Treating metastatic non-small cell lung cancer (NSCLC) patients with the immunotherapy drug pembrolizumab after they've completed locally ablative therapy - meaning all known sites of their cancer were either treated with surgery, radiation, or other definitive treatments - almost tripled the median progression-free survival (PFS) compared to the historical average.
Research from the Abramson Cancer Center at the University of Pennsylvania found the average PFS of study participants was 19.1 months, compared to 6.6 months.
JAMA Oncology published the findings.
Lung cancer is, by far, the leading cause of cancer death in America, and NSCLC is the most common type.
Chemotherapy is the standard treatment, but recent data have shown that patients with limited metastatic disease may have more options.
"Multiple trials have shown that if we use these definitive treatment techniques on all visible tumour sites, patients can end up with better outcomes than what they would get with chemotherapy alone, so our trial went one step further and added immunotherapy," said lead author Joshua M. Bauml, MD, an assistant professor of Hematology-Oncology in Penn's Perelman School of Medicine.
The study's senior author was Corey J. Langer, MD, a professor of Hematology-Oncology at Penn.
For this study, 45 NSCLC patients with four or fewer metastatic sites underwent LAT, then received pembrolizumab.
In addition to the significant increase in overall average PFS, the average PFS from the start of pembrolizumab was 18.7 months.
Importantly, the treatment did not lead to any new safety issues or decreases in patient quality of life.
"Our understanding of which metastatic patients may benefit from curative therapies as opposed to palliative therapies is still evolving, but our data show promise that the addition of immunotherapy can bring make a difference," Bauml said.
Researchers say the approach needs further study and that they are still evaluating the impact of this combination on overall survival.
However, they note that this study accrued 45 patients from February 2015 through September 2017, a significant number for a single site and evidence that a larger, multi-centre, randomised controlled trial to test this approach is feasible.