Radiation Therapy

for Bladder Cancer

Radiation therapy may be an integral part of the treatment ofbladder cancer. However, since cancer of the bladder is not exclusively treatedwith radiation therapy, it may be important for patients to be treated at amedical center that can offer multi-modality treatment involving medicaloncologists, radiation oncologists, and surgeons.

Radiation therapy or radiotherapy uses high-energy rays to damageor kill cancer cells by preventing them from growing and dividing. Similar tosurgery, radiation therapy is a local treatment used to eliminate or eradicatecancer that can be encompassed within a radiation field. Radiation therapy isnot typically useful in eradicating cancer cells that have already spread toother parts of the body. Radiation therapy may be externally or internallydelivered. External radiation delivers high-energy rays directly to the cancerfrom a machine outside the body. Internal radiation, or brachytherapy, involvesthe implantation of a small amount of radioactive material in or near thecancer. Currently the use of radiation therapy alone as a primary treatment forbladder cancer has largely been replaced by the combined use of radiationtherapy and chemotherapy. The main use of radiation therapy is in combination with chemotherapy for treatment of patients with stage II-III disease orrecurrent cancer. However, radical cystectomy remains the primary modality forthe treatment of stages II and III bladder cancer.

Chemotherapy and Radiation Therapyfor Primary Treatment

Over the past decade, many clinical trials in the United Statesand Europe have evaluated the combination of radiation and chemotherapy asinitial treatment of patients with stage II-III bladder cancer for the purposeof preserving the bladder. Bladder-preserving therapy is appealing becausepatients who achieved a complete response to treatment can often avoid surgicalremoval of the cancer unless they experience recurrence of their cancer. Inaddition to helping patients avoid cystectomy, early treatment withchemotherapy may also kill cancer cells that have already spread away from thebladder.

In some clinical trials, approximately half or more of patientswho were treated with bladder-preserving therapy (initial TUR of as much canceras possible, plus chemotherapy and radiation therapy) survived cancer-freethree to four years after treatment. Although these results appear as good asthose observed with surgery (radical cystectomy), there have been no directcomparisons of radical cystectomy to combination chemotherapy and radiationtherapy. While bladder-preserving therapy has been widely adopted for thetreatment of stage II-III bladder cancer, some physicians still think it shouldbe limited to clinical trials and not adopted as standard therapy.

Palliative Radiation Therapy

The goal of palliative therapy is to decrease the symptoms ofcancer, such as pain, in order to improve a patient’s quality of life. For somepatients with advanced bladder cancer, radiation therapy may be used to shrinkthe cancer and relieve cancer symptoms.

Delivery of Radiation Therapy forBladder Cancer

Modern radiation therapy for bladder cancer is administered viamachines called linear accelerators, which produce high energy externalradiation beams that penetrate the tissues and deliver the radiation dose deepinto the areas where the cancer resides. These modern machines and otherstate-of-the-art techniques have enabled radiation oncologists to significantlyreduce side effects, while improving the ability to deliver a curativeradiation dose to cancer-containing areas and minimizing the radiation dose tonormal tissue. For example, with modern radiation therapy, skin burns almostnever occur, unless the skin is being deliberately targeted or because ofunusual patient anatomy or extension of the cancer close to the source.

Simulation

After an initial consultation with a radiation oncologist, thenext session is usually a planning session, which is called a simulation.During this session, the radiation treatment fields and most of the treatmentplanning 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 tablecan be raised and lowered and rotated around a central axis. The “simulator”machine is a machine whose dimensions and movements closely match that of anactual linear accelerator. Rather than delivering radiation treatment, the simulatorlets the radiation oncologist and technologists see the area to be treated. Theroom is periodically darkened while the treatment fields are being set andtemporary marks may be made on the patient’s skin with markers. The radiationoncologist is aided by one or more radiation technologists and often adosimetrist, who performs calculations necessary in the treatment planning. Thesimulation may last anywhere from 15 minutes to an hour or more, depending onthe 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, thepatient is given multiple tattoos which mark the treatment fields and replacethe marks previously made with markers. These tattoos are not elaborate andconsist of no more than pinpricks followed by ink, appearing like a smallfreckle. Tattoos enable the radiation technologists to set up the treatmentfields each day with precision, while allowing the patient to wash and bathewithout worrying about obscuring the treatment fields. Radiation treatment isusually given in another room separate from the simulation room. The treatmentplans and treatment fields resulting from the simulation session aretransferred over to the treatment room, which contains a linear acceleratorfocused on a patient table similar to the one in the simulation room. Thetreatment plan is verified and treatment started only after the radiationoncologist and technologists have rechecked the treatment field andcalculations and are thoroughly satisfied with the setup.

Side Effects of Radiation Therapy

The majority of patients are able to complete radiation therapyfor bladder cancer without significant difficulty. Side effects and potentialcomplications of radiation therapy are limited to the areas that are receivingtreatment with radiation. The chance of a patient experiencing side effects,however, is highly variable. A dose that causes side effects in one patient maycause no side effects in other patients. If side effects occur, the patientshould inform the technologists and radiation oncologist because treatment forthese 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 iscompleted. 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 onhow much bone marrow is in the treatment field and whether the patient haspreviously received or is receiving chemotherapy. These changes in cell countsare usually insignificant and resolve once the radiation is completed. However,many radiation therapy institutions make it a policy to check the blood countsat least once during the radiation treatments.

It is not unusual for some patients to note changes in sleep orrest patterns during the time they are receiving radiation therapy and somepatients will describe a sense of tiredness and fatigue.

Late complications are infrequent following radiation treatment ofbladder cancer. Potential complications do include bowel obstruction, ulcers orcancers caused by the radiation. The probabilities of these late complicationsare also affected by previous extensive abdominal or pelvic surgery, radiationtherapy and/or concurrent chemotherapy.

Strategies to Improve Treatment

The progress that has been made in the treatment of bladder cancerhas resulted from improvements in multi-modality treatment and doctor andpatient participation in clinical studies. Future progress in the treatment ofbladder cancer will result from continued participation in appropriate studies.

Supportive Care: Supportivecare refers to treatments designed to prevent and control the side effects ofcancer and its treatment. Side effects not only cause patients discomfort, butalso may prevent the optimal delivery of therapy at its planned dose andschedule. In order to achieve optimal outcomes from treatment and improvequality of life, it is imperative that side effects resulting from cancer andits treatment are appropriately managed. For more information, go to Managing Side Effects.

Next: Precision Cancer Medicine for Bladder Cancer