Cancer that begins in the large intestine is known as colon cancer. Although it can affect people of any age, it occurs more frequently in older adults. Symptoms for colon cancer may not appear until the disease progresses to the second stage or later. However, recognizing some early warning signs can help with the early diagnosis and treatment of colon cancer. Treatments for this condition will vary by the stage and type of colon cancer. Signs and symptoms of colon cancer Stage 0 This is the earliest stage of colon cancer, where the abnormal cells are only noticed in the lining of the colon. It is also known as carcinoma in situ. Most people may not notice any symptoms during this stage of cancer. However, some early warning signs to watch out for include: Narrow ribbon-like stools Rectal bleeding that is bright or dark red Tenesmus, or a feeling of heaviness or having to pass stool, but nothing passes Anemia Persistent abdominal pain Stage 1 By this stage, the cancer has penetrated the lining of the colon or rectum and affected the muscle. However, it has not yet reached the lymph nodes or other body parts. Common symptoms one may notice during this stage include:

Colon or colorectal cancer begins in the colon—the longest part of the large intestine. Along with the rectum, the colon makes up the lower end of the digestive system. Cancer in this region is the third most common form of the condition, with the American Cancer Society suggesting that 1 in 23 men and 1 in 25 women are at risk of developing the disease. Here, recognizing the signs can help one seek timely treatment.  Early signs The early stages of colon cancer rarely cause visible symptoms. However, one may experience some of these early signs for about a year or two before they get a diagnosis. Abdominal pain: Pain is a common cancer symptom. With colon cancer, one may observe tenderness in the lower abdomen as well. Rectal bleeding: One may observe bright, red blood in the stool and persistent diarrhea as early signs of colon cancer. Anemia: Colon cancer causes inflammation and blood loss, which results in iron deficiency, leading to anemia. As the cancer progresses, one may start to experience some of the following symptoms, usually observable between stages 0 and 2: Changes in bowel habits: Constipation and diarrhea are common early signs of the condition. Cancer in the colon can affect the frequency of bowel movements.