On the list of possible topics for a comedy movie, cancer falls somewhere near the bottom between starving orphans and abused puppies.

But in the new film "50/50," the topic works because the filmmakers realize that while there's absolutely nothing funny about cancer, it can be faced with humor. Director Jonathan Levine and writer Will Reiser, who based the script on his own experience with a tumor on his spine, show that even in the face of a horrible illness it's OK to laugh.

Joseph Gordon-Levitt turns in a powerful and believable performance as Adam, a young cancer patient who struggles to hide his vulnerability by holding his emotions close to his vest. Gordon-Levitt delivers a controlled performance. Instead of showing his emotions with large gestures, most of his acting is done through his eyes.

Rick Bentley's one-minute review

As Adam goes through his chemotherapy and faces the realities of his battle, his strength and optimism give way to fear and confusion. In lesser hands, this role could have gone over the top emotionally, changing the film's focus for the worse. This is not a movie about a young man with cancer but a film about how life-shattering news can be faced with dignity and hope.

Reiser's script also shows how others deal with the news of cancer. Seth Rogen's character provides much of the comedy – even coming up with a way to use his best friend's cancer to pick up women. These kind of elements keep the film from being overly sentimental or trite.

The weakest link is the relationship Adam has with his therapist (Anna Kendrick). It's contrived and feels out of sync with rest of the grounded script. It's too much of a contrast to the rest of the movie.

The film gets a boost from first-rate supporting performances by Anjelica Huston, Serge Houde, Matt Frewer and Philip Baker Hall. The biggest surprise is Bryce Dallas Howard, who plays a bigger villain than the cancer. This performance redeems the weak work she did in "The Help."

The best acting – other than an Oscar-worthy performance by Gordon-Levitt – comes from Rogen. Comic relief with such a serious topic is tricky. Levine gets a thoughtful – and still funny – performance from Rogen, and it's the best performance he's ever done.

The title, "50/50," refers to Adam's chance of survival, but it could also describe the odds of this film working. The cast and crew took a chance making a comedy about such serious subject and the result is a winner.