Understanding Radiation for Mesothelioma
Radiation therapy uses high-energy beams to damage cancer cells and stop them from growing. For mesothelioma, radiation plays a supporting role: it is rarely used alone but can be valuable when combined with surgery and chemotherapy. Radiation is most often used to reduce tumor size, relieve symptoms, or target cancer cells that remain after surgery.
How Radiation Therapy Works
Radiation works by damaging the DNA inside cancer cells. When the DNA is damaged beyond repair, the cells die or stop dividing. Because mesothelioma tumors grow in thin layers around organs rather than forming a single mass, delivering radiation precisely is challenging. Modern techniques like intensity-modulated radiation therapy (IMRT) allow more targeted treatment.
Types of Radiation for Mesothelioma
Intensity-Modulated Radiation Therapy (IMRT)
IMRT uses computer-controlled beams that conform closely to the shape of the tumor. This approach:
- Delivers higher doses to cancer cells
- Minimizes exposure to surrounding healthy tissue
- Reduces side effects compared to conventional radiation IMRT is particularly useful for pleural mesothelioma because the radiation can be shaped to follow the curved lining of the lung.
External Beam Radiation Therapy (EBRT)
This is the most common form of radiation. A machine directs beams at the tumor from outside the body. Treatment sessions are typically given daily over several weeks.
Brachytherapy
In some cases, radioactive material may be placed directly into or near the tumor. This is less common for mesothelioma than other cancers.
When Radiation Is Used
After Surgery (Adjuvant Radiation)
Radiation is often given after pleurectomy/decortication or extrapleural pneumonectomy to:
- Target microscopic cancer cells left behind
- Reduce the risk of local recurrence
- Treat areas where tumor removal was incomplete A retrospective analysis of 22 studies involving 142 patients treated with postoperative radiation showed encouraging results:
- One-year local control rates: 73.5–100%
- Median overall survival: 26.9–38.0 months
Before Surgery (Neoadjuvant Radiation)
Less commonly, radiation may be given before surgery to shrink tumors and make them easier to remove. This approach is typically part of a clinical trial.
For patients with advanced mesothelioma or those who are not surgical candidates, palliative radiation can reduce pain, improve breathing, and control symptoms. It uses lower doses and shorter courses to minimize side effects while providing relief.
Radiation Outcomes and Effectiveness
What Radiation Can Do
- Control local tumor growth
- Reduce pain and other symptoms
- Extend survival when combined with surgery and chemotherapy
- Prevent tumor recurrence in treated areas
Radiation alone is unlikely to achieve remission in mesothelioma. The disease spreads along tissue planes, making complete eradication with radiation difficult. Radiation is most effective as part of multimodal treatment combining surgery, chemotherapy, and radiation.
Study Results
Research on radiation for mesothelioma shows:
| Measure | Outcome |
|---|---|
| One-year local control | 73.5–100% |
| Median progression-free survival | 5.1–8.0 months |
| Median overall survival | 26.9–38.0 months |
| Grade 3–4 toxicity rate | 13% or less |
| These results come from a systematic review of patients receiving radiation as part of multimodal treatment. |
Side Effects of Radiation
Side effects depend on the area being treated and the radiation dose.
Common Side Effects
- Fatigue: The most common side effect; may persist for weeks after treatment
- Skin changes: Redness, irritation, or peeling in the treatment area
- Difficulty swallowing: If the esophagus is in the treatment field
- Shortness of breath: May worsen temporarily during treatment
- Nausea: Less common, usually mild
Managing Side Effects
Most side effects are temporary and improve after treatment ends. Your radiation oncology team can provide:
- Skin care recommendations
- Medications for nausea or discomfort
- Nutritional guidance
- Energy conservation strategies
Long-Term Effects
Radiation to the chest can sometimes cause:
- Pulmonary fibrosis (scarring of lung tissue)
- Heart effects (if the heart is in the treatment field)
- Rib fractures in treated areas Modern techniques like IMRT have reduced these risks significantly.
Radiation Combined With Other Treatments
Trimodality Therapy
Some patients receive a combination of:
- Surgery (P/D or EPP)
- Chemotherapy (pemetrexed + platinum drug)
- Radiation therapy This trimodality approach aims to remove visible tumor, kill circulating cancer cells, and prevent local recurrence.
Radiation With Immunotherapy
Clinical trials are currently studying radiation combined with immunotherapy drugs like Keytruda (pembrolizumab). The goal is to determine:
- The safest and most effective radiation dose
- Whether radiation can enhance the immune response
- Optimal sequencing of treatments
The Radiation Treatment Process
Planning Phase
Before treatment begins, you will have a planning session called a simulation:
- CT scans map the tumor and surrounding structures
- Marks or small tattoos guide precise beam placement
- The radiation oncologist designs a treatment plan
Treatment Sessions
Radiation is typically delivered:
- Five days per week (Monday through Friday)
- Over 4–6 weeks for adjuvant therapy
- In shorter courses for palliative care Each session lasts 15–30 minutes, though the actual radiation delivery takes only a few minutes.
Follow-Up
After completing radiation, regular follow-up appointments monitor:
- Treatment response
- Recovery from side effects
- Signs of recurrence
What is the goal of radiation in my treatment plan?▼
Goals vary: adjuvant radiation after surgery targets microscopic disease and reduces recurrence risk, while palliative radiation focuses on symptom relief. Understanding your specific goal helps set appropriate expectations.
How many treatments will I need?▼
Adjuvant therapy typically involves 4-6 weeks of daily treatments. Palliative courses are shorter, sometimes just 1-2 weeks. Each session lasts 15-30 minutes, with actual radiation delivery taking only minutes.
What side effects should I expect?▼
Common effects include fatigue, skin changes, and difficulty swallowing. Most are temporary and improve after treatment. IMRT reduces side effects compared to conventional radiation.
Are there clinical trials combining radiation with newer therapies?▼
Yes, trials are studying radiation combined with immunotherapy drugs like pembrolizumab to determine if radiation can enhance immune response. Ask your oncologist about trials you may qualify for.
Key Takeaways
Radiation therapy serves an important role in mesothelioma treatment, particularly when combined with surgery and chemotherapy. While it cannot cure mesothelioma on its own, radiation can control local tumor growth, relieve symptoms, and contribute to longer survival as part of a comprehensive treatment plan. Understanding the benefits and limitations of radiation helps patients and families make informed decisions about care.