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Liquid biopsy promising for diagnosing HPV-associated head-neck cancer

Clinical Cancer Research
Reuters Health - 09/12/2021 - Liquid biopsy was more accurate, faster, and less costly than a standard clinical workup for diagnosing HPV-associated head and neck squamous cell carcinoma (HPV+HNSCC) in a proof-of-concept study.

"Current diagnostic approaches for these cancers are invasive, and have high costs and variable sensitivity," Dr. Daniel Faden of Mass Eye and Ear in Boston told Reuters Health by email. "We hypothesized that combining an ultra-sensitive HPV DNA liquid biopsy with a standard physical exam and cross-sectional imaging findings would not only provide enough information to make the diagnosis of HPV-associated head and neck cancer, but also be more accurate, faster and less expensive."

As reported in Clinical Cancer Research, Dr. Faden and colleagues enrolled 70 patients with a new or suspected diagnosis of untreated oropharyngeal squamous cell carcinoma (OPSCC), nasopharyngeal carcinoma (NPC) or sinonasal squamous cell carcinoma (SNSCC) and 70 controls. The mean age in the HPV+HNSCC group was 62 and 52% were men; the mean age in the control group was 54 and 32% were men.

Blood was collected, processed for circulating tumor HPV DNA (ctHPVDNA), and analyzed with custom assays for HPV genotypes 16,18, 33, 35 and 45.

The sensitivity of ctHPVDNA for detecting HPV+HNSCC was 98.4% and specificity, 98.6%. Sensitivity and specificity of a composite non-invasive diagnostic using ctHPVDNA plus imaging/physical exam were 95.1% and 98.6%, respectively.

The diagnostic accuracy of the non-invasive approach was significantly higher than standard of care, according to the Youden index (0.937 vs. 0.707). Further, costs were 36%-38% less than a standard clinical work up, and the median diagnostic interval was 26 days less.

Regarding the diagnostic interval, Dr. Faden explained, "This measure takes into account a number of factors including the time it takes to be referred to and receive an appointment with a specialist; time for scheduling a tissue biopsy; time for review of the biopsy by a pathologist, etc."

"Additionally, the diagnosis of HPV+HNSCC can be challenging to confirm with the most common approach, a needle biopsy, meaning a repeat biopsy is often necessary," he said. "In this study, 28% of patients had to undergo repeat biopsy."

"Using a liquid biopsy could shorten the diagnostic interval by cutting out some of these steps," he noted. For example, a simple blood draw could be ordered by any provider, with no need to schedule a tissue biopsy. That alone resulted in a decrease in cost of at least $6,000, according to the study authors.

"Additionally," Dr. Faden said, "since the liquid biopsy was found to be highly accurate, the need for repeat testing would also be reduced. We found the time (from first presentation) to diagnosis was shortened to 15 days, which is a 63% decrease."

Dr. Adam Jacobson, Director of the Division of Head and Neck Surgery in the Department of Otolaryngology-Head and Neck Surgery at NYU Langone Health in New York City commented in a email to Reuters Health, "This is a very promising approach that would potentially provide our patients with a more sensitive and specific test paradigm that is non-invasive and faster than the traditional gold standard of a tissue diagnosis, which requires sophisticated pathological tests that are time consuming and expensive."

"Additionally," he said, "it would potentially negate the need for an invasive procedure (beyond a blood test) in order to make an accurate timely diagnosis."

Nonetheless, he added, "This study needs to be replicated at other institutions to determine if the high sensitivity and specificity of this approach is replicable."

SOURCE: https://bit.ly/31GWhRv Clinical Cancer Research, online December 2, 2021.

By Marilynn Larkin

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