How Does Chemotherapy Work for Mesothelioma?

Mesothelioma Surgery

Surgery is often the primary treatment option for mesothelioma, especially when the disease is diagnosed at an early stage. The goal of surgery can be curative (to remove as much of the cancer as possible) or palliative (to relieve symptoms and improve quality of life).

Extrapleural Pneumonectomy (EPP)

• Procedure: EPP is a radical surgery used primarily for pleural mesothelioma. It involves the removal of the affected lung, the pleura (lining of the lung), the diaphragm, and part of the pericardium (lining of the heart).
• Purpose: This surgery is generally performed on patients with early-stage mesothelioma who are in good overall health. It aims to remove all visible tumor tissue and is often followed by chemotherapy or radiation therapy to target any remaining cancer cells.
• Risks and Benefits: EPP is a complex and high-risk surgery, but it can offer significant survival benefits for some patients, particularly when combined with other treatments.

Pleurectomy/Decortication (P/D)

• Procedure: P/D is a less aggressive surgery compared to EPP. It involves the removal of the pleura and any visible tumors without removing the entire lung.
• Purpose: P/D is often recommended for patients who are not candidates for EPP due to health concerns or the extent of the disease. It can help reduce symptoms and control the spread of cancer while preserving lung function.
• Risks and Benefits: P/D has a lower risk of complications compared to EPP and can improve quality of life by reducing symptoms such as chest pain and difficulty breathing.

Cytoreductive Surgery with HIPEC

• Procedure: For peritoneal mesothelioma, cytoreductive surgery combined with Hyperthermic Intraperitoneal Chemotherapy (HIPEC) is the standard approach. This involves the surgical removal of visible tumors in the abdomen, followed by the application of heated chemotherapy directly into the abdominal cavity.
• Purpose: The heated chemotherapy aims to kill any remaining cancer cells and reduce the risk of recurrence.
• Risks and Benefits: This aggressive treatment can significantly extend survival for patients with peritoneal mesothelioma, but it is a complex procedure that requires a high level of expertise.

Chemotherapy for Mesothelioma

Chemotherapy is a systemic treatment that uses drugs to kill cancer cells or stop their growth. It is often used in conjunction with surgery or as a standalone treatment when surgery is not an option.

Systemic Chemotherapy

• Common Regimens: The most common chemotherapy regimen for mesothelioma includes a combination of pemetrexed (Alimta) and cisplatin. This combination has been shown to improve survival and reduce symptoms in patients with pleural mesothelioma.
• Purpose: Chemotherapy is used to shrink tumors before surgery (neoadjuvant chemotherapy), kill remaining cancer cells after surgery (adjuvant chemotherapy), or control the growth of the disease in advanced stages.
• Side Effects: Chemotherapy can cause side effects such as nausea, fatigue, hair loss, and increased susceptibility to infections. However, newer drugs and supportive therapies have made it easier for patients to tolerate these treatments.

Intraperitoneal Chemotherapy

• HIPEC: In the treatment of peritoneal mesothelioma, HIPEC (discussed earlier) delivers heated chemotherapy directly to the abdomen, maximizing its effectiveness while minimizing systemic side effects.
• Use in Combination: This method is typically used in combination with cytoreductive surgery for a more aggressive approach to treatment.

Radiation Therapy for Mesothelioma

Radiation therapy uses high-energy rays to target and kill cancer cells. It is often used as part of a multimodal treatment plan for mesothelioma.

External Beam Radiation Therapy (EBRT)

• Procedure: EBRT is the most common type of radiation therapy for mesothelioma. It involves directing radiation from outside the body to the tumor site.
• Purpose: Radiation therapy can be used before surgery to shrink tumors, after surgery to kill any remaining cancer cells, or palliatively to relieve symptoms like pain and difficulty breathing.
• Side Effects: Common side effects include fatigue, skin irritation at the treatment site, and shortness of breath. Advances in radiation technology have improved precision, reducing damage to surrounding healthy tissues.

Brachytherapy

• Procedure: Brachytherapy involves placing radioactive material directly into or near the tumor. This method delivers a high dose of radiation to the cancer cells while sparing nearby healthy tissue.
• Use in Mesothelioma: Brachytherapy is less commonly used for mesothelioma but may be considered in certain cases where a highly localized treatment is beneficial.

Immunotherapy for Mesothelioma

Immunotherapy is an emerging treatment option that harnesses the body’s immune system to fight cancer. It has shown promise in treating mesothelioma, particularly in cases where traditional treatments are not effective.

Immune Checkpoint Inhibitors

• Drugs Used: Immune checkpoint inhibitors, such as pembrolizumab (Keytruda) and nivolumab (Opdivo), block proteins that prevent the immune system from attacking cancer cells.
• Purpose: These drugs help the immune system recognize and destroy mesothelioma cells, offering a new treatment avenue for patients with advanced disease.
• Effectiveness: Immunotherapy has been particularly effective in certain patients, leading to longer survival times and improved quality of life. However, it does not work for everyone, and research is ongoing to determine which patients are most likely to benefit.

CAR T-Cell Therapy

• Procedure: This experimental therapy involves modifying a patient’s own T-cells (a type of immune cell) to target and kill mesothelioma cells. The modified cells are then infused back into the patient’s body.
• Current Status: CAR T-cell therapy is still in the early stages of research for mesothelioma, but it represents a promising area of treatment development.

Targeted Therapy for Mesothelioma

Targeted therapy uses drugs or other substances to specifically target and attack cancer cells without harming normal cells. This approach is based on the genetic mutations or other specific characteristics of the cancer cells.

VEGF Inhibitors

• Drugs Used: Bevacizumab (Avastin) is a targeted therapy that inhibits vascular endothelial growth factor (VEGF), a protein that helps tumors form new blood vessels. By blocking VEGF, this drug can starve tumors of the blood supply they need to grow.
• Use in Combination: Bevacizumab is often used in combination with chemotherapy for treating pleural mesothelioma.

PARP Inhibitors

• Purpose: PARP inhibitors block a protein that cancer cells use to repair DNA damage. This makes it harder for the cancer cells to survive and multiply.
• Current Research: PARP inhibitors are being studied in clinical trials for their effectiveness in treating mesothelioma, particularly in patients with specific genetic mutations.

Palliative Care for Mesothelioma

Palliative care focuses on relieving the symptoms and improving the quality of life for patients with advanced mesothelioma. It is not aimed at curing the disease but at managing pain, breathlessness, and other symptoms.

Pain Management

• Medications: A variety of pain-relieving medications, including opioids, can be prescribed to manage pain effectively.
• Procedures: Procedures such as nerve blocks or the placement of catheters can also help control pain.

Symptom Relief Procedures

• Thoracentesis and Paracentesis: These procedures involve draining fluid from the pleural or abdominal cavity to relieve pressure and reduce symptoms such as shortness of breath and abdominal pain.
• Pleurodesis: A procedure that involves injecting a substance into the pleural space to cause the layers of the pleura to stick together, preventing fluid buildup.

Conclusion

The treatment of mesothelioma requires a personalized approach, tailored to the type and stage of the disease, as well as the patient’s overall health and preferences. Surgery, chemotherapy, and radiation therapy remain the mainstays of treatment, but newer approaches like immunotherapy and targeted therapy are offering hope for improved outcomes. Palliative care also plays a crucial role in managing symptoms and enhancing the quality of life for patients with advanced disease. As research continues, the treatment landscape for mesothelioma is likely to evolve, bringing new options and hope to those affected by this challenging disease.

Sources:

• National Cancer Institute - Mesothelioma Treatment
• American Cancer Society - Treatment Options for Mesothelioma
• Mayo Clinic - Mesothelioma Treatment Overview
• Centers for Disease Control and Prevention (CDC) - Mesothelioma Treatment and Care