Tim Brokaw
Brokaw,74, is an NBC news special correspondent and former Nightly News anchor.Twitter

NBC News correspondent Tom Brokaw has revealed he is suffering from multiple myeloma, a type of bone marrow cancer.

The 74-year-old journalist was diagnosed with the condition at the Mayo Clinic in August last year, but doctors are optimistic about his treatment and recovery.

Earlier this week, Brokaw explained his decision to continue to work while undergoing treatment , including contributing to the NBC's coverage of the winter Olympics in Sochi.

"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," he said in a statement.

"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."

Brokaw, who hails from South Dakota, began his journalism career with NBC News in 1966 when he joined the network's Los Angeles division.

He was anchor of the network's flagship news broadcast, NBC Nightly News for 22-years until he was replaced by Brian Williams in 2004.

Although there is no cure for multiple myeloma, which arises when plasma cells become abnormal, it is considered to be treatable. Symptoms include tiredness, infections and bone pain.