Higher doses of radiation concurrently with chemotherapy improve survival in patients with stage III lung cancer, according to a study published in the April 1 issue of the International Journal of Radiation Oncology*Biology*Physics. However, the potential toxicity associated with higher dose is leading researchers to consider PET imaging to guide more targeted treatment.
Standard treatment for this stage of lung cancer--when the tumor is likely too large to be removed through surgery--involves a combination of radiation therapy with chemotherapy. But, the new study found that giving chemotherapy at the same time as the radiation enhances the effect of both. Further, increasing the dose of radiation over the course of treatment also increased survival.
"When patients are diagnosed with stage III lung cancer, surgery is often not an option, and survival rates are typically quite low. Finding new ways to improve survival, even in small increments, is crucial," said the study's senior author Feng-Ming Kong, MD, PhD, associate professor of radiation oncology at the University of Michigan (U-M) Medical School in Ann Arbor and chief of radiation oncology at the Ann Arbor VA Healthcare System.
Researchers at the U-M Comprehensive Cancer Center examined 237 patients who had been treated for stage III non-small cell lung cancer at U-M and the VA Ann Arbor. The investigators compared survival among patients treated with radiation alone, with radiation followed by chemotherapy, and with radiation and chemotherapy given at the same time. Thirty-one patients were also enrolled in a study in which the radiation dose was increased throughout the course of the treatment.
Patients treated with radiation alone had the worst overall survival rates, living only an average 7.4 months after diagnosis, according to the authors. Adding chemotherapy increased survival to 14.9 months when it was administered after completing radiation and 15.8 months when administered at the same time as radiation. After five years, 19.4 percent of the patients receiving concurrent chemotherapy were still alive, compared to only 7.5 percent of patients receiving sequential chemotherapy.
"Our study shows chemotherapy helps, and high dose radiation helps. But it's challenging to administer these treatments at the same time because of the potential toxicity associated with the high dose radiation," Kong said.
The U-M researchers said that they are currently looking at using PET imaging during the course of lung cancer treatment to personalize high dose radiation therapy in many individual patients. As the tumor becomes smaller during treatment, increasing the radiation dose will become more tolerable because it is targeting a smaller area. The U-M researchers believe this strategy could lead to improved treatment outcomes in many patients. Kong currently is leading a clinical trial that is following patients through their treatment to look at the impact on survival of increasing radiation dose.