Editor’s note: Cancer Q&A is a monthly column in which health professionals from Baystate Regional Cancer Program, based in Springfield, address issues related to cancer in a question-and-answer format.
Radiation therapy, also called radiotherapy, chemotherapy and surgery comprise the three most common treatments for cancer.
Radiation therapy — radiation and radioactivity date back over 100 years — has seen major advances in the last few decades thanks to technological advances in both engineering and computers. Advances in radiation treatment planning, the ability to deliver radiation much more precisely and at higher doses, all while sparing surrounding healthy tissue, has resulted in fewer side effects, better results and less treatment time for some patients.
Q: What is radiation therapy?
A: Radiation is simply energy from the electromagnetic spectrum. Part of the spectrum is visible light. As you increase the energy, you get to x-rays, then further up to gamma rays.
External beam radiation, radiation delivered to patients from the outside aimed at the body, most commonly uses gamma rays. Other types of external beam radiation can use charged particles, such as electrons, and in some rare cases protons.
Internal radiation, known as brachytherapy, is a technique where a radioactive source is inserted into a particular area of the body, such as the uterus. It delivers radiation from the inside out, which in certain cancers is important because there is no other safe way to get the radiation there without the risk of damaging too much normal tissue.
Q: How important is radiation therapy in cancer treatment?
A: Approximately half of all cancer patients will require radiation at some point in their lives. For many patients, the treatment will be part of an attempt at cure or control, but for many others, radiation may be used to make them feel better or prevent further problems.
Q: What is the role of the radiation oncologist?
A: The first job is to meet the patient and assess whether he or she would benefit from adding radiation to the treatment plan.
For many cancers, multiple treatments are combined to gain the best possible result. For example, a combination of chemotherapy and radiation may be given to a patient prior to surgery. In this type of treatment strategy, close coordination between physicians is essential. At Baystate, we have multidisciplinary tumor conferences for all of the major cancers. In these meetings, all of the involved specialties discuss the most appropriate way to treat a given patient.
Q: Are there times when radiation therapy would not be used?
A: Yes, there are many situations when radiation is not the best choice. Sometimes it is based on patient preferences, risk of side effects, or even the biology of the tumor.
The key is that every patient and every cancer is different, and we treat every patient as an individual. There is no cookbook recipe to follow for everyone.
Q: What are the most common side effects associated with radiation therapy and how are they managed?
A: Radiation, unlike chemotherapy, is targeted. With the exception of fatigue, which varies widely from patient to patient, the side effects during treatment are directly related to the part of the body being treated. For example, someone being treated for head and neck cancer may have difficulty swallowing or mouth and gum sores, while radiation therapy targeting the stomach or abdomen could cause nausea, vomiting and diarrhea.
In most cases, the side effects are tolerable without any medications. However, in some cases, they do require medications or changes in diet.
Q: How has the medical linear accelerator changed over the years since its first use back in 1956 to treat a young boy with a cancerous eye tumor?
A: The development of the modern linear accelerator is an example of miniaturization and computerization. The original linear accelerators had an actual radioactive source hidden behind lead doors. The radiation was shielded from parts of the body by thick lead panels.
Modern linear accelerators, like the Elekta VersaHD, that was just installed at Baystate’s D’Amour Center for Cancer Care, has no live radioactive source. It is like a light; when the switch is off, there is no radiation, no risk; when the switch is on, there is radiation.
In addition, the beam is now shaped by multi-leaf collimators (tiny computer controlled pieces of lead) that move to form the shape of the target being treated. These MLCs, as they are called, can even move while the machine is turning and delivering treatment to further improve the dose that is given and reduce side effects. This technique, called Intensity Modulated Radiation Therapy (IMRT), essentially breaks the individual beams into thousands of unique beams, shaping the radiation based on specific anatomy.
Q: What are the latest advancements in radiation therapy?
A: As with everything in medicine, there is a push for more effective, safer and less expensive treatments. Radiation oncology is no different.
We are learning that more precise, higher dose treatments given over a shorter period of time may be as effective as longer courses of radiation that are often given. These shorter, higher dose treatments, when used for the brain, are called Stereotactic Radiosurgery (SRS). In other parts of the body, it is called Stereotactic Body Radiotherapy (SBRT). With pressures in the healthcare industry to reduce costs without reducing efficacy, these more advanced treatments are poised to play a larger role in the treatment of cancer in the near future.
Dr. Michael J. Yunes is a radiation oncologist at Baystate Regional Cancer Program based in Springfield.