When it comes to predicting long-term outcomes after neoadjuvant immunotherapy, pathologic complete response (pCR) edges out circulating tumor DNA (ctDNA) clearance. A large analysis of nearly 2,200 patients across 8 solid tumor types found pCR to be a more consistent predictor of event-free survival — though neither marker is reliable enough on its own for clinical decision-making just yet.
A major post hoc analysis published in the Journal of the National Cancer Institute compared two key response markers — pathologic complete response (pCR) and circulating tumor DNA (ctDNA) clearance — in patients with resectable solid cancers treated with neoadjuvant or perioperative immunotherapy. The verdict: pCR is the more reliable predictor of long-term disease control across tumor types.
The study pooled individual patient data from 29 phase 2 and 3 trials, covering 8 cancer types including non-small cell lung cancer (NSCLC), triple-negative breast cancer (TNBC), melanoma, and bladder cancer. While both markers showed promise, pCR proved more consistent — particularly in NSCLC and TNBC — whereas ctDNA clearance showed significant variability across trials, likely due to differences in tumor biology and assay methods.
Key Takeaways:
Why it matters: As immunotherapy becomes standard in earlier cancer treatment settings, identifying reliable surrogate endpoints is critical for designing smarter trials and making better treatment decisions. This analysis reinforces pCR's role while highlighting the need for more standardized ctDNA assays before the marker can be used confidently in the clinic.
