Fifty-three women in a federal cancer detection program had breasts removed needlessly for what turned out to be noncancerous conditions, a panel of scientists told the National Cancer Institute yesterday.

The panel was named by the institute to help decide whether to continue a nationwide program giving 200,000 women annual breast X-rays and other tests to seek cancers.

Dr. John Bailar, editor of the Journal of the National Cancer Institute and a critic of the X-ray program, called the new discovery "appalling."

Dr. Oliver H. Beahrs of the Mayo Clinic, chairman of the scientific advisory group, was less critical.

He called the result "not unexpected" since use of the X-rays finds many very early and tiny cancers and many equivocal or puzzling lesions.

Nonetheless, he and his panel recommended that in the future "concurrent" pathological review be used - that is, review by more than one pathologist - on all "minimal" lesions that might be cancerous or otherwise threatening.

Dr. Charles Smart of Salt Lake City, who chaired the treatment review group of Beahrs' panel, said the 53 cases probably represent only a few of many such misjudgments being made in "close calls" by pathologists in hospitals all over the country.

More and more, he said, leaders among both surgeons and pathologists are recommending that in such minimal or doubtful cases, surgery be not immediately performed. Breasts are frequently removed immediately following a biopsy, where a pathologist looks at a quickly frozen section of the breast tissue.

In such cases, said Smart, an increasing number of authorities believe that surgery should wait for more careful laboratory studies, even though these take a few days.

The Beahrs panel also recommended that the cancer institute complete its three-year-old effort to give a large number of the 200,000 women an Xray every year for five years.

The panel said the study shows "promise" that finding early cancers will lead to more cures. The project has found some 2,500 cancers since its start in 1973.

But because of the fear that the repeated X-rays may cause more cancer than they cure, the panel recommended that the NCI further narrow the numbers of women given such tests.

The NCI-American Cancer Society project originally sought to give annual Xrays and other tests to women aged 35 to 74. Early this year the NCI recommended that routine Xrays be limited to women over 50, and used in women aged 35 to 49 only if they had a previous breast cancer or a mother or a sister who had breast cancer.

Yesterday the panel urged changing the last part of that guideline to limit the regular Xrays in women aged 35 to 39 to those who already had a breast cancer and therefore face the highest risk of developing another.

The panel also recommended dropping thermography tests, which seek to detect cancers by focusing on the heat they emit, from the screening, since the test has been missing too many cancers.

The panel said the Xrays are finding hundreds of very early, still noninvasive and very tiny cancers and equivocal, possible cancerous conditions that would never be found by any other method.

This very achievement, said Dr. Beahrs, is forcing pathologists into making many difficult decision over whether a given lesion is "malignant," that is, cancerous, or "benign."

These case, he said, would include the 53 that the panel's expert pathologists believe to be benign, though pathologists at the hospitals where the women were treated called them malignant.

The 53 represent 11 per cent of 462 "minimal" cancers reviewed by the panel, but only 2.9 per cent of all 1,810 apparent cancers discovered by the project from January, 1973, to June, 1976.