When Dr. Santos Shetty heard Sen. Edward Kennedy suffered a seizure over the weekend, his first thought was "I wonder if he has a brain tumor?"

Shetty's suspicions were confirmed Tuesday when Kennedy's doctors at Massachusetts General Hospital in Boston said he had a malignant glioma in the left parietal lobe, a part of the brain that helps govern sensation, movement and language.

The 76-year-old senator and sole surviving son of America's most storied political family suffered the seizure at the family compound in Hyannisport on Saturday.

Kennedy was with family at the hospital Tuesday as the diagnosis was announced.

"Obviously, it's tough news for any son to hear," said Robin Costello, a spokeswoman for one of Kennedy's sons, Rep. Patrick Kennedy, D-R.I. "He's comforted by the fact that his dad is such a fighter, and if anyone can get through something as challenging as this, it would be his father."

At Caritas Holy Family Hospital in Methuen, doctors treat approximately 30 similar brain tumors per year, said Shetty, the medical director of radiation oncology at the hospital.

"The best result we see is when a surgeon can actually go in and remove the tumor," Shetty said.

Major advances in drugs, technology and treatment have radically improved in recent years. Brain tumors can also be treated with stereotactic radiosurgery — a special radiation beam that "very precisely" administers a high dose of radiation to the tumor, Shetty said.