For some, however, the diagnosis was painfully familiar. WebMD talked to three survivors of brain cancer similar to that affecting the senator, including two who have survived it for more than 10 years. Their advice to Kennedy: Don't listen to statistics, and don't give up hope.
Here are their stories:
Jim Owens, 46, Minneapolis, vice president of an engineering and construction firm for air conditioning and heating. Diagnosed originally with oligodendroglioma of the right parietal lobe in 1998; five recurrences since then, with diagnosis revised to a mixed or malignant glioma.
A long-time athlete, Jim says his love of sports, as well as his love for his wife and young son, now 8, keeps him fighting.
The first symptom came out of the blue. "I was training for a marathon and had a seizure at the end of a workout," he says of that day in 1998, right before the tumor was found. "I had no idea what it was. Half my body went numb."
Thankfully, friends who were with him insisted he go to the hospital immediately, despite his protests that he was fine and it was nothing. After a battery of tests, Jim was told nothing that night. "It wasn't until early the next afternoon the doctor said, 'It's bad. You have a brain tumor.'"
He was taken into surgery, but then there was more bad news: "The tumor was wrapped around the motor strip," says Jim, referring to the band running down the lobe of the brain that controls bodily movements.
So they presented the next options: radiation and chemotherapy.The tumor began shrinking, and Jim kept fighting. He got married. A year after the diagnosis, he competed in the Ely Wilderness Trek, a 15-kilometer cross-country ski race. "I finished, but it wasn't pretty," he says, laughing.
He and his wife, Barb, welcomed a son, Max, in August 1999.
Jim has had multiple recurrences, beginning in January 2003, fighting each time by seeking out multiple opinions, agreeing to join a clinical trial, and taking drugs approved for other cancers that might help his."Every time I would have a recurrence, it would take a couple days to get myself standing up straight again," he says.
He found renewed resolve each time."The cancer is not going to run my life. I am going to reclaim my life and live my life."
"I'm having the best spring I've had in years," he says. With his brother, he is training for the Ride for Roses in Austin in October, an event sponsored by the Lance Armstrong Foundation. In 2004, he rode with Armstrong, a cancer survivor, on a coast-to-coast benefit bike tour.
To help others, he blogs and posts info on his own web site, Jim's Journey.
This spring is especially sweet because of his latest MRI results, Jim says. "I've had two MRIs in a row and we have heard the word 'reduction,'" he says, meaning the tumor is shrinking again. "We haven't heard that word since 2003. I'm so thrilled and so happy."
To Kennedy, he would say: "Have hope. You are going to have a lot of statistics thrown at you. Don't listen to the worst-case scenario. Look at all your options, including new drugs. The biggest thing is to really have hope."
Maria Hartmann, 59, Miami, Fla. Diagnosed in 1998 with malignant glioma.
"I was at my house, with my mother-in-law, and the World Series was on. My husband was at the game."
The seizure hit."I was convinced I was epileptic," Maria says. The battery of tests run on her once she was rushed to the hospital suggested otherwise. The doctor told her she had a glioblastoma.
The surgeon at the University of Miami removed what he could and inserted a thin wafer to deliver chemotherapy.
"After that came conventional chemo and radiation twice a day," Maria says. "I was 49."
"I told myself, either I live or I die. I knew I was not going to die. I had a lot of faith. I am very strong. I said, 'I am not going to let this get me.'"
Part of that strength, she says, comes from her immigrant parents. "I was born in Cuba, and I came with my parents as a political refugee. It took a lot of guts for my family to leave everything and come here. I say, for my sister and myself, that was our first lesson in courage. My parents were very strong; I never heard any complaints in our house. They gave us strength."
At the same time as she was fighting her brain cancer, her brother-in-law was fighting stomach cancer. "My sister kept saying, 'I cannot lose my sister and my husband at the same time.' My surgery was in January 1998. I went with him to all his chemo and radiation. He died in May 1998."
When Maria's 25th wedding anniversary came around, she was still in chemo. She told her husband where she wanted to go -- Lourdes, a Christian pilgrimage destination. Her son, now 30,and daughter, now 28, went along.
"It's a place of inspiration," she says. "Everyone is looking for a cure.The waters are cold. There is nothing in the water, it is just our faith. There is a big tank of water where you submerge. I couldn't go in beyond my knees. '''
"I only wanted strength -- strength to endure whatever I had to endure."She has had good news. "It's been five years or more that the MRI came back with no change."
"I would tell Sen. Kennedy not to give up. I wrote him a note, [advising him] not to listen to statistics. Because many things can happen."
"I believe my recovery is a miracle."
Sara Bennett, 60, office supply store employee, Elyria, Ohio. Diagnosed May 7 with left temporal lobe glioblastoma.
In her work for a large chain office supply store, Sara shows customers how the machines work. "I never had any problem when a customer was coming in to make a purchase. I could tell them anything about the product."
Suddenly, that changed. "I'd be explaining a printer to a customer and halfway through the conversation, I'd lose my thought, I couldn't explain it."
Beginning in March 2008, she began to notice daily headaches, not typical for her.
By early May, she took a week off and got herself a thorough physical, a CT scan, and an MRI.
Her doctor then sent her to the Cleveland Clinic, where she got the bad news.
She underwent surgery in early May, and then during a checkup in the doctor's office had seizures. Looking back, she realizes she had suffered seizures while working at the computer.
Soon, she will start radiation and chemo.
A widow who lost her husband in 1999 and has eight grown children, she is still in good spirits."I don't get down, I don't let myself get down. It's like I have an inner peace. The doctors and everyone I have talked to have been very honest. They have explained things 100 percent."
Her religious faith helps keep her calm, she says. What also helps? She is convinced that "my husband has been watching out for me. That may sound strange to some people."
But she believes it is true.
Kennedy's strength -- some of it, unfortunately, from dealing with so many family tragedies -- will keep him going, Sara says. "He seems to have a very good outlook."