Preparing for the Age of 100: Japan's Cancer Prevention Plan

Japan's Nikkei business news is launching the "Centenarian Era plan" to prepare for a time when everyone lives to be 100. As part of this plan, the focus is on reducing the harm of smoking and exploring the relationship between smoking and cancer, as smoking is considered a barrier to good health and longevity. While smoking is a known cause of cancer, there is debate about whether alternative products such as heated and electronic cigarettes can lower the risk of cancer.

According to the population statistics of the Ministry of Health, Labour and Welfare, 378,385 people died of cancer in Japan in 2020, making it the main cause of death among Japanese people for 39 consecutive years. This accounts for about 30% of all deaths, and the number is expected to continue to increase as the population ages. While treatments, such as the development of new drugs, are rapidly advancing, it is important to also focus on changing lifestyle habits and promoting cancer prevention.

Half of Japanese people have cancer.

According to data from the National Cancer Registry, which registers newly diagnosed cancer patients, 65.5% of Japanese men and 51.2% of women will develop cancer at some point in their lives in 2019. The most common types of cancer in Japan are said to be prostate, colon, stomach, lung, and liver cancer for men, and breast, colon, lung, stomach, and uterine cancer for women.

Photo credit: Nikkei News Japan

Looking at cancer death rates by location, the top cancers for men in order are lung cancer, colon cancer, stomach cancer, pancreatic cancer, and liver cancer. The order for men's cancers is colon cancer, lung cancer, pancreatic cancer, breast cancer, and stomach cancer.

Image Source: Nikkei Asian Review (Japanese news publication)

Is Smoking Really Linked to Cancer? The National Cancer Center has established a team of researchers to investigate the scientific evidence behind cancer risk assessment and prevention guidelines. The team is currently focusing on verifying cancer risks. While smoking is often associated with cancer, the team aims to gather concrete evidence to support or disprove this link.

Results have shown that smokers are 1.53 times more likely to develop cancer than those who never smoke (1.64 times higher for males and 1.34 times higher for females). It is widely known that smoking has a particularly strong impact on the development of lung cancer, with smokers being four to five times more likely to develop lung cancer than non-smokers.

Photo credit: Nikkei Asian Review.

Smoking is not the only activity that can increase the risk of cancer, according to a recent study. Researchers have found that smoking also increases the risk of liver cancer, stomach cancer, colon cancer, esophageal cancer, pancreatic cancer, cervical cancer, head and neck cancer, and bladder cancer. Head and neck cancer refers to any cancer that forms above the neck (excluding the brain and eyes), such as oral and pharyngeal cancer. Additionally, the study suggests that smoking almost certainly increases the risk of acute myeloid leukemia and potentially breast cancer.

Factors that Damage Genes

So why does smoking cause cancer? Understanding the mechanisms behind cancer can help explain the reason. The human body is made up of many cells, and cancer is a disease where the genes in these cells are damaged, leading to abnormal cell growth.

Cigarettes are made by burning tobacco and inhaling smoke, which contains substances and additives from the tobacco and compounds produced by the burning process. Among these chemicals, about 70 carcinogenic harmful substances with cancer-causing potential have been identified. Toxic substances are believed to reach the lungs through smoking, spread throughout the body via the bloodstream, and cause cancer by damaging genes.

However, there are numerous causes of cancer, including viruses that can lead to cancer such as hepatitis B and C, and human papillomavirus (HPV) which can cause cervical cancer. It can be said that various factors are intricately intertwined. The research team also investigated the cancer risks associated with food, beverages, nutrients and so on, but did not find anything as harmful as smoking.

Equal to the number of people who quit smoking.

Next, we investigated whether heating non-combustible cigarettes can effectively reduce the risk of tobacco-caused cancer. First, let us closely examine the harmful effects of cigarettes.

When most people think of the harmful effects of tobacco, they think of nicotine. Nicotine is the primary ingredient found in tobacco leaves and, although it has not been found to be carcinogenic, it is highly addictive. This nicotine is also present in heated-but-not-burned tobacco products like cigarettes.

On the other hand, many substances that are classified as carcinogens are chemicals that are produced by combustion. Substances such as butadiene, benzene, acrolein, and carbon monoxide are recognized by the World Health Organization (WHO) as carcinogens. A study conducted by the National Institutes of Health in the United States compared various types of cigarettes with heated, non-combustible cigarettes and found that the latter significantly reduced the four aforementioned carcinogenic substances, which are gaseous components produced during the combustion process.

Apart from the ingredients, some research has actually focused on people switching from smoking to heated-not-burned tobacco. Researchers from the Philip Morris International research institute in the USA conducted a study on 160 Japanese smokers, aged between their 20s and 60s, who have smoked cigarettes, heated-not-burned tobacco or quit smoking, to investigate their levels of detection in urine and blood.

The results confirmed that after using heated tobacco for five days, the levels of these four substances decreased to levels commonly seen in people who have quit smoking. This number remained consistent throughout the 90-day study period and was significantly different from those who continued smoking. It has been proven that switching to heated tobacco can decrease the intake of carcinogenic substances.

However, it is still unclear how much overall cancer risk will be reduced as some carcinogens may not be diminished even if smokers quit. Another study found that few substances showed significant differences among smokers, so further research is needed.

Efficiently reducing the use of high-risk "roll-your-own tobacco".

We consulted Dr. Peter Harper, an oncologist and Chairman of the London Oncology Clinic, who has been treating cancer patients for years and is well-versed in reducing the harm caused by tobacco.

Is the concept of harm reduction in tobacco necessary?

Smoking is the most common lifestyle factor that leads to cancer. Quitting smoking can effectively reduce the risk, but in Japan, among those who receive medication treatment for quitting smoking, the quit rate is 27.3% nine months after treatment ends, 8.2% after one year, and 6% after four years. Some individuals report a need for an alternative, so reducing smoking through such a method is a good idea as smoking remains highly dangerous.

What measures should be taken to promote harm reduction in tobacco use in Japan?

Japanese people have a strong sense of not wanting to disturb others, and have taken measures such as wearing masks and maintaining social distancing to combat the novel coronavirus. This practice is widespread, but smoking cessation measures have not made progress among workers who have high smoking rates.

How can we educate medical professionals on reducing harm?

In the medical field, few people smoke to begin with. Even if you explain that heated tobacco products are less harmful than cigarettes, the current situation is that people should quit smoking altogether, without even considering the idea of reducing harm. I haven't seen any data showing that tobacco is less harmful. I think it's because I don't trust tobacco companies. I'll be convinced by research results published by the government. What healthcare professionals need is cessation resources for those who can't quit smoking, instead of blaming them.

Will switching to heat-not-burn cigarettes reduce the harm caused by smoking and decrease cancer risk?

Currently, there is some promising data, such as a decrease in hospitalizations due to cardiovascular disease. However, we need to view cancer through a period of decades. Although the results of previous measures, such as reducing exposure, are visible, it is difficult to come to a conclusion about data suggesting that "heating, not burning, cigarettes reduces harm and lowers cancer rates." Even if there is a period of preheating smoking, it is challenging to prove a correlation between smokers and a decrease in cancer incidence rates.

Support for offshore outsourcing.

Regarding the concept of "reduced harm" cigarettes, some countries classify them as such, however, there are also countries that ban the sale of these new cigarettes and responses among nations are also fragmented.

Photo credit: Japan's Nikkei News.

The heated tobacco products that are rapidly gaining popularity in Japan, as well as the electronic cigarettes that use liquid containing nicotine and inhale steam through electric heating without using tobacco leaves, are known as new types of cigarettes and have become widespread around the world since the 2000s. However, many countries initially restricted their sale.

In Japan, heated non-combustible tobacco products that use tobacco leaves are classified as "tobacco products," while electronic cigarettes that do not use tobacco leaves are not classified as such. In Japan, electronic cigarettes that contain nicotine are considered "medical devices" and are not approved products. However, in many countries, electronic cigarettes containing nicotine are more popular than heated tobacco products.

One such country is the United Kingdom, where electronic cigarettes are allowed as harm reduction tools for smokers. The country's Medicines and Healthcare Products Regulatory Agency (MHRA) has determined that their harm is 95% lower than that of traditional cigarettes. They have implemented policies that allow the use of electronic cigarettes as aids to quitting smoking.

The US Food and Drug Administration (FDA) approved for the first time in 2019 the sale of heated non-combustible cigarettes from some brands, and approved the sale of electronic cigarettes from some brands for the first time in 2021. The reason provided is that data show that harmful substances absorbed into the body are lower compared to traditional cigarettes.

Although not a new phenomenon, Sweden has become a harm-reducing alternative to smoking. Traditional snuff, known as "snus," is popular in the country and involves placing a small pouch of processed tobacco under the upper lip to ingest nicotine. As a result, Sweden has the lowest smoking rate in Europe and the fewest tobacco-related deaths.

In this scenario, some countries that initially banned the use of new types of cigarettes are now allowing their sale. Whether the new cigarettes, which are being marketed as tobacco alternatives, will eventually lead to smoking cessation and a reduction in adverse health effects remains to be seen.

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