A new study from the National Cancer Institute: the number of breast cancer cases diagnosed each year in the U.S. could rise 50 percent in the next 15 years. The study estimates that by 2030, there will be 441,000 new breast cancers diagnosed yearly in U.S. women ages 30 to 84. That's up from 283,000 breast cancer cases in 2011.

Why Breast Cancer Cases Are on the Rise

Reasons for the rise in breast cancer cases, according to researchers are:

• Population is growing, so there will be more cases
• People are also living longer, and cancer risk increases with age
• Different generations of women may also have differences in lifestyle factors that could affect the risk of breast cancer

For example, women in today's older generations may have been less likely to have breastfed their children. New estimates include cases of both invasive breast cancer and "in situ" conditions

• In situ aka ER-positive breast cancer (driven by estrogen)
  • Considered either the earliest form of breast cancer, or a precancerous state
  • Detected almost entirely through screening, but in the new study, the researchers assumed that levels of screening would remain about the same as they are now

More Breast Cancer in Older Women

Researchers predict more breast cancers diagnosed in older women:

• Breast cancers in women ages 70 to 84expected to account for 35 percent of cases in 2030
• Accounted for 24 percent of all cases in 2011
• In contrast, proportion of breast cancers in women ages 50 to 69 is expected to decrease from 55 percent to 44 percent

Researchers are also estimating that the proportion of in situ cases driven by estrogen will increase:

• Expected to account for 29 percent in 2030
• Accounted for 19 percent of all in situ cases in 2011

The good news is the study estimates there will be fewer breast tumors that are not driven by estrogen (ER-negative breast cancer), which are the most difficult types of breast cancer to treat. The reason for this decrease is unknown but may be due to an increase in women both breastfeeding or delaying their first pregnancy.

A younger age at first pregnancy, and not breastfeeding have both been linked with an increased risk of ER-negative breast cancer. Researchers came up with estimates by analyzing data from the National Cancer Institute and took into account population projections from the U.S. Census Bureau. They then used a mathematical model to make their predictions.

Samadi's Take: More Research is Needed

More research must be done on why ER-negative breast cancers are declining. It may provide researchers with clues about how to prevent this type of breast cancer. We have no sure way to prevent breast cancer, but there are things you can do to reduce your risk, like changing risk factors that are under your control.

But we are certain that obesity, little to no physical activity, and poor diet have all been linked to breast cancer.

Breast Cancer Risk Factors:

• Being a woman is the biggest risk factor for developing breast cancer. About 190,000 new cases of invasive breast cancer and 60,000 cases of non-invasive breast cancer this year in American women.
  
• Age. As with many other diseases, your risk of breast cancer goes up as you get older. About 2 out of 3 invasive breast cancers are found in women 55 or older.
  
• Family history. Women with close relatives who've been diagnosed with breast cancer have a higher risk of developing the disease. If you've had one first-degree female relative (sister, mother, daughter) diagnosed with breast cancer, your risk is doubled.
  
• Genetics. About 5% to 10% of breast cancers are thought to be hereditary, caused by abnormal genes passed from parent to child.
  
• Personal history of breast cancer. If you've been diagnosed with breast cancer, you're 3 to 4 times more likely to develop a new cancer in the other breast or a different part of the same breast. 
  
• Radiation of face or chest before age 30.If you had radiation to the chest to treat another cancer (not breast cancer), such as Hodgkin's disease or non-Hodgkin's lymphoma, you have a higher-than-average risk of breast cancer. If you had radiation to the face at an adolescent to treat acne (something that’s no longer done), you are at higher risk of developing breast cancer later in life.
  
• Certain breast changes. If you've been diagnosed with certain benign (not cancer) breast conditions, you may have a higher risk of breast cancer.
  
• Race/ethnicity. White women are slightly more likely to develop breast cancer than African American, Hispanic, and Asian women. But African American women are more likely to develop more aggressive, more advanced-stage breast cancer that is diagnosed at a young age.
  
• Being overweight. Overweight and obese women have a higher risk of being diagnosed with breast cancer compared to women who maintain a healthy weight, especially after menopause. Being overweight also can increase the risk of the breast cancer coming back in women who have had the disease.
  
• Pregnancy history. Women who haven’t had a full-term pregnancy or have their first child after age 30 have a higher risk of breast cancer compared to women who gave birth before age 30.
  
• Breastfeeding history. Breastfeeding can lower breast cancer risk, especially if a woman breastfeeds for longer than 1 year.
  
• Menstrual history. Women who started menstruating younger than age 12 have a higher risk of breast cancer later in life. The same is true for women who go through menopause when they're older than 55.
  
• Using hormone replacement therapy.Current or recent past users of HRT have a higher risk of being diagnosed with breast cancer. Since 2002 when research linked HRT and risk, the number of women taking HRT has dropped dramatically.
  
• Drinking alcohol. Research consistently shows that drinking alcohol increases a woman's risk of breast cancer.
  
• Lack of exercise. Research shows a link between exercising regularly at a moderate or intense level for 4 to 7 hours per week and a lower risk of breast cancer.
  
• Smoking. Smoking is linked to a higher risk of breast cancer in younger, pre-menopausal women. Research also has shown that there may be link between very heavy second-hand smoke exposure and breast cancer risk in postmenopausal women.