POLYPS AND HOW THEY RELATE TO COLORECTAL CANCER
Colorectal cancer is a cancer of the large intestine (colon), the lower part of your digestive system. Rectal cancer is a cancer of the last part of your colon. Together, colorectal cancer is the #2 cause of cancer-related deaths in the United States (second to lung cancer.)
In most cases of colon cancer, the process begins in the form of a polyp. These are benign (non-cancerous) clumps of cells that are often small and produce few symptoms other than silent and slow bleeding (which may manifest as dark stool.)
POLYPS ARE OF 2 MAIN TYPES AND MAY BE HYPERPLASTIC OR ADENOMATOUS.
- Hyperplastic polyps are benign and have no potential to develop into cancer.
- Adenomatous polyps come in different varieties all of which have the potential to develop into cancer.
It is not possible to distinguish adenomatous from hyperplastic polyps in the body so the current standard of care is to completely remove any colon polyps to permit complete analysis.
On occasion, it may be found that colon cancer has already developed in a removed polyp. In such cases, if the cancer has been completely removed, no further tissue removal is necessary. In cases where residual cancer is left, or if there is uncertainty if cancer cells remain, removal of the affected portion of the colon is indicated (see below.)
Screening tests, as well as simple lifestyle and diet changes, can greatly reduce your overall risk of developing colon cancer because most polyps can be found and removed before they turn into cancer.
SIGNS AND SYMPTOMS OF COLON POLYPS / COLORECTAL CANCER
Polyps rarely cause symptoms by themselves. On occasion, polyps may bleed and this will typically manifest as dark or tarry stool. Such a finding should prompt a phone call to your physician.
There are often no symptoms of colorectal cancer during its early stages. When symptoms do occur, they will vary according to the location and size of the cancer.
Symptoms may include:
- Prolonged changes in normal bowel habits, including diarrhea or constipation.
- Changes in size or shape of bowel movements (i.e., narrow, pencil-thin stools).
- Persistent abdominal pain or distention.
- Rectal bleeding or blood in your stool – either bright red or dark depending on where to cancer is located.
- Unexplained weight loss or change in appetite.
There are many factors that may influence the development of colon cancer. Some include:
- Age: your chance of having colorectal cancer goes up over the age of 50.
- Family history: your risk is higher if a close family member (sibling, parent) has colon cancer.
- History of colonic polyps: certain polyps increase the risk of cancer, especially if they are large or come in large numbers.
- Inflammatory bowel disease: a long-standing history of ulcerative colitis or Crohn’s disease is associated with increased risk.
- Diabetes: people with diabetes have a 40% increased risk of colon cancer.
- Diet: a diet high in fats (especially animal fats) may increase your risk for colon cancer.
- Cigarette smoking/alcohol: may increase your risk.
- Sedentary lifestyle.
- Race: African Americans have the highest number of colorectal cancer cases in the United States and the reason is still unknown.
SCREENING AND DIAGNOSIS
Most colon cancers develop from adenomatous polyps, so early and routine screening is very important for detecting colon cancers. Common screen procedures include:
- Digital rectal exam: This is done in the office and is usually painless. A doctor uses a gloved finger to examine the last few inches of your rectum. This exam cannot detect polyps or abnormalities higher in your colon/ rectum.
- Fecal occult blood test: This test checks your stool sample for hidden blood. Very small amounts of blood can be in the stool when polyps or cancers start to form. It can either be done in the doctor’s office or by yourself at home using a special kit. If the results are positive for blood, further test are needed to find the exact cause of bleeding.
- Flexible sigmoidoscopy: This test is typically done in the office. Your doctor uses a slender lighted tube attached to a video camera so that he/she can examine your rectum and sigmoid colon. If a polyp or abnormality is found, you will be recommended to undergo a formal colonoscopy to examine the entire colon and rectum and to remove or biopsy any polyps detected.
- Colonoscopy: This is the most comprehensive and sensitive test for colon cancer. The instrument is a longer version of the flexible sigmoidoscopy and allows the entire length of the colon and rectum to be examined. The day before, you will be asked to undergo a bowel prep to clean out your colon. And during the procedure, you will receive a mild sedative to make the procedure more comfortable. Most patients go home the same day.
TREATMENT FOR COLORECTAL CANCER
There are four main types of treatment for colorectal cancer:
- Radiation therapy
- Targeted Drug Therapy
The treatment or combination of treatments depends on the stage or extent of cancer present: location of the cancer, how far the cancer has penetrated the wall of the bowel, and whether the cancer has spread to the lymph nodes and other parts of your body.
TREATMENT FOR COLORECTAL CANCER: SURGERY
Surgery is the main treatment option for colon cancer.
Segmental Colectomy is a surgical procedure that removes the part of your colon that contains the cancer, plus a margin of healthy colon on either side to make sure no cancer is left behind. The two ends of the colon are typically then reconnected.
Traditionally, surgery for colon cancer has been done through one large incision in the abdomen. More recently, several large-scale studies have been done to prove that laparoscopic surgery can be used to safely remove colon cancer and reattach the ends.1 This is known as a laparoscopic colectomy. In each of the studies, researchers have shown that colon cancer patients treated by laparoscopic colectomy have the same propensity for survival as those treated with open colectomy but receive all the benefit of the quicker recovery of a laparoscopic operation.
In laparoscopic colectomy, surgeons utilize special instruments and cameras that are inserted inside the body through multiple small incisions, rather than one large incision. Patients usually recover faster after this technique and leave the hospital earlier on average than patients who choose open surgery. The cosmetic benefits also apply. Not everyone is a candidate for laparoscopic colectomy. People who have large tumors or those who have had many abdominal surgeries in the past, may not be candidates for this technique. This should be discussed with your surgeon as the decision is always dependent on your unique situation and your surgeon’s level of comfort.
RISKS OF LAPAROSCOPIC COLECTOMY FOR COLON POLYPS OR COLON CANCER
The risks of any surgery must be weighed against the risks associated with disease state requiring the intervention. In the case of polyps or cancer, the risks of developing or leaving known cancer in the body are greater than the risks described below and surgery is thus indicated.
Major risks of laparoscopic colectomy for colon polyps or cancer can include, but are not limited to:
- Wound infection (1-3%) possibly requiring the opening of wound, drainage, antibiotics and prolonged wound care.
- Abdominal cavity infection (1-3%) possibly requiring antibiotics, drainage of the infection via a catheter or reoperation to drain the infection.
- Leakage from the re-connection points (anastomotic leak) (5-10%) resulting in infection and possibly drainage of the infection via a catheter or re-operation to drain the infection. Re-operation may also require the creation of a temporary colostomy to allow the body time to heal the infection. This can typically be reversed 4-6 months later.
- Bleeding from surgical sites (1-3%) requiring observation, blood transfusion or re-operation.
TREATMENT FOR RECTAL CANCER: RADIATION THERAPY
Radiation is typically reserved for patients with rectal cancer only because it is dangerous to radiate the small bowel that comes in contact with the areas of the colon other than the rectum. Radiation therapy involves treatment with powerful energy rays that kill cancer cells.
If the cancer is large or if the cancer’s location makes surgical treatment difficult, radiation therapy may shrink the tumor before surgery.
There are two main types of radiation therapy, depending on the source of the high energy rays:
- External radiation therapy is used most commonly for people with colorectal cancer. Treatments are typically given 5 days a week for several weeks. Each treatment lasts only a few minutes.
- Internal radiation therapy involves placing small seeds of radioactive material directly into or near the cancer.
This allows high energy rays to focus directly onto the tumor. This technique is more frequently used with rectal cancer, prostate cancer, and in older or ill patients who would not be able to withstand surgery.
Radiation therapy causes several side effects: nausea, skin irritation, diarrhea, rectal or bladder irritation, or fatigue
TREATMENT FOR COLORECTAL CANCER: CHEMOTHERAPY
Also known as “chemo” and is the use of drugs that kill cancer cells. They may be given intravenously or taken by mouth. The drugs penetrate through the bloodstream, making them effective for cancers that have spread throughout the body.
Chemotherapy after surgery can increase the survival rate for some patients with invasive colorectal cancer. However, there are negative aspects to chemotherapy as well. While killing cancer cells, chemotherapy drugs can also damage normal, healthy cells too. This leads to side effects such as:
- Nausea, vomiting
- Hair loss
- Increased risk of infection
- Bleeding or bruising
- Mouth sores /ulcers
Most side effects (such a hair loss) will resolve when chemotherapy is completed.
TREATMENT FOR COLORECTAL CANCER: TARGETED DRUG THERAPY
These drugs target the special defects that allow cancer cells to grow and proliferate. Currently, there are 3 drugs available to patients with advanced cancers and are still experimental.