50/50

If you’re feeling charitable, “50/50’’ may strike you as a brave attempt to broaden a Judd Apatow-style raunchfest to include death and disease along with the usual sex, drugs, and bromance. If you’re not in the right mood, you may feel it stuffs cancer into a small, inappropriate box. The truth splits the difference: Too pat and contrived to be the Oscar bell-ringer early reports have claimed, “50/50’’ is most affecting when it shows callow young dudes struggling to come to terms with the ultimate party crasher.

So, yes, it’s about cancer and it’s a comedy - or, rather, the film paints a serious subject with a coat of nervous frat-boy guffaws. Based very loosely on screenwriter Will Reiser’s own battle with a rare sarcoma, “50/50’’ casts Joseph Gordon-Levitt as Adam Lerner, a 27-year-old producer for Seattle Public Radio who goes into a doctor’s appointment with a sore back and comes out with a 50 percent chance of survival.

When Adam gets the news, director Jonathan Levine (“The Wackness’’) has the sound bottom out and the background go blurry, a hackneyed cinematic trick that still works. Less clear is what we’re supposed to think about the doctor (Andrew Airlie), a cold fish who can’t even make eye contact with his patient. There’s an entire arena of social commentary there that “50/50’’ glances off without actually confronting. (In general, the medical community remains in the far background of this movie.)

Anyway, why waste time when you can get down to the business at hand: jokes about blow jobs and medicinal marijuana. Adam is a tightly wound worrywart (Gordon-Levitt, one of our most likable young stars, plays the part without glamour or ego), but his best friend is a gravel-voiced party animal named Kyle. Even if Seth Rogen didn’t co-produce the film and wasn’t a close pal of screenwriter Reiser, he’d have to be here, since, for better and for worse, he’s our national Id by now.

Kyle blurts out all the things you’re not supposed to say about cancer - its uses as a chick magnet, for one thing - while being there for his bro in matters of hair shaving (a very funny scene) and transportation to and from chemotherapy. Adam doesn’t drive, a trait that hints at an infantilism that “50/50,’’ again, doesn’t explore. The movie tiptoes around its most terrifying idea, that young men in today’s culture can put off maturity for so long that it’s possible to die before you grow up.