Editor's note: Moses Christian completed the Los Angeles Marathon on March 9, finishing the course with a time of 9:36:01.

It's possible that Sunday's Asics Los Angeles Marathon will be the last race for Moses Christian. Or, it could be the start of a new streak.

It's hard to say, because Christian is 81 and finally feeling the full impact of the prostate cancer he's battled for 19 years. He's been amazingly resilient, but the only certainty is that Christian will start Sunday's marathon. He's made up his mind.

And if he starts, he'll finish.

Christian has entered 182 official marathons and completed every one. He's not fast, and is in fact getting noticeably slower. But Christian -- who usually runs with a pink Loma Linda Lopers running club hat and blue running shorts -- is determined.

"Let me tell you, there were many times I could have stopped," says Christian, a still-practicing physician and surgeon in Los Angeles who began running at 61. "But I have finished all my marathons. Once I started, whether pain or no pain, I finished. So I intend to finish it."

Since 1999, Christian had run at least one marathon every month, combating his cancer the entire time with a holistic approach that emphasized a good diet, sleep, exercise and reducing his stress. He chose not to have surgery, chemotherapy or radiation treatments. After he ran a marathon last November, however, Christian's streak came to an end.

In December, he felt intense pain in his upper back. The cancer had spread to his spine, and Christian was hospitalized.

"He was really sick and he thought that was it, that it had spread everywhere and that he was going to die," says his wife, Lena.

Yet gradually, the pain subsided and his status improved enough to allow him to go home. Eventually, he went back to work and began walking again, with the help of some cousins who came over to visit. Then, said Lena, her husband made a pronouncement.

The entirety of the L.A. Marathon experience kept Moses Christian coming back year after year. Joe Klamar/AFP/Getty Images

"Suddenly I heard, 'I think I can walk the L.A. Marathon,'" she says. "No, I didn't expect it."

So on Sunday, Christian will walk the route, with his cousins by his side. After not doing a marathon for three months, he's back on the roads of Los Angeles. There was a time he could finish a marathon in just under five hours. Then his time slipped to six hours and eventually 6½. It could take him nine hours Sunday, though he says if he starts feeling good, "I may do a little running, also."

He has completed the Los Angeles Marathon every year but one since 1994 and feels its pull again. Moving, feeling good, being a part of the whole scene, it just makes him happy.

"But the main thing is, I want to finish it," he says. "I want to get the medal."

The streak

Christian, a general-practice physician and surgeon who lives in the L.A. suburb of Loma Linda, was born in India, where he attended medical school. Later he studied in Canada and the U.S., which became his home in 1967. He had never been a runner when his cousin, Devadas Moses, also a physician, coaxed him into running when Christian was 61.

Once he started and joined the Loma Linda Lopers, he became intrigued with doing a marathon.

"I wondered how people ever do 26 miles," he said. "Because they are human beings, and I'm a human being, if they can do it I am also going to do it. So I wanted to prove to myself I can do one marathon."

Then after doing his first, in Carlsbad, Calif., he did a second, the Los Angeles Marathon.

"No doubt, when you do the marathon, it's hard, but after you finish, the enjoyment, the glory, the finish line, the medal, people congratulating you, it boosts your ego so much that you never want to stop," he says, laughing.

Christian loved running marathons so much he often ran unofficial routes of his own. He counts 182 official marathons and about 37 others.

"He'd do a marathon in the evenings," says his son, Rajan, 44, who lives in nearby Redlands. "On the streets behind his house. He'd leave at 10 and come back at like 4 a.m. 'I just did a marathon.' He's got incredible discipline."

By 1999, Christian had decided to do at least one marathon a month, and his love affair with running took him all over the United States; to Dubai, Nepal and Canada; and to the African continent. He once climbed Mt. Kilimanjaro in Tanzania, then ran a marathon the next day.

He still marvels at the beauty of the Big Sur Marathon, and the peace and joy he felt to be a part of it. And he was at Boston in 2013 when the race was stopped because of the bombings, taking off down streets away from the cordoned-off finish area to complete his 26.2 miles.

Running and completing races became his passion, and his medals came to decorate his home and office. He admits his streak, which lasted nearly 14 years, became something he treasured.

"It was just a challenge," he says. "Once you do one a month, you want to make sure you do the next one, too. At times when your legs are hurting and you're in pain, I said, 'No, no, I must do it anyway.' So it's just a streak. Once you have a streak, you don't want to break it."

Running with cancer

All the while, Christian was running with prostate cancer, diagnosed in 1994. When he learned of his disease Christian decided against surgery or chemo and radiation treatments because of their often toxic side effects.

As a physician he knew the pros and cons, and as a Seventh-Day Adventist he had faith in a more holistic approach to deal with the cancer. He believed his vegetarian/vegan diet and exercise would boost his immune system, and for 19 years he was able to live the life he wanted.

"I did a full-time job as a doctor and I kept running quite freely and the doctors were surprised that I lived this long and carried on a very healthful life," he says.

At 61, he says his doctor told him he would have two or three years to live.

As Christian approaches the finish line in life, he's grateful for what running has given him. Courtesy of Moses Christian

"So 61 became 65," he says. "Nothing happened. Seventy, 75. I said, 'My, God has been good to me. I still live.' And I come to 80, 81½, now I'm getting more pains and I have to face the fact that one of these days I will go. And I will be happy that, thank God, I lived much longer than I expected, and I will be happy to do what God wants me to do."

After returning from the hospital in December, Christian had no energy. His wife says he was in pain and depressed until one day in January when a surgeon friend called to ask Christian to assist him on a surgery.

"He went that morning and he came back that evening a totally different man, with a spring in his step," says Lena Christian. "From that day, he's been going to work."

And it got him moving again. Christian isn't certain if he'll be able to do another marathon after Sunday. He wants to, but says it depends on his health. The cancer is in his bones, but has not yet spread to his soft tissue, he says. That may give him more time. He intends to maintain a positive attitude and see what happens.

"I think a lot of it is in the mind," he says.

His son, Rajan, is also a marathoner, having run 75 races, including more than 70 with his father since 2007. He's not certain if his father will be able to do another marathon after Sunday.

"But I'm surprised he's even doing this one, honestly," he says.

Rajan attributes much of what his father has been able to accomplish to his positive outlook and integrative lifestyle. He says his father's running makes him happy, his diet keeps him healthy, his work keeps him sharp and connected, his faith fuels his spirit and his willingness to give and to help others spreads more positive energy into the world.

Rajan says his father has done overseas missionary work, given money to help build medical clinics and donated time and money to help Christian's sister's orphanage in India.

"He donates his time, his skill and his money. He's done that for years," says Rajan, who adds that his father has "this mind-body connection that keeps him going."

Feeling blessed

When Christian walks to the starting line Sunday, he won't be the oldest runner in the race. He will be outranked by at least five others, two of whom are 86. He also won't be the fastest, most famous, shortest or tallest, but he may be the most grateful after discovering running at a late age and being able to enjoy it for so long.

The octogenarian with the pink hat and the slow gait believes running has not only added much pleasure to his life, but says it's helped sustain his body and soul. He talks about the endorphins it creates and how exercise is an elixir.

"After you finish you feel happy," he says. "That's why they say it's good for people who have depression and anxiety and sleeplessness ... Any disease, you name it.

"It's wonderful."