Rose Kushner's 1974 breast cancer helped change the treatment-of-choice for this still unconquered disease that strikes an estimated 115,000 women in this country every year and kills about 30 percent of them.

Her recurrence three years ago may do the same thing.

In the last decade, activist Kushner and some sympathetic gynecologists and researchers have been able to demonstrate that the once-routine Halstead radical mastectomy -- painful, disfiguring and demoralizing -- was no more effective than lesser procedures in the long-term survival of breast cancer victims.

Moreover, the practice of allowing a woman to go into a hospital for a "biopsy" and wake up with a mastectomy was discredited. The two-step procedure -- biopsy first, decision about treatment afterwards -- was found not to affect the spread of the disease, and is now recommended by cancer experts. In some states, the two-step procedure is a legal right.

Some women still wake up from a biopsy to discover a breast removed, and the Halstead radical is still done -- but less often.

But even while these controversies simmer, new ones continue to arise. One concerns the extent of breast surgery necessary. The other involves the widespread acceptance and, says Kushner, "indiscriminate use" of adjuvant chemotherapy -- treatment with extremely toxic chemicals -- along with the cancer surgery.

Kushner is a journalist and author whose cancer led her to her expertise and activism, including membership on the National Cancer Advisory Board. She discovered, after her cancer recurred, that a new and ominous movement was taking hold among breast cancer clinicians -- the routine, even wholesale, use of adjuvant chemotherapy based often on studies that have failed to withstand scientific scrutiny.

The current issue of CA, the American Cancer Society Journal for Clinicians, contains an article by Kushner wondering "Is Aggressive Adjuvant Chemotherapy the Halsted Radical of the '80s?" In other words, is it "therapeutic overkill" to use toxic chemicals that kill healthy as well as cancerous cells and compromise the quality of a patient's life by causing "baldness, nausea and vomiting, diarrhea, clogged veins, financial problems, broken marriages, disturbed children, loss of libido and loss of self-esteem. . ."?

Based on her study of published and unpublished material, and her presence at professional meetings, Kushner concludes that "most evidence today indicates that the toxic regimens are of only marginal benefit to the vast majority of women who develop breast cancer."

Two of her major findings:

The government's SEER program -- the "Surveillance, Epidemiology and End Result" survey and follow-up of breast cancer patients -- found that of some 60,000 followed from 1973 to 1980, "those who were given only a single course of cytotoxic cell-killing chemotherapy had more than eight times the relative risk of developing a type of leukemia within three years after treatment" than did women who did not receive the chemotherapy.

"Many adjuvant drugs could damage chromosomes and create a mutant strain of new cancer cells that are then resistant to most weapons we now have in our anticancer arsenal," evidence now suggests. In other words, even if the drugs might increase the time before a recurrence occurred, the recurring cancer might not then respond to any treatment.

Chemotherapy -- the use of drugs to kill or immobilize cancer cells -- has been highly successful in controlling certain cancers such as childhood leukemias and Hodgkin's disease. Kushner emphasizes that the evidence building up against its use as an adjunct to other breast cancer treatments -- surgery or radiation -- does not diminish its usefulness in these other cancers. Because concern is broadening, the issue of adjuvant treatments for breast cancer will be reviewed at a National Institutes of Health concensus development conference in September. Meanwhile, Kushner will continue her campaign to include quality-of-life considerations in decisions on treatment. And she will continue to wage her own anti-breast cancer war on other fronts.

For example, she was treated with a relatively new drug, an anti-estrogen agent called tamoxifen, sold under the brand name Nolvadex. It appears to have virtually no side effects, and preliminary reports from studies awaiting publication suggest that -- especially in postmenopausal women, who account for about 80 percent of the breast cancers -- it is probably the best choice of treatment, along with whatever surgery is elected. Newest information, says Kushner, suggests that women on tamoxifen -- a hormonal therapy -- can elect chemotherapy later, if needed. But tamoxifen therapy is less successful on women who already have had chemotherapy.

Researchers believe that the antiestrogen agent acts by preventing the cancer cell from dividing, probably meaning that she will have to use the drug for the rest of her life. However, Kushner notes. "I still have my hair, and I feel great."

Now, about 11 years after her primary breast cancer, Kushner has discovered that it may have been caused by the diethylstilbestrol (DES) she took during one of her pregnancies. It has been known for some years that the female children of DES mothers were especially vulnerable to vaginal cancers. A recent study, published in the November New England Journal of Medicine -- documented a "moderately increased" incidence of breast cancer in women who took DES. Kushner is involved in this controversy as well, as women's groups prepare a class-action suit similar to the one filed on behalf of the DES daughters.

Results of another expected-to-be-published study are beginning to trickle out of professional conferences. The study will demonstrate, The Wall Street Journal reported recently, that for about 60 percent of breast cancer victims, the simple removal of the cancer -- a so-called lumpectomy -- may be all the surgery needed. Financed by the National Cancer Institute and headed by Dr. Bernard Fisher of the University of Pittsburgh, the study is expected to find this: In three groups of women treated by modified mastectomy, lumpectomy or lumpectomy with radiation, there was no significant difference in survival or rate of recurrence. The Wall Street Journal article was based on a speech Fisher made to a Canadian medical conference. Resources

Rose Kushner's book "Alternatives" ($12.95, 427 pp., Kensington Press) and other information is available from the Breast Cancer Advisory Center, P.O. Box 224, Kensington, Md. 20895.

For information and an updated copy of "The Breast Cancer Digest," write Breast Cancer, National Cancer Institute, Bethesda, Md. 20205 or call 800-4-CANCER. (In the District and Northern Virginia, call 636-5700.)

To participate in free experimental breast cancer treatments, call Dr. Peggie Findlay, National Cancer Institute, (301) 496-5457.