(FORTUNE Magazine) – Coronary heart disease kills almost six times more women than breast cancer does. Even so, if you ask a woman what disease she's most afraid of, her answer will likely be breast cancer.

There are many risk factors--obesity, having children late in life, hormone replacement therapy, beginning menstruation early and menopause late, the high-dose oral contraceptives that were popular years ago. The risk doubles if one first-degree relative has had breast cancer; it increases fivefold if more than one has been affected.

Only 5% to 10% of breast cancers are primarily due to genetic mutations, but the consequences are significant. For women with a strong family history of breast cancer, we'll check for two specific genes, BRCA1 and BRCA2. When a mutation has occurred, a prophylactic bilateral mastectomy can reduce the risk of developing breast cancer by more than 90%. Because of the horrifying implications for the patient and her daughters, our genetics counselors review and discuss the entire subject with the patient before genetic testing is performed.

For women who are at high risk, one preventive option is tamoxifen, a drug that decreases risk but can cause hot flashes, blood clots, and other side effects. Another drug being studied is raloxifene.

But what is frustrating is that some 75% of all breast cancers occur in women who are not obviously at risk. Although no one has demonstrated that self-exams improve outcome, the truth is that women, not their physicians, discover most lumps. We recommend checking once a month on the same date or just after the menstrual period, when fluid retention is least. If a new lump (they're usually painless) doesn't go away after one cycle, it's time to see a physician.

A recent study published in Britain's Lancet claimed that mammograms don't save lives by detecting breast cancer. Every medical institution has since had its say. Along with the Secretary of Health and Human Services and the American Cancer Society, Mayo firmly believes in yearly mammograms for women over 40.

If anything suspicious turns up on the first view, our radiologists pursue further evaluation with magnification views or ultrasound. If it's called for, we do a fine-needle or core biopsy, sometimes stereotactically (a 3-D process that pinpoints the area). If an open biopsy is required, a surgeon will step in.

Years ago the breast, the lymph nodes, and part of the underlying muscle were removed in most cases. We're much more conservative now. For small cancers, a lumpectomy followed by six weeks of radiation may be all that's needed. In many new cases, we'll sample at least one underarm lymph node as a guide to treatment. For large cancers or cancers that have spread, chemotherapy is an option.

Research is ongoing, and improvements are likely in the coming years. In the meantime, the debate over mammography has, if nothing else, alerted the world to the huge number of breast-cancer survivors. In fact, when breast cancer is detected and treated at an early stage, a woman has a greater than 95% chance of still being alive five years later.

For more information on this topic: Go to mayoclinic.com. Mayo Clinic offers Executive Health programs at Mayo Clinics in Jacksonville, Fla.; Rochester, Minn.; and Scottsdale, Ariz.