WAUSAU — Of all the diseases we face as women, few may concern us more than breast cancer. Almost certainly, you know someone — a loved one, a friend, a neighbor — whose life has been touched by the disease.

Even though breast cancer is far too common, some facts about it may still surprise you, says Dr. Cecilia Strode, a surgeon on staff at Aspirus Wausau Hospital. Here is a look at five of them:

1. The biggest risk factors for cancer are being female and advanced age. As you get older, your risk of breast cancer goes up. Most breast cancers are found in women ages 55 and older. Less than 5 percent of breast cancers occur in women younger than 40, but breast cancer is the leading cause of cancer death in women ages 20-39.

2. Most breast cancer is not inherited; however a family history does raise your risk. Only 5 percent to 10 percent of all breast cancers appear to develop directly from gene defects – such as those in the BRCA1 or BRCA2 gene – passed on from a parent. A woman with a first-degree relative (mother, sister or daughter) has twice the risk as a woman without any family history. If she has more than one first-degree relative, she has three to four times the risk.

“While having a close relative with breast cancer does raise your risk, less than 15 percent of women who get breast cancer have a family history of the disease,” Strode said.

3. A preventive mastectomy doesn’t completely eliminate the risk of breast cancer. Some women who are at high risk for getting breast cancer opt to have both breasts removed to avoid the disease. A preventive mastectomy can, in fact, reduce the risk of developing breast cancer by 90 percent or more. But some risk still remains, since even a mastectomy can’t remove all breast tissue.

4. Dense breasts are a risk. Women with dense breasts — breasts with more fibrous and glandular tissue and less fatty tissue — have up to twice the risk of breast cancer as a woman with average breast density. Dense breasts may also make mammograms less accurate.

Ask your doctor if your breasts are considered dense — you can’t tell by touching them. If the answer is yes, the two of you can discuss whether you need additional imaging tests, such as an ultrasound or MRI.

5. Obesity plays a factor. Obesity after menopause will increase your risk of breast cancer, with significant increase for women who have gained more than 55 pounds since the age of 18.

Aspirus is a nonprofit, community-directed health system based in Wausau, Wisconsin.

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