There was Robert Mitchum, who most recently played Captain Pug Henry in "The Winds of War," undergoing an identity crisis.

Looking out at the crowd gathered for Washington's 10th annual Cancer Ball, Mitchum told of a woman who had greeted him effusively in the receiving line: " 'I almost called you Father,' she said, 'you were so wonderful in "The Thorn Birds." ' " Mitchum, wearing a droll expression, waited as his audience laughed heartily.

Saturday night, the ballroom at the Washington Hilton was transformed into a busy fantasyland, its theme borrowed from Lewis Carroll's "Alice in Wonderland." There was the giggling silly duo of Tweedle Dee and Dum, and the giant and habitually late rabbit (he ran around all evening saying, "I'm late, I'm late . . . for a very important date"). There also was an enormous Humpty Dumpty, who often could be found on the dance floor boogieing to the music of the band, Six Pence. Above the buffet tables stood elaborate ice sculptures of different "Alice" characters.

Although people traded compliments and business cards, many conversations touched on the underlying reason for the ball. Eppie Lederer, known as Ann Landers to her millions of readers, spoke solemnly at her table about the need for cancer research: "One out of every four people is going to get cancer in his or her lifetime . . . Cancer is the most terrifying word in the English language.

"A tremendous amount of progress has been made," she said. "Leukemia was a death sentence 20 years ago." Thanks to research, she explained, that is no longer the case.

Landers was there to receive the American Cancer Society's Stanley G. Kay award in recognition of her work in the fight against cancer. Through her syndicated column she has urged readers to write Congress in support of the National Cancer Act, prompted readers to quit smoking and publicized the importance of self-examination for breast cancer.

Landers, elegantly dressed in a cream-colored sequined gown, was surrounded by a smorgasbord of stars, who were trying (starstruck fans continuously interrupted them to ask for autographed menus) to nibble at some of the buffet-style delicacies that included whole split lobsters, sushi, oysters topped with foie gras and all sorts of pastas. It was a tossup between the stars and the menu as to which was more varied. The celebrity guests included Ana Alicia ("Falcon Crest"), Cliff Robertson (who will be joining the cast of "Falcon Crest" next season in the role of a neurosurgeon) and Priscilla Barnes ("Three's Company").

Robertson sat quietly at the celebrities' table next to Mitchum, intent on finishing a bowl of ice cream and good-naturedly putting his spoon down between bites to pick up a pen and autograph the deluge of menus from a cluster of adoring women. Asked why he was there, he answered lightly, "It helps me absolve myself of some of my Calvinist guilt."

The evening, for which guests paid $250 apiece, raised more than $500,000 for the American Cancer Society, which "is $100,000 more than last year's ball," according to chairman Alan I. Kay, who has chaired the ball for three consecutive years. "It's now become the largest one-night affair for cancer in the world. The money will go to research, patient home care and education." Kay, who lost his brother Stanley to cancer in 1981, has been instrumental in encouraging members of the Washington business community to underwrite the expenses of the ball.

Nina Selin, who was on the ball's executive committee and chose the party's menu, could be seen flitting from the pasta bar to the ice cream bar, then on to the hot appetizer bar--anywhere food could be found--making sure the pasta was spiced correctly, the ice cream was hard enough, the hors d'oeuvres were bite-sized. She wanted the food to be perfect. "I don't do this for the glory . . . I do it because I care . . . I care because I had cancer. When I was getting radiation treatment at Sloan-Kettering I saw kids with shaved heads . . . I care because it's something you can do something about."