Colorectal Cancer

Overview

Colorectal cancer, also known as colon cancer or rectal cancer, is a type of cancer that develops in the colon or rectum. The colon and rectum are parts of the digestive system, with the colon being the large intestine and the rectum being the lower part of the colon that connects to the anus.

Polyps (growths) in the inner lining of your colon cause colon cancer to form. Precancerous polyps can be found and removed using screening tests and therapies available to healthcare professionals. Colon cancer can spread to other parts of your body if it is not treated. Fewer individuals are passing away from colon cancer as a result of these tests, early diagnosis, and innovative types of therapy.

The lengthy tube that assists in moving digested food to your rectum and out of your body, the colon (large intestine), is where colon (colorectal) cancer first appears. Layers of mucous membrane, tissue, and muscle make up your intestinal wall. The mucosa, or innermost lining of your colon, is where colon cancer first develops. It is made up of cells that produce and secrete fluids, including mucus. These cells have the potential to alter or mutate and become a colon polyp. Colon polyps might develop into cancer in the future. (A colon polyp develops cancer after around 10 years, on average.) The cancer spreads through a layer of tissue, muscle, and the outer layer of your colon if it is not discovered and/or treated. Your lymph nodes or blood arteries may allow the colon cancer to spread to other places in your body.

Symptoms

Colon cancer can exist without showing any signs. Even if you experience symptoms, you might not be able to tell if physical changes are indications of colon cancer. This is true because certain colon cancer symptoms are also present in other, less dangerous diseases. The following are typical signs of colon cancer:

• Persistent changes in bowel habits (constipation, diarrhea, or stool consistency)
• Bleeding from the rectum or blood in the stools
• Ongoing abdominal discomfort (cramps, gas, or pain)
• A sensation that your bowels aren’t totally emptied
• Weakness or exhaustion
• Unaccounted-for weight loss

Early on in the illness, colon cancer is often symptomless in many patients. Depending on the size and location of the cancer in your large intestine, symptoms may differ when they do appear.

Causes

Most colon cancers have unknown causes. Colon cancer often starts when normal colonic cells experience DNA abnormalities (mutations). DNA contains instructions that inform a cell what to do. Normally, cells divide and grow in an organized way, but when a cell becomes cancerous due to DNA damage, it continues to divide unnecessarily, forming a tumor. These cancer cells can invade healthy tissue and metastasize to other parts of the body.

Risk factors include:

• Age: Most cases occur after age 50
• Family history: Having a close relative with colorectal cancer increases risk
• Personal history: Prior polyps or colorectal cancer increases the likelihood
• Inflammatory bowel disease (IBD): Conditions like ulcerative colitis or Crohn’s disease raise the risk
• Genetic syndromes: FAP and Lynch syndrome significantly raise the risk

Diagnosis

Diagnosing colorectal cancer typically involves several steps:

• Screening tests: Colonoscopy and similar exams help find polyps or early signs
• Biopsy: Tissue samples from suspicious growths are analyzed for cancer cells
• Imaging tests: CT, MRI, or PET scans determine how far the cancer has spread

Treatment depends on the cancer’s stage and other individual factors. It may involve surgery, radiation, chemotherapy, targeted therapy, immunotherapy, or combinations. The goal is to remove the cancer, prevent recurrence, or manage symptoms.

Treatment

The treatment plan is influenced by the tumor’s size, stage, location, whether the cancer is recurrent, and the patient’s overall health. Options include:

• Surgery: Often the first-line treatment for localized colon cancer
• Chemotherapy: Used before or after surgery to target remaining cancer cells
• Radiation therapy: Common for rectal cancer or palliative relief
• Immunotherapy & targeted therapy: Used especially in advanced or metastatic cancer
• Palliative care: Helps relieve symptoms and improve quality of life

In early stages, surgery may be curative. More advanced stages may require a stoma for temporary or permanent waste removal. Surgeries may be open or laparoscopic, and robotic assistance is often used for precision.

Prevention

While colorectal cancer can’t always be prevented, you can significantly reduce risk with proactive measures:

• Get regular screenings (e.g., colonoscopy, sigmoidoscopy, FOBT, FIT)
• Eat a healthy diet rich in fiber (fruits, vegetables, whole grains) and low in red/processed meats
• Exercise regularly
• Limit alcohol intake
• Avoid tobacco use
• Maintain a healthy weight

Early detection saves lives—over 90% of people treated for early-stage colorectal cancer live more than 5 years after diagnosis. New therapies and early screenings are improving outcomes. Speak with your healthcare provider about your screening schedule and new treatment options that might be available for you.