Global experts in epidemiology warn that rising inequality multiplies cancer incidence

22 Sep 2023
Global experts in epidemiology warn that rising inequality multiplies cancer incidence

“Cancer is now the leading cause of death in 57 countries, including Spain and the whole of Europe” and by the end of this century it will be “the leading cause of death before the age of 70 in all countries throughout the world,” said Elisabete Weiderpass, director of the International Agency for Research on Cancer (IARC), during the conference How to reduce the risk of cancer? Prevention through research, organised on the occasion of World Cancer Research Day.

The event, which was open to the public and held at the CaixaForum Madrid Auditorium, was dedicated to cancer prevention.

It is an important area because, according to data from the IARC, the specialised cancer agency within the World Health Organization (WHO), about half of all cancer cases are due to preventable causes and are therefore avoidable by changing habits and eliminating carcinogens.

The incidence of cancer is increasing.

Over the next two decades, an increase of 47% is expected, which means “increasing pressure on public finances and health budgets,” Weiderpass warned.

The situation in Spain is entirely in line with the global scenario, explained Marina Pollán, director of the Epidemiology and Public Health Networking Biomedical Research Centre (CIBERESP): “We are one of the countries with the longest life expectancy, but this ageing population is exposing our public health system, which has been very good and universal, to a tsunami of cancer cases, because population ageing translates into an increase in chronic diseases.”

The annual cost of cancer is estimated to be at least 1.2 billion (millions of millions) dollars worldwide, Weiderpass said.

This figure, which includes both specific spending on health care and medicines, and indirect costs – for example, productivity lost due to premature deaths – is growing in all countries.

But the increase is not evenly spread.

It will be especially acute in poor countries: “nations with fewer resources, without the technology to diagnose and treat cancers and without an adequate political climate to ensure effective prevention, will be the most affected,” Weiderpass warned, adding that “promoting equitable access to treatments will be crucial to address this great challenge over the next 20 years”.

The impact of poverty on the risk of developing cancer is also seen in rich countries, taking into account the incidence in different social groups.

Weiderpass showed data on cervical cancer, preventable with periodic testing and with the human papillomavirus (HPV) vaccine.

“In Europe, there is a huge disparity in mortality figures from cervical cancer between better off and better educated women, and the poorest and least educated,” said the director of IARC.

To avoid this, “screening campaigns should be aimed primarily at women of low socioeconomic status.”

As for the main habits and carcinogenic substances, Weiderpass stressed above all tobacco: “It’s public enemy number one. The most important measure we should take today is to eliminate tobacco worldwide,” she said emphatically, “and I am very concerned about new ways of using it, such as vaping, because they are an open door for new generations to become dependent on this substance that kills many people.”

The WHO relies on the evaluations of Weiderpass’s Agency to identify and classifycarcinogens.

There is currently enough evidence to classify as carcinogenic to humans not only tobacco but also alcohol, sausages (processed meats), ionising radiation, air pollution and more than a hundred other substances.

The herbicide glyphosate, widely used in European agriculture, is “probably carcinogenic”, because the WHO has strong evidence that it causes cancer in animal and cell models, but not enough data in humans.

In this same category are red meat, night shift work , high temperature frying and the pesticide DDT, among others.

Aspartame, a sweetener whose consumption, Weiderpass noted, does not prevent obesity, is considered “possibly carcinogenic.”

It is in a subgroup of the classification in which evidence in humans is lower, and which includes risks such as that of occupational exposure of hairdressers and barbers.

The experts also pointed to obesity as a factor of increasing importance, which increases the risk of developing 12 different types of cancer.

Weiderpass recalled the importance of limiting the intake of high-calorie and ultra-processed products; eating more fruit, vegetables, legumes, whole grains and nuts; and physical activity on a daily basis.

When it comes to alcohol, “it’s linked to up to seven different types of cancer. Just two glasses of alcohol a day is enough to cause very considerable damage,” Weiderpass said.

Another risk factor is infections.

The most important pathogens are Helicobacter pylori, human papillomavirus (HPV) and hepatitis B and C.

“Fortunately, we have at least two very effective vaccines: against HPV and against hepatitis B,” Weiderpass added.

“Investing in vaccination is one of the most effective measures a government can take.”

Marina Pollán provided up-to-date figures on smoking and obesity in Spain: 20% of adults smoke, and two thirds of men and half of women are overweight.

As in other countries, this problem affects more disadvantaged areas to a greater extent.

The abandonment of the Mediterranean diet (vegetables, legumes, fruit, olive oil, nuts, little meat) is already noticeable in clinical practice: “We are switching over to an Anglo-Saxon diet”, and the consequences are already being seen in the incidence “especially of colon cancer, which is currently one of the main types of tumour in our country”.  

The Mediterranean countries, Italy, Greece and Spain, “currently have the highest rate of overweight and obese children”.

Binge drinking among young Spaniards is also a concern: “They drink a lot of alcohol in a very short space of time. We do not yet have an epidemiological measure of how that translates into cancer incidence, but it’s not going to be good,” predicts the director of the National Centre for Epidemiology.

Recent research, says Pollán, shows that “the greatest association between alcohol and breast cancer occurs with consumption in adolescence”; also, that “those who start drinking as teenagers, maintain or increase their consumption later on.”

Weiderpass, Pollán and the director of CNIO Maria A Blasco – who explained how CNIO conducts its research – insisted during a roundtable discussion on the importance of public prevention policies.

We have to make it “easy to be healthy and difficult to be unhealthy”.

For example, through taxes.

Evidence suggests that increasing the price of tobacco, for example, decreases consumption.

Regulations are necessary especially for factors where we cannot choose whether we expose ourselves to them or not, such as air pollution or the consumption of pesticides banned in Europe, but not in other regions from which fruit and vegetables are imported.

Weiderpass noted that scientific evidence on prevention has been compiled in a European Code Against Cancer, which includes lesser-known habits, such as:

  • The recommendation of breastfeeding
  • Moderating hormone replacement therapy treatments
  • Vaccinating newborns against hepatitis B and girls against HPV
  • Finding out if we are exposed to radon at home
  • Finding out if we are exposed to carcinogenic substances at work.

Work is currently underway to adapt this code to other regions of the planet and “it is very important to establish a global cancer code”, which also serves to prevent relapses in cancer survivors.

Source: Centro Nacional de Investigaciones Oncológicas