One out of every 11 women develops breast cancer," notes engineer Zsigmond Sagi, "but if a victim can detect the disease in an early stage, it's almost always curable."

With that in mind, Sagi (pronounced shoggy) has invented the Breast Cancer Screening Indicator (BCSI)—a small device that when tucked into a woman's bra will indicate an abnormality long before a lump can be discovered by self-examination. Since Sagi's device can find a tumor the size of a pinhead, it may not only save lives but prevent disfiguring mastectomies. A tiny cancer could be removed with minor surgery. "A woman can't feel cancer," he explains. "It starts in the body years before it is caught. I want the BCSI to be a tool in a woman's hand."

Once marketed, probably next year, the BCSI should diminish the cost of hospitalization for biopsies and the risk of mammographies. It consists of two polyester foam pads, lined with three triangular foil disks that have been treated with heat-sensitive chemicals. Since cancerous tissue is warmer than normal skin, the BCSI registers hot spots. Suspect areas are indicated when green dots on the foil turn opaque white. Any change in color is a signal to see a doctor. A feverish breast is not always, of course, a warning of cancer. It may mean a temporary inflammation or cyst.

The pads, which will cost about $5 a pair (and are not reusable), are inserted into the cups of a close-fitting bra and worn for 15 minutes on the first day of the menstrual cycle. That, Sagi says, "is a time when a woman's body, which has been going through hormonal changes, returns to normal" and is also an easy date to remember. Women past menopause can use a random date each month.

The BCSI is being tested on 250 paid volunteers, aged 38 to 75, by Prof. Betty Hamilton of the Georgetown University School of Medicine. "We hope," Hamilton says, "that a woman will get to know her breast pattern like a thumbprint." Research is being funded by Fabergé, the cosmetics manufacturer, which expects to market the BCSI when it is approved by the Food and Drug Administration.

Sagi, 49, fled his native Budapest in 1956 after the Hungarian revolution and settled in New Jersey, where he spent a decade in the research department of the Singer Company. Among his many inventions for the sewing machine firm is the Zigzag Skip-Stitch. In 1977 he opened his own Arden Laboratories in Whippany, N.J. to develop and market table soccer games. A professional soccer player in his homeland, he oversees a school program in northern New Jersey involving 10,000 youngsters. Lest there be confusion between Sagi's lab and Fabergé's archcompetitor Elizabeth Arden, the company insisted before assuming sponsorship that Sagi change his company's name to BCSI Laboratories.

After his father died of lung cancer in 1978, the inventor, who remains a chain smoker, vowed to try to find a means of combatting the disease. When he read of an infrared-ray screening test used at Manhattan's Sloan-Kettering Institute to detect breast cancer, he conceived the idea that led to the BCSI. (His invention could someday be employed to discover other cancers.)

Sagi, who lives with his wife, Barbara, and sons Zsigmond, 18, and Zultan, 13, in Danville, N.J., is confident that the BCSI will revolutionize breast cancer detection methods. "I have eliminated the word 'impossible' from my vocabulary," Sagi observes. "Everything is possible. I have to believe in what I'm doing. It's the only way."