2. Colon cancer is a type of cancer that begins in the large intestine (colon). The colon is the
final part of the digestive tract.
Colon cancer typically affects older adults, though it can happen at any age. It usually begins
as small, noncancerous (benign) clumps of cells called polyps that form on the inside of the
colon. Over time some of these polyps can become colon cancers.
Polyps may be small and produce few, if any, symptoms. For this reason, doctors recommend
regular screening tests to help prevent colon cancer by identifying and removing polyps
before they turn into cancer.
If colon cancer develops, many treatments are available to help control it, including surgery,
radiation therapy and drug treatments, such as chemotherapy, targeted therapy and
Colon cancer is sometimes called colorectal cancer, which is a term that combines colon
cancer and rectal cancer, which begins in the rectum.
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
6. DIAGNOSING COLON CANCER
Colonoscopy uses a long, flexible and slender tube attached to
a video camera and monitor to view your entire colon and
rectum. If any suspicious areas are found, your doctor can pass
surgical tools through the tube to take tissue samples (biopsies)
for analysis and remove polyps.
7. Treatment for colon cancer usually involves surgery to remove the cancer. Other
treatments, such as radiation therapy and chemotherapy, might also be
Removing polyps during a colonoscopy
Endoscopic mucosal resection. Larger polyps might be removed during
colonoscopy using special tools to remove the polyp and a small amount of the
inner lining of the colon in a procedure called an endoscopic mucosal resection.
Minimally invasive surgery (laparoscopic surgery). Polyps that can't be removed
during a colonoscopy may be removed using laparoscopic surgery. In this
procedure, your surgeon performs the operation through several small incisions
in your abdominal wall, inserting instruments with attached cameras that display
your colon on a video monitor. The surgeon may also take samples from lymph
nodes in the area where the cancer is located.
8. Chemotherapy uses drugs to destroy cancer cells. Chemotherapy for colon
cancer is usually given after surgery if the cancer is larger or has spread to
the lymph nodes. In this way, chemotherapy may kill any cancer cells that
remain in the body and help reduce the risk of cancer recurrence.
Chemotherapy might also be used before an operation to shrink a large
cancer so that it's easier to remove with surgery.
Chemotherapy can also be used to relieve symptoms of colon cancer that
can't be removed with surgery or that has spread to other areas of the body.
Sometimes it's combined with radiation therapy.
For some people with low-risk stage III colon cancer, a shorter course of
chemotherapy after surgery may be possible. This approach may reduce the
side effects compared with the traditional course of chemotherapy, and may
be just as effective.
10. Radiation therapy uses powerful energy sources, such as X-
rays and protons, to kill cancer cells. It might be used to
shrink a large cancer before an operation so that it can be
removed more easily.
When surgery isn't an option, radiation therapy might be
used to relieve symptoms, such as pain. Sometimes radiation
is combined with chemotherapy.