Types of Radiation Therapy to Treat Lung Cancer and Emerging Technology
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Your cancer journey can be challenging, fraught with numerous tests and treatments along the way. Sometimes it may feel overwhelming as your doctor adds more to your already full plate during each visit. Radiation therapy is a common approach when it comes to treating lung cancer. The field of cancer research is constantly evolving, bringing forth new technological advancements in radiation therapies. It is understandable if you are unsure about the different types of radiation therapies and how they apply to your treatment. This article will shed light on the different types and provide a sense of understanding as you navigate your unique treatment plan.
Firstly, there are two main categories of radiation used in lung cancer radiation therapy (RT):
- External radiation: irradiate cancer site using a large machine outside the body
- Internal radiation: implant a small radioactive source in close proximity to the cancer site inside the body
Examples of specialized radiation therapy in each category
External beam radiation therapy | Internal beam radiation therapy |
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The types of radiation you would get depend on the following factors, with the aim to target the tumor while minimizing damage to normal tissues nearby:
- The type of cancer
- The size of a tumor
- The tumor location
A linear accelerator is a machine producing X-rays (photon beams) used in RT. The beams are invisible and cannot be felt when they pass through your skin. Tumor cells tend to be more sensitive to radiation than normal cells. This difference in sensitivity helps damage and destroy cancer cells selectively while minimizing harm to nearby healthy tissues.
Conformal radiotherapy has been used in cancer treatment for a few decades. Three-dimensional CRT is capable of targeting the tumor from different directions at different doses/strengths, while IMRT is the more sophisticated variant of 3D CRT.
Related: Radiation Therapy for Lung Cancer
Stereotactic body radiation therapy (SBRT)
This specialized form of RT is commonly used in lung cancer treatment. It is characterized by the use of just a few fractions with a high dose per fraction, ensuring reliability and reproducibility. SBRT requires
- Patient immobilization
- More precise repositioning of the patient during every session, from simulation to every treatment session
- Use of high-resolution image guidance
- Use of multiple treatment fields
In the management of early-stage 1 non-small cell lung cancer (NSCLC), it is an alternative to surgery for non-surgical candidates (people who are too old or frail and those who refuse).
In the case of treating advanced-stage cancer, it is an option when there are multiple metastatic tumors in the lungs and other body parts (to minimize organ removal by surgery).
Related: Stereotactic Body Radiation Therapy and What to Expect During Treatment
Proton beam radiation therapy (PBRT)
Conventional radiation therapy delivers X-rays (photon beams; not charged), while PBRT uses charged particles (proton beams).
“Photons pass through the cancer and out the other side, so on this exit, they hit normal cells and tissue. Proton therapy, on the other hand, stops at the tumor. There is no exit dose.” Dr. Akila Viswanathan, Interim Director of Radiation Oncology and Molecular Radiation Sciences.
Proton therapy (right) targets the tumor with a high dose of radiation without "exit dose", sparing healthy tissue. The traditional X-ray therapy produces high amount of "exit dose", thereby has a high risk of side effects in patients.
As precise as the X-rays-based RT can be, if a radiation dose leaks beyond the tumor (exit dose), normal cells nearby can be damaged, resulting in side effects. One of the latest PBRT techniques, FLASH, is currently tested in human trials treating bone cancer patients.
Brachytherapy
Source: Wikimedia Commons
Brachytherapy is a minimally invasive procedure involving the placement of radioactive sources directly into or near the tumor within the lung. This technique is typically used palliatively to treat small, localized lung cancers that obstruct airways. It delivers a high dose of radiation precisely to the cancerous tissue while minimizing exposure to healthy surrounding organs. Brachytherapy effectively targets and shrinks the tumors, thereby relieving the airway symptoms.
Radiation therapy offers a range of precise and effective treatment options for lung cancer patients with different health conditions. It is important to discuss all available options with your healthcare team to make informed decisions tailored to your unique cancer journey.