Brenda Spriggs, MD, MPH, MBA
Colon cancer is one of the major causes of cancer death in the United States. Every year, roughly 100,000 new cases of colon cancer are diagnosed, according to the National Cancer Institute in 2009. Colon cancer can develop in patients for years before symptoms appear. Since the right side of the colon is large, cancers of the right colon grow to relatively large sizes before causing any symptoms.
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Cancers in the right colon often cause blood loss over time. This process of slowly losing blood eventually leads to iron-deficiency anemia, which means a low count of red blood cells or hemoglobin.
According to an August 2007 article in "Diseases of Colon & Rectum," the American Gastroenterological Association recommends that patients diagnosed with anemia without an obvious cause be referred urgently to a specialist to check for colon cancer. This study reported that roughly 6 percent of patients who had anemia without an obvious cause had right side colon cancer.
Fatigue and Weakness
Patients with cancer in the right colon are also likely to experience fatigue, shortness of breath and weakness. These symptoms are the direct result of anemia.
Patients with cancer in the right-side colon experience many symptoms that are common to colon cancer. The most common symptoms of colon cancer are rectal bleeding and changes in bowel habits (e.g., constipation or diarrhea). In a study published in the October 1999 issue of the "American Journal of Gastroenterology," S.R. Majumdar and colleagues reported that roughly 60 to 80 percent of colon cancer patients have rectal bleeding and changes in bowel habits at the time of diagnosis.
Other symptoms of colon cancer include abdominal pain, anorexia, nausea and vomiting. Colon cancer patients might also experience unexplained weight loss. However, weight loss tends to be associated with advanced colon cancer, according to "Clinical Oncology."
A cluster of symptoms--for instance, anemia, rectal bleeding and constipation--is a strong indication of right-sided colon cancer.