In the Ritz-Carlton Hotel meeting room in Georgetown, Will, a cancer survivor, and
his friend Seth are talking to a reporter:

WILL: It’s been six years, cancer-free.

SETH: He’s still in remission, though.

WILL: Still in remission.

SETH: Remission never ends, apparently.

WILL: I don’t actually know when it ends.

SETH: We don’t know the definition of remission. We keep joking about it. We have no idea. Are you constantly in remission?

WILL: I just remember the doctor said, yeah, you’re in remission.

SETH: You’re just still in remission?

REPORTER: At what point do you get out of it?

SETH: When you die. Of old age.

This is the way Will Reiser and Seth Rogen actually talk about cancer. It’s also the way Adam (played by Joseph Gordon-Levitt) and Kyle (portrayed by Rogen) talk about cancer in the movie “50/50.” That’s not a coincidence.

Reiser, 31, wrote the screenplay for the film, opening nationwide Friday, after surviving his own cancer scare in 2005. After a massive, malignant tumor was discovered in his spine when he was 25, the then-aspiring scribe looked to close friends like Rogen — the writer and actor best known for the sarcastic-yet-sympathetic burnouts he played in “Knocked Up” and “The Pineapple Express” — for support.

Their relationship, as well as Reiser’s recovery — which involved surgery and a painful rehabilitation that still requires him to do physical therapy — laid the foundation for what would become “50/50,” an emotional and often surprisingly funny film that allows Rogen, 29, to take on the role that he once assumed for Reiser: the wise-cracking buddy who buoys his sick friend’s spirits . . . in his own, semi-misguided way.

Actual exchange from “50/50”:

ADAM: You really think that a girl’s going to go for me just because I have cancer?

KYLE: For the millionth time, yes!

“Because we were so young . . . we were not very good at expressing our emotions,” says Reiser of the way he and Rogen handled his diagnosis. “We’re comedy writers, so we would just joke about it. That was our way of coping with it.”

“As opposed to now,” adds Rogen with his signature staccato chuckle, a laugh that somehow manages to channel both Barney Rubble and Fred Flintstone at the same time.

The two first met while working in an environment where the ability to generate a joke was particularly valued: “Da Ali G Show,” Sacha Baron Cohen’s absurdist HBO series in which political and cultural figures were interviewed by Cohen while he assumed the guises of white rapper Ali G or clueless Kazakh reporter Borat. Rogen was a writer and Reiser was an associate producer responsible for booking guests without revealing that they’d be participating in a comedic sneak attack instead of a real talk show.

“It was this giant ruse,” Reiser says now. “I was always under high levels of stress.”

Rogen says his friend often looked rundown, which he and others assumed was a natural byproduct of attempting to deceive unsuspecting VIPs every day. Seven months after their work on “Ali G” finished, Reiser found out he had cancer.

Initially, a doctor told the Tarrytown, N.Y., native that he had lymphoma. For a week, he thought he was terminal. But after submitting to numerous tests and seeing, by Reiser’s estimate, a dozen doctors, lymphoma was ruled out, the tumor was found and the surgery scheduled. If he hadn’t been fearless and persistent, he says, he might not have found the true cause of his illness so quickly.

“My producing on ‘Ali G’ really prepared me for navigating the cancer train,” he quips.

While Reiser puttered along, wearing a back brace and attempting to regain his strength post-surgery, he and Rogen talked frequently about how the whole life-altering Big C experience — with its sobering reminders of mortality mixed with cringeworthy questions from acquaintances about Reiser’s bucket list — could be made into a motion picture.

“It was never, like, as simple as we’ll just make a movie about what’s happening,” says Rogen, who co-produced “50/50” — the title refers to Adam’s alleged odds of beating his disease — and helped develop the script. “It was, you know, a nerdy Jew gets cancer and becomes a hit man.”

Eventually, Rogen and Reiser realized that the best way to tell the story was as honestly as possible.

“We don’t need to have him be a hit man,” Rogen says they concluded. “We can just have him work at NPR.”

So in 2008, Reiser created his pseudo-alter ego — Adam the soft-spoken public radio producer who finds out he has neurofibrosarcoma — and wrote the script. While many plot points synched up closely with Reiser’s experiences, others were fictionalized. Adam goes through chemotherapy; Reiser did not. Adam’s father in the film has Alzheimer’s; Reiser’s does not.

At Kyle’s urging in “50/50,” Adam attempts to pick up women by telling them he has cancer. Reiser and Rogen never did that, but Reiser points out that during his illness, he did set Rogen up with Lauren Miller, to whom the “Green Hornet” star is now engaged.

All those elements, whether based on actual events or merely inspired by them, seem to ring true for some fellow cancer survivors who have seen the finished cinematic product. “50/50” recently screened here in Washington at an event sponsored by Live Strong, Lance Armstrong’s cancer advocacy organization. Tamika Felder, who was diagnosed with cervical cancer at age 25 and has been free of the disease since 2006, was in the audience that night. While she says a few minor details may be a tad off — Gordon-Levitt’s character would have lacked eyebrows after all that chemotherapy, for example — “50/50” still struck a chord with her.

“I want[ed] it to show what we go through as young-adult cancer patients because how often do we get an opportunity to get our voice heard on the big screen in such a real way?” says Felder, an Upper Marlboro, Md., resident who started her own nonprofit, Tamika & Friends, to raise awareness about cervical cancer prevention. “And I have to tell you, from the time that movie started playing, I could not believe it. I could not believe how accurate it was.”

“50/50” has been getting strong early reviews and was warmly received earlier this month at the Toronto Film Festival. But responses from fellow survivors such as Felder are what have most surprised and gratified both Reiser and Rogen.

Reiser remains in good health. He’s beginning work on a screenplay called “Jamaica,” based on another autobiographical experience: the time he took a vacation with his grandmother, found out they had accidentally been booked at a couples resort, then realized she was in the early stages of Alzheimer’s.

Jonathan Levine, who directed “50/50,” is already attached to direct. And Rogen jumped on board again as a producer after the pleasant experience he had with Reiser on “50/50 .”

“I’ve lost friends writing scripts with them,” says Rogen, “and I’ve gotten even closer writing scripts with them. I’m happy to say I got closer with Will writing this one.”