DAYTONA BEACH, Fla. — The share of doctors who use breast X-rays to look for cancer in symptom-free women has doubled to nearly 100 percent in five years, marking a milestone in early cancer detection, said the president of the American Cancer Society.

Ninety-six percent of physicians said last year they used mammograms to screen symptom-free women at least some of the time, compared with 49 percent in a 1984 survey, said Dr. Robert Schweitzer.

While that does not mean all women are receiving the mammograms as often as the cancer society recommends, the trend is “an important milestone in the road toward that goal,” Schweitzer said.

The percentage of doctors who said they met or exceeded the cancer society’s recommended mammogram guidelines tripled, from 11 percent in 1984 to 37 percent in 1989.

Schweitzer discussed the survey findings at a science writers conference sponsored by the cancer society.

Under the society’s guidelines, a woman with no symptoms of breast cancer should get a mammogram between ages 35 and 39, a test that serves as a “baseline” for comparison in future tests. Women 40 to 49 should have a breast X-ray every one to two years, depending on physical condition and previous mammogram results, and those age 50 and over should have one every year.

Mammograms and other cancer screening tests are aimed at finding cancer in its early stages, when it is more curable.

The physician survey was commissioned by the cancer society. It covered 1,029 general and family practitioners, internists and obstetricians and gynecologists.

Results were weighted so that the percentages would reflect all doctors in those specialties now practicing in the continental United States. The margin of error was generally plus or minus 2 percent to 3 percent.

Sixty-one percent of physicians said they were giving greater emphasis to early breast cancer detection in symptom-free patients than they had five years ago. In 1984, 39 percent had said they were giving it increased emphasis.

Forty-four percent said they were putting greater emphasis specifically on mammograms last year, compared with 14 percent in 1984.

The survey also found that the number of doctors who check for blood in the stool, a potential sign of colorectal cancer, rose from 75 percent in 1984 to 89 percent in 1989.

Schweitzer said the only screening test not reported to be widely used was proctosigmoidoscopy, in which a tube-shaped device is used for inspecting the colon. Forty-nine percent of doctors reported using that test last year, up from 35 percent in 1984.

Only 23 percent of physicians said last year that they followed or exceeded cancer society guidelines for the test, which the society recommends every three to five years in symptom-free persons age 50 and over.

Forty-one percent of doctors said they use chest X-rays to screen symptom-free patients, a practice the cancer society does not recommend.