Salivary salvation

A simple swish-and-spit test could soon lead to early detection of head and neck cancer, and boost survival rates

January 17, 2008|By Dennis O'Brien | Dennis O'Brien,Sun Reporter

Joe Moffett wishes the spit test was available four years ago, before the tumor near the base of his tongue put him through months of radiation treatments, chemotherapy and surgery -- plus the hassle of taking nourishment through a feeding tube inserted at Johns Hopkins Hospital.

"Having a test out there, I could have avoided a whole lot. But still, I thank the good Lord I'm alive, and I'm excited about this test. It could help a lot of people," said Moffett, 69, a retired Army pilot from Dillon, S.C.

Researchers at Hopkins published findings this month showing they are close to developing a mouth rinse that can detect head and neck cancer such as Moffett's.

The approach is based on a premise -- gaining wide recognition among medical researchers -- that much of our biological profile is contained in our saliva.

"When you swish and spit, you shed an enormous amount of DNA," said Dr. Joseph A. Califano, the head and neck surgeon developing the saliva test at Hopkins' Kimmel Cancer Center.

Califano has been trying to design a DNA-based saliva test for head and neck cancer for at least five years. At stake, he says, is earlier detection for the seventh-most-common cancer in the United States.

An estimated 45,000 people are diagnosed with head and neck cancer each year, and 12,000 die from it annually, according to the American Cancer Society.

Head and neck cancer usually begins in the moist tissues that line the mouth, nose and throat, and includes cancers that afflict the mouth, nose, sinuses, salivary glands, throat and lymph nodes in the neck.

A biopsy will determine if someone has cancer. But patients often don't consult a physician until it's too late because the symptoms -- a lump on the neck, a hoarse voice, a sore neck or a persistent sore throat -- can often be attributed to other ailments.

"It's a silent cancer. It can be in an area you can't see, so we should be looking for other approaches to diagnose it," said Dr. Len Lichtenfeld, deputy medical officer of the American Cancer Society.

Moffett's only symptom was an inch-long lump, spotted by his wife, on the left side of his neck. "My wife touched my throat and said, `You have a knot there,'" he recalled.

Early detection can save 90 percent of those diagnosed, but the survival rate in cases of a late-stage diagnosis slips to 30 percent, experts say.

"Sometimes, we don't detect it until the symptoms have progressed pretty far, and by then it's just too late," Califano said.

In the study, Califano asked volunteers to brush the insides of their mouths, then rinse and gargle with a salt solution. Researchers filtered cells from the rinsed saliva to look for any of 21 bits of chemically altered genes associated with head and neck cancer. The test was given to 211 people with head and neck cancer and 527 healthy volunteers.

The study, published Jan. 1 in Clinical Cancer Research, was funded by the National Cancer Institute and the National Institute of Dental and Craniofacial Research. The work is an important step toward cutting cancer deaths, experts say.

"The science is interesting; it certainly is cutting edge, and we think this is where the future of cancer testing is going to be," Lichtenfeld said.

Scientists elsewhere are developing saliva tests to detect HIV, Alzheimer's disease, rheumatoid arthritis, osteoporosis, Type II diabetes and other cancers.

"It's the future of cancer diagnosis," said Dr. Feng Jiang, an assistant professor of pathology at the University of Maryland School of Medicine developing a lung cancer test from sputum.

In the study, researchers were able to identify more than half the people with cancer. But since the report was published, Califano said, he has pinpointed alterations in three additional genes that will make it possible to detect head and neck cancer in up to 90 percent of cases.

No test is 100 percent accurate, but Califano is designing a kit for doctor's offices to screen high-risk patients. He anticipates that it will be available in a few years.

"If these markers work as well as I think they will, we'll have a product out there relatively quickly," he said.

Those at high risk are people older than 50 who are heavy drinkers and smokers, as well as people with a previous history of head and neck cancer.

Moffett hadn't smoked for decades and had no family history of cancer. He suspects his cancer was linked to exposure to Agent Orange in Vietnam.

Researchers determined in 2003 that some 21 million gallons of the Agent Orange defoliant were sprayed in Vietnam between 1961 to 1971. Named for the color of the identification band on its containers, the defoliant was made with toxic compounds that have been linked to cancers, neurological disorders, miscarriages and birth defects.

Moffett, a father of two and a grandfather of two, cannot be sure that exposure to Agent Orange caused his cancer, but several members of his aviation unit have also developed various cancers.

But he is glad to be alive. When he was initially diagnosed with cancer four years ago, he was given a 50 percent chance of survival, he said. He is now cancer-free.

"I have no symptoms at all of cancer. It's marvelous. I thank the good Lord for all the prayers I received," he said.

dennis.obrien@baltsun.com

Did you know?

Each of us produces about 3 pints of saliva a day.

In addition to doctors trying to use the liquid to detect cancer, saliva is vital to digestion and dental hygiene.

Without saliva, swallowing would be nearly impossible, and we wouldn't be able to taste our food.

Eating and kissing stimulate the salivary glands.

Foods with high amounts of salt and sugar are linked to the production of higher levels of saliva.

Standing or lying creates more saliva than sitting.

[[Sources: Encyclopedia Britannica,Kidshealth.org, American DentalAssociation]]

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