Why is cancer becoming more and more common today when technology is so advanced?

2/4 is "World Cancer Day", and almost all web pages are reposting the WHO's statistics on cancer. The WHO said that 10 million people died of cancer in 2020. Breast cancer has become the most common cancer, and about 400,000 children are diagnosed with cancer every year. This set of figures is really shocking! It stands to reason that now that the economy and technology are so developed, people's living standards are getting higher and higher, and the incidence of diseases, especially cancer, should be getting lower and lower. How can it be so high?

Here, we first need to correct a point of view: that is, although the incidence of cancer has been increasing, there has actually been no significant increase in cancer in the same age group.

For example, the age-standardized incidence of cancer remains basically unchanged, and even shows a downward trend.

That is to say, taking age into account, the incidence of cancer has not increased.

So, what is age standardization? In layman's terms, when considering the incidence of cancer, we should not only look at the total number of people, but also the age group.

Let's take a simple example

There are 1,000 people in Village A, and 50 of them died this year;

There are 1,000 people in Village B, and 10 of them died this year.

The most intuitive, simple and crude explanation is that the mortality rate in Village A is 5%, and that in Village B is 1%.

So some people were shocked. Could it be that something unclean or messy happened in Village A, which led to such a high death rate in Village A?

Then you look at the population structure of the two villages in more detail and find that Village A is a typical left-behind elderly village with too many elderly people. Village B is a new village with mostly young people, so it is normal for Village A to have a high mortality rate.

So the age correction problem was invented, which is the age-standardised rate (ASR).

So why are the overall incidences of cancer increasing?

Taking China as an example, the overall cancer incidence rate is currently on the rise. The key factor behind this is age.

Someone once said that if you live long enough, you will get cancer sooner or later. Although this statement may not be correct, it does reflect the problem.

The blue line in the figure represents the total incidence and mortality. In terms of gender, green is for males and red is for females. Incidence means onset and mortality means death.

But the important factor behind this is: aging.

The primary risk factor for cancer is not diet or environment, but age. It has been proven around the world that cancer increases with age.

In other words, as long as China's aging population continues to increase, an increase in the incidence of cancer is an inevitable fact.

Do you understand? The increasing incidence of cancer in China is because with the rapid economic growth and improved living conditions, the life expectancy of Chinese people is constantly increasing, and the primary risk factor for cancer is age.

In other words, the main reason for the increase in cancer we see is nothing else but the fact that people are living longer and longer, and the aging problem ultimately changes the entire ratio. In other words, it is caused by changes in the age structure.

The red frame in the picture keeps moving upwards, and will become a high-risk group for cancer in the future

Of course, there are no other reasons besides the above factors?

The answer is no

I have mentioned in an article before that the characteristics of Chinese cancer are:

1. The overall incidence of cancer is similar in rural and urban areas, with lung cancer, stomach cancer and esophageal cancer ranking in the top three, followed by liver cancer and intestinal cancer. This distribution is different from that in the United States. Our diet plays a big role in this.

2. When it comes to a specific type of cancer, the two show typical differences. The incidence of lung cancer and colon cancer in cities is significantly higher than in rural areas. This has a lot to do with urban air quality and the fact that urban residents consume too little fiber.

Rural areas are the hardest hit by esophageal cancer and gastric cancer. This may be due to nutrition problems and dietary structure problems in rural areas, such as the large intake of pickled foods and leftovers. There are also dietary hygiene issues.

3. 30-44 years old is a period of rapid change for cancer. When you reach middle age, you must pay attention to your health.

4. Men should pay attention to the prostate and women should pay attention to the thyroid gland. These two diseases have suddenly accelerated in recent years.

5. Lung cancer is the leading cause of death among men. There is clear evidence that smoking causes lung cancer. Therefore, for the sake of your health, it is better to smoke less.

However, are we hopeless?

Not necessarily. The United States, which has always been the most promising country in everyone's eyes, has achieved a reversal.

The incidence of cancer in the United States has continued to decline for 20 years. Can we wait until this turning point?

The overall cancer mortality rate in the United States increased throughout most of the 20th century. After reaching its peak in 1991 (215.1 per 100,000 people), it began to decline gradually, and by 2011 (168.7 per 100,000 people), it had fallen by 22%, saving more than 1.5 million people from cancer deaths.

This is a graph showing cancer incidence (dashed line) and mortality (solid line) trends in the United States.

This is a graph showing cancer incidence (dashed line) and mortality (solid line) trends in the United States.

In terms of the overall cancer incidence rate, the rate for women remained basically the same as in previous years, while it decreased by 3.1% each year (from 2009 to 2012) for men. The main reason was the successful development of screening markers for prostate cancer, the most common cancer in men.

According to the changes in many medical data trends over the years, our future is likely to follow the American model. With the discovery of detection methods such as various screening markers, changes in medical conditions, and improvements in environmental quality (this should happen), China will inevitably go through this process, that is, achieve a turning point in cancer. This is our hope.

Finally, the best way to prevent and treat cancer is early detection and early treatment, so regular physical examinations for cancer-related markers are crucial.