Much of the information on colon cancer surgery also applies to rectal cancer surgery. However, there are some differences in details, since the rectum is located in a less accessible part of the body.
If the cancer in the rectum is nothing but a small polyp or a surface lesion, the surgeon may be able to perform a transanal resection. This procedure does not require an abdominal incision, since the instruments are inserted through the anus.
Surgery on larger cancers of the rectum is more challenging than surgery on cancers of the colon. The reason for this is that the rectum is located in a tightly packed area, the pelvis, and is close to the bladder, urethra, anal sphincter, nerves, and several other important structures, making access more difficult.
SURGICAL OPTIONS FOR RECTAL CANCER
There are several surgical procedures for accessing the cancer of the rectum:
• Transanal Excision
• Low Anterior Resection, or LAR
• Abdominoperineal Resection, or APR
• Pelvic Exenteration
The choice of treatment and expected outcome depend on the exact location of the tumor within the rectum, and on the stage of the cancer. This is determined by:
• How deeply the tumor has invaded the wall of the rectum
• Whether the cancer has spread to the lymph nodes
• Whether the cancer has spread to other organs
The main technical challenge is to remove all the cancerous tissue and achieve a cure, without damaging the nerves or the anal sphincter muscles. Damaging them may lead to incontinence—leakage of urine or stool.
Stage 0 and some stage I rectal cancers can be treated with transanal excision. A few stage I rectal cancers, and most stage II and III rectal cancers are treated with low anterior resection or abdominoperineal resection— removal of the tumor. A generous margin of healthy tissue around the tumor has to be removed as well, to decrease the chance of leaving cancerous cells behind.
Only about five out of a hundred patients with early stage rectal cancer can be treated with this type of local therapy. More commonly, more extensive surgery is necessary. If the cancer has advanced locally, adjuvant (additional) treatment with radiation therapy and chemotherapy may be recommended.
In some instances, such as when the cancer is large and bulky and close to the anal sphincter, or when the surgeon thinks that the anus and rectum may need to be removed, radiation therapy, with or without chemotherapy, may be given before surgery. This pre-treatment is called neoadjuvant therapy. The goal is to shrink the tumor enough to make it possible for the surgeon to remove the entire tumor, but preserve the anal sphincter.
Let’s review the surgical procedures in detail.
Some early stage rectal cancers that are located close to the anus and have not spread to adjacent tissues can be removed through the anus, instead of through the abdominal wall. This procedure is called transanal excision. It is generally done in the operating room under general anesthesia. Your surgeon will determine whether the procedure will be done on an outpatient basis, or if you will be admitted to the hospital.
Since the abdomen is not entered and the bowel is not disturbed, transanal excision is easier on your body. But it does require a surgeon who is well-versed in this type of surgery.
An experienced colorectal cancer surgeon can often remove just the tumor and a small amount of surrounding tissue, while leaving the anus and sphincter intact. This sphincter-sparing procedure allows patients to retain bowel function and eliminates the need for a permanent colostomy.
Sphincter-sparing surgery is an option for patients with small early stage (stage I) rectal cancers that are near the anus but have not spread to the anus or the anal sphincter itself.
Before surgery you will probably have a test called endorectal ultrasound, or ERUS, to assess the extent of spread of cancer cells into adjacent tissues and lymph nodes. If there is spread, your surgeon will not perform a transanal resection, but will choose a more extensive procedure.
LOW ANTERIOR RESECTION, OR LAR
Low anterior resection is the surgical procedure most frequently used to deal with cancers of the rectum. This surgery is similar to a colon resection: it is performed under general anesthesia, through a single incision in the lower part of your abdominal wall. The affected part of the rectum is removed, and the end of the colon is reattached to the anus, so that feces can be passed normally.
ABDOMINOPERINEAL RESECTION, OR APR
Abdominoperineal resections use two incisions—one through the abdomen, the other through the perineum (the area between your legs, around the anus). Working through these incisions, the surgeon can remove a tumor near the bottom end of the rectum.
The surgery will involve the rectum, the anus and surrounding tissue. Because there will be no tissue left to reconstruct a functioning anus, you will have a permanent colostomy.
Both LAR and APR procedures can be performed utilizing minimally invasive surgery (MIS) techniques.
Urinary function may change since the nerves that control urinary function lie in the pelvis, and might have been bruised during this extensive surgery. In certain cases, the surgeon will be able to perform a nerve sparing procedure, and preserve nerve function. Some patients need a urinary catheter for longer than usual, or medications, or both, until normal bladder function returns. Usually, patients don’t have permanent loss of urinary control (urinary incontinence).
If the cancer has spread to nearby organs, you may need a more complex operation: a pelvic exenteration. Depending on how far the cancer has proliferated, the exenteration surgery will remove the rectum, bladder, and prostrate or uterus. A colostomy is always required for this procedure, as well as a urostomy if the bladder is removed.
RECOVERY AFTER RECTAL SURGERY
Whether you had a low anterior resection or an abdominoperineal resection, you will remain in the hospital for approximately four to seven days, and then convalesce at home for three to six weeks. If you had a pelvic
exenteration, your hospital stay and home recovery may be longer. Ask your surgeon how and when you may resume your normal activities. You may want to refer to Chapter 6, for information on how to recover faster, and improve your comfort.
Will the operation be successful? It is not possible to answer this question with certainty. Your expected results will depend on several so-called prognostic factors.
The most important prognostic factor is the stage of the tumor—in other words, the extent of spread of the tumor into the bowel wall and beyond. Obviously, if the cancer has infiltrated the surrounding tissues, removing all of the cancerous cells might be difficult. The more extensive the surgery, the more side effects you can expect. Only your surgeon will be able to give you an assessment of what you can expect in your particular case.
Another important factor that has a bearing on the outcome is the experience and skill of the surgeon who will perform the operation.Working in a confined space, with limited visibility such as exists in the pelvic area, is best left to specialists with extensive experience in this type of procedure. Feel free to ask your surgeon about his or her particular skills, experience, and recent results.
Sexual Side Effects of Rectal Surgery
One issue that is sometimes overlooked is the impact of colorectal cancer treatment on your sexual life. This oversight is understandable, since when you are facing a cancer diagnosis and your life is at stake, sexuality may not be on the top of your list.
The stress of treatment, the toll taken by surgery, the side effects of chemotherapy, can all contribute to low energy levels, and loss of sexual interest. Usually after the side effects of treatment abate, you will be able to return to the same level of sexual activity as you enjoyed before surgery. But there may be physical reasons for sexual problems that may not resolve with time.
One of the reasons is the fact that surgery on the rectum often damages the nerves that are involved in sexual function.
Men who have an AP resection may have “dry” orgasms following surgery, because of damage to the nerves that control ejaculation. Sometimes the surgery causes retrograde ejaculation, which means the semen goes backward into the bladder. AP resection should not stop your erections or ability to reach orgasm, but your pleasure at orgasm may be less intense.
Women who have an AP resection may expect to develop vaginal dryness, and may experience painful intercourse (dyspareunia) particularly if the posterior part of the vagina was surgically removed during the procedure.
Try to overcome any inhibitions you might have, and bring up the topic of possible sexual side effects when you discuss your upcoming surgery with your physician. Being prepared for the worst can only lead to a pleasant surprise. Do discuss any sexual side effects that you might develop after surgery. Your physician or nurse can offer many suggestions that you may find helpful.