Federal health officials expect to continue their controversy-ridden program to X ray the breasts of 140,000 women over 50 on the basis of conclusion by a group of experts yesterday that annual X rays will help prevent many future cancer deaths in this age group.

The committee chaired by Dr. Samuel Thier of Yale, advised many restrictions in the federal program as it has been conducted. Dr. Arthur Upton, director of the National Cancer Institute, said these probably would be implemented as soon as possible.

Statistically; one woman in seven can expect to die of breast cancer. It was to try to reduce this toll that the cancer institute and American Cancer Society four years ago began a program that so far has given at least one X ray - and one a year in many cases - to 280,000 women from ages 35 to 74.

Critics have pointed out that in women under 50 the risk of X-ray radiation causing cancer outweighs any known benefits. The Thier committee, completing three days of deliberations at the National Institutes of Health yesterday, agreed.

To help settle the question at all ages, the cancer institute named a review group under Dr. Oliver Beahr's of the Mayo Clinic, and a "consensus" group under Thier to give it advice. Accepting most of the Beahrs group recommendations and often going beyond them, the Thier committee concluded:

That the 27 medical centers (including Georgetown University) which are still examining some 200,000 of the women should finish giving all those over 50, and a small group of younger women should now include only those from 35 to 49 who have had one breast cancer and those from 40 to 49 with a mother or sister who has had breast cancer.

That there is no scientific evidence yet that any women below 50 will have their lives saved by such X-rays. But in the "high risk" group, Thier said, a concerned woman and her doctor may agree that some X-rays are desirable.

That there is also no basis for saying how often younger women should have such X-rays. But despite the panel's more limited advice, one member - Dr. Leo Rigler of the University of California at Los Angeles - said he "personally" would recommend a "base-line" examination in "all" women exams starting at 50.

More studies are needed to explore the value of X-raying younger women, though the panel did not agree on how to conduct them.

That all women in the federal program, and by implication all women getting breast X-rays, should be informed that each "rad" of X-radiation will itself increase their chances of developing cancer by 1 per cent, for instance, from one chancein seven to one chance in 6093 for a single exam, one chance in 6.86 for two.

That no such exam should require more than one rad of radiation at midbreast, and women should be advised how much radiation the test will require.

That in view of the fact that at least 53 women so far have had breasts removed needlessly for what turned out to be benign conditions, three pathologists should review each of the many tiny breast cancers (less than one centimeter in size) and some equivocal kinds of cancers (papillary and intraductal) being found by these X-rays.

Their emphasized that these recommendations apply only to healthy, symptomless women. He said any women with breast lumps or other breast symtoms should not hesitate to have X-rays if doctors need them for their diagnoses.