Learn about cancer

chinacdc.cn | Updated: 2023-04-27
Cancer is a chronic disease, which is often preventable and treatable.
The occurrence of cancer is a chronic process. It usually takes 10 to 20 years, or even longer, for normal cells to evolve into cancer cells.
 
According to the World Health Organization (WHO), one-third of cancer can be completely prevented, one-third of cancer can be cured if detected at early stages, and existing medical measures can alleviate the pain or improve the quality of life for another one-third of cancer patients.
 
Studies show that prevention (such as health communication, tobacco and alcohol control, and early screening) and standardized treatment have significant effects on reducing the incidence rate and mortality rate of cancer.
 
Cancer is not contagious, but some cancer-causing microorganisms are infectious.
 
Cancer is not contagious per se, but some cancer-causing microorganisms are contagious, and people who frequently come into contact with them have an increased possibility of being infected.
 
Worldwide, 16.1 percent of tumors are associated with pathogens, with 6 percent of cancer deaths caused by infectious pathogens in developed countries and up to 22 percent in developing countries.
 
The International Agency for Research on Cancer (IARC) has identified 11 infectious pathogens/classes that can cause cancer in humans, including one bacterium, seven viruses, and three major parasites. Each source of infection causes at least one type or even several types of cancer.
 
(1) Bacterium: Helicobacter pylori (HP).
(2) Seven viruses: Human papillomavirus (HPV), hepatitis B virus (HBV), hepatitis C virus (HCV), EBV, Kaposi sarcoma-associated herpesvirus (KSHV), human T-cell lymphotropic virus-1 (HTLV-1) and human immunodeficiency virus (HIV).
(3) Three kinds of parasites: Schistosoma aegypti, Opisthorchis viverrini and clonorchis sinensis.
 
 
Cancer screening contributes to its early detection
Cancer screening is the most important way to detect cancer at an early stage. 
 
Different from general health check-ups, cancer screening is an examination carried out by oncology experts according to the examinee’s conditions and individual needs. 
 
For example, lung CT scan should be the focus during lung cancer screening. Patients suspected of gastric cancer or with a family history of high-risk gastric cancer can receive a gastroscopy. Digital rectal examination is a simple method used for screening rectal cancer, and is necessary for those with long-term bloody stools or abnormal bowel habits.