TOPLINE:
Adding metastasis-directed therapy (MDT) to systemic therapy improves progression-free survival (PFS) to 10.3 months vs 2.5 months with systemic therapy alone in patients with oligometastatic pancreatic ductal adenocarcinoma (PDAC).
METHODOLOGY:
- Researchers conducted a phase 2 multicenter, randomized basket trial involving 41 patients with oligometastatic PDAC in the EXTEND trial.
- Participants were randomly assigned 1:1 to receive MDT plus systemic therapy or systemic therapy alone.
- MDT included definitive local therapy, with stereotactic ablative radiotherapy recommended when feasible. Members of the control group were allowed to receive MDT if their disease progressed.
- The primary endpoint was PFS, measured from random assignment to radiologic progression, clinical progression, or death.
- “Secondary endpoints included overall survival, time to next-line systemic therapy, time to local failure, time to new lesion formation, toxicity, and quality of life,” the authors said.
TAKEAWAY:
- According to the authors, adding MDT to systemic therapy significantly improved PFS to 10.3 months vs 2.5 months with systemic therapy alone (P = .030).
- The hazard ratio for PFS was 0.43 (95% CI, 0.20-0.94), indicating a substantial reduction in the risk for disease progression or death with MDT.
- No grade 4 or 5 treatment-emergent adverse events were observed, suggesting that MDT is a safe addition to systemic therapy.
- Longer PFS and overall survival were associated with activated systemic immunity after MDT, suggesting that “an activated systemic immune profile, supported by a diverse T-cell receptor repertoire, might promote immunosurveillance of distant microscopic disease.”
IN PRACTICE:
“No other PDAC-specific trials have been reported, and tumor-agnostic studies, such as SABR-COMET or the National Health Service single-arm registry study, have not published PDAC-specific outcomes. Thus, the EXTEND trial provides the strongest evidence to date in favor of the existence of an oligometastatic state in PDAC.”
SOURCE:
The study was led by Ethan B. Ludmir, MD, and Alexander D. Sherry, MD, both of the University of Texas MD Anderson Cancer Center, Houston. It was published online on August 5 in The Journal of Clinical Oncology.
LIMITATIONS:
The study’s broad enrollment criteria may have introduced heterogeneity in the patient population, potentially affecting the generalizability of the findings. The study was not powered to evaluate overall survival, and the small sample size may have limited the robustness of the results. Crossover and non–cancer-related deaths could have influenced the comparisons, and quality-of-life data were limited because of the COVID-19 pandemic. The definition of oligometastasis used in the trial may have oversimplified the complex spectrum of the disease.
DISCLOSURES:
Dr. Ludmir disclosed employment with Alaunos Therapeutics and consulting for Xerient. Dr. Sherry reported employment with MD Anderson Cancer Center and honoraria from Sermo. One coauthor has an uncompensated relationship with Polaris Consulting. Another coauthor has stock ownership in BriaCell and a consulting or an advisory role with Regeneron. Additional disclosures are noted in the original article.
This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article first appeared on Medscape.com.