A new study presented at the International Association for the Study of Lung Cancer 2025 World Conference on Lung Cancer (Abstract MA11.09) demonstrated that monitoring circulating tumor DNA (ctDNA) may aid in refining and personalizing the use of consolidation immunotherapy in patients with limited-stage small cell lung cancer (SCLC).
The research, led by scientists at the National Cancer Center of China, assessed ctDNA in 177 patients with limited-stage SCLC treated with chemoradiotherapy (CCRT), 77 of whom received consolidation immune checkpoint inhibitors (ICIs). ctDNA was measured at multiple time points to evaluate its ability to predict survival outcomes and immunotherapy benefits.
“This is the first study to show that early ctDNA detection after induction chemotherapy can help identify patients who are more likely to benefit from consolidation immunotherapy,” said Nan Bi, MD, of the Chinese Academy of Medical Sciences. “It’s a step toward precision immunotherapy in limited-stage SCLC.”
Key findings included:
- Consolidation ICI improved overall survival vs CCRT alone (hazard ratio = 0.41; P = .031).
- Patients who were ctDNA-positive post induction had significantly better progression-free and overall survival with ICIs compared with CCRT alone.
- ctDNA-negative patients did not show added benefit from ICIs.
- Maintaining ctDNA negativity during immunotherapy was associated with better prognosis.
- ctDNA post induction was more predictive of treatment response than ctDNA post radiotherapy.
The study used next-generation sequencing with a 139-gene lung cancer panel to assess ctDNA at ultradeep coverage (30,000×). Advanced statistical models including time-dependent Cox regression were employed to eliminate immortal time bias.
“These findings offer a compelling rationale for integrating ctDNA-based stratification in future limited-stage SCLC trials and may help guide real-time decisions on the use of consolidation ICIs,” Dr. Bi said.
Disclosure: For full disclosures of the study authors, visit cattendee.abstractsonline.com.
