Radiation oncology is a medical specialty that uses radiation therapy to treat cancer. Radiation therapy involves the use of high-energy radiation, typically in the form of X-rays, to kill or damage cancer cells. It’s a highly effective treatment option that can either shrink tumors, alleviate symptoms, or cure cancer, depending on the type and stage of cancer. Radiation therapy can be used alone or in combination with other treatments like surgery, chemotherapy, or immunotherapy.
How Radiation Therapy Works:
Radiation therapy works by damaging the DNA of cancer cells. When the DNA is damaged, the cancer cells cannot grow or divide, eventually leading to their death. While normal healthy cells can also be affected by radiation, they are typically able to recover more effectively than cancer cells. Radiation is carefully targeted to minimize damage to surrounding healthy tissues.
Types of Radiation Therapy:
- External Beam Radiation Therapy (EBRT):
- This is the most common type of radiation therapy, where radiation is delivered from outside the body, usually via a machine called a linear accelerator.
- The patient typically lies on a treatment table, and the radiation beam is directed precisely at the tumor site.
- The treatment is painless and typically lasts only a few minutes, though the setup and planning process can take longer.
- Internal Radiation Therapy (Brachytherapy):
- In brachytherapy, a radioactive source is placed directly inside or very close to the tumor. This can be done for cancers like prostate, cervical, or breast cancer.
- The radiation source is typically delivered through needles, seeds, or catheters inserted into the tumor or body cavity.
- Systemic Radiation Therapy:
- This involves the use of radioactive substances that are administered through the bloodstream. The most common example is radioactive iodine therapy, which is used to treat thyroid cancer.
- The radioactive substance travels through the bloodstream and targets cancer cells throughout the body.
- Stereotactic Radiation Therapy:
- This includes techniques like stereotactic radiosurgery (SRS) or stereotactic body radiotherapy (SBRT).
- These methods deliver high doses of radiation very precisely to small tumors, often in the brain or other areas of the body, in a single or a few treatments. It’s highly focused and minimizes exposure to surrounding healthy tissue.
Uses of Radiation Therapy:
Radiation therapy can be used in a variety of scenarios:
- Curative Treatment: Radiation therapy is used with the goal of completely eradicating cancer, especially in localized cancers. It’s often used when surgery isn’t an option or in combination with surgery and chemotherapy.
- Adjuvant Treatment: This is when radiation is used after surgery to kill any remaining cancer cells that may not have been removed, reducing the risk of recurrence.
- Palliative Treatment: For advanced or metastatic cancers, radiation therapy can help reduce symptoms (e.g., pain, bleeding, or obstruction) and improve quality of life. For example, radiation may shrink a tumor that’s causing obstruction in the airways or digestive tract.
- Neoadjuvant Treatment: Sometimes radiation therapy is given before surgery to shrink a tumor and make it easier to remove.
Side Effects of Radiation Therapy:
Radiation therapy is generally well-tolerated, but side effects can occur, depending on the area of the body being treated, the dose, and the length of treatment. These side effects are typically temporary and resolve after treatment ends, but some can persist long-term. Common side effects include:
- Fatigue: Feeling unusually tired, which can persist for weeks after treatment.
- Skin changes: Redness, dryness, or peeling of skin in the area being treated.
- Hair loss: Occurs only in the treated area (e.g., scalp, or in the case of head and neck cancers).
- Nausea and vomiting: Common with radiation to the abdomen or pelvis.
- Swallowing difficulties: If radiation affects the head and neck region, it may cause difficulty swallowing.
- Diarrhea or bladder issues: For pelvic radiation, these may occur due to the effects on the intestines or bladder.
More serious side effects may include long-term damage to organs or tissues near the treatment area, depending on the type of radiation used and the area being treated. Your radiation oncologist will monitor for these effects and may adjust treatment to minimize damage to healthy tissue.
Radiation Oncology Team:
A radiation oncologist is a medical doctor who specializes in treating cancer with radiation. The team often includes:
- Radiation Therapist (Radiologic Technologist): Operates the machines delivering radiation therapy.
- Medical Physicist: Ensures the accuracy and safety of radiation treatments by designing and calibrating the treatment plans.
- Dosimetrist: Calculates the exact radiation dose for a given treatment area.
- Nurses and Support Staff: Provide care and support to patients before, during, and after treatment.
Planning Radiation Therapy:
Radiation therapy requires careful planning to ensure that the radiation is delivered precisely to the cancer cells and minimizes exposure to healthy tissues. This typically involves:
- Imaging Studies: MRI, CT scans, or PET scans are used to determine the exact location and size of the tumor.
- Treatment Planning: The radiation oncologist, physicist, and dosimetrist work together to design a treatment plan, ensuring that the radiation beam is shaped and directed with great precision.
- Simulation: Before actual treatment begins, patients undergo a simulation process, which involves lying on the treatment table in a specific position. This helps ensure the correct alignment during each treatment.
Emerging Advances in Radiation Oncology:
The field of radiation oncology is evolving with advancements like:
- Proton Therapy: A type of radiation therapy that uses protons instead of X-rays. Proton therapy allows for highly precise targeting, making it useful for treating tumors near critical structures, such as in pediatric cancers or cancers of the brain and spine.
- Radiation-Sensitizing Drugs: Researchers are exploring drugs that can make cancer cells more sensitive to radiation, enhancing the effectiveness of treatment.
- Radiation and Immunotherapy Combinations: Some studies are investigating the combination of radiation with immunotherapy drugs, which may enhance the immune system’s ability to attack cancer cells after radiation treatment.
Conclusion:
Radiation oncology is a key part of cancer treatment, offering a non-invasive way to target and treat tumors. It can be used for curative, adjuvant, or palliative purposes, and the technology behind it continues to improve, making it even more precise and effective.