Colorectal cancer--or cancer that originates from the colon or rectum--is a prevalent form of cancer. The National Cancer Institute reports that 106,100 new cases of colon cancer and 40,870 cases of rectal cancer were diagnosed in the United States in 2009, and the two conditions led to almost 50,000 deaths. Colorectal cancers can develop from any of the cells within the colon or rectum, though most colorectal cancers arise from glandular tissue within the colon. Colorectal cancer is a potentially devastating disease, so understanding the disease's common effects may help with early detection and more effective treatment.
Constipation or Diarrhea
Constipation or diarrhea are common symptoms of colorectal cancers. Normally, the cells within the colon and rectum are responsible for absorbing water from the stool to help maintain hydration of the body and to allow for proper stool consistency. With cancer, the normal function of the colon cells becomes disrupted, so the result is abnormal stools. If the cells absorb too much water, this leads to constipation; if the cells absorb too little water, it leads to diarrhea. Although occasional diarrhea or constipation is relatively normal, Penn State University reports that persistent bowel movement problems may indicate colon or rectal cancer.
Bloody Stool
Another common symptom of colorectal cancer is blood in the stool. As cancer within the colon or rectum grows, the cancer cells actively damage neighboring healthy tissue to make more room for tumor growth. As the tissue becomes more and more damaged, the colon or rectum begins to bleed, which leads to blood in the stool. Bloody stool due to colorectal cancer appears as red or maroon stool, according to the University of Maryland Medical Center. In some cases, there may not be enough blood to be visible, and laboratory analysis of a stool sample is required to detect the blood.
Abdominal Pain and Swelling
As the colorectal cancer progresses and becomes larger, the tumor may eventually block the lumen, or the opening of the colon. Once this occurs, stool becomes impacted before the blockage site, which is called a bowel obstruction. Bowel obstruction leads to abdominal pain and swelling as stool builds up inside the colon, putting pressure on surrounding organs. Nausea and vomiting, fever and bad breath often accompany abdominal pain caused by a bowel obstruction, according to New York University. Abdominal pain and swelling due to a bowel obstruction can be fatal if left untreated. A bowel obstruction due to cancer indicates a very large tumor, which is also life-threatening. Individuals experiencing abdominal pain in combination with other symptoms of colon cancer should seek immediate medical attention.
