The growth story of "lung cancer"

Author: Wang Huiping, Wan Shan, Tang Qincai, School of Basic Medical Sciences, Three Gorges University

Illustration: Wang Huiping, School of Basic Medical Sciences, Three Gorges University

Reviewer: Huang Yiling, Associate Professor, School of Basic Medical Sciences, Three Gorges University

The incidence and mortality of lung cancer are the highest among malignant tumors in my country. According to data from the National Cancer Center, in 2016, there were 4.064 million new cancer patients in China, of which 828,000 were lung cancer patients, and there were 2.414 million new cancer deaths in China, of which 657,000 were lung cancer deaths.

So, what are the risk factors for lung cancer? What are the morphological characteristics of lung cancer? How will it develop? How can it be prevented? The following will answer these questions one by one.

Studies have shown that smoking and inhaling secondhand smoke, occupational exposure to carcinogens such as asbestos and silica, as well as indoor air pollution and atmospheric pollution are all associated with an increased risk of lung cancer, among which smoking is the most important cause.

The formation of lung cancer has a specific process. Let's take a look at how lung cancer is formed from a microscopic perspective (assuming that "I" am a normal cell of the bronchial mucosal epithelium)!

I was originally a normal cell living in the epithelium of the bronchial mucosa of my master's lungs. Because my master was addicted to smoking, many of my brothers and sisters became "melanized" (forming lung cancer cells).

The character of the "blackened army" has changed drastically (structural atypia). Before, we had a harmonious relationship with our brothers and sisters, and our arrangement was neat and regular, but now, everyone's arrangement is a mess. The appearance of the "blackened army" is also very different from before (cellular atypia). Some cells will become larger and become the "rock" in the tissue (tumor giant cells). Everyone's morphology is also different (polymorphism), some will have a bad head-to-body ratio (the ratio of the cell nucleus to the cytoplasm increases), and some will even become two-headed or multi-headed "monsters" (binucleated or multi-nucleated tumor cells). Generally speaking, the greater the difference between these "blackened army" (tumor cells) and the "indigenous residents" (normal cells), the greater the damage they cause to their owners.

Figure 1 Copyright image, no permission to reprint

If the "black army" forms a huge mass that surrounds the bronchus in the hilar area of ​​the lung, central lung cancer will be formed; if isolated nodular or spherical cancer tissue is formed in the peripheral part of the lung, peripheral lung cancer will be formed; if the "black army" diffusely infiltrates along the alveolar ducts and alveoli, and millet-sized nodules cover part of the lung lobe or the entire lung, diffuse lung cancer will be formed.

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The "black army" is extremely arrogant, and the owner's body usually shows obvious symptoms at this time, such as chest pain, cough, hemoptysis (blood in sputum), clubbing of fingers, etc.

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If the owner does not take it seriously and does not take any rescue measures, the "black army" will continue their expedition. They will metastasize along the lymph nodes to the hilar lymph nodes, and the next stop will be the mediastinum, supraclavicular, axillary and cervical lymph nodes. Lymphatic metastasis is the most common metastatic route of lung cancer.

Figure 4 Copyright image, no permission to reprint

In addition, a part of the "expeditionary force" can continue to metastasize to other lymph nodes at the next stop of the lymphatic circulation, and finally enter the blood through the thoracic duct. It can also directly invade the surrounding blood vessels and cause secondary hematogenous metastasis. Hematogenous metastasis is common in organs such as the brain, adrenal glands, bones, and liver.

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As a witness to this battle in the host's body, "I" truly realized the great harm that smoking brings to the human body. If you want to prevent the occurrence of lung cancer, you should start from the following points.

The most important thing is to quit smoking.

Remember to wear masks frequently.

To eat healthy,

A smile is essential when exercising.

Figure 6 Copyrighted images are not authorized for reproduction

References

[1]Zheng RS, Zhang S w, Zeng H m, et al.Cancer incidence and mortality in China, 2016[J].J Natl Cancer Cent, 2022(2):1-9.

[2] Sun Xin, Qin Wenjin, Liu Lili, et al. Latest research progress on risk factors for lung cancer[J]. Modern Oncology, 2022, 30(4): 753-756.

[2] Bu Hong, Li Yilei. Pathology[M]. 9th edition. Beijing: People's Medical Publishing House, 2018.

[4] Ge Junbo, Xu Yongjian, Wang Chen. Internal Medicine[M]. 9th edition. Beijing: People's Medical Publishing House, 2018.