Chuck Pagano is only the second head coach in recent NFL history to be diagnosed with cancer during the season, according to Indianapolis Colts Owner Jim Irsay.
Pagano was hospitalized Wednesday night and immediately began treatment after being diagnosed with "acute promyelocytic leukemia," a subtype of acute myeloid leukemia, "which is a cancer of the bone marrow tissue," according to his physician Dr. Larry Cripe, a leukemia expert from the Indiana University School of Medicine.
Here are a few things to know about leukemia and specifically acute promyelocytic leukemia or APL:
How common is APL?
Each year, more than 40,800 adults and 3,500 children are diagnosed with all kinds of blood and bone marrow cancer called leukemia, according to the National Cancer Institute. About 13,780 of these new cases will be adults diagnosed with acute myeloid leukemia (AML).
APL - the cancer Pagano has been diagnosed with - is a rare subtype of AML. Only 10% of AML cases, or about 1,300 people, are diagnosed with APL each year.
"Everyone who is diagnosed with acute myeloid leukemia faces a dangerous situation," Cripe told reporters Monday.
What are the symptoms?
Irsay told reporters Monday that Pagano was suffering from fatigue and unexplained bruising, and at the urging of his wife, Tina, the coach took advantage of a week with no game to go to the doctor.
Those are two common symptoms for leukemia, says Dr. Harry Erba, director of hematologic malignancies at the University of Alabama at Birmingham Cancer Center.
Fatigue, shortness of breath with exertion, sometimes a headache and a pale appearance are common symptoms of anemia that comes when the bone marrow isn't producing healthy blood cells, he says.
Pagano's physician told reporters on Monday that "the coach's bruising was due to the fact that his bone marrow was no longer producing in a normal number the factors that are needed for clotting."
What's the prognosis?
Acute leukemia symptoms appear abruptly, says Erba. "Without treatment, a patient's life span is a few weeks to a couple months," he says.
Fifty years ago there was no treatment, but now there's a very effective treatment regimen, Erba tells CNN. He says this specific type of leukemia is "exquisitely sensitive to vitamin A," so for the past 20 years, APL patients have been treated with a combination of standard chemotherapy and a derivative of vitamin A called all-trans retinoic acid or ATRA. Using this drug combination, Erba says, the cure rate for APL was about 70% to 80%.
But the addition of another drug - arsenic trioxide - has led to "the highest cure rates we have ever seen," Erba says. By combining all three treatments, patients have an 80% to 90% cure rate.
The chemotherapy kills cancerous blood cells, says Erba. That's not what ATRA and arsenic trioxide do. They actually tell leukemic cells to turn into normal cells. And since normal cells eventually die (that's what they're supposed to do), the combination of chemo and these cancer-cell converting agents is designed to eliminate the cancer cells with the hope that only healthy blood cells will grow back. It's a complicated regimen that will take many months.
Cripe says he is confident that Pagano will beat the cancer: "the goal of this is to cure the disease. A definition of a cure is really that the remission has lasted for three to five years, so there's a period of time of where there will be some uncertainty."
For now Pagano faces several weeks of chemotherapy, says Cripe, then after some convalescence, "he will receive several more cycles or months worth of chemotherapy. During that period, he will not be in the hospital, most likely, and he will be able to engage in his normal life to a limited degree."
When and if Pagano can resume his duties as head coach during this season is not clear at this time.
Erba says ATRA, which comes in a pill, can cause headaches and a rash. Arsenic trioxide is given intravenously but is usually very well tolerated, and the main side effects of the chemotherapy (daunorubicin plus cytarabine) are hair loss, some nausea, mouth sores, diarrhea and the risk of infection and needing blood transfusion.
Even though APL is a potentially very deadly cancer, patients do have good treatment options, which is why this coach's prognosis so favorable. In the future, APL patients may be able to skip the chemo entirely and just be treated with ATRA and the arsenic, if current clinical trials pan out. Those study results may be coming in the next few months.