09/06/2011 01:24 pm ET Updated Dec 06, 2017

'50/50': Will Reiser & Seth Rogen Heal By Writing Their Cancer Story

Adam Lerner hunches over his laptop, clawing nervously at his hair. Locked in a terrorized trance, he clicks to discover his fate, submitting to the cruel whim of an online medical dictionary. Technically, he's at his office desk, but as the last light flicks off, it's clear that he's fallen into the abyss of his own world, dragging along the impossible weight of a newly discovered tumor and the even heavier knowledge that he may never get out.

A 27-year old public radio producer, Lerner is in a committed relationship, has a great best friend, is in prime physical shape... and, as he just found out, is hosting a massive tumor on his spine. That he is a movie character, played in the upcoming indie dramedy "50/50" by Joseph Gordon-Levitt, is almost academic. Lerner exists on the intersection of reality and fiction, played with a haunting authenticity that owes both to the actor's talent and to Will Reiser, a cancer survivor and the writer of the loosely autobiographical feature.

"I think we started pressuring you to do it while you were still sick," Seth Rogen says to Reiser, as the two discuss the origin of the film in a conversation with The Huffington Post. Rogen, the comedy megastar, is Reiser's fellow "Da Ali G Show" alumni and best friend, just as he was when Reiser was diagnosed with cancer six years ago, when they were 24 years old.

The film, in many ways, was borne out of a coping mechanism for the young friends, Reiser explains, with comedy serving as an escape from the scary possibilities a more serious analysis would bring to the forefront.

"We were at a party one night and we were just talking about it," he remembers, following Rogen's recollection. "Sort of the way we dealt with it is we would kind of make jokes and try to find the humor in the situation; we were not good at talking about it at an emotional level, we didn’t sit down and have these really emotional conversations... at that age we were not equipped to deal with it that way."

And so while it was modern medicine that cured Reiser of his body's cancer, it was the process of taking the film from early concept to final draft -- Reiser as screenwriter, Rogen as producer -- that healed the hidden wounds that the disease had left in the psyche of everyone involved.

"The movie really forced us to have a lot of conversations that we didn’t have while we were going through all this stuff," Rogen says, "and I think we found, very quickly, the more conversations we had, the better the whole movie was going to be. The more we talked about who was insensitive and who could have communicated better and what people’s expectations of each other specifically were at that time, and how they maybe didn’t meet those expectations or didn’t understand those expectations -- I mean those were not conversations we had while we were going through it at all."

Though they created a fictional story that used their experience as an inspiration and jumping off point, both Reiser and Rogen agree that the initial draft of the screenplay relied on an overly glossy version of reality.

"I think the first draft I mean, Adam’s character was just much less flawed -- not to say it’s an incredibly flawed character, I mean, he’s a very good guy throughout the whole movie -- but I think it took those conversations for Will to... just to be comfortable writing it," Rogen explains.

"It’s a difficult thing to admit to certain things about yourself, like, I made my mother cry," Reiser agrees.

"They weren’t in there at first, just some of the more flawed aspects of the character, we had to squeeze them out," Rogen says, echoing Reiser. "It was just not -- and you can’t blame Will -- but as you’re going through it, it’s not your first instinct [to include them]."

To his credit, Reiser was open to amending the script, and the difficult process that doing so required.

"It was more for the purpose of the character but I think that in trying to develop that character we were talking about me," Reiser says, remembering back to the script's crunch time, a few weeks before they were set to go to production. It was then that the pair truly delved back into the difficult moments they had tried to superficially skate through at the time that they were happening.

It was in their subsequent search for realism that they uncovered hard truths.

"That was incredibly useful for me as a writer and also just my own understanding of what I went through and how my own behavior of how... the way I would try and control things and the sort of expectations you happen to place on people, the way I would just kind of avoid dealing with certain things," Reiser says, owning up to an understandable insensitivity while battling the disease. "These are things that anyone would go through when dealing with this kind of a situation. I just... I needed Seth to kind of help point it out to me so I could be more aware as a writer. It’s incredibly helpful, writing something personal when you have your friends as your producers."

The film's depiction of that inner turmoil and its consequences are visions of confusion, alienation and existential crisis. Getting there wasn't easy.

The final draft that appears on screen sees Adam float onward, haunted and stunned between bursts of defiance against the specter of dying and despondence at his crumbling reality. As the disease progresses, he's filled with a sort of rudderless angst borne of increasing self-doubt and more urgent confrontations with his mortality. His relationships, with both Kyle and his neurotic mother, strain as everyone grows more uncertain of what the future holds, and how best to react to the deterioration of his health.

Still, a lot of what Will went through was internalized, and his interactions with people already deeply entrenched in his life could only bring so much of that emotional struggle to the surface. That presented a difficulty of sorts, because emotional journeys in film, no matter how profound, have to be charted to be believed. So, in keeping with the fictionalization of the true life experience, in came a love story.

Anna Kendrick plays Katie, a graduate student training to be a therapist at the teaching hospital where Adam is receiving treatment. As her patient, theirs is a relationship both personal and emotional, which Reiser calls "vital to kind of humanize the experience."

"It was a great way to just get so much exposition out of Adam like, so much of what he’s internalizing and so much of the experience of what it’s like to be sick and to feel alienated and to kind of bring that out," he says.

Three years his junior and too inexperienced to have the confidence to assert herself, she's pushed further on the defensive by Adam's dismissal of her usefulness - he's just her third patient -- and unwillingness to buy into her advice. In that regard, the character is given her own arc, to explore another aspect of cancer's impact.

"I liked the idea of a young therapist," Reiser offers, "because I think it just shows how that at age, from all different points of view, how difficult it is to deal with something like this and you have all these young characters who are all kind of beginners, you know, no one quite knows how to deal with it."

There are, of course, plenty of laughs to be had in the film; though it's difficult to make cancer funny, the inherent discomfort of the situation, as well as Rogen's trademark irreverence, create a plethora of lighthearted moments. In fact, some of the funniest moments are the most truthful, reenactments of their awkward interactions through the course of Reiser's disease.

That included Kyle changing the dressing on one of Adam's surgical scars, which featured some inspired gagging and complaining.

"Seth really did do that and he really was horrified," Reiser laughs. "It was really traumatic for him to do that, to change that dressing."

A moment following one of his procedures made its way into the film, which the pair remembered with a lot of laughter -- years after the painful awkwardness of the original event. At the time, Rogen said he was walking on eggshells, unsure of how to approach his friend.

"I’ll tell you, I remember that, I was laying in that hospital bed and I was like in horrible condition and I felt like shit and Seth and our friend Dave walked in and the first thing out of his mouth was like, ‘Hey man, you look really great,'" he laughs, before, adding, to Rogen's great amusement, "They were still terrified because it’s just so weird... they brought me a book that was like, Great Jews in Sports History."

The verbal tiptoe and uncertain feeling the pair remember is transported in full to the screen, the palpable hesitation drawing laughs for its realism. Rogen says that it's a "real thrill" to act in scenes that feel especially close to him, and credits Gordon-Levitt for excelling in a nuanced, complicated role that, in those particular scenes, require him to be a stand-in for a best friend watching from on set.

"Joe really grounded the whole thing for me," Rogen says. "He was so real and so in it and looking at him, the scenes just instantly felt very real as soon as we would start doing them and I think it really helped me. I mean, it made it a lot easier for me to just kind of be as natural as I possibly could because of how real he was all the time."

It's that mix of authenticity, humor and poignancy amidst an emotional journey that presents such an engaging feature, which, above all else, the pair hope resonates with those who have gone through a similar experience.

"I think that people are really afraid to talk about illness, people are just afraid of illness in general. and I think, when you feel sick, you feel marginalized. You feel like you’re supposed to put on this happy face and not really talk about what you’re going through," Reiser says. "What I think is really the most gratifying about this entire thing is the fact that it connects with people and it’s starting a larger conversation. How could you ask for more?"

"50/50" hits theaters on September 30th.