How colorectal cancer is diagnosed?


According to, cancer is a disease characterized by the unchecked division of abnormal cells. When this type of growth occurs in the colon or rectum, it is called colorectal cancer (大腸癌). The colon and rectum (colorectum), along with the anus, make up the large intestine, the final segment of the gastrointestinal (GI) system. The large intestine is sometimes called the large bowel, which is why CRC is sometimes referred to as bowel cancer. The function of the large intestine is to absorb water and electrolytes from food matter and eliminate feces.

In 2020, there will be an estimated 104,610 new cases of colon cancer and 43,340 cases of rectal cancer diagnosed in the US (Table 1). Although the majority of CRCs are in adults ages 50 and older, 17,930 (12%) will be diagnosed in individuals younger than age 50, the equivalent of 49 new cases per day. An estimated 53,200 people will die from CRC in 2020, including 3,640 men and women younger than age 50.

There is a trend that more people younger than age 50 die from CRC. The diagnose of cancer is important and regular body check should be taken.

How colorectal cancer is diagnosed

There are many tests used for diagnosing colorectal cancer. Not all tests described here will be used for every person. Your doctor may consider these factors when choosing a diagnostic test:

  • The type of cancer suspected
  • Your signs and symptoms
  • Your age and general health
  • Your medical and family history
  • The results of earlier medical tests

In addition to a physical examination, the following tests may be used to diagnose colorectal cancer.

  • Colonoscopy. 
  • Biopsy. 
  • Biomarker testing of the tumor. 
  • Blood tests. 
  • Computed Tomography scan (CT scan). 
  • Magnetic resonance imaging (MRI). 
  • Ultrasound. 
  • Chest x-ray. 
  • Positron emission tomography (PET) or PET-CT scan.