This is a devastating diagnosis for the senator and his family, not the blood clot initially described, with a return to the Senate next week to vote on Majority Leader McConnell's latest charade of an ObamaCare repeal. As I weighed in on Senator McCain's recent surgery, I'll do the same based on the breaking news of his diagnosis.

By now, most readers already know that Senator John McCain has been diagnosed with a brain tumor – specifically, a glioblastoma. I take no pleasure is suspecting such a diagnosis, as I wrote a few days ago , based on a bit of medical logic and observation rather than what the media reported.

A glioblastoma is a primary brain tumor. It's malignant, or cancerous. The cause is unknown, but it is more common in the elderly. The tumor doesn't discriminate. Senator Ted Kennedy was diagnosed with this tumor in 2008 and eventually died. My best friend's mother also succumbed to a glioblastoma.

Kennedy suffered a seizure as his presenting sign. Unknown is what led McCain's doctors to suspect a brain tumor. The tumor was in his frontal lobe. Early media reports described "a blood clot above his left eye," which indicates the frontal lobe. This portion of the brain controls higher functions – personality, thoughts, social interactions, all intrinsically human behavior features.

Perhaps his behavior was off, noted by his staff and family, leading to exams and scans, which eventually identified something in his brain. The Washington Post reported his "bizarre questioning" of James Comey last month. Unexpected changes in behavior are a warning sign prompting further investigation.

The prognosis for a glioblastoma is poor, with a median survival of 15 months, the exact survival time for Senator Kennedy. Next for McCain is treatment. There are lots of options. Surgery to debulk the tumor. Chemotherapy. Radiation. Newer treatments such as immunotherapy as well as a host of clinical trials involving novel therapies. Ten percent of patients may live five years or longer.

When I was in medical school, a glioblastoma was described as follows. Imagine a bowl of semi-solidified Jell-O. Pour in a cup of thick motor oil. The oil will send black tentacles throughout the Jell-O, not mixing in with it, but eventually reaching all parts of the bowl. This explains the difficulty in removing such a tumor surgically, as it's everywhere. It is impossible to remove completely without taking most of the brain along with it. It is not a well encapsulated tumor that can be removed in one piece – not to mention extensive blood vessels growing between healthy brain and tumor.

This is a devious force of destruction with tentacles of death, well entrenched by the time the tumor is diagnosed.

Fortunately for McCain, he is receiving care at the Mayo Clinic, one of the top institutions for brain tumors. Kennedy received his care at Duke University, another great institution. Senator McCain has excellent health care insurance through Congress and has the means to afford paying out of pocket if necessary. The Mayo Clinic isn't an option for others, as Mayo is in network for only one specific Obamacare plan. Duke is in network for only a couple of Obamacare plans.

Sorry to bring politics into Senator McCain's medical situation, but as his fellow senators were unable to repeal or replace Obamacare this week, it's appropriate to illustrate the real-life consequences of the U.S. Senate's inability to legislate or govern. Many Americans with glioblastomas won't have the care options that members of Congress and their families have.

Perhaps Senator McCain will attempt to work part-time in the Senate, as Ted Kennedy did, or else enjoy time with his large family or advocate for true health care reform, as Senator Kennedy did for Obamacare, encouraging his fellow senators to fix an insurance system that denies so many the medical care that he, as a United States senator, will receive.

Despite disagreeing with Senator McCain politically, I thank him for his service in the military and the Senate and wish him and his family the best in the challenging months ahead. Godspeed.

Brian C Joondeph, M.D., MPS is a Denver-based physician and writer. Follow him on Facebook, LinkedIn and Twitter.