Ken Burns tackles history of cancer

Watch it online here.

Ken Burns' new documentary, Cancer: The Emperor of All Maladies, marks a contrast to the historical documentaries for which he's best known. Unlike the Civil War or the Roosevelt presidencies, the story of cancer doesn't yet have an ending.

Burns, the film's executive producer, says his approach changed as he learned more about the history of cancer research, and the challenges facing doctors and patients today.

"When we first started talking about it, we had this unbelievable optimism that we were on this cusp" of a new era, Burns says. Over time, "we began to realize how many times people had said, 'The cure is around the corner.'"

The three-part PBS documentary (Monday, 9 p.m. ET/PT, check local listings), opens with a parade of presidents — Lyndon Johnson, Richard Nixon, Bill Clinton and George W. Bush — predicting imminent progress against cancer.

Yet as the film notes, initial excitement about promising discoveries often gives way to the sinking realization that cancer is vastly more complicated than even top scientists had realized. ...