Why Do Doctors Use Chemotherapy and Radiation Together?

By: David Grew MD MPH

“Combining chemotherapy and radiation can have a synergistic effect, meaning the treatments work better together than separately…”

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As an oncologist, I've treated many cancer patients and frequently discussed the benefits and challenges of using chemotherapy and radiation together. 

Often, patients come to me with doubts and fears about these treatments, influenced by myths and misinformation they've heard. Questions like, "Doesn’t chemotherapy always cause unbearable side effects?" and "Will radiation therapy make you radioactive?!" are common. 

Additionally, the idea of combining these two treatments—chemotherapy and radiation—often seems even more intimidating to patients, as they fear a more dangerous and intolerable treatment regimen. 

In this blog, I'm going to talk about how chemotherapy and radiation work together in treating cancer, a combination known as chemoradiation, and how understanding these treatments better can help ease patients and families.

Understanding Chemotherapy and Radiation

Chemotherapy, or "chemo," is a type of cancer treatment that uses powerful drugs to kill cancer cells. These drugs can be taken orally in pill form or administered through an IV directly into the bloodstream. Chemotherapy works by targeting rapidly dividing cells, which include cancer cells. However, because it affects all rapidly dividing cells, it can also impact healthy cells, leading to side effects.

Radiation therapy is a more targeted treatment that uses high-energy rays or particles to destroy cancer cells. The radiation can come from a machine outside the body (external beam radiation) or from radioactive material placed inside the body near the cancer cells (internal radiation or brachytherapy). Radiation therapy damages the DNA of cancer cells, preventing them from growing and dividing. Unlike chemotherapy, radiation is usually localized, meaning it targets a specific area where the cancer is located.

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When Are Chemotherapy and Radiation Used Together?

Chemotherapy and radiation therapy are used together in various situations:

• Advanced Cancer: Chemoradiation is often used as the main treatment for advanced cancers that cannot be removed with surgery.
• Pre-Surgical Treatment: Chemoradiation can be used before surgery to shrink tumors, making them operable or reducing the risk of recurrence.
• Post-Surgical Treatment: Chemoradiation can be used after surgery to reduce the risk of the cancer coming back.
• Locally Advanced Cancer: Chemoradiation is used to treat locally advanced cancers where surgery is not feasible or would result in significant disfigurement.

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Additionally, this approach can be particularly effective in treating certain types of cancers, including:

• Lung Cancer: For patients with advanced lung cancer who have lymph node-positive disease and can't have surgery, the standard treatment is often radiation therapy combined with chemotherapy.
• Head and Neck Cancers: Chemoradiation can be used to shrink tumors either instead of surgery, before surgery or to target any remaining cancer cells post-surgery.
• Cervical Cancer: Combining these treatments can help cure the disease and improve survival rates.

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The Impact of Combined Treatment

Combining chemotherapy and radiation can have a synergistic effect, meaning the treatments work better together than separately. Chemotherapy can make cancer cells more sensitive to radiation, enhancing its effectiveness. This combined approach can lead to better tumor shrinkage, higher chances of controlling the cancer, and improved survival rates.

• Better tumor shrinkage: The combination of chemotherapy and radiation can result in more significant reduction in tumor size compared to either treatment alone. This is particularly beneficial when treating locally advanced cancers or when attempting to make inoperable tumors resectable (able to be removed by a surgeon).
• Higher chances of local disease control: By enhancing the effectiveness of radiation therapy, chemoradiation can lead to better control of the primary tumor and reduce the risk of local recurrence.
• Improved survival rates: Several studies have shown that chemoradiation can result in notable patient survival benefits compared to radiation therapy or chemotherapy alone, especially in cancers such as anal, cervical, non-small-cell lung cancer (NSCLC), and bladder cancer.
• Potential to avoid or delay surgery: In some cases, chemoradiation may allow for organ preservation by rendering unnecessary the need for surgical resection, while still achieving comparable survival outcomes.

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Understanding Side Effects of Chemoradiation

While it can be more effective in controlling cancer growth and improving survival rates, it also increases the risk of side effects. It is essential for patients to understand these side effects and take necessary precautions to manage them effectively.

Common Side Effects

• Fatigue: Both chemotherapy and radiation therapy can cause significant tiredness, which can worsen over time. Patients should rest when needed and engage in gentle exercises to maintain energy levels.
• Nausea and Vomiting: Chemotherapy often causes gastrointestinal upset, leading to nausea and vomiting. Patients should manage these symptoms with medication and dietary adjustments.
• Skin Changes: Radiation can cause skin irritation similar to a sunburn in the treated area. Patients should keep their skin moisturized and protected from the sun.
• Mouth Sores and Sore Throat: Radiation therapy can cause mouth sores and sore throats, particularly in cancers of the head and neck. Patients should practice good oral hygiene and manage pain with medication.
• Difficulty Swallowing: Inflammation of the esophagus is common with radiation therapy. Patients should monitor their swallowing and seek medical attention if they experience difficulty.

Rare but Serious Side Effects

• Lung Scarring or Inflammation (Pneumonitis): Chemoradiation can cause lung scarring or inflammation, particularly when treating lung cancer. Patients should monitor their lung function and seek medical attention if they experience breathing difficulties.
• Heart Problems: Radiation therapy near the heart can lead to cardiac issues. Patients should monitor their heart health and seek medical attention if they experience chest pain or other cardiac symptoms.
• Secondary Cancers: Long-term exposure to radiation therapy can increase the risk of developing secondary cancers. Patients should discuss their risk with their healthcare provider and take necessary precautions.

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Managing Side Effects

• Blood Tests: Regular blood tests are crucial to monitor blood cell counts and adjust treatment as needed. Patients should report any changes in their blood counts to their healthcare provider.
• Medications: Medications can help manage side effects such as nausea, vomiting, and pain. Patients should follow their healthcare provider's instructions for medication use.
• Dietary Adjustments: Patients should make dietary adjustments to manage gastrointestinal side effects. A balanced diet rich in fiber and fluids can help alleviate symptoms.
• Rest and Exercise: Patients should rest when needed and engage in gentle exercises to maintain energy levels and overall well-being.
• Support Systems: Patients should build a support system of family and friends to help them cope with the emotional and physical challenges of chemoradiation.

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In conclusion, while the combination of chemotherapy and radiation can be more taxing on the body, its potential to improve outcomes makes it a valuable option in the fight against cancer. 

This dual approach is based on decades of research and has become a cornerstone in the treatment of various cancers, offering hope for better control and long-term survival.

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References:

1. Healthline. (2023, June 22). Chemoradiation: When Used, How It Works, Duration, Side Effects. https://www.healthline.com/health/cancer/chemoradiation[1]
2. Healthline. (n.d.). Radiation vs. Chemo: Uses, Benefits, Side Effects, More. https://www.healthline.com/health/radiation-vs-chemo[2]
3. Macmillan Cancer Support. (n.d.). Chemoradiation treatment. https://www.macmillan.org.uk/cancer-information-and-support/treatments-and-drugs/chemoradiation[3]
4. Ramsay, K. S., Yap, T. H. L., & Sebag, M. (2021). Chemoradiotherapy in Cancer Treatment: Rationale and Clinical Applications. In Vivo, 35(1), 1-10. https://ar.iiarjournals.org/content/41/1/1[4]

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FAQs:

Are there any specific dietary recommendations for patients undergoing chemoradiation?

Yes, dietary adjustments can help manage gastrointestinal side effects such as nausea and vomiting. Patients are often advised to eat small, frequent meals, avoid spicy and fatty foods, and consume foods that are easy to digest. A balanced diet rich in fluids and fiber can help alleviate symptoms. Consulting with a dietitian can provide personalized dietary recommendations to support overall health during treatment.

What can patients do to manage the emotional and psychological impact of chemoradiation?

Patients can seek support from mental health professionals such as psychologists or counselors. Joining support groups where they can connect with others undergoing similar experiences can also be beneficial. Building a family and friends support system and engaging in relaxation techniques like mindfulness, meditation, or light physical activity can help alleviate stress and improve emotional well-being.

What are the long-term follow-up procedures after completing chemoradiation?

Long-term follow-up procedures typically include regular check-ups with the oncologist to monitor for any signs of recurrence and manage any lingering side effects. These appointments may involve physical exams, blood tests, and imaging studies. Patients should also report any new symptoms to their healthcare provider promptly. Long-term monitoring may also include preventive measures and lifestyle changes to reduce the risk of cancer recurrence and manage overall health.

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