NBC News’ Tom Brokaw revealed Tuesday that he has been receiving treatment for multiple myeloma – a rare form of cancer.

Multiple myeloma is a cancer of the antibody-producing cells in the bone marrow, which are part of the body’s immune system. The condition, which occurs when plasma cells in the bone marrow mutate and accumulate, can be diagnosed with either blood and urine tests. Though approximately three percent of people over age 50 may develop these plasma mutations, only one percent are at risk of developing multiple myeloma.

“Approximately 20,000 people are diagnosed with multiple myeloma each year, even though the premalignant condition is very common,” Dr. Frederic Reu, associate staff physician in the department of hematologic oncology and blood disorders at the Cleveland Clinic told FoxNews.com. “The malignant condition where these cells cause trouble is not common.”

Though it is unclear what causes multiple myeloma, the disease appears to carry genetic risks – first degree relatives of patients have an approximately two-fold risk of going on to develop the disease. African Americans also have a two to three times higher risk for multiple myeloma compared to Caucasians.

Symptoms of multiple myeloma can include dehydration, constipation, heart arrhythmias and seizures, weakened bones, paralysis and renal failure, according to Reu, who has not treated Brokaw.

Multiple myeloma is not a curable cancer and treatments for the disease typically aim to achieve at least a partial remission for patients.

“There is no single best way to determine how to treat myoloma patients,” Reu said.

Currently, most treatments for the disease includes the use of the drugs thalidomide, bortezomib and lenalidomide.  These drugs are used in some combination, along with a steroid, to control the disease. Side effects of treatment can include neuropathy, fatigue and blood clots, but these can all be controlled with an adjustment in treatment or another drug.

The survival rate for multiple myeloma patients is a median of seven years, though patients can live beyond 10 years. At some point, the cancer will reactivate, but by using different types of treatment, doctors can usually provide effective therapies for patients, Reu said.

Brokaw has continued to work since receiving his diagnosis in August, which isn’t uncommon amongst multiple myeloma patients, as the treatments typically don’t interfere with quality of life. While some treatments may include conventional chemotherapy, Reu said the doses are typically not so high that the patient can’t continue to work.

Reu is generally optimistic about Brokaw’s prognosis.

“He may do well for a long period of time, if he’s not unlikely and [doesn’t have] higher risks,” Reu said. “Most patients at first do quite well for a number of years.”