If you are over 30 and your life has not been intimately affected by cancer, stop reading and go check your voice mail. Listen for the friend's voice with the bemused detachment, carefully requesting a call back, as if prepping a report of bad news that's befallen a third party. Even when it's happening to you, it never feels like it's happening to you. The fear of cancer diagnosis—for ourselves, for our loved ones—is so mythic, that when it happens in real life, the grubbiness of the reality (tests, waiting, nausea, tests, waiting, hair loss, friends' oppressive sympathy and/or revulsion, leading to recovery and/or death) can feel like one more cosmic insult to life.

This grubby, day-to-day terrain of cancer diagnosis and treatment is where 50/50 lives. Based loosely on the experience of screenwriter Will Reiser, the film follows a 27-year-old man (played by Joseph Gordon-Levitt) as he navigates the boring, terrifying, soul-expanding crapfest that is Life with Cancer. The movie is set in Seattle (as approximated by Vancouver) and it's a perfect fit: Even before he's forced to avail himself of the region's renowned cancer-care industry, Gordon-Levitt's Adam is seen jogging in place at the corner of an empty intersection, waiting for the signal to change. He's careful, you see, and plays by the rules, and is health-conscious enough to jog, but none of this makes any difference when the cancer ax falls.

In both art and life, cancer diagnoses follow a familiar trajectory. Armed with Reiser's intimately knowing script, director Jonathan Levine waltzes through all the mandatory stations (getting the diagnosis, telling family and friends, beginning treatment) with a condensed wit that helps every predictable turn land with surprising force. Helping every step of the way is 50/50's stellar cast, from the omnipresent lead Gordon-Levitt (whose Rankin/Bass puppet face is put to beautifully nuanced use) to the all-star supporting cast: Anjelica Huston roars back to prominence with a twisty performance as Adam's barely contained mess of a mom, and Anna Kendrick's young medical student makes the film's rom-com aspirations not-ridiculous with her intelligent spontaneity and huge cute teeth. But the comedy star is Seth Rogen, cast in the same role he played in screenwriter Reiser's life—cancer guy's best friend—and fucking killing it, navigating the drama/comedy divide without a false step, and with jokes you'll still be laughing at the next day.

Did I mention 50/50 is funny? It is, and I mean hardcore, laugh-till-no-sound-comes-out funny. Before 50/50, the words "cancer comedy" were most recently applied to 2009's Funny People, but Judd Apatow's film chose to make the cancer comedian an actual, professional comedian, with limited success. 50/50 wisely understands that cancer can make a comedian (and tragedian) out of anyone. You'll laugh till you cry, and vice versa. Go see it.