Understanding Sen. Kennedy's Cancer Diagnosis

25 may 2008-- Massachusetts Sen. Edward Kennedy was diagnosed with a malignant brain tumor Tuesday after a related seizure sent him to the hospital over the weekend.
The 76-year-old senator was transported to Massachusetts General Hospital in Boston following the incident at his Cape Cod home. In a statement released by the Kennedy family, the seizure was attributed to a malignant glioma, a type of brain cancer.
Dr. Andrew Norden of the Dana-Farber Cancer Institute in Boston spoke with Michele Norris about possible treatments and the prognosis in Sen. Kennedy's situation.
What is a glioma?
It's a primary brain tumor, meaning it starts in the brain. It's not the kind of brain cancer that's spread by metastasis from another organ. Gliomas are the most common primary brain tumors in adults. When they are malignant, they can be quite difficult to treat. We see about 10,000 to 15,000 of them newly diagnosed in the U.S. each year.
What are the treatment options?
It's difficult to say for sure which treatment would be recommended for the senator because there are a number of different types of malignant gliomas and we don't yet know which type he has. But in general, the treatment consists of radiation and chemotherapy, given together for six weeks. Then there is a brief treatment break, followed by chemotherapy alone, in monthly cycles for six to 12 months.
The chemotherapy usually used for gliomas is an oral chemotherapy called temozolomide. It's well-tolerated by most patients.
Would there be an effort to remove it by surgery?
Yes, I think so. Typically, treatment for this type of tumor begins with maximal surgical resection. What that means is that a surgeon tries to take out as much of the tumor as can be safely done without causing the patient any harm. We don't know what kind of surgery the senator has had, but I imagine an attempt at a surgical resection was undertaken.
Would age be a factor, since the senator is 76?
Age is a factor. We know that on average older patients — which means over 80 in this population — don't have as favorable of outcomes as younger patients do. That said, there are older patients who do quite well, particularly healthy ones. And my understanding of the senator's current medical condition is that it's quite good, so I would expect him to do better than average.
Has the senator already undergone surgery?
He has. We know that he has had a biopsy according to the press release. It's difficult to know what is meant by the term biopsy in this situation, but every biopsy involves at least taking a piece of tumor to a pathologist to review and determine the type.
The tumor is said to be in the left parietal lobe. What does that tell you about prognosis and function, since this lobe controls sensory comprehension and visual control?
In general, the left parietal lobe is thought to be primarily important for sensory function on the right side of the body and also for visual sensation on the right. Because the parietal lobe is rather large and because every individual has somewhat different brain anatomy, it's very difficult to say in any individual case exactly what might be affected.
It's certainly possible to have a tumor in that location that causes no symptoms whatsoever; it's possible to have a tumor in that location that causes only occasional seizures, which might be managed with medication; or it's possible to have a tumor in that location that causes very significant numbness of the right side of the body and perhaps some difficulty seeing off to the right side. So without examining an individual patient it's difficult to determine, but those are the spectrum of things one might see.
What about speech?
In general, with a tumor in the parietal lobe, one would not expect significant speech difficulties. The speech centers are generally thought to be in the bottom portion of the frontal lobe and the top portion of the temporal lobe. One troubling problem with brain tumors, though, is they tend to have a fair amount of surrounding swelling.
So if this tumor in the left parietal lobe has some swelling involving speech areas, either in the frontal or temporal lobes, then it's possible to have difficulty either with expressive speech — finding words or simply getting fluent sentences out — or to have difficulty understanding speech, either spoken or written. But, again, one would need to examine an individual to determine if those deficits are present, and it's possible one would have no symptoms at all.
Because of high blood flow to the brain, is there worry that the tumor might be fast growing?
In general when one speaks of a malignant glioma, which is what they're calling Sen. Kennedy's tumor, we're talking of a tumor that is fast growing. Gliomas are graded on a scale of 1 to 4 by the World Health Organization, and grades 3 and 4 are also called malignant gliomas. That doesn't mean that they spread, but that they have the potential to grow quickly.
The most common gliomas are grade 4 tumors, which are called glioblastomas. But until we have a final pathology report, I don't think we'll know if that's the diagnosis.
The Kennedy family has reported that Sen. Kennedy has had no further seizures, is in good overall condition, and is up and walking around. What does that tell you?
That's a good sign. It indicates he hasn't had any serious consequences of the surgery. It also indicates that any swelling around this tumor is in reasonably good control. I suspect he's on medication to control swelling and also on medication to prevent further seizures. The fact that he's able to be up and about, watching television, which I understand he did over the weekend, indicates that he has made a good recovery, and I suspect he may be ready to leave the hospital in the next few days.