Spit Test to Monitor for Oral Cancer

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HPV oral cancer is an increasingly common cancer afflicting heterosexual individuals. The main way of diagnosing is by biopsy after an abnormal finding on oral examination. The main way of determining whether the cancer has come back after treatment is also by regular oral examinations.

However, Johns Hopkins researchers may have developed a "spit" test that can detect whether oral cancer may have recurred after treatment before any visible abnormalities may be visible on exam. Essentially, the test involves discovering whether any DNA of the HPV-16 virus is present in the spit or not. Here's what they found in their study group of 124 patients:

• 54% of patients with HPV oral cancer pre-treatment also had a positive spit test.
• After cancer treatment, only 5% had a positive spit test.
• 100% of patients who had a positive spit test both before AND after cancer treatment developed recurrent cancer within 7 months on average.
• For those who had a negative spit test after treatment, only 8% developed recurrent cancer.

Keep in mind that these results were based on a study population of only 124 patients, so before this testing becomes commercially available, more rigorous study in a much larger population of patients is needed.

** Update 2/2/16: Our office now offers the HPV spit test to see if HPV is present in the mouth/throat.**

This test should help in the monitoring for recurrent cancer after treatment, hopefully at an early and curable stage. Specifically, more frequent and careful monitoring will most likely be required for those patients who had a positive spit test both before and after cancer treatment.

Keep in mind that being HPV positive does NOT equal cancer and that the gold standard of biopsy will STILL be required for diagnosis since although this simple spit test can inform whether cancer MAY be present or not or predict its imminent recurrence, it won't be able to tell WHERE in the mouth the cancer has redeveloped or will develop.

Also HPV negative does not mean cancer is absent or will not happen. HPV positive/negative status is just a risk factor for cancer... just like smoking is a risk factor for cancer.

Keep in mind that this test is only applicable in the diagnosis of ONLY one type of cancer... squamous cell carcinoma... and only if caused by HPV-16 (squamous cell carcinoma can occur in the absence of HPV or due to a different HPV subtype like HPV-18). Please note that there are many other head and neck cancers which this test will not be able to detect such as acinic cell carcinoma, adenocarcinoma, mucoepidermoid carcinoma, neuroendocrine carcinoma, etc.

There is another type of blood/spit test that is also being developed at Johns Hopkins to help diagnose oral cancer whether due to HPV or not (rather than providing prognostic risk information like this test). Read more here.


Reference:
Prognostic Implication of Persistent Human Papillomavirus Type 16 DNA Detection in Oral Rinses for Human Papillomavirus–Related Oropharyngeal Carcinoma. JAMA Oncol. Published online July 30, 2015. doi:10.1001/jamaoncol.2015.2524