One of the most popular methods of radiation treatment applied to treat different types of cancer is external beam radiation therapy (EBRT). High-energy radiation is used in this non-invasive technique to target and kill cancer cells with little to no harm to nearby healthy tissue.
Being an essential component in modern oncology (cancer treatment), EBRT has seen significant advancement, making it a very accurate and successful treatment choice for many patients.
In this article, we will explore External Beam Radiation Therapy, providing a comprehensive overview of its types, treatment procedures, and potential side effects.
External Beam Radiation Therapy
External Beam Radiation Therapy (EBRT) is a noninvasive cancer treatment that targets and eliminates cancer cells using high-energy radiation, such as protons, electrons, or X-rays. The radiation is precisely focused on the tumour to minimise the impact on surrounding healthy tissue, and it is given from an external machine, usually a linear accelerator.
EBRT is a widely used therapy for various types of cancer. It can be tailored to the specific location, size, and shape of the tumour, making it a flexible and effective option in cancer treatment.
How External Beam Radiation Therapy Works?
EBRT uses a linear accelerator or other external machine to deliver radiation to the body. The machine generates high-energy X-rays or other particles, such as electrons, protons, or photons, directed at the tumour. The main objective of the EBRT procedure is to deliver a high radiation dose to the malignant region to damage the DNA of cancer cells. The damage stops the cells from proliferating and dividing, eventually resulting in their death.
Types of Radiation Used
Here are the types of radiation used in External Beam Radiation Therapy:
Photons
The radiation types that are commonly used in an EBRT treatment include gamma and X-rays. As photons can enter the body deeply, they can be used to treat tumours that are positioned at different depths. Photon-based therapies are used for a variety of cancers, including breast cancer, head and neck cancers, and lung cancer, because of their broad availability and efficacy.
Protons
EBRT, which uses protons rather than X-rays, is known as proton therapy. A higher radiation dosage can be given to the tumour with less damage to the surrounding healthy tissue since protons can be regulated with greater precision. For cancers in children and tumours in sensitive regions like the brain and eyes, proton therapy is especially beneficial because of its accuracy.
Electrons
Electron therapy is usually used for tumours located near the surface of the body. Electrons do not penetrate deeply, making them ideal for treating external cancers such as skin cancer. Electron therapy is also effective for treating tumours that involve the lymph nodes or areas close to the surface, minimising the risk of damage to deeper structures.
Types of External Beam Radiation Therapy
Described below are the types of External Beam Radiation Therapy:
Three-Dimensional Conformal Radiation Therapy (3D-CRT)
With this procedure, radiation can be given from several directions, following the shape of the tumour while preserving neighbouring healthy tissue. Imaging technologies such as CT or MRI are used to build a three-dimensional map of the tumour. It is especially helpful in treating tumours that are shaped irregularly or that are close to essential organs.
Intensity-Modulated Radiation Therapy (IMRT)
IMRT is an ultra-modern form of 3D-CRT that allows the radiation dose to be modulated across the treatment area. This technique improves the ability to target the tumour while reducing the hit to surrounding tissues. It is beneficial for complex cases where the cancer is close to essential structures.
Image-Guided Radiation Therapy (IGRT)
IGRT uses imaging techniques during the treatment session to ensure precise delivery of radiation to the tumour. It improves precision and lowers the possibility of damaging healthy cells, and it is beneficial for tumours that move as a result of breathing or other physiological processes.
Stereotactic Body Radiation Therapy (SBRT)
SBRT delivers a very high amount of radiation to small, well-defined tumours in fewer treatment sessions. It is often used for tumours in the lungs, liver, or spine and is known for its precision, typically completing treatment in just a few sessions, which makes it a convenient option for patients.
Proton Beam Therapy
Proton therapy delivers most of its radiation dose directly to the tumour with minimal exit dose, offering a unique advantage. It is especially useful in treating tumours close to vital organs like the brain or spinal cord. It is also the best option for treating cancers that need exact control over radiation exposure and paediatric patients.
Treatment Procedure
The process of undergoing EBRT involves several steps:
Consultation
The patient meets with a radiation oncologist to talk over the treatment options and determine if EBRT is appropriate. The doctor examines the patient’s medical history, performs a physical examination, and often asks for imaging tests to evaluate the tumour.
Simulation
The patient goes through a simulation to plan the therapy prior to starting treatment. The patient lies on a table in the same position as they will be treated during this session. Imaging scans are taken to spot the exact location and size of the tumour. The patient may also receive minor marks or tattoos on their skin to ensure consistent positioning during each session.
Treatment Planning
The medical physicist and radiation oncologist make a personalised treatment plan based on the images captured during the simulation. The radiation dosage, the angles at which the radiation beams will be given, and the total number of treatment sessions needed are all specified in this plan.
Treatment Delivery
Usually, the actual therapy sessions are short, lasting only a few minutes each. While the machine emits radiation from the predetermined angles, the patient lies down on the treatment table. EBRT is frequently given to patients five days in a row for a few weeks, depending on the tumour’s location and nature.
Follow-Up
After completing EBRT, patients have regular follow-up appointments to monitor the effectiveness of the treatment and manage any side effects.
Side Effects of External Beam Radiation Therapy
EBRT can have adverse effects, yet it is intended to do as minimal damage as possible to healthy tissue. These side effects vary depending on the area of the body being treated and the total dose of radiation. Common side effects include:
Fatigue
Many patients experience fatigue during and after radiation therapy. It is a common side effect that can be minor or severe. After treatment, fatigue can last for weeks or even months, impairing daily activities and general quality of life.
Skin Reactions
The skin in the treatment area may become red, irritated, or dry. In some cases, patients may experience peeling or blistering. These reactions can resemble a sunburn and require careful skin care to manage discomfort and avoid infection.
Nausea and Vomiting
Nausea and vomiting may result from radiation exposure to the abdomen or pelvis. These symptoms can be managed with medications. These side effects can also be reduced by dietary changes and increased water intake, which can help the patient maintain a healthy diet.
Hair Loss
In the treatment area, hair loss is possible, especially if the head is being treated. The radiation dosage and the treated area determine the extent of hair loss, which can either be temporary or permanent.
Changes in Appetite
During treatment, some patients may notice changes in their taste or appetite. Dietary counselling could be required to guarantee appropriate dietary intake throughout therapy, as this can result in weight loss or nutritional deficiencies.
Long-Term Effects
In some cases, EBRT can cause long-term effects, such as scarring, changes in organ function, or an increased risk of getting cancer again. The possibility that these side effects may not appear for several months or years following treatment highlights the importance of long-term follow-up care.
Conclusion
In conclusion, External Beam Radiation Therapy is a flexible and potent tool in the fight against cancer. Its ability to precisely target tumours while sparing healthy tissue has made it a standard treatment option for many types of cancer. It is expected that EBRT will become even more successful as technology develops, giving many patients hope all across the world. However, EBRT is not without risks and side effects, just like any surgical procedure. It emphasises the significance of careful planning, close monitoring, and patient care during treatment.
