The rectum is the last part of the intestine which starts at the end of the colon and leads to the anus. People sometimes differentiate between colon cancer and rectal cancer; however the two are usually referred to together as "colorectal cancer." While these two cancers can be quite close in proximity - the treatment styles are completely different.
The first step in rectal cancer treatment is understanding the stage of the cancer which helps your colorectal specialist determine the best course for treatment. If surgery is the right path for you, explore some of the various surgical approaches to treating rectal cancer.
LAR (Low Anterior Resection) is a common treatment for rectal cancer when the cancer is located well above the anus. During an LAR, the entire rectal cancer, adjacent normal rectal tissue and surrounding lymph nodes are laparoscopically removed through small incisions on the abdomen and then brought out through an incision made in the lower abdomen. After the cancer is removed, the cut ends of the colon and rectum are stapled or sewn back together. The passage of stool from the large intestine through the anus is therefore preserved.
If the cancer is lower in the rectum, the cut end of the large bowel may be attached directly to the anus, a procedure known as colo-anal anastomosis. Some surgeons will create a temporary ileostomy or colostomy to protect the delicate surgical connection of the large intestine to the anus. After the patient has recovered, the temporary ileostomy or colostomy is removed and stool is again passed normally.
Complications and symptoms: Patients undergoing an LAR may have lower abdominal pain afterwards. Less common complications include bleeding, infection and temporary difficulty emptying the bladder. Some men may also experience sexual dysfunction after surgery.
APR (Abdominoperineal Resection) is a common treatment for rectal cancer when the cancer is located close to the anus. During an APR, the entire rectal cancer, adjacent normal rectum, rectal sphincter or anus, and surrounding lymph nodes are removed through an incision in the lower abdomen and the perineum (the skin around the anus). Following removal of the cancer, the incision in the perineum is sewn shut. The cut end of the large intestine is attached to an opening in the abdominal wall, called a colostomy. This opening is covered with a bag, which serves to collect stool as it passes through the large intestine and through the colostomy. In contrast to a LAR, the colostomy is permanent.
Many patients would like to avoid a permanent colostomy. When the rectal cancer lies close to the sphincter or anus, an APR is typically recommended. In some instances, a more limited surgery can be used to avoid a colostomy, or radiation therapy can be used to shrink the rectal cancer prior to surgery allowing the patient to maintain control of bowel function. Some small rectal cancers that lie close to the anus can be removed with less extensive surgery called a local excision, but not all patients can undergo a local excision - see Local Excision to the right.
Local transanal excision can be performed to remove rectal cancer and preserve the anus, preventing complications that may occur with more extensive LAR or APR surgeries. Local excision is designed to remove the cancer and a small rim of normal bowel, without removing the anus. The surgery may be performed through the anus (transanal excision), which can be performed for small cancers that lie close (typically within 2 inches) from the anus.
For local excision to be effective, the entire cancer with a rim of normal tissue must be removed. Patients with cancers that are larger, more deeply invading, or appear aggressive under the microscope are better treated with traditional surgeries. In order to improve the cure rates after limited surgery alone, a combination of chemotherapy and radiation therapy is often administered for cancers that have grown into the muscular wall of the rectum.
Patients undergoing limited surgery may experience pain in the region of the perineum or tailbone. Less common complications related to surgery include bleeding, infection, and difficulty with healing of the rectal wall. In-hospital fatality is very rare after limited surgery, so be sure to ask your doctor about your options.
STRATEGIES TO IMPROVE TREATMENT
The progress that has been made in the treatment of rectal cancer has resulted from improved surgical techniques and the development of neoadjuvant and adjuvant treatments in patients with more advanced stages of cancer.
Improved Sphincter-Sparing Treatments: Because of the inconvenience of a colostomy, physicians are using sphincter-sparing treatments that allow patients with low-lying rectal cancers to keep the anus. Improved methods to select patients who can be treated with limited surgery followed by adjuvant chemotherapy and radiation therapy are being developed. More aggressive use of preoperative (neoadjuvant) chemoradiation may allow more patients with larger low-lying rectal cancers a chance to maintain anal function.
Neoadjuvant Therapy: When rectal cancer cannot be completely removed with surgery, a patient’s chance of cure is greatly diminished. Presurgery radiation and/or chemotherapy is referred to as neoadjuvant therapy. Neoadjuvant therapy can shrink some rectal cancers and therefore allow complete surgical removal. Determining the optimal neoadjuvant chemotherapy and radiation therapy is an area of current research.