Radiation Therapy: How It Works and Benefits in Cancer Treatment

Introduction: Key Points of Radiation Therapy

Radiation therapy is a form of cancer treatment that uses high-energy radiation to target and destroy cancer cells. It can be administered on its own or in combination with other treatments, such as chemotherapy, depending on the type and location of the cancer. Radiation therapy can be delivered externally or internally and is a crucial option for many cancer patients. It helps shrink tumors, alleviate symptoms, and improve survival rates.

Medications Used in Radiation Therapy

Below is a list of medications commonly used alongside radiation therapy. These drugs may enhance the effects of radiation or target specific types of cancer:

1. Accu-Chek (Accu-Chek)
2. Adcetris (Brentuximab vedotin)
3. Bexxar (Tositumomab)
4. Blinatumomab (Blinatumomab)
5. Carboquone (Carboquone)
6. Cyramza (Ramucirumab)
7. Doxil (Doxorubicin liposome)
8. Etopophos (Etoposide phosphate)
9. Gleevec (Imatinib)
10. I-131 (Iodine-131)
11. Ibrance (Palbociclib)
12. Keytruda (Pembrolizumab)
13. Lenvima (Lenvatinib)
14. Lu-177 (Lutetium-177)
15. Neulasta (Pegfilgrastim)
16. Opdivo (Nivolumab)
17. Pomalyst (Pomalidomide)
18. Revlimid (Lenalidomide)
19. Rituxan (Rituximab)
20. Tarceva (Erlotinib)
21. Thalomid (Thalidomide)
22. Trisenox (Arsenic trioxide)
23. Vectibix (Panitumumab)
24. Velcade (Bortezomib)
25. Xofigo (Radium-223)
26. Y-90 (Yttrium-90)

The generic name of a medication is the non-branded name that identifies the active ingredient. In the list above, the generic name is shown in parentheses next to the brand name.

How Does Radiation Therapy Work? Mechanism of Action

Radiation therapy works by using high-energy radiation to damage the DNA inside cancer cells, preventing them from growing and dividing. The radiation can be delivered externally, using a machine that directs radiation beams at the cancer (external beam radiation therapy), or internally, where radioactive substances are placed inside the body near the cancer cells (a process known as brachytherapy).

Medications used in radiation therapy work in different ways to enhance the effects of radiation or target specific types of cancer. For instance, radioactive isotopes like I-131 (Iodine-131) and Lu-177 (Lutetium-177) emit radiation directly to kill cancer cells. Others, such as Adcetris (Brentuximab vedotin) and Rituxan (Rituximab), are monoclonal antibodies that help the immune system more effectively target cancer cells when used alongside radiation therapy.

Benefits of Radiation Therapy in Cancer Treatment

Radiation therapy is highly effective in treating many types of cancer. It is often used when surgery is not an option or as an additional treatment to shrink tumors before surgery or eliminate remaining cancer cells afterward. Radiation therapy can also relieve symptoms in advanced cancer cases, such as pain or difficulty breathing caused by tumors.

Compared to treatments like chemotherapy, radiation therapy is often more targeted, focusing on a specific area of the body and minimizing damage to healthy tissues. In some cases, radiation therapy is combined with other treatments, such as chemotherapy or immunotherapy, to increase its effectiveness.

Potential Side Effects of Radiation Therapy

While radiation therapy is effective, it can cause a range of side effects. These vary depending on the area being treated, the radiation dose, and individual factors like age, overall health, and pre-existing conditions. Below is a list of potential side effects, ordered from most common to least common, along with their approximate occurrence rates when available.

Common Side Effects of Radiation Therapy (Greater than 1% Occurrence)

1. Fatigue (up to 90%): Fatigue is one of the most common side effects. It often begins after a few weeks of treatment and can last for weeks or months after therapy ends. Patients receiving treatment for larger areas or higher doses are more likely to experience fatigue.
2. Skin Reactions (up to 85%): Skin in the treatment area may become red, dry, itchy, or peel, a condition known as radiation dermatitis. The severity varies, with some patients experiencing mild irritation and others developing more severe burns. Patients with fair skin or those receiving radiation to areas with skin folds (e.g., underarms, groin) may be at higher risk.
3. Hair Loss (Alopecia) (up to 60%): Hair loss occurs in the area being treated. For example, radiation to the head may result in scalp hair loss. Hair loss is typically temporary, but in some cases, it may be permanent depending on the radiation dose.
4. Nausea and Vomiting (up to 50%): These symptoms are more common when the abdomen or brain is treated. Anti-nausea medications can help manage these side effects.
5. Loss of Appetite (up to 40%): Radiation therapy can lead to changes in taste and appetite, particularly if the treatment area includes the head, neck, or abdomen.
6. Diarrhea (up to 30%): Diarrhea is more common when radiation is directed at the abdomen or pelvis. Patients may need to adjust their diet or take medications to manage this side effect.
7. Mouth Sores (up to 20%): Radiation to the head and neck can cause sores in the mouth and throat, making it difficult to eat or swallow.
8. Difficulty Swallowing (Dysphagia) (up to 15%): This is a common side effect when radiation is directed at the neck or chest. It can make eating and drinking uncomfortable, and patients may need to modify their diet.
9. Urinary Problems (up to 10%): Radiation to the pelvic area can cause urinary symptoms such as increased frequency, urgency, or discomfort during urination.

Less Common Side Effects of Radiation Therapy (Less than 1% Occurrence)

Some side effects are rare but can still occur in certain patients. These include:

1. Heart problems
2. Lung damage (pneumonitis)
3. Secondary cancers
4. Infertility (when radiation is directed at the reproductive organs)
5. Bone weakening or fractures
6. Memory or cognitive issues (when radiation is directed at the brain)

Severe Side Effects of Radiation Therapy

In rare cases, radiation therapy can cause severe side effects, such as damage to internal organs, severe burns, or the development of secondary cancers. These side effects are more likely with higher doses of radiation or when radiation is combined with other treatments like chemotherapy. It is crucial to discuss the risks and benefits of radiation therapy with your doctor before starting treatment. If you experience any concerning symptoms, such as severe pain, difficulty breathing, or signs of infection, contact your healthcare provider immediately.

Our telemedicine providers are available to help you understand your treatment options and manage any side effects you may experience. Schedule a consultation with one of our doctors today to discuss your concerns.

Drug to Drug Interactions in Radiation Therapy

Radiation therapy can interact with certain medications, potentially increasing side effects or reducing the effectiveness of cancer treatment. It is essential to inform your healthcare provider about all medications you are taking, including prescription drugs, over-the-counter medications, and supplements. Common drug interactions in radiation oncology include:

Chemotherapy Drugs

Certain chemotherapy drugs, such as cisplatin or 5-fluorouracil, when combined with radiation therapy, can heighten the risk of side effects like nausea, vomiting, and damage to healthy tissues. While this combination is often used to enhance cancer treatment, it requires close monitoring to manage potential side effects from radiation therapy.

Immunosuppressive Drugs

Medications that suppress the immune system, such as corticosteroids or biologics, may increase the risk of infections or delay healing in patients receiving radiation therapy. This is particularly important for cancer patients, as a weakened immune system can complicate recovery and increase vulnerability to infections.

Anticoagulants (Blood Thinners)

Drugs like warfarin or aspirin can raise the risk of bleeding, especially if radiation targets areas with a high concentration of blood vessels. Patients undergoing external beam radiation therapy should be closely monitored if they are also taking blood thinners to prevent complications.

NSAIDs (Nonsteroidal Anti-Inflammatory Drugs)

Medications like ibuprofen or naproxen may increase the risk of gastrointestinal side effects when combined with radiation therapy, particularly if the abdomen is being treated. Patients should consult their healthcare provider before using NSAIDs during cancer radiation treatment to avoid potential complications.

Herbal Supplements

Certain herbal supplements, such as St. John’s Wort, can interfere with radiation therapy by reducing its effectiveness or increasing side effects. Always consult your healthcare provider before taking any supplements during cancer treatment, as they may impact the benefits of radiation therapy or interact with other medications.

Precautions and Contraindications for Radiation Therapy

Before starting radiation therapy, it is crucial to discuss your medical history and any pre-existing conditions with your healthcare provider. Certain factors may increase the risk of complications or make radiation therapy less suitable. These include:

Pregnancy

Radiation therapy is generally contraindicated during pregnancy, as it can harm the developing fetus. Women of childbearing age should use effective contraception during treatment to avoid the potential risks associated with radiation exposure during pregnancy.

Previous Radiation Therapy

If you have previously received radiation therapy to the same area, the risk of side effects may be higher. Your doctor will carefully evaluate whether additional radiation is safe, especially in cases like radiation therapy for breast cancer or prostate cancer, where repeated exposure may increase the likelihood of complications.

Autoimmune Disorders

Patients with conditions such as lupus or rheumatoid arthritis may be more sensitive to the effects of radiation and could experience more severe side effects. It is important to discuss your autoimmune condition with your healthcare provider to ensure your cancer treatment plan is tailored to minimize risks.

Infections

Active infections in the area being treated can increase the risk of complications. Your healthcare provider may delay treatment until the infection is resolved to ensure the effectiveness of radiation therapy and reduce the likelihood of adverse effects.

Heart or Lung Disease

Radiation to the chest area can increase the risk of heart or lung problems, particularly in patients with pre-existing conditions. For example, patients undergoing radiation therapy for breast cancer or lung cancer may require additional monitoring or adjustments to their treatment plan to protect heart and lung health.

Conclusion

Radiation therapy is a powerful option for treating many types of cancer, but it comes with potential risks. Understanding possible side effects, drug interactions, and precautions can help you make informed decisions about your care. Always discuss your treatment plan with your healthcare provider, and don’t hesitate to ask questions about any concerns you may have.

If you are considering radiation therapy or are currently undergoing treatment, our telemedicine providers are here to support you. Schedule an appointment today to speak with one of our doctors about managing side effects, drug interactions, and any other concerns you may have regarding your cancer radiation treatment.

James Kingsley

Learn More