Radiation therapy destroys or slows the growth of cancer cells by damaging their DNA. When DNA is damaged beyond repair, cancer cells stop dividing or die. The body then breaks down and removes these dead cells.
Radiation does not kill cancer cells instantly. It takes days or weeks of treatment for DNA damage to accumulate, and cancer cells may continue dying for weeks or months after treatment ends.
Types of Radiation Therapy
There are two primary types of radiation therapy: external beam radiation and internal radiation. The choice of treatment depends on factors such as:
- The type and size of cancer.
- Tumor location.
- Proximity to sensitive tissues.
- Overall health and medical history.
- Other treatments being received.
- Age and additional medical conditions.
- External Beam Radiation Therapy – This method uses a machine to deliver radiation precisely to the tumor from various angles. The machine does not touch you but moves around you, targeting a specific area. It is a localized treatment, meaning only the area with cancer is treated. For instance, lung cancer treatment targets the chest area only.
- Internal Radiation Therapy – Internal radiation involves placing a radiation source inside your body.
Brachytherapy: Uses solid radiation sources like seeds, ribbons, or capsules placed in or near the tumor. It treats only the specific area with cancer.
Systemic Radiation Therapy: Uses liquid radiation that travels through the bloodstream to target cancer cells throughout the body. It is delivered by swallowing, IV, or injection. Body fluids, like urine and sweat, may temporarily emit radiation during this treatment.
Why Radiation Therapy Is Used
Radiation therapy treats cancer and alleviates symptoms:
- To treat cancer: It can cure cancer, prevent its return, or slow its growth.
- To ease symptoms: Known as palliative treatment, radiation can shrink tumors to relieve pain or address issues such as difficulty breathing or loss of bladder control. For cancer that has spread to the bone, systemic radiation drugs (radiopharmaceuticals) can reduce pain.
Cancers Treated with Radiation Therapy
- External Beam Radiation Therapy: Used for many cancer types.
- Brachytherapy: Commonly used for cancers of the head and neck, breast, cervix, prostate, and eye.
- Systemic Radiation Therapy: Radioactive iodine (I-131) is often used for thyroid cancer. Targeted radionuclide therapy (e.g., molecular radiotherapy) is used for advanced prostate cancer or gastroenteropancreatic neuroendocrine tumors (GEP-NET).
Combining Radiation with Other Treatments
Radiation therapy is often used alongside surgery, chemotherapy, or immunotherapy. The timing depends on the cancer type and treatment goals:
- Before surgery -To shrink the tumor for easier removal.
- During surgery – Known as intraoperative radiation, it delivers radiation directly to the cancer while sparing nearby tissues.
- After surgery – To eliminate any remaining cancer cells.
Lifetime Dose Limits
There is a limit to how much radiation a specific area of the body can safely receive in a lifetime. If one area has already reached its safe dose, another distant area may still be treated.
Side Effects of Radiation Therapy
Radiation can damage healthy cells near the treatment site, leading to side effects. These vary based on the treatment area and can include skin changes, fatigue, and other localized effects. For detailed information, see the section on radiation side effects.
Cost of Radiation Therapy
Radiation therapy can be expensive due to the use of advanced technology and specialized healthcare providers. Costs depend on treatment type, number of sessions and local healthcare costs.
Dietary Needs During Radiation Treatment
Radiation may cause eating challenges, such as nausea or mouth sores, making it difficult to maintain weight. Proper nutrition is crucial for recovery.
- Inform your doctor if you experience eating problems.
- A dietitian can help create a plan to meet your nutritional needs.
Working During Therapy
Whether you can work during treatment depends on how you feel. Early in treatment, you may feel well enough to work full-time. As treatment progresses, fatigue and other side effects may limit your ability to work.
- Consider adjusting your work schedule or taking medical leave if needed.
- Discuss your options with your employer and check your insurance coverage during leave.
Recovery times vary. Some people feel better within weeks of completing treatment, while others take months to regain energy.
Here you can find useful read for what is Chemotherapy and how does it work?
Recourse: Cancer.gov
