What if you held a marathon and hardly anyone came?

That's what's worrying Sam LaBeach, director of Sunday's District of Columbia Marathon. As of mid-day yesterday, 1,105 runners had registered for the sixth annual race, compared with the 2,300 in 1984.

LaBeach said this week he will consider several options for future races, including finding a sponsor and offering prize and appearance money, or going to a shorter distance, perhaps converting the race to a half-marathon or 10-kilometer event.

"I was hoping we would have grown larger than we are," said LaBeach, who is deputy director of the D.C. Recreation Department. "This is the race's sixth year. I was hoping to have 4,000 or 5,000 runners. I was hoping for at least 3,000. I haven't attained that goal. We're going to evaluate our race after this year. We're going to evaluate it in terms of participation, just like when we got the original requests."

Registration will continue until 8 p.m. today at the L'Enfant Plaza Hotel in Southwest. LaBeach anticipates the usual accelerated prerace sign up. But its the trend that concerns him.

"It's going to be a hard decision," he said. "I hope people don't come to me and say, 'Why did you drop the marathon?' If the folks aren't interested, we have to find out what they want."

The original requests to stage a marathon came a decade ago, when fitness suddenly became increasingly prominent in the news, and the question of whether Washington would have its own marathon became a minor civic issue.

"We got 50 to 100 letters asking why Washington didn't have a marathon," he said. "But it wasn't so much the mail. It was the telephone. 'Why don't you put on a marathon?' "

So back in the mid-1970s, LaBeach answered the call. And Washington got what it wanted. And now, like a child who has eaten too much, it may be asking itself if it really wants what it has.

What it has is a spring marathon, to complement the older, more popular fall Marine Corps Marathon whose entry figures had increased consistently before leveling off this year. Still, the Marines have had more than 10,000 recruits the past four years.

D.C. Marathon runners also got a course that meanders through the city's eight wards. Still, it was a combined package that attracted 2,300 people at the zenith of its popularity in 1984.

Meanwhile, LaBeach works hard on this year's race and wonders about its future, considering possible changes in its format.

He says he could upgrade the guest list. Or he could give out nicer party favors. Or he could shorten the extravaganza.

"If it means running a half-marathon or a shorter race, we may have to," he said. "Also, I'm prepared to have a public relations person pursue a major sponsor. The only way to increase participation is to offer prize money."

The D.C. race is one of the few big-city marathons that offers no prize money and offers no appearance fees. Even the Boston Marathon, which long balked, finally decided to dole out the dollars for its 90th race, April 21. Almost immediately, the Boston event had its prestige restored.

The D.C. marathon will give out a few prizes to top finishers, but no cash. "Offering a TV set or a VHS is infinitesimal compared with the big money from the other cities," said LaBeach.

Another suggestion entertained by LaBeach is the idea of trying to attract competitors from around the world. "The members of the board have suggested we go international," he said. "An international competition would have a different flavor and we'd be approaching it from a different level."

A different level indeed, but a departure from the original idea. "The reason why we put on our marathon was to give hometown residents a chance to compete in a race," LaBeach said. "It was designed for our citizens.