Breast Cancer Prevention Now

By Graham A. Colditz, MD, DrPH

It is time to bring our focus back to lowering the risk or reducing the onset of new cases of breast cancer at all ages. Worldwide incidence of the disease is rising as societies across the globe modernize, which brings with it higher rates of breast cancer risk factors, such as overweight, lack of physical activity, and key reproductive factors like beginning families later in life and have fewer children.

While modernization has many important benefits, it is also directly driving up the risk of breast cancer. Globally, one in every four new cancers diagnosed in women is breast cancer, and over 1.7 million new cases are diagnosed each year.

We need a global breast cancer prevention strategy - now.

We currently understand how the longer interval from first menstrual period (menarche) to first baby increases lifetime risk for beast cancer. This interval has expanded over centuries in Western Europe following the Industrial Revolution, and - in dramatic fashion - over just a few decades in Asian countries. Data from China and Korea show a rapid decline in age at first menstrual period since World War II, as well as a decline in number of children, which has accelerated. The age women have their first babies is now above the Organization for Economic Cooperation and Development (OECD) average of 28 years old. This means that a typical woman has 16 or more years between her first period and her first baby (first birth at 28 minus first period at 12 years of age). In 1950 in China, this interval was just three years (first birth at 19 minus first period at 16).

Given these social movements, are there approaches early in life that can help mitigate the impact of these changes in reproductive factors? It appears so.

We, and others, have studied diet and physical activity as two key aspects of lifestyle, and then alcohol intake in later adolescence and early adult life.

• Eating a diet high in fiber and vegetable protein is related to significantly lower risk of both premalignant breast lesions and breast cancer.

• Being more physicaly active from ages 12 to 22 is powerfully protective against breast cancer.

• Avoiding alcohol before first pregnancy is strongly protective against both benign breast lesions and invasive breast cancer.

Together, we need to work to improve diet in children, adolescents, and young adults – fostering access to, and consumption of, fruits, vegetables, and whole grains – as well as reducing alcohol intake among women under age. Especially for high school- and college-aged women, we must create an environment that encourages less alcohol intake. Also important is sustaining physically active lifestyles through the adolescent and early adult years, which has both immediate and long-term benefits.

Multifaceted approaches are needed to achieve such behaviors across a broad set of the population, but doing so will have lasting benefits, not only for breast cancer but also colon cancer, heart disease, stroke, as well as mental health. Momentum in this direction can take time to gather, but is achievable and important, and can have a positive impact for generations to come.

Related posts

Preventing breast cancer: a diet with lots of fruits and vegetables
Reproductive risk factors drive risk of breast cancer in premenopausal women
Peanuts and lower risk of breast cancer
Hey, Mom & Dad, Early Life Can Be Important for Breast Cancer Risk

Reference
Colditz GA & Bohlke K. Priorities for the Primary Prevention of Breast Cancer. CA. DOI: 10.3322/caac.21225

Sitting, Cancer Risk, and Developing Strategies to do Something About It

Photo: Flickr/DanielGo

This post seems a bit cruel, coming out as it does during the current TV season's finale week and the beginning of the World Cup.  But, science doesn't rest - not even for Game of Thrones or the Brazilian national soccer team. So, neither do we.

Just released on the Journal of the National Cancer Institute's website is a new analysis by two German researchers that combined the results from numerous studies on sedentary behavior and found that the simple act of sitting can significantly increase the risk of multiple cancers, including colon cancer, endometrial cancer, and lung cancer.  Even in those who exercised regularly, being sedentary increased cancer risk.

The large analysis looked at data from 43 observational studies that included nearly 70,000 cancer cases.  The researchers found that, compared to those who sat the least, those who sat the most had a 24 percent higher risk of colon cancer, a 32 percent higher risk of endometrial cancer, and a 21 percent higher risk of lung cancer.  When looking only at TV viewing, the risks jumped considerably, with the risk of colon cancer increased by 54 percent and endometrial cancer by 66 percent.

Researchers hypothesized that time spent watching television was linked to greater risk than say, time spent sitting at work, because people who are watching TV are more likely to spend that time eating unhealthy foods, drinking alcohol, and smoking.

Although regular physical activity is a great boon to health, this new report also helped confirm that exercise is not enough on its own to protect against the health risks of an overall sedentary lifestyle.  Even after taking activity level into account, high levels of sedentary behaviors still increased the risk of colon cancer by 20 percent and endometrial cancer by 32 percent (see figure).

In an accompanying editorial, Washington University School of Medicine researchers, Lin Yang and CNiC's Graham Colditz, discuss how the continuing modernization of society sets the stage for increasingly sedentary lifestyles and the negative health effects that go with it.  To successfully combat sedentary lifestyles it will take approaches similar to those that helped rein in tobacco use and that have just started to show some success against obesity. The key is targeting multiple layers of society, and with appropriate resources.  These include worksite policies that can help reduce sitting time (such as, standing desks, regular standing/walking breaks, and active (vs. passive) commuting benefits) and programs focussed on youth that promote physical activities as an attractive choice to sedentary screen time.  

With recent high profile studies, sitting is quickly being recognized as the health risk that it is.  For many years, it was seen simply as the direct opposite of exercise and physical activity.  And while there are clearly close links between the two, it's now clear that it is an important cancer risk factor even in those who exercise regularly.

Because this relationship has taken a while to be broadly recognized, we're behind in developing strategies to effectively address the issue.  As Yang and Colditz state:  "strategies remain poorly defined to meet this goal [of reductions in sedentary behavior]."

Now that we have the results of this latest analysis to further show the impact that sedentary lifestyles are having on our health, it's time to develop an approach to address the issue with the energy and resources that are equal to its impact.

Becoming a Stand-Up: Fighting Disease with Desks

It was hard to miss the headlines this summer telling us that a new federal study confirmed what many disgruntled office workers had long suspected - that their desk jobs may just be killing them.  While the headlines were a bit overblown, they did capture the essence of what more and more evidence is showing, being consistently sedentary for long stretches of time increases the risk of heart disease, cancer, and early death.

In this latest study, women who sat for six hours or more each day were nearly 40 percent more likely to die during the 14 year study period than those who sat less than three hours per day.  Men who sat for six hours or more were 20 percent more likely to die.  

Perhaps most surprising to many, hitting the gym, walking, or doing other physical activities didn't counteract the effects of sitting, though not exercising certainly made the effects of sitting even worse, more than doubling the risk of dying.

With these results, many office workers and their bosses have taken note, and there seems to be a move in corporate America - as well as in home offices - to try to improve health by cutting back on sit-time, largely through innovations in desks.  Forbes.com alone ran at least five stories over the past spring and summer on stand-up desks, including one reviewing some of the current crop that may be seen in both corner offices and cubicles alike.  In October, Wired magazine posted specs on what to look for in stand up desks, including home-spun inexpensive alternatives. And this past Sunday, the New York Times ran an article on the growing acceptance of stand-up desks in the workplace - even the space-gobbling and pricey treadmill desks.

It's a common refrain here on CNiC that our surroundings can have a profound impact on the health choices we all make - or don't make.  It's hard to exercise if there are no sidewalks or parks in your neighborhood.  It's hard to eat healthy food during the day if there's nothing but fast food choices around your school or workplace.

With around 80 percent of US jobs now requiring little if any physical activity, beginning to change the office environment and culture around sitting could have an important impact on employee wellness as well as nationwide health.  Of course, we still need more sidewalks, parks, and produce stands but more stand up desks is still a good move in the right direction. 

Even small breaks are good

A study out this month in the journal Cancer, Epidemiology, Biomarkers & Prevention reviewed the literature on sedentary behavior and cancer. Ten of the 18 studies included in the review found a significant positive association between sedentary behavior and cancer risk - specifically cancers of the colorectum, endometrium, ovaries and prostate. Sedentary behavior isn't just a lack of physical activity - it is prolonged sitting or reclining. Someone can meet the physical activity guidelines of 30 minutes of moderate intensity physical activity each day (e.g., a brisk 30 minute walk) and still be quite sedentary if s/he spends the rest of the day sitting.

This is why more and more public health advocates are touting the value of lifestyle activity - the movement associated with daily living. And some, like Dr. Toni Yancey, are taking it a step further and advocating we build purposeful movement focused breaks into our workplaces. In today's Personal Health column, Jane Brody highlights Dr. Yancey's efforts and her new book "Instant Recess". In her book, Dr. Yancey suggests building two 10-minute breaks of a fun group activity into the work day. These kind of programs have proven successful in the business world at improving the health of employees and at improving productivity. Similar programs in schools have been shown to improve learning.

The value of these recess/activity breaks at reducing cancer risk has yet to be shown, but with so many other positive outcomes - most notably feeling better, they seem like a great idea and one CNiC can definitely get behind!