Radiation Therapy for Benign Disease
Radiation therapy is used almost exclusively for the treatment of cancer. It can kill fast-growing cancer cells much more readily than the slower-growing normal cells nearby and, in the right dose, kill all of the cancer cells while damaging only a fraction of the normal ones, often producing a cure with no significant, lasting side effects.
There are some benign conditions that can also be successfully treated with radiation therapy. These are characterized by uncontrolled growth of cells that are not truly malignant, in that they lack the ability to spread (metastasize), but can still do harm simply by benign overgrowth. Radiation can often stop these fast-growing cells and control the problem. In all of the conditions below, we must weigh the risks of radiation against the expected benefits, but often the balance favors the use of radiation.
Desmoid, or “aggressive fibromatosis”, is an uncommon but potentially debilitating condition where connective tissue cells, usually originating in a muscle of the trunk or proximal extremities, multiply and invade out of control. This produces stiffness and pain but, because the progress is slow and subtle, it is often overlooked as a “pulled muscle” or other condition that will take care of itself. When finally diagnosed by biopsy, it may have infiltrated widely through the original muscle and into adjacent muscles and fascia. It can sometimes be treated successfully by surgery, but because the abnormal cells look just like normal cells it is very difficult for the surgeon and the pathologist to know where the process ends. The surgeon tries to take a wide margin, without unacceptable loss of function for the patient, but often the margins are so scant that postoperative radiation therapy is warranted. The radiation dose needed to eradicate the process is almost as high as the dose for a malignant tumor. Radiation has the ability to treat a much wider margin than the surgeon can remove. Good teamwork between the surgeon and the radiation oncologist is essential in planning the area to be treated.
When your skin is cut, the cells along the edges start to reproduce rapidly to close the cut. When the cut is closed, the cells stop growing. We don’t really understand how they know when to stop, but usually they get it right and the resulting scar, if we’re lucky, is very small. Sometimes, though, the cells forming the scar don’t stop growing and they form a hypertrophic or “keloid” scar. Keloid scars are much more common in people of African descent, and are quite common in the upper chest area in people of other races. Sometimes they are just an annoyance, but in areas that are cosmetically sensitive they can be a real problem. Surgery can be done to remove the overgrown scar, but then there is the problem of whether the new scar will produce another keloid. Steroid injections are often given after the surgery, and often they are successful, but not always.
When necessary, radiation can often help in reducing the reappearance of a keloid. The best plan is to give the radiation immediately after the surgery – within hours, if possible. Sometimes a single large dose is used, but more commonly it will be three doses over three days. Good cooperation between the surgeon and the radiation oncologist is clearly needed. The treatment is not always successful, but the chance of keloid recurrence is significantly reduced. The radiation dose to confined to the skin, and the chance of later complications is very small.
At Inova Fairfax Hospital we have an “old-fashioned” superficial radiation therapy machine that is ideal for this treatment; we believe it is the only one in the metropolitan DC area. Other facilities must use electron beam radiation, which delivers the radiation more deeply in the subcutaneous tissues and is more expensive to use.
Sometimes, usually in the course of treatment of metastatic prostate cancer, it is necessary to “turn off” a man’s production of male hormones in order to retard the growth of the cancer. Many years ago this was done by removing the testicles, and later by giving the man large doses of estrogen, the primary female hormone. Estrogen had undesirable side effects including breast enlargement (gynecomastia) and a risk of accelerated heart disease. Now the usual approach is periodic injections of leuprolide or goserelin, plus an anti-androgen such as bicalutamide, flutamide, or nilutamide. Unfortunately, these latter drugs often still cause breast enlargement, which can be embarrassing or even painful.
Treatment with radiation can often prevent this breast enlargement. In order to be effective, the radiation should come before starting the drug, or at least before there is any sign of breast enlargement. What happens, in simple terms, is that the radiation kills or injures the latent breast cells that every man has under his nipple, so that they do not grow when his hormonal balance is changed by the drug. Once the latent breast tissue has developed, the radiation will do no good; surgery will be necessary if the man is troubled enough by the problem. The radiation dose is relatively low and the risk is extremely small.
Sometimes, after a fractured joint or surgery on a joint, the body will begin to form tiny pieces of bone in the surrounding muscles. This is called heterotopic ossification, and if it progresses it can lead to stiffness of the joint, pain, and in extreme cases even a fusion of the joint so that it cannot move at all. This is most common in the hip, but it can occur in other joints as well.
We believe that this happens because bone-making cells (osteoblasts) can get scattered into the muscles and tissues around the joint in an accident, or during surgery. The only thing these cells “know how to do” is produce bone. If we administer a dose of radiation therapy before they get a good start, there is an excellent chance of killing or injuring those cells, and the abnormal bone is not produced. Usually this is done within three days after surgery, or as soon as possible after the injury. Treatment is not always effective, but the chance of developing heterotopic ossification is greatly reduced and the risks are very small.