Timing may be key when adding immunotherapy to chemoradiation for lung cancer treatment, suggest findings presented September 30 at the American Society for Radiation Oncology (ASTRO) annual meeting in Washington, DC.
In her presentation, Kristin Higgins, MD, from the City of Hope Cancer Center in Atlanta, GA, discussed her team’s findings, which showed that lung cancer patients could benefit from adding immunotherapy to chemoradiation, but not if both treatments are given at the same time.
“This seemingly small difference in the timing of when the drug is delivered has a very significant impact on the results,” Higgins said in a prepared statement. “At the same time, we found that changing the way you deliver radiation, giving it twice daily, improved survival rates compared to the once-daily approach.”
Previous research suggests that immunotherapy given after the completion of radiation and chemotherapy can increase overall survival for people with limited-stage small cell lung cancer. Higgins and colleagues studied whether similar benefits could be had when delivering the treatments at the same time.
The group's analysis included data collected from 544 patients at 500 centers across the U.S. and 44 in Japan. The team randomized the patients into two cohorts, one for standard chemoradiation and the other for adding atezolizumab immunotherapy to chemotherapy.
Treatment with atezolizumab and chemoradiation at the same time did not improve survival rates compared to standard care.
| Survival rates in small-cell lung cancer patients by treatment arm | ||
|---|---|---|
| Measure | Standard treatment | Concurrent treatment with atezolizumab immunotherapy |
| 1 year | 82.6% | 80.2% |
| 2 years | 62.9% | 58.6% |
| 3 years | 50.3% | 44.7% |
| Median overall survival | 39.5 months | 33.1 months |
Also, adding concurrent immunotherapy to chemoradiation led to a median progression-free survival of 11.5 months compared to 12 months with standard treatment. Additionally, the experimental cohort experienced a distant metastasis-free survival of 13.2 months compared to 16.8 months in the standard treatment cohort.
Finally, the researchers found benefits for twice-daily treatments. The median overall survival for those treated twice per day was 35.4 months compared to 28.3 months for people treated once per day (hazard ratio = 1.44, with 1 as reference).
Higgins said that the results suggest a need to reevaluate current practice patterns that favor once-daily treatments. She added that while twice-daily radiation treatments may be cumbersome for doctors and patients, the results show their benefits.
