What is colorectal cancer and what can you do to prevent it

April 15-21 was the 22nd National Week of Cancer Prevention and Treatment Awareness in China.

Among all cancer types, colorectal cancer has noticeably become the third most prevalent cancer in China and its incident rate is still rising, partly a result of the shift in lifestyle and diet structure in the country and the aging of the population.

Nevertheless, colorectal cancer has a variety of treatment options and patient survival is relatively long. In addition, adoption of a healthy lifestyle and early diagnosis can effectively reduce its risks. Here are nine facts about colorectal cancer that you need to be aware of.

Prevalence

Colorectal cancer is the third-most common cancer in the world, with nearly 1.4 million new cases diagnosed in 2012, according to the World Cancer Research Fund. Males and females have a roughly equal risk. With an estimated number of more than 600,000 patients dying of the disease per year, the cancer is the fourth-most common cause of cancer death.

The numbers are increasing: It is predicted that 2.4 million cases of colorectal cancer will be diagnosed annually worldwide by 2035.

Regional differences

There is wide geographical variation in incidence across the world, with rates varying tenfold. The highest estimated rates can be found in Australia and New Zealand, the lowest in Western Africa, according to the World Health Organization.

However, there may be a high degree of underreporting in developing countries.

In particular, the incidence and mortality of the cancer is increasing rapidly in Asia. Countries such as China, Japan, South Korea and Singapore have experienced a two- to fourfold increase in incidence in recent decades.

Risk factors

Factors that may increase risk of colon cancer include old age - the great majority of people diagnosed with colon cancer are older than 50 - inflammatory intestinal conditions, a family history of colon cancer, a low-fiber, high-fat diet, alcohol, smoking and obesity.

Up to 10 percent of people who develop colorectal cancer have inherited gene defects (mutations) that cause the disease.

Disease development

Colorectal cancer occurs when malignant cells form in the wall of the bowel and grow into a tumor, usually over a period of several years.

As the cancer progresses, it invades the colon wall, the lymph nodes, then blood vessels and eventually spreads to other areas of the body.

Most colorectal cancers begin as a polyp. They are common in people older than 50 years of age, and most are not cancers. However, a certain type of polyp known as an adenoma may have a higher risk of becoming a cancer.

Symptoms

Symptoms can include change in bowel habits, constipation, weight loss, fatigue, rectal bleeding, abdominal pain or discomfort.

Colorectal cancer often keeps growing for years, without those affected noticing any symptoms. One-quarter of patients are diagnosed when the tumor has already spread.

Prognosis

The cancer is one of the most highly treatable of all the gastrointestinal cancers and with early diagnosis and effective treatment people can live with colorectal cancer.

However, once the tumor has spread to another part of the body, the chances of being cured dramatically decline: The five-year survival for stage I is 74 percent, whereas for stage IV it is only 6 percent.

Therapy

Dramatic progress has been made in the treatment of colorectal cancer. Many people with early cancer can have surgery to remove the tumor. Following surgery, some doctors will give radiotherapy and/or chemotherapy to prevent the cancer from coming back.

Chemotherapy is often supplemented with the use of targeted therapies. These new treatments help the body to control the growth of cancer cells by using drugs or antibodies to identify and attack specific cancer cells.

Screening

Early diagnosis is crucial to increasing the chances of defeating the disease. Screening has the potential to even prevent colon cancer because it can often detect pre-cancerous growths in the colon and rectum.

The rate at which people are diagnosed with colon cancer in the US has dropped 30 percent in the last 10 years for those aged 50 years and older, according to a new report from the American Cancer Society. Researchers credit the drop to more people getting recommended screening tests.

Several screening options exist. Patients should always discuss options with a doctor, and together decide which tests are appropriate.

Prevention tips

Everybody can take steps to reduce the risk of colon cancer by making changes in the everyday life. Among them are exercising regularly, eating vegetables and fruits regularly, maintaining a healthy body weight, avoiding excessive alcohol use and limiting the consumption of red and processed meats.

Another important aspect of prevention is spreading the word: organizations, families, and individuals can help raise awareness of the cancer as well as prevention and therapy options across communities.

zhuanti@chinadaily.com.cn

(China Daily 04/22/2016 page10)