Ethan Zohn has revealed that cancer has returned in his chest after 20 months in remission.

"It's localized in my lung area," the former Survivor: Africa winner and nineteenth-season The Amazing Race contestant told People. "But it's good that it's not all over my body."

Doctors confirmed Zohn had a cancer relapse on September 14, ending he hope that he had finally beaten his original April 2009 diagnosis of Stage 2 Hodgkin's disease, a cancer of the body's lymphatic system, People reported.

"I don't want fear or cancer to define me, but it's always in the back of your mind," Zohn, 37, said.

Zohn reportedly underwent SGN-35, a new "smart" form of chemotherapy, in October that was designed to attack only the cancerous cells in his body, avoiding hair loss. Following three months of treatment, Zohn now plans to undergo a second stem-cell treatment from one of his brothers who may be a positive match, according to People

"But the doctors won't tell me which one. They didn't want me to start treating one differently than the other," Zohn explained. "Of course my whole family is taking bets on who it is."

Zohn said his girlfriend of eight years, Jenna Morasca -- who was the winner of Survivor: Amazon and competed with Zohn during The Amazing Race's currently-airing season -- has been very supportive since they learned the bad news.

"She's taking it like the rock star that she is," Zohn told People. "We're both filled with fear and anger and anxiety and gratitude and frustration. But there's so much love there. It's this whole spectrum of emotions."

Despite his relapse, Zohn reportedly intends to participate in the New York City marathon this weekend to raise money for his Grassroot Soccer organization, which promotes HIV/AIDS prevention and education in Africa.

"The doctors think I'm crazy but they gave me the okay. Cancer isn't going to slow me down. I want people to know that you can still live a fulfilled life and move forward," Zohn said.

After learning he suffered from Hodgkin's disease in April 2009, Zohn immediately underwent an "aggressive" three-month chemotherapy schedule that initially yielded positive results in July 2009 following a PET scan.

However, that September, Zohn revealed there was "re-growth" of the cancer cells and he was "resistant to the first form of chemotherapy" -- leading to five weeks of radiation treatments and ultimately a clear PET scan in December 2009 in which he was believed to be cancer free. He received a stem-cell transplant shortly afterwards that served as a precaution.
About The Author: Elizabeth Kwiatkowski
Elizabeth Kwiatkowski is Associate Editor of Reality TV World and has been covering the reality TV genre for more than a decade.