The long road towards cancer prevention: 4 steps backward and 8 forward

Non-preventable cases of breast, prostate, lung, and colorectal cancer in 2050 in an elimination scenario of modifiable risk factors

Most Western countries have increasing number of new cancer cases per year. Cancer incidence is primarily influenced by basically avoidable risk factors and an aging population. Through hypothetical elimination scenarios of multiple major risk factors for cancer, we estimated the number of new cancer cases that are non-preventable in 2050. We compare numbers of new postmenopausal breast, prostate, lung, and colorectal cancer cases in 2021 to projected numbers of new cases in 2050 under prevention scenarios regarding smoking, overweight and obesity, and alcohol consumption: no intervention, 50%, and 100% instant reduction. Cancer incidence data were derived from NORDCAN, and risk factor prevalence data from the Danish National Health Survey. Cancer projections were calculated with the Prevent program. Hypothetical 100% instant elimination of major risk factors for cancer in Denmark in 2022 will result in unchanged numbers of new breast and colorectal cancers in 2050. The number of new prostate cancers will increase by 25% compared to 2021. Unchanged risk factor levels will result in noticeable increase in cancer burden. Increase in life expectancy and age will entail an increase in cancer incidence, despite maximum effect of preventive actions in the population. Our results are important when planning future health care.

Planning for tomorrow: global cancer incidence and the role of prevention 2020-2070

Cancer is currently the first or second most common contributor to premature mortality in most countries of the world. The global number of patients with cancer is expected to rise over the next 50 years owing to the strong influence of demographic changes, such as population ageing and growth, on the diverging trends in cancer incidence in different regions. Assuming that the latest incidence trends continue for the major cancer types, we predict a doubling of the incidence of all cancers combined by 2070 relative to 2020. The greatest increases are predicted in lower-resource settings, in countries currently assigned a low Human Development Index (HDI), whereas the predicted increases in national burden diminish with increasing levels of national HDI. Herein, we assess studies modelling the future burden of cancer that underscore how comprehensive cancer prevention strategies can markedly reduce the prevalence of major risk factors and, in so doing, the number of future cancer cases. Focusing on an in-depth assessment of prevention strategies that target tobacco smoking, overweight and obesity, and human papillomavirus infection, we discuss how stepwise, population-level approaches with amenable goals can avert millions of future cancer diagnoses worldwide. In the absence of a step-change in cancer prevention delivery, tobacco smoking will remain the leading preventable cause of cancer, and overweight and obesity might well present a comparable opportunity for prevention, given its increasing prevalence globally in the past few decades. Countries must therefore instigate national cancer control programmes aimed at preventing cancer, and with some urgency, if such programmes are to yield the desired public health and economic benefits in this century.

Tackling the tobacco epidemic in the Nordic countries and lower cancer incidence by 1/5 in a 30-year period-The effect of envisaged scenarios changing smoking prevalence

BACKGROUND

Tobacco smoking is a leading cause of cancer and the most preventable cause of cancer worldwide. The aim of this study was to quantify the proportion of the cancer burden in the Nordic countries linked to tobacco smoking and estimate the potential for cancer prevention by changes in smoking prevalence.

METHODS

The Prevent macro-simulation model was used, estimating the future number of cancer cases in the Nordic countries over a 30-year period (2016-2045), for 13 cancer sites, under different scenarios of changing smoking prevalence, and compared to the projected number of cases if constant prevalence prevailed.

RESULTS

A total of 430,000 cancer cases, of the 2.2 million expected for the 13 studied cancer sites, could be avoided in the Nordic countries over the 30-year period if smoking was eliminated from 2016 onwards. If prevalence of smoking is reduced to 5% by year 2030 and to 2% by 2040, 230,000 cancer cases could be avoided. The largest proportion of cancers can be avoided in Denmark, where smoking prevalence is the highest, and similar to the prevalence in many European countries.

CONCLUSION

A large amount of cancers could be avoided in the Nordic countries if smoking prevalence was reduced. The results from this study can be used to understand the potential impact and significance of primary prevention programmes targeted towards reducing the prevalence of tobacco smoking in the Nordic countries.

Avoidable cancers in the Nordic countries-The impact of alcohol consumption

BACKGROUND

Alcohol consumption is an important and preventable cause of cancer. The aim of this study was to quantify the proportion of the cancer burden in the Nordic countries linked to alcohol and estimate the potential for cancer prevention by changes in alcohol consumption.

METHODS

Using the Prevent macro-simulation model, the number of cancer cases in the Nordic countries over a 30-year period (2016-2045) was modelled for six sites, under different scenarios of changing alcohol consumption, and compared to the projected number of cases if constant alcohol consumption prevailed. The studied sites were colorectal, post-menopausal breast, oral cavity and pharynx, liver, larynx as well as oesophageal squamous cell carcinoma. The alcohol consumption was based on the categories of non-drinkers/occasional drinkers, light drinkers (<=12.5 g alcohol per day), moderate drinkers (>12.5 and ≤ 50 g/day) and heavy drinkers (>50 g/day).

RESULTS

About 83,000 cancer cases could be avoided in the Nordic countries in a 30-year period if alcohol consumption was entirely eliminated, which is 5.5% of the expected number of cases for the six alcohol-related cancer types. With a 50% reduction in the proportion with moderate alcohol consumption by year 2025, 21,500 cancer cases could be avoided. The number of avoidable cases was highest for post-menopausal breast and colorectal cancer, but the percentage was highest for oesophageal squamous cell carcinoma.

CONCLUSION

The results from this study can be used to understand the potential impact and significance of primary prevention programmes targeted towards reducing the alcohol consumption in the Nordic countries.

Avoidable cancer cases in the Nordic countries - The impact of overweight and obesity

BACKGROUND

Several types of cancers are causally linked to overweight and obesity, which are increasing in the Nordic countries. The aim of this study was to quantify the proportion of the cancer burden linked to overweight and obesity in the Nordic countries and estimate the potential for cancer prevention.

METHODS

Under different prevalence scenarios of overweight and obesity, the number of cancer cases in the Nordic countries in the next 30 years (i.e. 2016-2045) was estimated for 13 cancer sites and compared to the projected number of cancer cases if the prevalence stayed constant. The Prevent macro-simulation model was used.

RESULTS

Over the period 2016-2045, 205,000 cancer cases out of the 2.1 million expected for the 13 cancer sites (9.5%) that have been studied, could be avoided in the Nordic countries by totally eliminating overweight and obesity in the target population. The largest proportional impact was found for oesophageal adenocarcinoma (24%), and the highest absolute impact was observed for colon (44638) and postmenopausal breast cancer (41135).

CONCLUSION

Decreased prevalence of overweight and obesity would reduce the cancer burden in the Nordic countries. The results from this study form an important step to increase awareness and priorities in cancer control by controlling overweight and obesity in the population.

Convergence of decreasing male and increasing female incidence rates in major tobacco-related cancers in Europe in 1988-2010

INTRODUCTION

Smoking prevalence has been declining in men all over Europe, while the trend varies in European regions among women. To study the impact of past smoking prevalence, we present a comprehensive overview of the most recent trends in incidence, during 1988-2010, in 26 countries, of four of the major cancers in the respiratory and upper gastro-intestinal tract associated with tobacco smoking.

METHODS

Data from 47 population-based cancer registries for lung, laryngeal, oral cavity and pharyngeal, and oesophageal cancer cases were obtained from the newly developed data repository within the European Cancer Observatory (http://eco.iarc.fr/). Truncated age-standardised incidence rates (35-74 years) by calendar year, average annual percentage change in incidence over 1998-2007 were calculated. Smoking prevalence in selected countries was extracted from the Organisation for Economic Co-operation and Development and the World Health Organization databases.

RESULTS

There remained great but changing variation in the incidence rates of tobacco-related cancers by European region. Generally, the high rates among men have been declining, while the lower rates among women are increasing, resulting in convergence of the rates. Female lung cancer rates were above male rates in Denmark, Iceland and Sweden (35-64 years). In lung and laryngeal cancers, where smoking is the main risk factor, rates were highest in central and eastern Europe, southern Europe and the Baltic countries. Despite a lowering of female smoking prevalence, female incidence rates of lung, laryngeal and oral cavity cancers increased in most parts of Europe, but were stable in the Baltic countries. Mixed trends emerged in oesophageal cancer, probably explained by differing risk factors for the two main histological subtypes.

CONCLUSIONS

This data repository offers the opportunity to show the variety of incidence trends by sex among European countries. The diverse patterns of trends reflect varied exposure to risk factors. Given the heavy cancer burden attributed to tobacco and the fact that tobacco use is entirely preventable, tobacco control remains a top priority in Europe. Prevention efforts should be intensified in central and eastern Europe, southern Europe and the Baltic countries.

Recent trends in incidence of five common cancers in 26 European countries since 1988: Analysis of the European Cancer Observatory

BACKGROUND

Individual country- and cancer site-specific studies suggest that the age-adjusted incidence of many common cancers has increased in European populations over the past two decades. To quantify the extent of these trends and the recent burden of cancer, here we present a comprehensive overview of trends in population-based incidence of the five common cancers across Europe derived from a new web-based portal of the European cancer registries.

METHODS

Data on incidence for cancers of the colon and rectum, prostate, breast, corpus uteri and stomach diagnosed from 1988 to 2008 were obtained from the European Cancer Observatory for cancer registries from 26 countries. Annual age-standardised incidence rates and average annual percentage changes were calculated.

RESULTS

Incidence of four common cancers in eastern and central European countries (prostate, postmenopausal breast, corpus uteri and colorectum) started to approach levels in northern and western Europe, where rates were already high in the past but levelled off in some countries in recent years. Decreases in stomach cancer incidence were seen in all countries.

DISCUSSION

Increasing trends in incidence of the most common cancers, except stomach cancer, are bad news to public health but can largely be explained by well-known changes in society in the past decades. Thus, current and future efforts in primary cancer prevention should not only remain focussed on the further reduction of smoking but engage in the long-term efforts to retain healthy lifestyles, especially avoiding excess weight through balanced diets and regular physical exercise.

Cancer and inflammation: an old intuition with rapidly evolving new concepts

Recent scientific advances have contributed much to the dissection of the complex molecular and cellular pathways involved in the connection between cancer and inflammation. The evidence for this connection in humans is based on the association between infection or chronic sterile inflammation and cancer. The decreased incidence of tumors in individuals who have used nonsteroidal anti-inflammatory drugs is supportive of a role for inflammation in cancer susceptibility. The increased incidence of tumors in overweight patients points to a role for adipose tissue inflammation and energy metabolism in cancer. Energy metabolism, obesity, and genetic instability are regulated in part by the relationship of the organism with commensal bacteria that affect inflammation with both local and systemic effects. Different aspects of inflammation appear to regulate all phases of malignant disease, including susceptibility, initiation, progression, dissemination, morbidity, and mortality.