Since it is difficult to predict who will develop a tumor, doctors must develop methods by which to identify a growth in its early stages. This identification is extremely important in determining the success of treatment.

Troyan said that the best means by which to detect a growth is by the mammogram, a process which accurately identifies 85 to 90 percent of tumors, coupled with a self exam.

According to Hayes, women who are routinely screened are 20 to 30 percent less likely to die as women who are not screened.

Many researchers say that current identification methods are not reliable enough, because they miss 10 to 15 percent of tumors. "We need to find even earlier detection methods, " says Troyan.

Medical School Assistant Professor of Pathology Ann. D. Thor also emphasized the need for early detection and characterization. "The most important thing is to diagnose it, to diagnose it right, and to diagnose it early," says Thor.

Researchers agree that screening should start as early as possible. But the question of how early tumors need to be identified is still up in the air, and some even question whether screening women under the age of 50 is beneficial.

Dr. Daniel B. Kopans, associate professor of radiology at the Medical School, argues that the disadvantage to early screening is the cost of biopsies on benign growths.

"If we screen women under the age of 50, at what age [do we screen], how often, and is there an absolute benefit?" he said.

On another venture to examine the development of tumors, Dr. M. Judah Folkman, Andrus professor of surgery at Children's Hospital and the Medical School, is concentrating on the formation of blood vessels, a process called angiogenesis.

Angiogenesis is directly linked to tumor growth, says Folkman, by the fact that growth is limited by a finite number of blood vessels. Until new blood vessels are formed, a tumor cannot increase dramatically in size.

But when a protein, called bFGF, releases a chemical signal which stimulates the growth of blood vessels, the tumor gains momentum and its cells proliferate, allowing it to enlarge.

Clinical studies currently underway measure both the number of blood vessels and the amount of bFGF which is necessary to "turn on" angiogenests. Scientists believe that high levels of blood vessels and protein will correlate with a higher incidence of breast cancer, allowing for another diagnostic device.

Epidemiological studies, those which collect cast amounts of data useful in predicting risks, are also utilized by some scientists to determine the causes of breast cancer. Dr. Susan I. Troyan, a breast surgeon and director of research at the Faulkner Hospital in Jamaica Plain, is one such researcher.

By gathering data describing both the nature of the tumor, its treatment and the lifestyle of the patient, doctors at the Faulkner hope to target non-biological factors which might correlate to an increased risk of contracting the disease.

Other breast cancer experts deal directly with breast cancer victims, in clinical trials which explore methods by which an already existing disease can be stopped in its tracks.