Together, chemo and proton therapy lengthen survival for late-stage lung cancer patients

For patients with advanced, inoperable stage 3 lung cancer, chemotherapy and a specialized form of radiation treatment known as proton therapy offer improved survival when given together compared to traditional therapy, according to a new MD Anderson study.

Overall survival with chemo and proton therapy was 26.5 months, compared with 16 months for those who received chemo with traditional radiation, the current standard of care.

The findings represent the longest follow up to date of stage 3 lung cancer patients who have received proton therapy, said Joe Chang, M.D., professor of Radiation Oncology and the study’s corresponding author.

Lung cancer is the leading cause of cancer death in both men and women in the U.S. This year, more than 155,800 will die from the disease, which is usually diagnosed in an advanced stage.

“Advanced lung cancer patients with inoperable disease traditionally have been treated with concurrent chemotherapy and conventional photon radiation therapy. However, the therapy can be very difficult for patients due to associated toxicities and because many patients are also dealing with comorbidities,” explained Chang.

Proton therapy is an advanced type of radiation treatment that uses a beam of protons to deliver radiation directly to the tumor, destroying cancer cells while sparing healthy tissues. Protons enter the body with a low radiation dose and stop at the tumor, matching its shape and volume or depth. They deposit the bulk of their cancer-fighting energy right at the tumor, thereby reducing the dose to cardiopulmonary structures, which impacts the toxicity, functional status, quality of life and even survival for patients.

The study opened at MD Anderson in 2006; in this research, Chang and his colleague report on the study’s five-year results.

Chang noted his study is not without limitations. Of greatest significance: the study was designed more than a decade ago. While the study’s survival, recurrence rates and toxic effects are still favorable when compared to rates associated with the most advanced traditional photon radiation therapy, intensity modulated radiation therapy (IMRT), technology to diagnose and stage the disease, as well all treatment modalities have significantly improved. 

“When the study opened, PET imaging had just been approved for lung cancer staging. The image quality was poor and didn’t include a CT component in most facilities across the country,” said Chang. “Obviously, the technology has improved dramatically over the last decade and has made a significant impact on diagnosis and staging. Also, delivery of both the conventional intensity-modulated radiation therapy (IMRT) and proton therapy (IMPT), have improved, thereby reducing side effects for both treatment modalities.”  

For example, MD Anderson proton therapy patients with advanced lung cancer now can receive IMPT. The technique uses an intricate network of magnets to aim a narrow proton beam at a tumor and “paint” the radiation dose onto it layer by layer. Healthy tissue surrounding the tumor is spared, and side effects are even more reduced than earlier proton delivery, said Chang.  

A Phase II trial studying IMPT and concurrent chemotherapy is underway.

Chang also noted the advancements in cancer biology and immunotherapy and that both are important areas of research focus in combination with proton therapy.

Read more about this study in MD Anderson's newsroom.