Colorectal Cancer

Cancer that begins in the colon is called colon cancer, while cancer in the rectum is known as rectal cancer. Cancers that affect either of these organs may be called colorectal cancer. Though not true in all cases, the majority of colorectal cancers generally develop over time from adenomatous (precancerous) polyps.

Causes #

• In general, colon cancer begins when healthy cells in the colon develop changes (mutations) in their DNA.

• A cell’s DNA contains a set of instructions that tell a cell what to do.

• Healthy cells grow and divide in an orderly way to keep your body functioning normally.

• But when a cell’s DNA is damaged and becomes cancerous, cells continue to divide even when new cells aren’t needed.

• As the cells accumulate, they form a tumor.

• With time, the cancer cells can grow to invade and destroy normal tissue nearby.

• And cancerous cells can travel to other parts of the body to form deposits there (metastasis).

Symptoms #

• Change in bowel habits - Constipation, diarrhea, narrowing of stools, incomplete evacuation, and bowel incontinence although usually symptoms of other, less serious problems can also be symptoms of colorectal cancer.

• Blood on or in the stool - By far the most noticeable of all the signs, blood on or in the stool can be associated with colorectal cancer. However, it does not necessarily indicate cancer, since numerous other problems can cause bleeding in the digestive tract, including hemorrhoids, anal tears (fissures), ulcerative colitis, and Crohn’s disease, to name only a few.

• Unexplained anemia - Anemia is a shortage of red blood cells the cells that carry oxygen throughout the body. If you are anemic, you may experience shortness of breath. You may also feel tired and sluggish, so much so that rest does not make you feel better.

• Abdominal or pelvic pain or bloating

• Unexplained weight loss

• Vomiting

Diagnosis #

• Blood tests (Complete blood count, tumor markers and liver enzymes)

• Imaging tests (X-rays, CT scan, MRI scan, PET scan, ultrasound, angiography)

• Biopsy

• Diagnostic colonoscopy (done after you show symptoms, not as a routine screening test)

• Proctoscopy

Treatment #

Surgery #

• Surgery is the primary treatment for colorectal cancer that is limited to the colon.

• It aims to remove cancerous tissue, including tumors and affected lymph nodes, and prevent the cancer from spreading.

• The surgeon usually reconnects the bowel after removing cancerous areas, but they may need to create a stoma for drainage into a colostomy bag.

• Surgery may remove all traces of early stage cancer.

• In the later stages, surgery cannot stop the cancer from spreading, but removing a blockage can help ease any symptoms.

• Surgery for colon cancer may be open, involving a large incision.

• It may instead be laparoscopic, a less invasive type of surgery that requires tiny incisions.

• The surgeon typically uses robotic devices during the surgery.

Local excision #

This involves removing early cancerous tissues. During the procedure, a surgeon removes polyps and some colon tissue.

Colectomy #

• A colectomy involves removing some or all of the colon.

• If the surgery is partial, the surgeon reattaches the remaining segments.

• Other names for this approach are a hemicolectomy, a partial colectomy, or a segmental resection.

• A total colectomy involves removing the whole colon.

• This is less Source, and a surgeon may only recommend it if there are many polyps, for example.