In the United States, approximately 70% of oropharyngeal cancers (in the base of the tongue and throat) are caused by human papillomavirus (HPV), which can also cause cervical cancer. However, unlike the latter, there are no screening programmes for HPV-associated neoplasia in the “oropharyngeal area”. Consequently, diagnosis often comes too late, when a tumour has grown to a substantial size and spread to the lymph nodes.
In such circumstances, nearly all patients have to go through invasive procedures that can have significant side effects.
Now, a new study published in the Journal of the National Cancer Institute has opened up ground-breaking possibilities. Researchers from Mass General Brigham (an integrated health system in the Boston area) have developed an innovative blood test called HPV-DeepSeek, which can identify traces of cancer up to 10 years before symptoms appear. The system involves a liquid biopsy: instead of extracting tissues, oncologists analyse blood samples and search for tiny fragments of HPV DNA that have broken off from a tumour. As one might imagine, it is extremely difficult to pick out microscopic pieces of HPV genetic code among the thousands of billions of cells circulating in the blood. However, the researchers have shown that it can be done, using highly sophisticated techniques.
"Our study shows for the first time that we can accurately detect HPV-associated cancers in asymptomatic individuals many years before they are ever diagnosed with cancer,” states Daniel L. Faden, head and neck surgeon and lead study author. “We hope [...] to catch these cancers at their very earliest stages, which ultimately can improve patient outcomes and quality of life.”
Human papillomavirus is extremely widespread. It is primarily transmitted through sexual contact, not only between genitals but also in the form of oral sex, following contact with infected mucous membranes and skin. It is not spread through bodily fluids.
It is estimated that 85-90% of sexually active people will contract an HPV infection at least once in their lives, but in the vast majority of cases the body’s immune system will clear the virus. Only certain particularly aggressive strains might remain inside cells. Over time, a very small percentage of these will transform the cells, eventually leading to a precancerous condition, and then cancer.
All of this means that early diagnosis is crucial. This is made possible for cervical cancer thanks to Pap tests and HPV tests on cells collected from the cervix using special spatulas, ensuring that appropriate treatment can be provided when the situation is still under control. In developed countries, mass screening has paved the way to a huge reduction in uterine cancer. However, as mentioned above, this approach cannot be used for the oropharynx.
The US researchers tested the efficacy of HPV-DeepSeek by analysing 56 blood samples from the Mass General Brigham Biobank: 28 came from individuals who developed “HPV-associated head and neck cancer” (as it is known in the field) years later, and 28 came from healthy controls. The test detected HPV tumour DNA in 22 patients who later developed cancer, while all 28 control samples tested negative, thus confirming that the test is highly specific.
The researchers did not stop there. Applying AI models to an additional group of more than 300 cancer cases and control samples (from other hospitals), they enhanced the test and increased its sensitivity to 96%. This enabled HPV-DeepSeek to identify 27 out of 28 cancer cases, including samples collected more than 10 years earlier.
Of course, there is also another tool that has shown it has an extremely important part to play in preventing HPV infection: vaccination against the virus, which is recommended for both girls and boys, especially if it is done before they become sexually active.