The issue is not settled, but there is increasing evidence that a woman with a breast cancer that is small and discovered early may not need to have entire breast removed to survive.

A respected Italian cancer surgeon told a National Cancer Institute conference in Bethesda yesterday of doing a far lesser operation - removing only a fourth of the affected breast - in 301 women in the past six years.

The results of this, plus radiation of the remaining tissues, said Dr. Umberto Veronesi, head of Italy's National Cancer Institute in Milan, have been just as good as those in another 302 women who had the traditional kind of cancer surgery performed on nearly 107,000 American women each year. In tradition surgery, the entire breast and some other strutuce are removed.

Fisher has been directing a similar study at 35 American medical centers for two years. He called it the "most important" breast cancer study in the United States today, for if the results are the same as Veronesi's, hundreds of thousands of women may be able to protect both their lives and their bodies.

"We just don't have the data yet" to know, Fisher said, and "we may not know" for another five to six years.

The Italian data, and similar data from other cancer, were nonetheless called "exciting" by a National Cancer Institute expert panel. The Panel was named to try to reach a consensus on the best "standard" treatment today for early breast cancer.

The panel decided that removal of the breast and some underarm lymph nodes should be the standard treatment today for "stage one" and selected case of "stage two" breast cancer. Stage one means cancer at a single site in the breast; state two, cancer that has spread to the underarm nodes.

But the panel found that two possible alternatives "appear" to have good results: Treatment of the cancer by radiation alone and removal of just the affected part of the breast, with or without radiation too. But both alternatives are still in the "early" trial stage, the panel emphasized.

Veronesi agreed with this cautious approach. But he said that if his own wife has a small, early breast cancer - and if she declined to take part in his random trial of partial versus total breast removal - he would recommend that she have only the partial operation.

He made clear that this applies at this point only to women with breast cancers smaller than eigh-tenths of an inch in diameter. About one woman in three with a newly discovered breast cancer has a tumor this small.

Among such women, he said, 150 have been followed in Itlay now for five years. Half had just a quarter of a breast removed, and half the entire breast. All had at least some of the lymph nodes under their arms removed to see if there was any more cancer that required further treatment.

After five years, 88 to 90 percent of each group were alive. Amony Veronesi's entire six-year patient population of 603 women, there have been 20 deaths so far - 10 in the group with the complete breast removal, 10 in the group with the lesser operation.