A few weeks ago, John McCain seemed to be having a bit of word-finding problems (dysnomia) and was a bit confused as evidenced on some broadcast senate hearings. 3 days ago he underwent surgery for a blood clot (hematoma) in the left frontal lobe. At age 80, this isn't so surprising, as due to brain shrinkage (atrophy) blood clots can often form after minor trauma. Most clots are benign, in the sense that they are unassociated by other brain abnormalities. But in this case, McCain wasn't so lucky. He underwent a sub frontal (inferior to eyebrow) craniotomy for an 5 cm diameter blood clot. 5 cm is the size of a golf ball. The clot was located in the left frontal lobe, actually the part called pre-frontal lobe. This is the last cerebral area to mature, often not fully developed until age 25. The pre-frontal lobes are important in executive functioning (decision making), self-monitoring, especially in social situations. Emotional constraint is also a critical part of prefrontal function. Typically the left pre-frontal lobe is the more "analytical" portion relative to the right pre-frontal lobe but both are important regulators of cognitive, emotional, and social function.

The biopsy, which is routinely performed with any removal of tissue from inside the cranium, revealed glioblastoma. Glioblastoma is one of four grades of intrinsic malignant brain tumors. They are based upon unregulated growth of glial cells. Glial cells outnumber neurons 9:1. They play important roles in neural nutrition, protection, physical support, and very likely non-cognitive functions. Glial cells like neurons require blood supply. The blood vessels accompanied by normal glial cells are, for lack of a better word, normaL

Gliomas are typically divided into four groups, ranging in severity. The divisions are usually based upon tissue morphology (histology) but other factors enter into this. Mixed glioma types are not rare so that portions of the tumor may look more benign or less benign than other parts of the tumor. No matter what the grade of malignancy, ALL gliomas infiltrate surrounding normal tissue. Gliomas can be localized through direct vision or imaging to some extent, but the microscopic spread is impossible to detect with the naked eye, operating microscope and even sophisticated neuroimaging.

The four basic types of glioma, from least malignant to most malignant are:

1. Astrocytoma

2. Anaplastic astrocytoma

3. Glioblastoma

4. Glioblastoma multiforme

The Mayo Hospital derived biopsy report as well as the neuroimaging pre-operatively are so far unavailable to the public. Important considerations are location, size, histologic invasiveness and patient comorbidities.

"Cure" of gliomas is so rare as to be reportable in medical journals. Control is the best that can be hoped for, but control is not cessation of growth. In the usual cases of glioblastoma, the cavity left in the brain from tumor resection can be filled up with new malignant tumor in a surprisingly rapid manner. The faster this occurs, the worse the prognosis.

Typical surgical adjuncts consist of chemotherapy and external radiation. Intracranial radiation may also be used for high local dosing but is generally ineffective for diffuse control. The typical radiation is whole head with/or without stereotactic (highly focused) radiation. Treatment doses can be anywhere from 20 to 30 sessions, usually administered either 5 times a week or every other day, depending upon circumstances.

The acute and subacute results of whole head radiation are not simple. Besides the inevitable hairloss, intense scalp "sunburn" occurs. Taste sensation is lost or severely reduced, at least temporarily. Appetite is markedly curtailed, so weight loss and relative malnutrition occur in the subacute period.

But more importantly in the perspective of John McCain as a sitting United States Senator, his ability to function during the period of radiation will be completely halted. Chemotherapy, deepening upon the agent(s) used may have additional negative aspects.

Despite all the optimism voiced on TV, by all the pols, etc., the prognosis for John McCain returning to work in a productive manner is close to zero. A neurosurgeon from Mayo said on television yesterday that survivals of 5 years or longer have occurred. But such prolonged survivals are almost unheard of for grades 3 and 4 gliomas. Even if McCain survives to his next election, extremely unlikely in my opinion, he will be almost totally, if not totally, ineffective as a legislator--regardless of your opinion of his politics.