Thousands of younger women with advanced breast cancer can be saved if they are treated with new batteries of anticancer chemicals after surgery, a government panel said yesterday in an advisory to the medical profession.

"Adjuvant chemotherapy" -- use of combinations of chemicals as well as surgery to combat breast cancers -- was endorsed for all pre-menopausal women with cancer spread to their lymph nodes.

Latest studies show these women have a 45 percent chance of surviving at least five years if they have breast surgery alone, but a 60 percent chance if they they have a year of chemotherapy, too.

The recommendation, one of several on breast cancer treatment and the first saying adjuvant chemotherapy should be made routine for any group, came from a 10-member Consensus Development Panel assembled by the National Institutes of Health.

The panel is one of a series convened by NIH in the past few years to try to make recommendations on unsettled questions -- and get practical recommendations to doctors earlier. Each consists of leading physicians, as well as other scientists and consumers.

One American woman in 11 gets breast cancer at some time, and 108,000 are expected to develop it this year.

Of these, about 40 percent are in their pre-menopause years. Forty to 50 percent of women of all ages have some cancerous spread to their lymph nodes by the time their disease is found. The new recommendation could thus affect around 20,000 women a year.

The panel said adjuvant chemotherapy for post-menopausal women is also showing "encouraging" results, but it will be another few years before enough studies are completed to make these results certain.

The panel definitely recommended against chemotherapy in early, localized disease.

It also recommended against routine use now of still another chemical that is showing early encouraging results. This new drug, called Tamoxiphen, suppresses hormonal activity, and thus tumor growth, in some women with advanced breast cancers.

The best use of anticancer drugs requires close supervision and expertise in all cases, the panel said, and drugs should be given "only by or under the supervision" of a doctor experienced in their use.

In practice, said Dr. Stephen Carter, of Palo Alto, Calif., the panel's chairman, this means treatment should be given and treatment options weighed by "a well-trained oncologic team," a surgeon, pathologist, radiologist and chemotherapist (usually on oncologist or hematologist), as well as a hospital staff member who helps the patient adjust. Carter said many community hospitals now have such teams.

And he emphasized that the panel's recommendations are not intended as rigid rules for every patient, but as guidelines for doctors and patients to discuss.

Many doctors think adjuvant chemotherapy is already well enough established to use in postmenopaual patients too with advanced cnacers.

Many are using Tamoxiphen to try to suppress advanced or recurrent breast cancers. It has far fewer side effects than other so-called hormonal therapies. These include use of the synthetic hormone diethylstillbestrol (DES) and removal of such hormone-produucing organs as the ovaries or the adrenal or pituitary glands.

But chemotherapy has side effects too. It may suppress bone marrow production and increase susceptibility to infection. It may temporarily cause nausea, vomiting, appetite loss, weakness, mouth ulcers and hair loss. In the longer run, there is a chance of heart damage, sterility and, in breast cancer treatment, a chance or two in 100 of actually causing another cancer.

But it is now certain, the panel said, that in pre-menopausal women with advanced breast cancers, chemotherapy's advantages outweigh its risks.

In other cases, Carter said, "You have to sit down with your patient and present the possible advantages and disadvantages, in the light of present -- and rapidly changing -- knowledge.

"Some patients are activists and want 'every chance.' Others may not want to go through a whole year of chemotherapy until we're absolutely sure of its results."