"I'm giving up one night of sleep to help cancer research," said comedian Alan King, the master of ceremonies at the gala benefit ball for the District of Columbia division of the American Cancer Society.

So did many of the 1,200 guests who attended the annual fund-raiser on Saturday night at the Washington Hilton.

King had to be in New York City at 6:30 yesterday morning to shoot scenes in a new movie. But for nearly half the guests, the party went on into the early-morning hours until it was time for an elegant breakfast of omelettes with smoked salmon, eggs hussard and bagel with cream cheese.

What started out in 1974 as a wine-and-cheese party, which raised $12,552, has become one of Washington's most stylish and sprightly annual parties and the most successful cancer fund-raising event in the United States.

"We will raise $400,000 this year. That's clear," said Alan I. Kay, who collaborated with his wife, Dianne, as cochairman for the dinner-dance for the second year in a row. "The $200 for a ball ticket goes entirely to cancer research. All that glitter out on the floor is taken care of by contributions from corporations and benefactors."

A sophisticated and dramatic decor greeted guests in the ballroom. Musical "G" clefs in tiny white lights blinked against a background of black-and-red fabric panels. Gigantic ice sculptures--a grand piano, a cello, a huge fish among others--marked the many buffet tables, which dispensed everything from fresh-shucked oysters to roast pheasant with morels and grapes to hazelnut cheesecake diamonds.

Entertainers wandered through the crowd, miming, manipulating puppets, dancing on stilts, enlivening the scene in costumes such as Robot Man or Charlie Chaplin.

Guests were greeted by a receiving line that included the Kays; honorary chairmen Sen. Strom Thurmond (R-S.C.) and Nancy Thurmond; comedian King, and two television and film stars, Linda Blair and Donna Mills.

Mills, who plays the suburban vamp on "Knots Landing," says she doesn't lightly make her choices for charity appearances.

"I check out the ratio of what goes for administrative expenses versus research and benefits," she said, emphasizing her seriousness. "I'm here tonight because it is for a good cause. Not many of us have been untouched by the tragedy of cancer among our relatives of friends. I stopped smoking five years ago."

The door prizes were as lavish as the party--a $2,000 shopping spree at any Hecht's store, two round-trip air tickets to Paris, a one-year lease of a new turbo-charged diesel Mercedes-Benz with a price tag of $31,883 (including a hand-waxing polish job), one-week vacations in exotic spots, and 18-karat gold watches.

The two leading rivals in Washington's mayoral race--Patricia Harris and incumbent Marion Barry--helped draw the winning tickets. Mills chose the winner of a year-long lease on the Mercedes sedan. And, as such things often turn out, it went to Mrs. George Weiss, of Potomac, Md., who already owns two Mercedes.