Senator John McCain, 80, has been diagnosed with brain cancer after doctors found a primary glioblastoma brain tumor after surgery to remove a blood clot above his left eye, the New York Times reported. Before his diagnosis, McCain experienced symptoms of brain cancer including blurred vision and fatigue, highlighting the importance of recognizing these often hard-to-miss signs of glioblastoma.

McCain was brought to the hospital on Friday, July 14 to remove a blood clot via a minimally invasive, yet “significant” incision above his eyebrow that involved removing a bone underneath the eyebrow and then putting it back in, CNN reported. However, tests showed that the senator also had a primary glioblastoma brain tumor. Signs of the disease are easy to mistake for common maladies and fatigue, which can lead to a late diagnosis.

Read: Glioblastoma Treatment Breakthrough: 'Untreatable' Brain Cancer Tumor Stabilized With Malaria Drug

Prior to receiving this news, McCain had complained of feeling fatigued, having a foggy mind, and experiencing occasional double vision, all of which prompted his doctor to schedule the senator for a CT scan and later an MRI. These symptoms are also in line with what the American Brain Tumor Association describes as early symptoms of a glioblastoma.

In addition, other early symptoms can include headaches, nausea, vomiting and drowsiness. Depending on the location of the tumors in the brain, other symptoms such as weakness on one side of the body, memory and speech difficulties, and vision problems can also occur.

According to the American Brain Tumor Association, a glioblastoma is the most common type of cancerous brain tumor. Although the specifics of McCain’s case have not been made known to the public, primary glioblastoma brain tumors are particularly destructive and grow at accelerated speeds when compared to other types of glioblastomas.

"It's a very aggressive tumor," said CNN Chief Medical Correspondent Dr. Sanjay Gupta, CNN reported. "This is the same tumor that Ted Kennedy had."

Treatment And Survival

These brain tumors are more difficult to treat than tumors found in other areas of the body because they contain many different types of cells; treatments that may kill some cells can leave others unharmed. What’s more, the particular shape of these tumors also makes them more difficult to treat. They tend to have long finger-like tentacles that can be hard to remove completely through surgery, especially when they grow into more important areas of the brain.

The median survival rate for this type of tumor with the proper treatment is about 14 months, and the two-year survival rate is 30 percent. Younger patients usually tend to have better survival rates than other patients. While only about 10 percent of patients with this particular type of tumor will live five years or longer, five-year survival is closer to 25 percent for children.

McCain and his family are currently reviewing treatment options, however, he will have to wait to begin until the incision wounds from his initial blood clot removal surgery are healed — a process that can take three to four weeks.

See Also:

Glioblastoma Multiforme Breakthrough: Scientists Figure Out The Cells Responsible For Seizures In Brain Cancer Patients

Early Signs Of Brain Cancer: Changes In Blood May Indicate Cancer 5 Years Before Symptoms Begin