Senator John McCain has been diagnosed with brain Cancer

The 80-year-old Arizona senator underwent a 3 to 4 hour surgery to remove a blood clot above his left eye last Friday, which led to the discovery of his tumor. While his office confirms he is recovering “amazingly well” in his home, post-surgical lab results revealed the presence of brain cancer associated with the blood clot.

Nearly 14,000 men will be diagnosed with malignant tumors of the brain or spinal cord in 2017, and 9,620 of those cases will be fatal, according to the American Cancer Society (ACS). But these types of tumors are rare—your lifetime chance of developing one is less than 1 percent.

Glioblastomas are a high-grade astrocytoma, or tumors that start in your glial cells, the most abundant type of cell in your central nervous system. Glioblastomas grow quickly and make up about two thirds of astrocytomas, making it the most common type of malignant brain tumor in adults, according to the ACS.

Currently, there aren’t any early-detection brain tumor screening guidelines, but there are some symptoms you can watch out for, like drowsiness, headaches, blurred vision, and balance problems.

Luckily, McCain doesn’t skip his annual check-ins, due to his history of skin cancer. In fact, his doctors discovered the blood clot that led to his diagnosis during a routine physical exam, according to CNN.

During his appointment, he mentioned feeling fatigued and foggy, as well as having problems with his vision. McCain’s doctor recommended a CT scan, and once they reviewed those results, he was asked to immediately come back for an MRI.

The clot was located above McCain’s left eye, which required “a significant operation” that required the removal of a bone underneath his eyebrow, which then later had to be put back, practicing neurosurgeon Sanjay Gupta, M.D., told CNN.

The operation went smoothly—and McCain even cracked a joke after waking up. Now that he is recovering, he must go over treatment options with his doctors, which will probably include radiation and chemotherapy. The 2-year survival rate for adults being treated for aggressive glioblastoma is 30 percent. However, one 2009 study suggests that 10 percent of glioblastoma patients may live up to five years or longer, according to American Brain Tumor Association.

The news has stunned Washington, and has prompted responses from President Donald Trump and former president Barack Obama.

McCain has always been a fighter—as a Vietnam prisoner-of-war survivor and active politician—and his family states that he continues to be, despite his diagnosis. His daughter Meghan McCain tweeted Wednesday: “It won’t surprise you to learn that in all this, the one of us who is most confident and calm is my father. He is the toughest person I know.”