Former “NBC Nightly News” anchor Tom Brokaw recently broke the news that he has multiple myeloma, a type of cancer affecting a particular kind of cell in the bone marrow.

Brokaw, 74, got his start at NBC News in 1966 and went on to anchor the network’s flagship news program from 1982 to 2004. He says he was diagnosed with multiple myeloma this past August, and that his doctors at the Mayo Clinic are encouraged by his progress under treatment.

"With the exceptional support of my family, medical team and friends, I am very optimistic about the future and look forward to continuing my life, my work and adventures still to come," Brokaw said in a personal statement released by the network. "I remain the luckiest guy I know. I am very grateful for the interest in my condition, but I also hope everyone understands I wish to keep this a private matter.”

Multiple myeloma is a relatively uncommon cancer – the American Cancer Society pegs the average person’s lifetime risk of getting it at 1 in 149 (or .67 percent). Still, about every year, more than 24,000 people are diagnosed with it, and about 11,000 people die from it. This kind of cancer is more common in older people, men and African-Americans, and it may run in families, according to the National Institutes of Health.

The cancer begins in plasma cells, which are a type of white blood cell. As one of the foot soldiers of the immune system, the plasma cell’s job is to secrete antibodies to help fight infection. The cancer can start with just one abnormal plasma cell that begins replicating itself. Researchers still aren’t exactly sure what initially causes the plasma cell to go rogue, but there may be an underlying genetic abnormality.

In people with multiple myeloma, abnormal plasma cells begin to accumulate in the bone marrow, which can interfere with red blood cell production, damage bones and tissue, and interfere with the body’s immune system. Common symptoms include bone pain, broken bones, fatigue, weight loss, frequent infections, thirstiness and frequent urination.

There is no cure for multiple myeloma, but there are several options for courses of treatment. For newly diagnosed and recently treated cases, there’s an intravenous-delivered drug called bortezomib, which belongs to a class of drugs called proteasome inhibitors. These kinds of drugs block the action of cellular complexes called proteasomes, which break down proteins. Inhibiting proteasomes helps to encourage rapidly dividing cells, such as cancer cells, to self-destruct.

Another line of treatment is the drug thalidomide, a sedative once used to treat morning sickness but taken off the market after it was discovered to cause birth defects. In cancer patients, however, thalidomide inhibits new blood vessel growth, which is a powerful way of suppressing tumor growth. Multiple myeloma can also be treated with chemotherapy or radiation. Corticosteroids like dexamethasone may be used to stop white blood cells from congregating to areas damaged by cancerous myeloma cells, which reduces swelling and inflammation, along with the attendant pains. Stem cell transplants – from either a patient or a donor – may also be given to replace blood marrow damaged by the cancer.

The median survival rate – meaning the amount of time half the patients stay alive with the disease – for people with multiple myeloma varies by stage. At stage I, the median survival rate is a little more than five years; for stage II, it’s just under four years; for stage III, half of patients have less than two and a half years to live, according to the ACS.

Catherine Broome, a hematology oncologist at Georgetown's Lombardi Cancer Center in Washington, D.C., told USA Today that some patients can expect to survive more than a decade, thanks to new treatment options that "have changed the whole story."