Milwaukee ? Patients with advanced head and neck cancers do better if chemotherapy is added to the radiation and surgery that is standard treatment now, two new studies suggest.

But the benefit comes at a cost — 2 percent of patients in one study died from the treatment, and one in four had serious side effects.

Still, these are landmark findings that should change the standard of care for people with such tumors, which have a high rate of recurrence and kill more than half of those they afflict within five years, said Bruce Campbell, a Milwaukee doctor who helped conduct one of the studies.

“If we can nurse people through treatment, we hope they’ll have a better response to therapy,” said Campbell, interim director of the cancer center at Froedtert Memorial Lutheran Hospital and the Medical College of Wisconsin.

The research is reported today in the New England Journal of Medicine.

Head and neck cancers include tumors of the tongue, mouth, nose and throat. They are the sixth most common type of cancer worldwide. About 37,000 cases are diagnosed in the United States each year, not including brain tumors or esophageal cancer, which are different types of cancer.

The new research involves advanced squamous cell tumors, which originate in cells lining structures in the head and neck and often spread to nearby lymph nodes. Smoking and other tobacco use accounts for 85 percent of cases, according to the National Cancer Institute.

They’re a particularly difficult cancer to control — 30 percent recur despite treatment, which is usually surgery followed by radiation. Some small studies have hinted that giving chemotherapy along with radiation might help. The new studies are the largest and most rigorous ones to test that approach.