Human papillomavirus (HPV), the most common sexually transmitted infection (STI) in the United States, can lead to serious health complications, most notably oropharyngeal cancers or cancers that form in the back of the throat. Johns Hopkins researchers have developed tests that can accurately predict recurrences of oral cancers among HPV patients using DNA fragments from blood and saliva.

"There is a window of opportunity in the year after initial therapy to take an aggressive approach to spotting recurrences and intensively addressing them while they are still highly treatable," Dr. Joseph Califano, professor of Otolaryngology - Head and Neck Surgery, member of the Johns Hopkins Kimmel Cancer Center said in a statement. "Until now, there has been no reliable biological way to identify which patients are at higher risk for recurrence, so these tests should greatly help do so."

Califano and his colleagues gathered blood and saliva samples from 93 oropharyngeal cancer patients who had previously undergone treatment in the form of surgery, radiation by itself, or a combination of radiation and chemotherapy. Blood and saliva samples were extracted before and after treatment was performed at the Johns Hopkins Hospital or Greater Baltimore Medical Center. DNA was amplified and measured from blood and saliva samples, using polymerase chain reaction.

Results of polymerase chain reaction tests revealed that DNA extracted from saliva was able to predict recurrences of oral cancer in HPV patients 20 percent of the time. DNA taken from the blood of HPV patients was able to predict recurrences of oral cancer 55 percent of the time. By combining DNA from the blood and saliva of HPV patients, researchers were able to predict recurrences of oral cancer 70 percent of the time. Screening for HPV DNA fragments showed cancer cells in the mouth and neck area.

HPV patients suffering from oropharyngeal cancer are examined every one to three months after their diagnosis to check for recurrences in the form of ulcers, lumps, or pain in the neck. Imaging tests used to spot lesions that could point to a recurrence are generally unreliable due to their placement in the patient’s tonsils, throat, and base of the tongue. As the rates of HPV-related oral cancer diagnoses continue to rise in the U.S., blood and saliva screening may become a valuable tool for physicians.

Out of an estimated 30,000 oropharyngeal cancer cases in the U.S. each year, around 70 percent are attributed to HPV. HPV-related oral cancer survival rates within the first two years of diagnosis can be as high as 90 percent. However, survival rates within the two years after a recurrence has been spotted can drop to around 50 percent. The research team from Johns Hopkins said DNA test screening from blood and saliva samples could drastically improve these figures.

Source: Ahn S, Chan J, Califano J, et al. JAMA Otolaryngology – Head & Neck Surgery. 2014.