Quotes of the Day

"I don't smoke. I don't drink. I recycle." Yet Adam (Joseph Gordon-Levitt), a producer for an NPR station in Seattle, has contracted spinal cancer at the precocious age of 27. When he tells his pal Kyle (Seth Rogen) that his odds of survival are 50/50, Kyle tries to be cheerful. "If you were a casino game, you'd have the best odds," he says, and proceeds to itemize celebrities who contracted and beat cancer — "Lance Armstrong gets it all the time." At Kyle's urging, Adam uses his condition as a pickup line at bars. "How'd you get it?" a girl asks, and he surmises, "Bad mattress."

A cancer comedy that doesn't quite live up to its killer premise and affecting backstory, 50/50 follows Adam through his CT scan and chemotherapy treatment, his oddly even-tempered reaction to the awful news (he jumps quickly to Stage 5 acceptance) and the flailing attempts of those around him to provide support. The film is Terms of Endearment with less hugging, Dolphin Tale with a human patient, Soul Surfer with a menacing spine instead of a missing arm, Burt Reynolds' disease-and-suicide farce The End with a more chipper outlook. And given Kyle's mission to get girls for his disadvantaged friend, it's also The 40-Year-Old Virgin. Except that Adam is younger, already has a girlfriend and could die by the end of the movie.

Could, as in won't. The origins of 50/50 are familiar to anyone who has seen Rogen's guest spots on virtually every TV show this week. (I think I spotted him in the Tampa Bay dugout during Wednesday night's Yankees-Rays game.) Again and again he has told the true-life tale of Will Reiser, who worked with Rogen on Da Ali G Show back in 2003. It was then that Reiser, in his early 20s, learned that he had spinal cancer. He wrote a movie script turning a comic light on his experiences and, eight years after his half-death sentence, has a complete-remission bill of health and the critics' prognosis for a popular movie.

To assuage audiences' uneasiness about the topic under review, Reiser and director Jonathan Levine, who did the strenuously zany weed comedy The Wackness, surround Adam with characters so conventional that you could plot their narrative arcs from their first scenes. Kyle is, well, Seth Rogen in every other film: the hearty, horny dope smoker who tries to take over someone else's life by turning it into an exact copy of his own but is, au fond, a mensch. To show solidarity with his cancerous buddy, Rogen has to wear a frowny face once or twice but usually covers the concern with his famously deep, persistent and hiccuppy laugh, which makes him sound like a catarrhal Santa Claus. (He ought to see a doctor about that.)

The movie has Adam befriended by two other cancer patients (Philip Baker Hall and Matt Frewer), who inject some furtive life into the gloom. But the women in this comedy of discomfort too snugly occupy generic roles. Adam's mom Diane (Angelica Huston) is the overbearing Jewish mother, whose first response on learning of her son's ailment is "You waited a couple of days to tell me?" followed instantly by "I'm moving in." Diane (who answers nearly every phone call from her son with a barking "Omigod, what's wrong?") is in desperate need of some redeeming features; most of 50/50's creators have Jewish mothers who will see the movie, so you can bet she'll get some. And since Adam's lady love Rachel (Bryce Dallas Howard, breaking Jessica Chastain's recent headlock on roles for youngish redheads) is up to no good — we know this because she's emotionally evasive and squeamish about hospitals — that leaves an opening for his neophyte counselor, Katie (Anna Kendrick), with her clumsily expressed good intentions and random empathetic insights, to graduate to the Perfect Girlfriend category.

All these roles could have been found at a garage sale of comedy stereotypes. To the extent that 50/50 works, it's because of Gordon-Levitt, one of my favorite actors. You could call him my Ryan Gosling. I praise his every performance — as the Chandleresque teen hero of Brick, the lovelorn yupster of (500) Days of Summer, the fighter in Inception's rotating hallway — and hope he'll enjoy a breakthrough to stardom. It's about time: he has been onscreen since he was 7, played the teen alien boy on 3rd Rock from the Sun and invests all his roles with a sensible sweetness that subtly hints at a pain he's too courteous to express.

He plays that underlying angst to perfection in 50/50, whether appraising himself with a shaved head during his chemo doses ("I look like Voldemort") or taking consolation from a greyhound that Adam has been given as a pet and is now his bed partner. In Gordon-Levitt's surgeon-adept hands, Adam's big tell-off moment — when he orders someone off his front porch — is accomplished in a whisper that makes the confrontation much more powerful than a Pacino-like shout would. His beautifully judged performance lends about 48 points to a movie whose Metacritic score deserves to be no higher than 50.

• Richard Corliss