As a long-time fashion photographer, David Jay had shot photos of a model named Paulina numerous times. They became close friends as well. Paulina was diagnosed with breast cancer at age 29. After her mastectomy, Jay asked her to pose for yet another picture, but the stark black-and-white image laid bare the big scar that ran across her chest.

"I didn't realize the effect the photograph would have on Paulina," Jay said. "When she saw that picture, it helped her come to terms with what had happened to her."

Paulina was the first of about a hundred women who are part of "The SCAR Project." The images document young women with breast cancer. The youngest is 18. The oldest is in her mid-30s. They are nudes from the waist up, exposing the very raw reality of the disease.

Jay began the project 7 years ago, mostly to raise awareness about breast cancer in younger women. According to the World Health Organization, breast cancer is the leading cancer killer among women ages 20-59 around the world. And a study released earlier this year indicated a rise in the number of U.S. women ages 25 to 39 who are diagnosed with metastatic breast cancer.

"Like most people, I thought of breast cancer as your mother's or your grandmother's disease," Jay said. "Certainly not the disease of a young, very healthy woman."

Beginning with Paulina in Sydney, Australia, Jay has photographed women from all over the world in his New York City studio. The images document the process of battling cancer and coming to terms with the disease. About 10 percent of the women included in the project will die from breast cancer.

"These women are dealing with deep, deep scars, not just physical," Jay said. "I think the physical scars, as deep as they are, are the least of the problem."

Over the years, Jay said he has gotten thousands of emails from women diagnosed with the disease who have seen photos from "The SCAR Project."

"The women write that they feel like a monster, and are embarrassed to show their children what they look like, or their husbands have never seen them in the light," he said. "But they see themselves in the photos and think how beautiful these women are."

The tagline for the project is "Breast Cancer Is Not a Pink Ribbon." With its unflinching look at the disease's effects on the human body, the project shows the viewer what "she sees when she looks in the mirror. Seeing the truth is often not so easy," Jay said.

Photos from "The SCAR Project" have been included in a book, as well as a documentary called "Baring It All." Large-scale images of 30 women are included in an exhibition traveling across the U.S., currently in Houston.

ABC News' Henry Gretzinger contributed to this report.