Abstract

The incidence and mortality of anal squamous cell carcinoma (ASCC) are rising, with greater than 80% of cases linked to human papillomavirus (HPV), primarily HPV16. Post-treatment surveillance can be challenging due to the limitations of anoscopy, digital anal rectal exam (DARE), and imaging. Plasma tumor tissue modified viral (TTMV)-HPV DNA has shown strong sensitivity, specificity, and predictive value in detecting the recurrence of HPV-driven oropharyngeal cancer. Here, we investigate the ability of TTMV-HPV DNA for the early recurrence detection of ASCC. This retrospective clinical case series included 117 patients with HPV-driven ASCC across 7 U.S. centers, monitored with TTMV-HPV DNA during routine clinical care between March 2020 and June 2024. Physician-reported clinical data and biomarker testing data were combined to create a comprehensive, longitudinal dataset for evaluating test performance metrics. Patients had a median age of 63 years and median post-diagnosis follow-up of 19 months. HPV status was primarily confirmed by TTMV-HPV DNA (52%) or p16 immunohistochemistry (39%). Of those tested for TTMV-HPV DNA pretreatment, 85% had a positive result. TTMV-HPV DNA clearance during or within three months post-treatment was associated with significantly better recurrence-free survival. The per-patient surveillance sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 82.8%, 98.4%, 96.0%, and 92.5%. Of 24 patients with a documented recurrence and a positive TTMV-HPV DNA test, the test was the first evidence of recurrence in 14 patients (58.3%), with a median lead time of 59 days (range: 10-536). TTMV-HPV DNA accurately resolved 94.3% of cases with indeterminate clinical findings. TTMV-HPV DNA testing provides a sensitive and specific approach for detecting patients with recurrent ASCC and resolving the status of patients with indeterminate clinical findings.