Radiation Therapy for Bladder Cancer
Radiation therapy may be an integral part of the treatment of bladder cancer. However, since cancer of the bladder is not exclusively treated with radiation therapy, it may be important for patients to be treated at a medical center that can offer multi-modality treatment involving medical oncologists, radiation oncologists, and surgeons.
Radiation therapy or radiotherapy uses high-energy rays to damage or kill cancer cells by preventing them from growing and dividing. Similar to surgery, radiation therapy is a local treatment used to eliminate or eradicate cancer that can be encompassed within a radiation field. Radiation therapy is not typically useful in eradicating cancer cells that have already spread to other parts of the body. Radiation therapy may be externally or internally delivered. External radiation delivers high-energy rays directly to the cancer from a machine outside the body. Internal radiation, or brachytherapy, involves the implantation of a small amount of radioactive material in or near the cancer. Currently the use of radiation therapy alone as a primary treatment for bladder cancer has largely been replaced by the combined use of radiation therapy and chemotherapy. The main use of radiation therapy is in combination with chemotherapy for treatment of patients with stage II-III disease or recurrent cancer. However, radical cystectomy remains the primary modality for the treatment of stages II and III bladder cancer.
Chemotherapy and Radiation Therapy for Primary Treatment
Over the past decade, many clinical trials in the United States and Europe have evaluated the combination of radiation and chemotherapy as initial treatment of patients with stage II-III bladder cancer for the purpose of preserving the bladder. Bladder-preserving therapy is appealing because patients who achieved a complete response to treatment can often avoid surgical removal of the cancer unless they experience recurrence of their cancer. In addition to helping patients avoid cystectomy, early treatment with chemotherapy may also kill cancer cells that have already spread away from the bladder.
In some clinical trials, approximately half or more of patients who were treated with bladder-preserving therapy (initial TUR of as much cancer as possible, plus chemotherapy and radiation therapy) survived cancer-free three to four years after treatment. Although these results appear as good as those observed with surgery (radical cystectomy), there have been no direct comparisons of radical cystectomy to combination chemotherapy and radiation therapy. While bladder-preserving therapy has been widely adopted for the treatment of stage II-III bladder cancer, some physicians still think it should be limited to clinical trials and not adopted as standard therapy.
Palliative Radiation Therapy
The goal of palliative therapy is to decrease the symptoms of cancer, such as pain, in order to improve a patient’s quality of life. For some patients with advanced bladder cancer, radiation therapy may be used to shrink the cancer and relieve cancer symptoms.
Delivery of Radiation Therapy for Bladder Cancer
Modern radiation therapy for bladder cancer is administered via machines called linear accelerators, which produce high energy external radiation beams that penetrate the tissues and deliver the radiation dose deep into the areas where the cancer resides. These modern machines and other state-of-the-art techniques have enabled radiation oncologists to significantly reduce side effects, while improving the ability to deliver a curative radiation dose to cancer-containing areas and minimizing the radiation dose to normal tissue. For example, with modern radiation therapy, skin burns almost never occur, unless the skin is being deliberately targeted or because of unusual patient anatomy or extension of the cancer close to the source.
After an initial consultation with a radiation oncologist, the next session is usually a planning session, which is called a simulation. During this session, the radiation treatment fields and most of the treatment planning are determined. Of all the visits to the radiation oncology facility, the simulation session may actually take the most time. During simulation, patients lay on a table somewhat similar to that used for a CT scan. The table can be raised and lowered and rotated around a central axis. The “simulator” machine is a machine whose dimensions and movements closely match that of an actual linear accelerator. Rather than delivering radiation treatment, the simulator lets the radiation oncologist and technologists see the area to be treated. The room is periodically darkened while the treatment fields are being set and temporary marks may be made on the patient’s skin with markers. The radiation oncologist is aided by one or more radiation technologists and often a dosimetrist, who performs calculations necessary in the treatment planning. The simulation may last anywhere from 15 minutes to an hour or more, depending on the complexity of what is being planned.
Once the aspects of the treatment fields are satisfactorily set, x-rays representing the treatment fields are taken. In most centers, the patient is given multiple tattoos which mark the treatment fields and replace the marks previously made with markers. These tattoos are not elaborate and consist of no more than pinpricks followed by ink, appearing like a small freckle. Tattoos enable the radiation technologists to set up the treatment fields each day with precision, while allowing the patient to wash and bathe without worrying about obscuring the treatment fields. Radiation treatment is usually given in another room separate from the simulation room. The treatment plans and treatment fields resulting from the simulation session are transferred over to the treatment room, which contains a linear accelerator focused on a patient table similar to the one in the simulation room. The treatment plan is verified and treatment started only after the radiation oncologist and technologists have rechecked the treatment field and calculations and are thoroughly satisfied with the setup.
Side Effects of Radiation Therapy
The majority of patients are able to complete radiation therapy for bladder cancer without significant difficulty. Side effects and potential complications of radiation therapy are limited to the areas that are receiving treatment with radiation. The chance of a patient experiencing side effects, however, is highly variable. A dose that causes side effects in one patient may cause no side effects in other patients. If side effects occur, the patient should inform the technologists and radiation oncologist because treatment for these side effects is almost always available and effective.
Radiation therapy to the abdominal/pelvic area may cause diarrhea, abdominal cramping, or increased frequency of bowel movements or urination. These symptoms are usually temporary and resolve once the radiation is completed. Occasionally abdominal cramping may be accompanied by nausea.
Blood counts can be affected by radiation therapy. In particular, the white blood cell and platelet counts may be decreased. This is dependent on how much bone marrow is in the treatment field and whether the patient has previously received or is receiving chemotherapy. These changes in cell counts are usually insignificant and resolve once the radiation is completed. However, many radiation therapy institutions make it a policy to check the blood counts at least once during the radiation treatments.
It is not unusual for some patients to note changes in sleep or rest patterns during the time they are receiving radiation therapy and some patients will describe a sense of tiredness and fatigue.
Late complications are infrequent following radiation treatment of bladder cancer. Potential complications do include bowel obstruction, ulcers or cancers caused by the radiation. The probabilities of these late complications are also affected by previous extensive abdominal or pelvic surgery, radiation therapy and/or concurrent chemotherapy.
Strategies to Improve Treatment
The progress that has been made in the treatment of bladder cancer has resulted from improvements in multi-modality treatment and doctor and patient participation in clinical studies. Future progress in the treatment of bladder cancer will result from continued participation in appropriate studies.
Supportive Care: Supportive care refers to treatments designed to prevent and control the side effects of cancer and its treatment. Side effects not only cause patients discomfort, but also may prevent the optimal delivery of therapy at its planned dose and schedule. In order to achieve optimal outcomes from treatment and improve quality of life, it is imperative that side effects resulting from cancer and its treatment are appropriately managed. For more information, go to Managing Side Effects.