Radiation oncology is a term that doesn’t need much explaining if you understand what each word means. Oncology is the science of cancer and oncologists are doctors who specialize in diagnosing and treating cancer. Radiation is exposure to radiotherapy. So radiation oncology is simply the use of radiotherapy in order to treat cancer either as a standalone treatment or part of a bigger treatment regimen. Radiotherapy is required in the treatment of about 40% of cancers which is a pretty significant figure. Doctors who specialize in this area are called radiation oncologists. They’re the ones who decide the method of administration of radiotherapy as well as the dose and anything else that might be related to the treatment of cancer using radiation.
The team
There are more people involved in the process than just the radiation oncologist. We also have radiation therapists who operate the radiation equipment and make sure that patients get the correct dose of radiation that they need and that little to no damage is done to the surrounding healthy tissue that should not be receiving the therapy.
Another group of people who are involved in the process are radiation oncology medical physicists. It’s their job to make sure that all the equipment that’s used is as safe as can be. If there’s any error or damage to the equipment then both the radiation therapist and the patient can suffer from lots of side effects of radiation which should definitely be avoided.
We also have radiation nurses who mainly deal with patients who have cancer. They’re mostly there during the treatment sessions and are there to answer questions that the patients might have. They also have the knowledge and skills in order to help patients cope with the side effects of the treatment.
In general, four groups of people are involved in radiation oncology. We have the doctors who adjust the treatment plan according to each patient, the radiation therapists who administer the correct doses and operate the equipment, the radiation oncology medical physicists who make sure the equipment and machines are working in optimum conditions, and we have radiation nurses who are there for the patients in case they need anything regarding info about their treatment and its side effects.
The importance of radiation oncology
Cancer is one of the leading causes of death worldwide. It’s up there with cardiovascular disease and accidents. There are ways for people to minimize their risk of getting cancer by following screening protocols such as those of breast cancer, not smoking, exercising, and eating healthy, but at the end of the day there’s no way to completely stop someone from getting cancer. Eventually the situation we find ourselves in is that someone has cancer and now it’s time to look for treatment.
It’s estimated that in 2018 alone almost 2 million Americans will be diagnosed with cancer and almost a quarter of these will die from it. According to statistics from 2015, almost 40% of both men and women will get cancer at some point in their lives. About 150 billion dollars were spent in the United States in 2017 for the treatment of cancer.
Cancer is certainly somewhat of a big deal and maybe some people think it’s a serious disease but a rare one. Sadly cancer is increasing in our communities. There are several treatment options for cancer. The best and most curative treatment is surgery. If a tumor is detected early before it metastasizes to other areas of the body then it can be completely resected and a patient can be cured. Radiation is another major tool oncologists have in the fight against cancer. Sometimes radiation is used in combination with surgery such as in breast cancer.
One of the ways doctors can deal with breast cancer is by performing conservative surgery where only the breast lump is removed. In this kind of treatment, which many people prefer as it conserves the rest of the breast and the cosmetic appearance, radiation therapy is given after the surgery in order to lower the recurrence rate. There are several examples of the combination of radiation with surgery when it comes to treating cancer. Other modalities of treatment include chemotherapy, immunotherapy, and sometimes hormone therapy in particular tumors.
Radiation oncology is so important because of its widespread use. We mentioned that around 40% of cancer patients can benefit from radiotherapy and that’s pretty significant. Radiotherapy has so many applications and can be used to treat so many tumors. It can also be added to multiple treatment plans. It can be used with surgery, with chemotherapy, with both, or as a standalone treatment. Considering the burden of cancer not just in the United States, but all over the world, it’s no surprise that there’s a specialty dedicated to this form of cancer treatment alone.
How does it work
Radiotherapy works by killing cancer cells. It does this by producing oxygen radicals from oxygen present within the tissue. Oxygen radicals are destructive and result in the death of these cells. The more vascular a tumor is the more oxygen it has and consequentially the greater the damage radiation will be able to make. That’s why tumors with plenty of fibrosis and restricted oxygen supply can be somewhat resistant to this method of treatment.
Cancer isn’t always curable and sometimes palliative therapy is the only option left. This happens in end stage cancer where there’s no hope of a cure. Palliative therapy is simply making the remaining time the patient has as comfortable as possible. This can include certain tubes to facilitate feeding or drugs to minimize side effects. It can also include radiation therapy which won’t cure the cancer, but at least slow down its growth and may even shrink it a little bit.
Side effects of radiotherapy
Side effects can be divided into immediate and late. Immediate side effects are those that occur during the duration of the treatment course and up to 6 months after it’s over.
Immediate side effects include skin reactions, swelling, hair loss, and generalized fatigue.
Some of the late side effects include fibrosis which is the tissue and skin becoming thicker and tougher. You may also notice some broken blood vessels under the skin, this is a condition called telangiectasia and unfortunately there’s no treatment for it.
Generally speaking late side effects are more severe but luckily they’re relatively rare compared to the milder immediate side effects.
Most common cancers
Overall the most common cancer in the world in both men and women is skin cancer. Skin cancer, however, is easily noticeable and so it’s usually treated quickly. Following skin cancer we have 3 leading cancers in each sex.
For men the leading cancers are prostate, lung, and colon cancer. For women they are breast, lung, and colon cancer. As you can see lung and colon cancer are extremely common in both genders. Generally speaking men are way more likely to have cancer than women. The exceptions to this are breast cancer and cancers in the female genital tract which men obviously can’t get.
The commonest cancers can also be divided according to age. In children the commonest cancers in order are leukemia, CNS tumors, lymphoma, neuroblastoma, and Wilm’s tumor (in the kidney). Ages 20-30 the commonest cancers are germ cell tumors, thyroid cancer, and lymphoma. Above the age of 50 is where cancers are mostly present and this is when we see prostate/breast, lung, and colon cancer.
History of radiation oncology
You know what seems like a really primitive tool right now? The x-ray. Whether you’re a doctor or not, when you think of an x-ray you’re thinking that’s the oldest diagnostic or medical tool of all time. Despite of how old it is, x-rays are still very useful to doctors even now with all of our MRIs and CT scans. It all started in 1896 when a German physicist, Wilhelm Conrad Roentgen, introduced the x-ray. It was a new kind of ray and the “x” was an algebraic symbol for an unknown quantity. X-rays changed the world. Only the top hospitals had x-rays and they were the most expensive tools at the time. Imagine the buzz if being able to capture the bones of your hand or face with a simple device.
Why are we talking about x-rays? Because that’s how it all started. They were used for diagnosis by medical professionals very soon after their discovery and a couple of years later they were used to treat cancer. In the beginning of the 20th century, in 1901 to be exact, Roentgen won the Nobel Prize in physics. It was the first award of its kind. Radiation was used in diagnostic machines such as x-rays but by giving radiation daily, it was noticed that some patients with cancer started to get better. This discovery was made in France. Upon that discovery, machines and equipment used to deliver radiotherapy began to be manufactured and with time they’ve only gotten better, safer, and more accurate when it comes to delivering the right dose in the right location.
Sadly things didn’t continue to get better for radiation; because as we all know radiation can be harmful for the body as well. Soon after it was discovered as a therapeutic tool, it was noticed that in can cause cancer too. A very primitive method was used in order to get the approximate correct dose for patients back in the early 20th century. Radiologists would expose their forearms to radiation until their skin started to turn pink. It would look like a mild sunburn. This was called the “erythema dose” and this is what early radiologists use to find the correct dose to give to patients. Later on they discovered that this was a terrible idea. Many of these radiologists eventually developed leukemia. They were delivering uncalculated doses of radiation to themselves and at the same time they were doing this on a daily basis. A patient with cancer would perhaps need to receive radiation therapy for a few months, but a radiologist would go through this for years and often multiple times a day considering they had more than one patient per day. It was a primitive method and they did the best they could with what they had which must be respected.
Over the past 50 years radiation therapy starting booming as newer technologies were discovered that allowed better usage of it. One of these is CRT. CRT stands for conformal radiation therapy. This process uses CT images and combining them using special software in order to get a very precise 3D image of where the rays should be directed. This allows the treatment to achieve its maximum effect while minimizing the damage as much as possible. In order to keep the patient still and avoid distorting the rays, patients are fitted with a plastic cast in order to keep the body part fixed in place in the same position for the duration of the session and each successive session further on. The beams are directed in the exact shape of the tumor according to the constructed 3D image to make sure that nothing is missed and the entire tumors receives the treatment. They’re also directed towards it from several directions. IMRT, intensity modulated radiation therapy, is a lot like conformal radiation therapy (CRT) with the ability to change the intensity of the beams directed at the tumor. This allows decreasing the intensity reaching the healthy and normal surrounding tissue to avoid adverse effects while continuing to give the tumor itself high doses.
So far we’ve been talking about delivering radiation through x-rays. There are also techniques that can deliver it through proton beams and one of these is called conformal proton beam radiation therapy. What makes protons special is their ability to penetrate without causing damage. Protons don’t cause damage to the structures they pass through, but they are very hazardous to what they face at the end of their path. So if they’re adjusted so that the last thing they meet are the cancer cells then they’re going to very effective in killing them and at the same time very safe for the healthy tissue which may be present even above the tumor in the form of normal healthy skin and fat for instance.
An obstacle that might face radiology oncologists is that some tumors can be very small, but at the same time they would respond to really well to radiotherapy. The issue can be delivering high and accurate doses of radiation to a small and confined tumor. One example of this can be brain cancer. So a technique called stereotactic radiation therapy is used where special equipment such as the Gamma Knife can be used to deliver radiation in a small and confined area. Don’t get it confused, however. The term “knife” here doesn’t imply using any actual knife or cutting of any kind.
Surgeons may need to deliver radiation to a tumor while they’re operating. This is an effective way of preventing recurrence especially in tumors present in the abdominal or pelvic cavities. This technique is called intraoperative radiation therapy which is pretty self explanatory. Surgeons can also move healthy tissue out of the way enabling them to direct the full dose towards the tumor and the area where it was present.
Finally we have modifiers or sensitizers that maximize the response of the cancer cells to the radiation therapy. These substances are called chemical modifiers or radiosensitizers. More research is being done in order to make sure that only cancer cells absorb these substances because if healthy ones absorb them too then they’re going to be negatively affected by the treatment.
As you can, most of the advancements made in the field of radiation oncology are directed towards efficiency and specificity. Scientists are always looking for ways to deliver higher doses of radiation to the tumor, but only to the tumor. We don’t want to affect and harm the surrounding healthy tissue and cause them to become cancer cells through faulty treatment.
Becoming a radiation oncologist
It’s a long road to becoming a radiation oncologist as it’s considered a subspecialty of a subspecialty. First of all you would have to get an internal medicine residency after medical school which is about 3-4 years long. After that you would need to qualify for an oncology fellowship which is another 2-3 years. After that you’ll need another 2-3 years of a radiation oncology fellowship so you’re looking at a pretty long road. It’s a pretty rewarding job regardless as you get to help a lot of people and if you work in research who knows what you might discover?
Future of radiation oncology
The future is already kind of here. We have software and equipment to give us 3D images of tumors and the technology to administer the radiation accurately in a 3D manner to fit the tumor. We have tools such as the Gamma Knife to deliver effective doses in confined spaces in small restricted tumors such as in brain cancer. We can also deliver radiation intraoperatively in order to decrease the risk of recurrence.
Scientists and companies are also working on substances that increase the sensitivity of the cancer cells to the hazards of radiation, but the challenge is to prevent healthy cells from absorbing these substances. Work is being done in order to prevent that. An alternative is to administer substances that shield the healthy cells from radiation and/or allow them to recover quickly from its effects.
Cancer is a leading problem all over the entire world, not just in the United States. Countries spend billions each year on cancer whether it’s through insurance for the treatment of patients or on research in order to cure or even prevent cancer. As our lives involve more carcinogens such as cigarettes and processed foods the incidence of cancer will only rise. Radiation therapy started from a simple x-ray and who knows what might happen over the next few years? Perhaps we’ll be able to cure some cancers completely with radiotherapy using small doses and fewer side effects.
This is a field with lots of potential. We’ve already discussed how many new technologies related to it were discovered in the past 30 years which is a very short time in the world of medicine. If you’re someone who wants to become a doctor but would like to discover something and not only see patients then this field is one of those where you can make a difference in that area. If you or someone you know suffers from cancer the best people to consult about treatment options are those specialized in oncology which certainly includes radiation oncologists. They’ll be able to tell you whether radiotherapy would be a suitable and effective treatment option in your case.
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