Ethan Zohn at the New York City Marathon race expo picking up his official race packet and bib. (Evan Agostini/For SoyJoy)

Ethan Zohn completed the New York City Marathon on Sunday, just one week after revealing that his cancer had returned.

“I'm so sore...but it was worth it. Take THAT [cancer],” Zohn tweeted.

The “Survivor” winner ran the marathon in four hours and 20 minutes. “I'm still so pumped up from yesterday that I cant sleep....or walk...and I love every second of it,” he said on Twitter.

The reality star described the run to People, saying, “It was like walking into a surprise party that was organized just for me. 'Go Ethan! Keep running! Outrun cancer!' It was really an incredible experience.”

Zohn was first diagnosed with Hodgkin’s lymphoma in 2009. He is currently undergoing chemotherapy treatment for the next three months, then will receive a stem-cell transplant.

“Finishing the marathon gave me more confidence and strength. It really felt like all of New York was cheering for me today. And I am going to get through this,” Zohn told People.