mortality (and mortality from cancer). from all causes) in smokers. (see table 3)
Steady upward trends in mortality rates were also observed for pancreatic, liver, and lung cancer at all ages, colorectal cancer at most ages, breast cancer at younger ages, and prostate and endometrial cancer at older ages. (see figures 3 and 4 and links to supplementary data).
Compared with the general population, people with type 2 diabetes had a more than 1.5-fold increased risk of mortality from colorectal, pancreatic, hepatic, and endometrial cancers throughout the study period (see table 4). Despite national reports from this period* showing a decrease in breast cancer mortality in younger age groups in this study, this new research also showed an increase in breast cancer mortality rates by 4.1% per year in younger women. with type 2 diabetes. The authors suggest “From this perspective, our results suggest that it may be useful to extend breast cancer screening to young women with type 2 diabetes. screening procedures, cost-effectiveness analyzes are needed to define the appropriate time window and identify subgroups that may benefit most”. They add that there are currently studies investigating extending the existing breast cancer screening window from 50-70 years to 47-73 years in the general population; in addition, women with a family history of breast cancer or specific genetic mutations are screened at a younger age, but no current guidelines specifically consider the increased risk of breast cancer in women with diabetes.**
On overall cancer mortality in people with diabetes, the authors say: “The prevention of cardiovascular disease has been and still is considered a priority in people with diabetes. Our results challenge this view, showing that cancer may have overtaken cardiovascular disease as the leading cause of death in people with type 2 diabetes. Cancer prevention strategies, therefore, deserve at least a similar level of attention as cancer prevention. cardiovascular disease, particularly in older people and for some cancers such as liver, colorectal and pancreatic. Personalized interventions should also be considered for smokers, who have had higher and increasing cancer mortality rates. Interventions for smokers, in addition to smoking cessation, may include campaigns to raise cancer awareness and improve early detection. For people with type 2 diabetes, early cancer detection through changes to existing screening programs or further investigations for suspected/nonspecific cancer symptoms may reduce the number of preventable cancer deaths.”
The authors conclude: “In conclusion, our findings highlight the increasing burden of cancer in people with type 2 diabetes, particularly in older individuals, and highlight the need to prioritize cancer prevention, research, early detection and treatment in this population, especially for colorectal cancer, pancreatic, liver and endometrial cancer, whose mortality rates were substantially higher in individuals with type 2 diabetes than in the general population”.