Tenderness, insight guide ‘50/50’ humor

It could have been agonizingly mawkish – the story of a young man with everything ahead of him who learns he has a rare form of spinal cancer, one that he only has a 50 percent chance of surviving.

Instead, “50/50” is consistently, uproariously funny, written with humanity and insight and directed with just the right tone every time.

Comedy writer Will Reiser crafted the script based on his own cancer diagnosis when he was in his early 20s. His words are filled with dark humor and a wry recognition of the gravity of this situation, but also with real tenderness. His characters are so well-drawn that even when you see obvious developments looming on the horizon, they still feel fresh and offer some moments of surprise.

It helps a great deal to have Joseph Gordon-Levitt, an actor of great range and subtlety, in the starring role. His character, Adam, a reporter at Seattle’s public radio station, receives the diagnosis after having a doctor examine him for chronic back pain.

Adam goes through all the requisite stages of denial, frustration, fear and eventually acceptance, but he does so with such believable imperfection, he never feels like a saint or a martyr. He’s not always gracious in the face of adversity; he can be a little surly and smug and emotionally closed-off. He doesn’t even return phone calls from his understandably concerned mother (Anjelica Huston).

But Adam has a great balance in his lifelong best friend and co-worker, the garrulous and lovably crass Kyle (Seth Rogen). Again, here’s an example of how “50/50” sneaks up on you: You think you know this guy, and then he shows a kindness and generosity you’d never expect.

And it gives Rogen, who’s also a producer on the film, a rare opportunity to show some dramatic ability. Sure, he uses his buddy’s illness to line up sympathy sex for both of them but, you know, he means well.

Similarly, Anna Kendrick as Adam’s inexperienced young therapist, Katherine, seems like the kind of eager-beaver, overachiever role Kendrick has played before in films like “Up in the Air” and “Rocket Science.” But there’s a softness we’ve not seen from her before, a femininity that’s appealing.

Bryce Dallas Howard, meanwhile, says all the right things but doesn’t really mean them as Adam’s girlfriend. She insists she’ll stick by him no matter what, but it’s clear from the start that she’s really trying to convince herself she’s capable of such loyalty.

Just when “50/50” threatens to become too unbearably sad, a character will say or do just the right thing to break the tension. It doesn’t let up necessarily, but it does provide a balance.

And it concludes in the most delicate way, with a moment that’s a lovely mix of romanticism and restraint. Perfect endings are hard to come by: “50/50” has one, and it wraps up one of the year’s best films.