ASTRO 2019: Circulating Tumor DNA and Survival in HPV-Positive Oropharyngeal Cancer
Posted: Tuesday, September 24, 2019
According to research presented at the 2019 American Society for Radiation Oncology (ASTRO) Annual Meeting (Abstract LBA5), a significant association has been identified between detectable levels of circulating tumor DNA (ctDNA) and poor survival outcomes in patients with human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma.
“HPV ctDNA is a highly sensitive and specific means of determining HPV status prior to treatment and remains detectable for many patients post-op,” concluded David Routman, MD, of the Mayo Clinic, and colleagues. “Risk stratification using a complement of ctDNA and historical risk factors may be instrumental in improved patient selection for treatment intensity decision making for patients with HPV-associated oropharyngeal squamous cell carcinoma and warrants further study.”
The study collected serum samples from 29 patients with HPV-associated oropharyngeal squamous cell carcinoma who had not yet undergone treatment as well as 7 patients with the same cancer but no association with HPV. In addition, a group of 46 patients with HPV-associated oropharyngeal squamous cell carcinoma who had undergone surgery for the disease had serum samples collected prior to beginning adjuvant therapy.
All detected ctDNA was HPV type 16. In the treatment-naive group, 93% of patients had detectable ctDNA, compared with none in the HPV-negative control group. Of the patients who had been treated with surgery, 43% had detectable ctDNA, including 47% with high-risk features. At a median follow-up of 20 months, one patient had been excluded from the postoperative group due to incomplete adjuvant therapy, and 24% of the remaining postoperative patients had recurrent disease. Of them, 64% had detectable ctDNA compared with 35% whose disease did not recur. A significant association was noted between detectable ctDNA and 24-month progression-free survival (45% vs. 84%, P = .04) and overall survival (80% v.s 100%, P = .02). Overall, detectable ctDNA (hazard ratio = 3.31, P = .05) and T4 tumors (hazard ratio = 14.3, P < .01) were also associated with recurrent disease.
Disclosure: The study authors’ disclosure information may be found at redjournal.org.