Understanding risk of breast cancer

One in eight women in the United States will be diagnosed with breast cancer in her lifetime. However, the good news is that death from breast cancer has declined since the 1990s. For that, we can attribute better screening, early detection, increased awareness, and improved treatments.

Every October, I talk about the risks of breast cancer and encourage you to lower the risks you have control over and get a yearly mammogram. Believe me, I’m not changing my tune now. What I want to focus on today is understanding risk. You see, even though you might be at high risk, it doesn’t necessarily mean that you will develop breast cancer. But, then again, you might.

Susan G. Komen’s website says that knowing the basic types of risk helps you understand your chances of getting breast cancer.

“The most basic type of risk is absolute risk. Absolute risk is a person’s chance of developing a certain disease over a certain period of time. Absolute risk is estimated by looking at a large group of people who are similar in some way (age, for example) and counting how many people in the group develop a certain disease over a certain period of time,” Komen says.

Absolute risks are measured in a time period, say five years, ten years, and lifetime. The one-in-eight statistic I quoted at the top is an absolute risk.

“It doesn’t necessarily mean one in eight women you know will get breast cancer. It’s more that on average, in a group of eight women of varying ages, one in eight would be expected to be diagnosed with breast cancer,” Komen says.

Risk factors are related to genetics, lifestyle, reproduction, and the environment. Of the factors that increase risk, one of the most prevalent is age. It’s an absolute that older women are at higher risk for breast cancer than younger ones.

“A relative risk shows how much higher, how much lower or whether there’s no difference in risk for people with a certain risk factor compared to people without the factor,” Komen says. “A relative risk compares two absolute risks. The numerator (the top number in a fraction) is the absolute risk among people with the risk factor. The denominator (the bottom number) is the absolute risk among those without the risk factor

“The absolute risk of those with the factor divided by the absolute risk of those without the factor gives the relative risk.” Got that?

Think about this. Inactive women have a 25 percent higher risk of breast cancer than active women. Since older women are more likely to get breast cancer, a lack of exercise significantly impacts breast cancer risk in older women than in younger ones. Make sense?

Why would you want to calculate your risk? Because knowing your risk factors and discussing them with your primary care provider will determine things like the frequency of screenings and needed lifestyle changes you’re willing to make.

Although men can get breast cancer, being a woman is the biggest risk factor for the disease. Follow that risk with age. Roughly two out of three invasive breast cancers are found in women 55-plus. In addition, family history plays a part. Komen says that if a first-degree female relative (sister, mother, daughter) is diagnosed with breast cancer, your risk is doubled.

“About five percent to ten percent of breast cancers are thought to be hereditary, caused by abnormal genes passed from parent to child,” Komen says. And, if you’ve been diagnosed with breast cancer, you’re three to four times more likely to have a recurrence in the other breast.

White women are slightly more at risk than those of other races, but black women are more likely to develop more aggressive and more advanced-staged breast cancer while diagnosed at a younger age. Overweight women, especially after menopause, are at higher risk. Women who had their children later in life or have had no children raise the scale.

Then there’s drinking alcohol, having dense breasts, lack of exercise, smoking, hormone replacement therapy, and more. But I’m running out of room. You can research the risks yourself. So, I’ll sign off by reminding you to know the warning signs and to make your appointment for your annual mammogram today.

Kathy Hubbard is a member of the Bonner General Health Foundation Advisory Council. She can be reached at kathyleehubbard@yahoo.com.