In the previous theory, we saw cancer and types of cancers. In this theory, we shall see carcinogenic agents, treatment, preventive measures, and treatment.
Carcinogenic agents:
Agents which cause cancer are known as carcinogenic agents.
These agents may be physical, chemical, ionising radiation and biological agents.
1.  Physical irritant:
Physical irritants cause significant inflammation through friction, pressure, heat, dryness or occlusion.
  • Lung cancer, cancers of the oral cavity, pharynx (throat) and larynx are caused by heavy smoking.
  • Oral cancer is caused by betel and tobacco chewing.
  • Excessive exposure to sunlight may cause skin cancer.
2.  Chemical agents:
These are hazardous substances that can increase the risk of cancer.
Nicotine, caffeine, coal and oil combustion products, pesticides, asbestos, nickel, certain dyes, and artificial sweeteners are all known to cause cancer.
3.  Radiations:
Radiation such as X-rays, gamma rays, radioactive chemicals, and non-ionizing radiations such as UV rays cause DNA damage, which leads to cancer.
4.  Biological agents:
These include cancer-causing viruses known as oncogenic viruses.
Treatment of cancer:
The following are some of the methods involved in the treatment of cancer.
1.  Surgery:

It is a method in which the tumours are removed from the body to prevent the further spread of cancer.
2. Radiation therapy:
Tumour cells are irradiated with fatal doses of radiation while normal cells around them are protected.
An illustration showing radiation therapy
3. Chemotherapy:
It entails the administration ofanticancer medications, which stop cancer cells from dividing and are used to kill them.
4.  Immunotherapy:
It's a cancer treatment that boosts your immune system's ability to fight cancer. In this method, the biological response modifiers such as interferons activate the immune system, thereby destroying tumours.
An illustration showing immunotherapy
Preventive measures for cancer:
  • Primary prevention and early detection should be the goal of cancer control programmes.
  • To prevent lung cancer, avoid tobacco smoking, and take precautions to avoid exposure to toxic industrial pollutants.
  • Should avoid excessive radiation exposure to prevent skin cancer.
A picture explains the prevention of heart disease.