CHICAGO - When patients with stage III non-small cell lung cancer are treated with prophylactic cranial irradiation, their risk of developing brain metastases decreases by more than 50% compared to patients who don't receive this treatment.
However, the unwanted side effect is significantly increased risk of short- and long-term memory loss, according to radiation oncologists who conducted the first randomized study to analyze neurocognitive and quality-of-life factors for non-small cell lung cancer patients who received prophylactic cranial irradiation. They reported their findings at the American Society for Radiation Oncology (ASTRO) annual meeting being held November 1-5 in Chicago.
In the study, 127 cancer treatment centers affiliated with the Radiation Therapy Oncology Group (RTOG) participated in the RTOG 0214 study, enrolling 340 patients who had completed definitive therapy without progression. Clinical trial enrollment began in September 2002 and was closed in August 2007.
All patients had neurocognitive function assessments upon enrollment, and again 12 months later, to measure neurological deterioration. A 10-point change out of 100 was considered clinically relevant with respect to quality of life, according to Dr. Benjamin Movsas, chairman of radiation oncology at Henry Ford Hospital in Detroit.
After baseline testing, half of the patients were randomly assigned to receive 30 Gy of prophylactic cranial irradiation in 2 Gy fractions. The other half served as the control group. None of the patients were receiving chemotherapy, the side effects of which could impact neurological function.
One-year survival outcomes and disease-free survival outcomes were similar for both groups and were not statistically significant. However, the incidence of developing brain metastases at one-year follow-up was 7.7% for the group that received prophylactic cranial irradiation compared to 18% for the control group.
On the negative side, the patients who received prophylactic radiation had a greater decline in immediate recall (p = 0.03) and delayed recall (p = 0.008). Movsas said that memory loss was not substantial. He noted that the memory loss seemed to peak three months after treatment and slowly begin to return to baseline levels over time.
The findings of the study are provocative and merit additional research, according to Movsas.
Related Reading
Cranial irradiation decreases brain metastases, June 2, 2009
Quality of life suffers with cranial radiation to prevent lung cancer metastases, December 10, 2008
Prophylactic cranial irradiation reduces brain metastases, August 16, 2007
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