(RxWiki News) Cancer can seem unpredictable, but a new study suggests that simple tests may help predict when one type of cancer will come back.
The study focused on patients with cancers of the back of the throat, often tied to the human papillomavirus (HPV).
The study found that patients whose blood or saliva tests showed evidence of HPV DNA after treatment were more likely to have their cancer return.
"Seek medical advice if you develop a non-healing sore in your mouth."
Some forms of HPV, specifically a type called HPV-16, can lead to certain forms of cancer, called oropharyngeal cancers. This can include cancers in the back of the throat, tongue and tonsils, explained the Centers for Disease Control and Prevention (CDC).
According to the CDC, no FDA-approved test will confirm oral HPV, and most people discover oropharyngeal cancer after symptoms like sore throat, enlarged lymph nodes, ear aches or pain when swallowing develop.
The study was conducted by Joseph A. Califano, MD, of the Department of Otolaryngology at Johns Hopkins Medical Institutions in Baltimore, MD, and colleagues.
The study authors wanted to see whether it was possible to test for HPV-16 in the plasma (blood) or saliva of oropharyngeal cancer patients as a way to also detect the cancer's development or return.
To do so, Dr. Califano and team focused on 93 oropharyngeal cancer patients who had undergone treatment. The patients were all drawn from the Johns Hopkins Medical Institutions and Greater Baltimore Medical Center between 1999 and 2010 and followed for an average of 49 months.
The patients' blood and saliva were tested both before and after they received treatment for oropharyngeal cancer, in three-month intervals. The researchers analyzed the samples, looking for evidence of HPV DNA and seeing whether the presence of HPV DNA was associated with different health outcomes in the patients.
Of the 93 patients, 81 were determined to have tumors that were tied to HPV-16. A total of 19 patients (20 percent) had cancer recur after treatment. This was the case in 14 HPV-16 patients and five of the non-HPV-16 patients.
After analyzing the data, Dr. Califano and team found that patients whose saliva or blood samples contained HPV DNA after treatment had an increased risk of cancer recurrence.
The researchers noted that finding HPV DNA in patients' saliva after treatment helped predict cancer recurrence in 18.8 percent of cases; finding HPV in patients' blood after treatment predicted cancer recurrence in 55.1 percent of cases; and finding HPV DNA in both the blood and saliva after treatment predicted cancer recurrence in 69.5 percent of cases.
An average of 4.4 months passed between when HPV-16 DNA was found in a patient's blood or saliva sample and when the tumor recurrence was detected in their normal care.
“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," Dr. Califano said in a press release.
The study explored a fairly small sample size of patients, and there were few instances of cancer recurrence. Further research involving more participants is needed to confirm these findings, the study authors noted.
The study was published online July 31 in JAMA Otolaryngology – Head & Neck Surgery. The study was also presented at the American Society of Head & Neck Surgery Otolaryngology 2013 Annual Meeting in April 2013. The study authors reported no conflicts of interest.