Photo/Illutration Junichi Okubo, a cancer survivor, runs near the Imperial Palace in Tokyo in February. (Ryo Ikeda)

Where Junichi Okubo was once told that he likely had only several years to live and could walk a mere five meters, now he’s able to run a 250-kilometer race.

Okubo, 55, a cancer survivor who still suffers from a pulmonary dysfunction, completed the grueling race in the Marathon des Sables in Morocco last spring.

With one-third of his lungs not functioning due to interstitial pneumonia, Okubo continues practicing to break his own record for a full marathon of 3 hours and 25 minutes set 16 years ago.

“I want to prove that I can still improve on what I did before developing carcinoma,” he said.

A native of Nagano Prefecture, Okubo was an employee of a foreign-affiliated brokerage. In 1999, he began running at the suggestion of a business acquaintance.

Okubo, who was initially reluctant, gradually came to love the sport. The harder he trained, the faster he could run. He made it to the finish line in the Lake Saroma 100-km Ultra Marathon in Hokkaido every year since 2003.

In 2007, Okubo was diagnosed with testicular cancer when he was hospitalized for a broken leg. He was 42. The tumors had spread to his abdomen, lungs and neck. He also came down with interstitial pneumonia.

He was told by a doctor that the five-year survival rate was 20 percent or lower.

Battling the harsh prognosis, Okubo put up a poster for the 100-km race in Hokkaido on the wall of his hospital room. He could think positively while looking at it, although how treatment would turn out was uncertain.

“I want to stand on the starting line again free of cancer someday,” he recalled thinking at the time.

Nine months later, he left the hospital. Okubo could walk no more than 5 meters. His doctor told him that it would be difficult to compete in a marathon again.

Okubo worked hard to rehabilitate himself and completed the 100-km race in 2013 for the first time in seven years. It took him an additional two years to break his own record in the competition.

Okubo also operates the 5 Years website, one of the nation’s largest online forums for cancer survivors to interact with one another. The number of registered members topped 8,600 in its five years of operations.

“It’s not the end of the world even if one develops cancer,” Okubo says.