Circulating human papillomavirus DNA sequencing as a biomarker of response in advanced cervical cancer

Despite intense multi-modal treatment, the prognosis for advanced cervical cancer remains poor. The recent increase in cervical cancer cases worldwide highlights an urgent need for clinically validated biomarkers to guide patient management. Our pilot study investigates the utility of human papillomavirus (HPV) circulating tumor deoxy ribonucleic acid (ctDNA) in metastatic and recurrent cervical cancer. We investigated the association of HPV ctDNA levels, early kinetics, and detection of viral-host integration sites with response and outcomes.

Serial plasma samples were prospectively collected from 21 patients with metastatic/recurrent cervical cancer. HPV ctDNA genotyping and quantification were conducted using a previously validated hybrid capture next-generation sequencing-based method. Mutation profiles within ctDNA were investigated simultaneously using a bespoke panel. In addition, high-confidence HPV integration was detected and quantified in ctDNA using SearcHPV. Differences in progression-free survival and overall survival were also evaluated between patients with high-confidence integration sites detected at baseline and those with low or no-confidence integration sites using the Kaplan-Meier method and log-rank tests to compare groups.

This pilot study cohort included 21 patients with HPV-associated cervical cancer. Treatments included front-line platinum-based chemotherapy without (n = 4) or with (n = 5) bevacizumab, bevacizumab monotherapy (n = 2), or subsequent therapy (n = 7). A total of 3 previously treated patients were included to study HPV kinetics during observation. At baseline, HPV ctDNA was detected in 20 of 21 patients (95.2%). From baseline to the first assessment, a change in HPV ctDNA was significantly associated with type of response in patients on treatment (n = 18) (p = .049) and across all patients (n = 21) (p = .008). A total of 26 unique mutations were detected in either plasma or tissue. Of these, 11 of 26 were only detected in plasma, 9 of 26 were only detected in tissue, and 6 of 26 were detected in plasma and tissue. Patients with a high-confidence HPV integration site detected within ctDNA at baseline have inferior overall survival compared with patients with low-confidence or undetectable integration.

In this pilot study, a decrease in HPV ctDNA was associated with response to treatment in metastatic and recurrent cervical cancer. HPV site integration and mutation-based ctDNA may have application to personalized therapy and should be evaluated in larger studies.