Lung Cancer Treatment Reduces Bone Toxicity
CancerWise - February 2009
Patients with locally advanced non-small cell lung cancer who are treated with proton beam therapy and chemotherapy may have fewer instances of bone marrow toxicity than patients who receive the standard treatment of intensity-modulated radiation (IMRT) and chemotherapy.
This may help them avoid some side effects and withstand more aggressive treatment.
This first-of-its-kind study was reported by M. D. Anderson researchers at the November 2008 Chicago Multidisciplinary Symposium in Thoracic Oncology.
Significance of results
Lung cancer is the leading cause of cancer death in the United States, according to the American Cancer Society. In 2008, approximately 215,000 people will be diagnosed with lung cancer, and approximately 114,000 people will die from the disease.
IMRT and chemotherapy, the standard of care for this type of cancer, provide a 25% five-year survival rate, the best outcomes available. But this method of treatment also carries a high risk of bone marrow toxicity and unpleasant side effects.
Bone marrow toxicity lessens the amount of hemoglobin, neutrophils, lymphocytes and white blood cells in patients’ blood. This further weakens their already compromised immune systems and can make it even more difficult to withstand aggressive treatment. Bone marrow toxicity can lead to infection, bleeding, fatigue and even death.
"As a physician, I have seen how IMRT and chemotherapy affect patients' overall health. They are tired, suffer from night sweats, are prone to infection and have to compromise their treatment,” says Ritsuko Komaki, M.D., professor in M. D. Anderson's Radiation Treatment Center and lead author on the study.
"Our goal is to find the best way to treat the cancer without further weakening the patient,” she says. “With proton therapy, we may now have an option that lessens this toxicity so that treatment dosage can be maximized."
Protons are heavier than X-rays, allowing them to travel in straight paths through the body without being deflected. Proton beam therapy strips away the electrons in cancer cells, mutating the cells' structure so they cannot divide and multiply. While standard radiation therapy destroys the tumor and the healthy tissue around it, proton therapy can target a tumor precisely with little damage to normal tissue.
Proton beam therapy may be especially valuable for patients who are the most vulnerable to bone marrow toxicity or those whose normal cells are growing, such as children.
"Proton therapy may promise safer and more effective treatment for children, whose bone marrow is still developing, and elderly patients who are more prone to complications and cannot withstand aggressive treatment,” says James Cox, M.D., professor and head of M. D. Anderson’s Division of Radiation Oncology and the study's senior author.
This is the first study to examine the benefits of proton beam therapy and concurrent chemotherapy in advanced lung cancer patients.
Researchers compared bone marrow toxicity levels in 142 patients treated for lung cancer between January 2003 and June 2008. All of the patients received chemotherapy.
- 75 patients were treated with IMRT
- 67 patients were treated with proton beam therapy
After 17 months, patients treated with chemotherapy and proton beam therapy experienced significantly less reduction in hemoglobin, neutrophils and lymphocytes.
M. D. Anderson is working with Massachusetts General Hospital to enroll patients in a clinical trial to confirm these initial findings.
— Adapted by Dawn Dorsey from an M. D. Anderson news release