Radiation Injuries from Cancer Treatment
What is a radiation injury?
Radiation therapy, alone or in combination with surgery and chemotherapy, is commonly used for the treatment of many cancers. Although radiation therapy can usually be delivered without resulting in long-term injury, it can occasionally lead to permanent side-effects. In severe cases, the radiation leads to scarring (fibrosis) and/or damage to the blood supply of the normal tissues in the irradiated field. It is this scarring and damage that leads to the side-effects seen in patients with radiation injury. When these complications occur, they become apparent 6 months or more after the radiation exposure. In some cases, these complications will occur many years after treatment
What complications can be seen after radiation?
The chance of complications after radiation depends upon the dose and location of radiation treatment, and whether or not it was combined with chemotherapy and/or surgeries in the treated region. Radiation that was given in the abdomen for gynecologic, testicular or pediatric cancers can cause scarring of the kidney or the ureters (the urinary tubes connecting the kidney to the bladder). Radiation that was given in the pelvis for problems like prostate, bladder, colorectal and cervical cancer can also damage the urinary structures. Some of the more common complications from pelvic radiation include strictures of the urethra (about 1 in 20 persons) and urinary urgency and frequency (about 1 in 10). Although often these common complications can be managed with medications, about 1 in 20 persons will require a surgical procedure to repair the damage. In rare cases, a fistula (a hole between the bladder or urethra and the rectum or skin) can occur. Severe complications like fistulas occur in fewer than 1 in 1000 patients who receive modern external beam radiotherapy, but in about 1 in 100 patients who receive high-dose-rate brachytherapy.
How are radiation injuries treated?
The treatment of radiation damage depends upon the nature of the problem. Chronic wounds can sometimes be treated with a trial of hyperbaric oxygen. If there is a surgical problem, this can be addressed by a urologist. Surgery may involve a variety of procedures depending upon the nature of the problem. The damage can be so varied from radiation that each patient will need to have a thorough evaluation to find out the extent of damage and create a strategy to improve or fix the damage that has occurred. This evaluation often involves tests, like CT scans or scope procedures. Once the extent of the problem has been fully assessed, then a surgical strategy can be developed. Having an expert specialty surgeon trained in repairing radiation injuries is required to achieve the best functional outcomes after severe radiation injury.
What is a fistula?
A fistula is an abnormal hole in the bowel or the bladder. A recto-urethral fistula is a hole between the urethra (urinary channel) and the rectum. This hole leads to leakage of urine into the rectum and feces travelling into the bladder.
The most common cause of this problem is either surgery on the bowel, cervix or uterus or treatment for prostate cancer. Treatments for prostate cancer that can cause a fistula include any form of radiation therapy, cryotherapy, radical prostatectomy, and high intensity focused ultrasound
One of the telltale signs of a fistula is urine leaking out the rectum. Another sign is severe urinary tract infections. Patients can sometimes become very ill at the time of diagnosis of this fistula.
It is important to divert the flow of feces away from the urinary tract and treat infections when a fistula is first diagnosed. The way the feces are diverted is a colostomy. In this surgery the colon or small bowel is brought up to the skin and sewn in place. A stoma bag is pasted to the skin to collect the feces. This is a temporary measure until infection can be treated and the fistula is repaired. Often patients need to wait between the colostomy placement and the fistula repair to allow infection and inflammation to resolve. Occasionally fistula will heal spontaneously with only the colostomy surgery.
The treatment of a recto-urethral fistula is not easy. Each fistula is different and needs to be fully evaluated. Most fistulas can be treated by closure of the fistula and placement of a muscle flap from the leg between the rectum and the urethra. This muscle flap is essential to allow for healthy healing of this area. The hole in the rectum can also for the most part be simply closed. In some cases of large fistula a piece of the lining of the inner cheek, called buccal mucosa is used to close the hole in the prostate and urethra. The lining of the inner cheek is very similar to the lining of the urethra. This surgery takes several hours and the recovery will take many weeks afterward, but it is one of the only reliable ways of getting these fistula to close.
The recovery from this type of surgery is difficult. There are incisions that are extensive and adequate time must go by before removal of catheters from the urinary system. Usually, this is 4-6 weeks. Once the fistula has healed and an adequate time has passed to make sure the hole will not recur than the colostomy can be reversed. This time frame is usually about 3-6 months after removal of all the urinary catheters. During this post operative period patients are followed very closely by Dr. Myers and the staff at University of Utah. Follow up with an outside urologist can also usually also be arranged in close conjunction with our hospital. This can be done throughout the nation.