By Debbie Saslow, PhD

There are a limited number of things that women can do to lower their risk of breast cancer, including getting regular physical activity, limiting alcohol, and maintaining a healthy weight. Breastfeeding has often been included in the protective behaviors against breast cancer, but the research has been inconsistent.

Looking at the research on breastfeeding and breast cancer risk, it is clear that this has been a difficult area to study. If breastfeeding does lower risk, the level of protection is small and depends on women breastfeeding for a long time.  In countries such as the U.S., most women who breastfeed their babies stop after several months, or they breastfeed less frequently as they start to supplement with formula and baby food. Women who have many children and breastfeed each baby for a long time seem to be at somewhat lower risk of breast cancer than women who have smaller families and breastfeed for a shorter time. Studies that have found that breastfeeding does lower breast cancer risk have also found that protection builds up over time (that is, duration of breastfeeding) and number of children that are breastfed.

The major study (Collaborative Group on Hormonal Factors in Breast Cancer; Lancet, 2002 Jul 20; 360 (9328): 187-95) that supports breastfeeding as protective against breast cancer was published in 2002. The researchers analyzed 47 studies in 30 countries; these studies had information about 50,000 women with invasive breast cancers and 97,000 women without breast cancer.  The study authors found that the rate of breast cancer diagnoses was slightly lower among women who had breastfed and among women who had breastfed for longer periods of time. More...

The Relationship between Weight and Breast Cancer

By Lauren Teras, PhD

Breast cancer is the most common cancer among women today. More than 1 million women world-wide are diagnosed with this cancer each year, mostly in the 50 and older age group.  Breast Cancer Awareness Month highlights this international public health problem, and it is a good time to consider ways in which we can reduce our risk of this cancer.  While many factors beyond our control contribute to risk, like age and family history, we do know of a few ways we can lower the risk of breast cancer.

Worldwide obesity has more than doubled since 1980. Once considered a problem only in high income countries, being overweight and obese is now dramatically on the rise all over the world, particularly in urban areas. As of 2008, the World Health Organization estimated that 1.4 billion adults were overweight, including 300 million obese individuals.  In the year 2000, for the first time in human history, the number of adults worldwide who were overweight was greater than the number of adults who were underweight. In fact, approximately 65% of the world's population lives in countries where being overweight and obese kills more people than being underweight. The U.S. is near the front of the pack as the country with the 4^th highest rate of obesity; about 2/3 of people in America are overweight, including approximately 1/3 are obese. More...

By Marji McCullough, ScD, RD

Before writing a blog about soy and breast cancer, I took an informal poll of a few friends to get a sense of what women believe about soy.  I asked them, "What do you know about eating soy food?  Is it good for you? Not good for you?" (I didn't even mention breast cancer.)  The responses I got were,  "I think it acts like estrogen in the body"; "Consuming any soy products increases the risk of breast cancer"; "I don't eat it a lot because I heard something negative but I can't remember what it was;" and "I've heard you should only have it in moderation."  Apparently, people are hearing that soy may not be good. But what's the truth? In this blog I'll walk you through what we know and what we don't know about soy and breast cancer, and give you some practical tips on eating soy. More...

By Mia M. Gaudet, PhD

Certain types of cancer often seem to run in families. Sometimes, it's because families share certain risk factors (like smoking) that can cause cancer. Other times, though, there is an inherited link - a slight difference in the genetic code that is passed down from generation to generation.

Only about 5% - 10% of all cancers are inherited. It's an important area of research because identifying genetic causes of cancer could help us understand who might need to be screened for a certain type of cancer more often, or take other steps to protect themselves from this disease. This is the first blog in a series where we'll explore what researchers have learned about some of the cancers that have a strong genetic link, and who might be candidates for genetic counseling and testing. Today we'll focus on breast cancer. More...

By Ted Gansler, MD, MBA, MPH

You have probably seen and heard a lot about breast cancer during the past few weeks, but as we approach the end of this year's breast cancer awareness month this is a good time to ask how much of the information you encountered is actually true. See if you know which of the following statements are true and which are false... More...

By Debbie Saslow, PhD

A recent study has shown that for some women diagnosed with breast cancer, extensive lymph node surgery isn't needed. This is great news because removal of lymph nodes in the armpit area can have debilitating and life-long side effects.

Here is a little background: In the United States, about 210,000 new cases of invasive breast cancer will be diagnosed this year. Of the invasive cancers, about 30% of cases, or 63,000 cancers, will be diagnosed at the "regional stage," which means the cancer has spread to nearby lymph nodes. The findings of this study are important for women in this group.

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