How much do you know about cancer?

I saw some netizens asking why some people who smoke all their lives never get cancer, while some people who don't smoke get cancer? What's going on? What is the probability of a carcinogen causing cancer? To explain this question, we have to mention statistics. In fact, this is the charm of statistics. Today, let's talk briefly about statistics, carcinogens, and immunotherapy.

01. About Statistics

What netizens have seen is that some people smoke but do not get cancer, while others do not smoke but get cancer. This is called a case report. The world is so big, and what we see is limited after all.

I often tell people a story: There are 1,000 people in Village A, and 50 of them get cancer this year; there are 1,000 people in Village B, and only 10 of them get cancer. The most intuitive, simple and crude way to put it is that the cancer incidence rate in Village A is 5%, and in Village B is 1%.

So some people were shocked. Could it be that something unclean or messy happened in Village A that caused the cancer incidence rate in Village A to be so high?

The authorities immediately sent people to investigate. After a detailed look, they compared the population structure of the two villages and found that Village A was a typical left-behind elderly village with too many elderly people, while Village B was a new village with mostly young people, so it was normal for Village A to have a high cancer incidence rate.

This is the beauty of statistics, it can provide you with different perspectives. So, it is not that there is something unclean or bad feng shui in Village A.

02. How big is the risk of carcinogenic factors?

As for the carcinogenic factors you mentioned, how big is the risk? Because the range of carcinogenic factors is too large, there are physical (such as nuclear radiation), chemical (such as aflatoxin), and biological (such as HPV virus). Here, let's take tobacco as an example. This paper mentions that 90% of lung cancer in the United States is caused by smoking.

It is estimated that about 90% of male lung cancer deaths and 75%-80% of female lung cancer deaths in the United States each year are caused by smoking.

Hecht S S. Tobacco smoke carcinogens and lung cancer[J]. JNCI: Journal of the National Cancer Institute, 1999, 91(14): 1194-1210.

Finally, probability is a possibility, not a certainty, just like a car accident may happen, but it is not certain. But friends, I believe that in the face of life and death, even a small probability event is enough to make people uneasy.

The following figure is a statistical analysis I did in the cancer map

【Cancer 1】China Cancer Map——Diet and Air Issues That Cannot Be Avoided

We can see that lung cancer itself has become the cancer with the highest incidence in my country. And because lung cancer develops insidiously and common symptoms are mostly non-specific, 68% of patients are already in the advanced stage when diagnosed. Data show that the 5-year survival rate of patients with advanced lung cancer in the past was less than 5%. "Cancer" is certainly dangerous, but with the development of modern medicine, in addition to traditional surgery, radiotherapy and chemotherapy, innovative treatment options, such as targeted therapy and immuno-oncology (IO) therapy, have given more and more patients with advanced lung cancer hope.

03. About tumor immunotherapy

If you have paid attention to the 2018 Nobel Prize in Physiology or Medicine, you will remember that the Nobel Prize was awarded to immunotherapy, also known as tumor immunotherapy. Unlike traditional treatments, immuno-oncology (IO) therapy does not directly act on the tumor itself, but fights the tumor by activating the patient's own immune system, with the characteristics of small toxic side effects and long-lasting efficacy.

More specifically, the Nobel Prize that year was awarded to PD-1 inhibitors. I have introduced it in detail in my column. If you are interested, you can send me a private message.

Simply put, tumors deceive immune cells and multiply wildly, but PD-1 inhibitors remove this disguise, thereby stimulating the body's immune system to kill tumor cells. Because of this, PD-1 has become a star in cancer treatment since its appearance, and was quickly approved by the FDA as a new option for cancer treatment. Various countries have also approved and introduced PD-1 inhibitors.

Finally, it is a commonplace to say that each patient's situation is different, and whether a certain treatment plan can be used cannot be generalized. Before choosing any treatment plan, you should fully communicate with your doctor and take the medicine according to the doctor's instructions.