Colorectal cancer is the third most common cancer of both men and women in the United States. The American Cancer Society estimates that approximately 106,000 new cases of colon cancer and 41,000 new cases of rectal cancer are diagnosed each year. Over 57,000 people die of colorectal cancer each year. The incidence of colorectal cancer is rising, and the incidence increases with age. The most common form of colorectal cancer is an adenocarcinoma. Adenocarcinomas are cancers that arise from the glands that line the inside of the intestinal tract. Multiple other forms of colon and rectal cancer can occur but are exceedingly uncommon.

Background information about the colon and rectum

The colon and rectal are parts of the intestinal tract for the digestive system. The digestive system as a whole takes the food that you eat and extracts the nutrients that the body needs. What is left after the body extracts the nutrients is known as stool or feces.

After the food is chewed and swallowed it passes through the stomach. The stomach grinds the food into a slurry mixture that then passes into the small intestine. The small intestine is the place where the majority of nutrients are extracted. Once the nutrients have been extracted then the residual passes into the colon. The function of the colon is to reabsorb the water so that the stool towards the end of colon in the rectum is a solid. The length of the colon is approximately 5 feet, however it is longer in some individuals than others. The length of the rectum is relatively uniform and approximately 6 to 8 inches. The colon is divided into four sections. The first portion is the cecum and ascending colon. This originates in the right lower portion of the abdomen at the site of the appendix. The ascending colon rises from the lower portion of the abdomen up towards the ribs. At the right sided of the rib cage the ascending colon turns toward the left side of the abdomen. The second portion of the colon is called the transverse colon. This travels transversely from the right upper portion of the abdomen to the left upper portion of the abdomen. The third portion of the colon is the descending colon. This is the portion of colon that travels from the left upper abdomen to the left lower abdomen. The final portion of colon is called the sigmoid colon. This is a S-shaped portion of colon that connects into the rectum, which then empties out through the anus.

Signs and symptoms of colon and rectal cancer

In some individuals the symptoms of colon cancer are related to the blood loss from the cancer inside the lining of the colon. This can sometimes cause anemia and sometimes present as blood in the stool. Sometimes symptoms can include pain and bloating. Other individuals may experience a change in their bowel habits to include increased constipation or change in the size of the stool itself. However, many colon and rectal cancers do not cause any of these symptoms and are simply found a routine screening examination. Certainly anyone with the above symptoms should be evaluated by their physician. It is the recommendation of the American Cancer Society that all individuals 50 years of age or older should be screened with colonoscopy.

Colonoscopy is a procedure performed by insertion of a flexible lighted tube to examine the inside lining of the colon and rectum. If a suspicious mass or lesion is identified then a biopsy can be performed. This involves removing either a portion or the entire lesion and sending it to a pathologist for examination under a microscope.

Treatment

Colon and rectal cancer are treated differently. Rectal cancer is considered to be a more aggressive cancer and therefore typically treated more aggressively. Rectal cancer is most often treated with a combination of surgery, radiation therapy, and chemotherapy. The typical order of treatment would be to undergo chemotherapy and radiation therapy first to be followed with surgical resection. The exception of this would be in a case of a very early rectal cancer, which can be in some instances be removed by a surgical procedure through the anus and not require an open surgery. For rectal cancers that cannot be removed through the anus, chemotherapy and radiation therapy are followed by surgical resection. Depending on the response of the cancer to the chemotherapy and radiation therapy, the rectum may or may not be able to be reconnected. If the rectum cannot be reconnected than a permanent colostomy will be placed. A colostomy is a bag worn on the side of the abdomen into which the stool empties.

Colon cancer, on the other hand, is treated in most cases with surgical resection as the first treatment modality. Based on the finding of the pathologist after surgery has been completed, chemotherapy maybe recommended based on the depth of invasion of the tumor and the presence or absence of metastatic cancer to the surrounding lymph nodes.

Types of colon resection

The extent of surgical resection of a colon cancer depends on the location of the cancer itself. The most common locations of colon cancer include the sigmoid colon and the ascending colon. Ascending colon cancer is treated with a right hemicolectomy. This includes resection of the cecum up to the transverse colon. The small bowel is then directly reconnected back to the transverse colon. In individuals with this operation, the need for any type of ostomy is extremely small. The bowel movements are typically more frequent and slightly looser than before surgery. Most people resume normal bowel function over several months.

Cancers of the sigmoid colon are treated with a low anterior resection or a sigmoid colon resection. With both of these surgeries the majority of the sigmoid colon and some of the rectum is removed. A direct connection is made between the remaining colon and rectum so that the need for an ostomy is extremely small. Bowel movements following this type of surgery are again typically looser and more frequent than before surgery. Most people recover normal bowel function over the course of several months. Recovery of normal bowel function may take as long as six months depending on whether additional treatment such as chemotherapy is recommended.

Cancers of the transverse or descending colon are less common. These require a segmental resection of a portion of the colon. Direct connection between the residual ends is then performed.

Laparoscopic surgery

Most of our surgeons perform laparoscopic assisted colon resections. The utilization of laparoscopy allows for a majority of the surgery to be performed through small incisions. Then a medium sized incision is performed to allow removal of the region of colon with the cancer. The bowel connection is then performed and the incision closed. The major benefit of laparoscopic assisted procedures is the minimal incision required. This allows for an earlier recovery without compromising the success of the cancer operation.

Metastatic colon and rectal cancer

With increased aggressiveness of the cancer, the possibility of metastatic cancer rises. Metastatic cancer is cancer that has left the place where it started and traveled through the body to other locations. The most common site of first spread are the lymph nodes that surround the colon. The next most common site of metastatic cancer would be the liver. Other locations would include lung, brain, and the internal lining of the abdomen. Metastatic cancer is often treated with chemotherapy. In isolated cases of cancer spread to the liver, this can sometimes be either resected or destroyed by varying techniques.

Overall the diagnosis of cancer is a very anxiety-provoking event. In order to understand the basis of the treatment it is helpful to be as informed as possible. Several questions that you may want to address with your doctor would be:

1. Where is my cancer located?
2. How far has my cancer spread?
3. What treatment options do I have?
4. What potential risks or side effects are associated with the treatment options and how might these treatments affect my quality of life?

There are many useful resources for individuals diagnosed with cancer. These include:

1. The American Cancer Society at www.cancer.org.
2. The National Compressive Cancer Network at www.nccn.org.
3. People Living With Cancer at www.plwc.org.
4. The National Cancer Institute at www.cancer.gov.
5. The Society of Surgical Oncology at www.surgonc.org.

PMA/em