Sen. John McCain has been diagnosed with the aggressive brain cancer glioblastoma, his office said on Wednesday. McCain had undergone surgery to remove a blood clot above his left eye last week, and a subsequent pathology report of that tissue found that it was cancerous.

“The Senator and his family are reviewing further treatment options with his Mayo Clinic care team,” his office said in a written statement.

Here are five things to know about glioblastoma and McCain’s future health.

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What is glioblastoma?

Glioblastoma is the most common form of brain cancer, making up 16 percent of all brain malignancies. It is rare, striking some 3 people out of 100,000 in the U.S. (there will be an estimated 13,000 new cases this year), more men than women, and more whites than people of other races. The only known cause is ionizing radiation including that received for another tumor (McCain is not known to have had such therapy), though some studies have suggested an increased risk from some pesticides and petroleum products. Glioblastoma is also very aggressive, so much so that surgery almost never produces a cure; by the time it is diagnosed glioblastoma has almost always spread to multiple regions of the brain that cannot be reached through surgery. Virtually unique among cancers, however, glioblastomas do not spread to organs beyond the brain such as the lungs or bones, for reasons scientists do not understand.

Is it related to McCain’s previous cancers?

McCain has had multiple cases of melanoma, a skin cancer, that have been removed surgically according to health records he made public during his 2008 presidential bid. However McCain’s glioblastoma is a primary tumor, doctors said in the note issued by his office, meaning that it arose independently of those previous bouts of cancer.

What treatments come next?

According to the note from McCain’s physicians, “treatment options may include a combination of chemotherapy and radiation.” But it’s not clear yet what the timetable is for those treatments. For now, McCain is home in Arizona. “Further consultations with Senator McCain’s Mayo Clinic care team will indicate when he will return to the United States Senate,” his office said in a statement.

What’s the prognosis?

Not good. After undergoing surgery, radiation, and chemotherapy, some 70 percent of patients suffer further spread of their glioblastoma along with such serious side effects as cognitive decline and strokes. In a statement, McCain’s physicians said that “the tissue of concern was completely resected by imaging criteria,” meaning that when they performed the procedure to remove a blood clot above his left eye last week they got everything that was visible. Unfortunately, “micro-metastases” — just a few malignant cells that spread from the initial tumor — cannot be seen on CT or MRI scans, and “surgery alone is never curative for this disease,” said Dr. David Reardon, head of neuro-oncology at Boston’s Dana-Farber Cancer Institute. Barely 5 percent of patients with glioblastoma are alive after five years, and only half make it past 15 months. Reardon cared for Sen. Edward Kennedy of Massachusetts, who was diagnosed with glioblastoma in May 2008 and died in August 2009.

Are there any experimental treatments on the horizon?

Yes: some 157 clinical trials in the U.S. are testing experimental treatments on adults with glioblastoma. In one promising approach, scientists at Dana-Farber are creating personalized cancer vaccines that target the specific molecules on a single patient’s tumor; the vaccine triggers the immune system to attack those molecules, and hence the tumor, an approach that produced encouraging results when it was recently tried in melanoma.

Personalized cancer vaccines rally the immune system to identify and kill cancerous cells based on genetic information from the patient's own tumors. Alex Hogan, Hyacinth Empinado/STAT

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  • Melanoma can be tricky to deal with. Usually they’re filled with Melanin and are black appearing . They can lose their black color. Usually special stains and electron microscopy can still make a diagnosis. When they are anaplastic they can mimic almost any other tumor. Who reviewed the path and were special stains done both for melanoma and for gbm? Was any tumor saved for a vaccine?

  • The wife of my pastor in Montana died of this a couple of years ago, she was in her early 50s. She survived two years, but a friend’s husband lived only five months.

  • I am politically the total opposite of Senator McCain! If he was elected President when he ran, I truly believe he would have been a great president. Senator McCain is in my prayers and I hope he can beat this thing! The odds are against him, but they have been against him before. He is a survivor! I wish him the best of luck and a speedy recovery! If anyone can beat it, he definitely can do it!

  • Sad to learn of this hero’s diagnosis. Fortunately, Senator McCain is not at risk of having his access to medical care revoked by the Senate.

  • Joanna, While I know nothing of the substance that Dr. Lerman describes, I seriously doubt that, with an MD and PhD, he is confused by the two medical conditions. Further, he does not state that eye drops containing dorzolamide are a “cure” (your word) but rather a preventative for glioblastoma. Do you understand the distinction?

    • To Sue Fraser Frankewicz: They must have seen a tumor in the lob of the brain.
      May I have your email, please

  • Many people reading the article will be confused to see glioblastoma described as “most common form of brain cancer” and also “rare”. Part of the confusion comes from the author giving the statistic that the tumor strikes “3 people out of 100,000 in the U.S. “. Actually, it strikes 3 people out of 100,000 in the U.S. PER YEAR, meaning that about 220 out of every 100,000 people get and die of this tumor in their lifetime, i.e., half a percent of the entire population. Most people knew someone who died of glioblastoma, and many are aware of public figures such as Senator Kennedy who did as well. There are various definitions of rare, and the only reason glioblastoma meets some definitions of rare (but not others) is that people die of it so quickly.

    • Correction: 220 out of every 100,000 people works out to 0.2% of the entire population

  • As a lay outsider with personal knowledge of the course of one instance of glioblastoma 25 years ago, my observations:
    1. The discovery inquiry, screening for it is as primitive as then. The symptom then was a recurring infrequent intense headache. McCain’s prior symptoms are unreported, but his inability to cognate well was blatant at the recent public hearings 30 days ago. Nobody was questioning if the symptoms could be this cancer. In the earlier case, the neurologist who used the available technology claimed to have seen nothing on a scan taken during the period of first reported headache episodes.
    Apparently, there is no assessment plan to look for the early signs, nor to scan the brain to read the early stage of this cancer.
    2. Missing here is a description of the stages of impairment due to the cancer’s growth.
    Personal comment. There is no explanation of why the blood clot existed, why there was and maybe will be bleeding present

    • Cancers in general are associated with tendency to cause blood clots. Sometimes, a cancer’s first symptoms is spontaneous blood clots.

  • Cancer prevention with eye drops containing dorzolamide
    Michael Lerman, Ph.D., M.D.
    Cancer causing Genes Expert,
    Laboratory of Immunobilogy, NCI, USA, 1980-2008,
    Board Member, Affina Biotechnologies, Inc., USA, present
    Email: lermanmi@gmail.com

    Cancer cells cannot exist without trans-membrane carbonic anhydrases, which regulate pH inside and around the cancer cells. For that reason inhibitors of CA9, CA12, and CA14 inhibit and prevent cancer growth. Late professor Thomas Marren, developed soluble preparation of sulfonamide/dorzolamide to treat and control glaucoma. I discovered that these inhibitors totally suppress these enzymes and inhibit cancer cell growth. Daily intake of this drug (1-2 drops in the eye or nose) is safe and would prevent/cure cancer. This is effective, not expensive and already approved by the FDA for topical application in the eye to treat and manage glaucoma.

    Daily intake of this drug (1-2 drops in the eye or nose) is safe and would prevent/cure cancer.

    • Michael Lerman, glaucoma (a disease of the eye) and glioblastoma are two completely different diseases ! Please stop giving false hopes to people diagnosed with glioblastoma and their families. There is currently no known cure for glioblastoma.

    • Joanna, While I know nothing of the substance that Dr. Lerman describes, I seriously doubt that, with an MD and PhD, he is confused by the two medical conditions. Further, he does not state that eye drops containing dorzolamide are a “cure” (your word) but rather a preventative for glioblastoma. Do you understand the distinction?

    • Michael Lerman,
      You appear to be totally confused. Glaucoma is not the same as glioblastoma, and stating that a ‘cure’ for the former is also a cure for the latter is completely irresponsible.

      Also, please show me peer reviewed papers, outside of a small number using mouse models, where dorzolamide has been shown to, in your own words ‘prevent/cure cancer’?

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