What is radiation therapy and what are the different types

Understanding Radiation Therapy

Radiation therapy is a cancer treatment that uses high-energy rays or particles to damage cancer cells' DNA, preventing them from growing and dividing. It's one of the most common cancer treatments—about half of all cancer patients receive it at some point.

How Radiation Works

When radiation targets cancer cells, it damages their genetic material (DNA) so severely that they can't repair themselves or reproduce. Normal cells can often repair this damage better than cancer cells, which is why radiation can be effective while causing manageable side effects.

Main Types of Radiation Therapy

1. External Beam Radiation Therapy (EBRT)

This is the most common type. A machine outside your body (called a linear accelerator or "linac") directs radiation beams at the tumor from various angles. The radiation passes through your skin to reach the cancer inside.

Subtypes include:

• 3D Conformal Radiation: Uses CT imaging to shape radiation beams to match the tumor's exact shape
• Intensity-Modulated Radiation Therapy (IMRT): Adjusts the intensity of radiation beams to deliver higher doses to the tumor while sparing nearby healthy tissue
• Volumetric Modulated Arc Therapy (VMAT): A newer form of IMRT where the machine rotates around you, delivering radiation from multiple angles in one smooth motion
• Stereotactic Body Radiation Therapy (SBRT): Delivers very high, focused doses in just a few treatments, often used for small tumors or specific situations

2. Internal Radiation Therapy (Brachytherapy)

Radioactive material is placed directly inside or very close to the tumor. This allows doctors to deliver high radiation doses to the cancer while limiting exposure to surrounding tissue.

Common forms:

• Implant brachytherapy: Radioactive seeds or pellets are surgically placed inside the body
• Surface brachytherapy: Radioactive material is applied to the skin surface

3. Systemic Radiation Therapy

Radioactive substances are injected into your bloodstream or swallowed, allowing them to travel throughout your body to find and treat cancer cells.

Examples include:

• Radioactive iodine: Used primarily for thyroid cancer
• Radiopharmaceuticals: Newer targeted approaches that deliver radiation specifically to cancer cells

Combination Approaches

Radiation is often combined with:

• Chemotherapy: Enhances radiation's effectiveness
• Immunotherapy: May improve treatment outcomes
• Targeted therapy: Addresses specific cancer characteristics
• Surgery: Used before or after radiation to remove tumors

What to Expect

Most external beam radiation involves:

• Planning session: CT scans and imaging to map the exact treatment area
• Daily treatments: Usually 5 days a week for several weeks
• Each session: Typically 15-30 minutes (though setup takes longer than actual radiation)
• No pain during treatment: Though you may experience side effects over time

Key Questions to Ask Your Radiation Oncologist

1. Which type of radiation therapy do you recommend for my specific cancer?
2. How many treatments will I need, and how long will the course last?
3. What side effects should I expect, and how can we manage them?
4. Will radiation be combined with other treatments?
5. How will we monitor my response to treatment?

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According to the American Cancer Society and NCCN (National Comprehensive Cancer Network) Guidelines, radiation therapy decisions are individualized based on cancer type, stage, location, and your overall health. Your radiation oncologist will determine the most appropriate approach for your specific situation.

This information is for educational purposes only. Always consult your healthcare team for personalized medical advice and decisions.