Breast Cancer Prevention Starts in Childhood

Linda Brookes, MSc; Graham A. Colditz, MD, DrPH

December 08, 2014

Editor's Note: Should breast cancer prevention begin in childhood? Although recommendations for prevention of breast cancer focus primarily on middle-aged women, some researchers advocate beginning risk modification in early life. Foremost among them is Graham A. Colditz, MD, DrPH, Niess-Gain Professor and chief of the Division of Public Health Sciences of the Department of Surgery at Washington University School of Medicine in St. Louis, Missouri.

Earlier in the year, Dr Colditz was presented with the 2014 American Association for Cancer Research (AACR) Award for Outstanding Achievement in Cancer Prevention Research for his commitment to the prevention and control of chronic diseases, including breast cancer. In his award lecture, given at the AACR's 13th Annual International Conference on Frontiers in Cancer Prevention Research, Dr Colditz outlined strategies that he believes should be developed for delivery of breast cancer prevention through healthcare providers, regulatory approaches, communities, and families.

Dr Colditz emphasized that breast cancer prevention efforts will have the greatest effects when they are initiated early in life. To further explain how he believes early preventive measures could be brought into practice, Dr Colditz spoke with Linda Brookes, for Medscape, about how physicians can help their female patients lower their risk for breast cancer earlier in life.

Breast Cancer Screening Is Not Prevention

Medscape: What are the main factors in early prevention of breast cancer that physicians need to convey to their patients?

Dr Graham Colditz

Dr Colditz: There is clear and growing evidence that diet composition in childhood and adolescence, physical activity, and alcohol intake before birth of the first child are all importantly related to the risk for premalignant breast lesions and invasive breast cancer.[1,2] Part of the motive in our trying to get this message out is the fact that 21% of breast cancers are diagnosed in premenopausal women,[3] and yet most of our discussion about prevention of breast cancer really starts with screening. That is detection, not prevention.

Growing scientific evidence indicates that childhood and adolescent lifestyle is clearly driving the risk for breast cancer. How we structure diet, level of activity, and alcohol intake in childhood and adolescence, and typically up to age 30, establishes a woman's lifetime risk for breast cancer. It is time that we acknowledge that breast cancer is the number-one cancer diagnosed in women in the world[4] and start doing something serious about preventing it.

Medscape: Organizations representing other medical specialties, such as diabetes, are also campaigning vigorously for a healthier lifestyle in children and adolescents to prevent disease in early adulthood. How does education about breast cancer prevention differ from this?

Dr Colditz: The recommendation of a healthy, plant-based diet is clearly consistent with diabetes prevention, but it is probably even stronger for breast cancer.[5] Regarding physical activity and avoiding weight gain, I think the message is the same for both breast cancer and diabetes. These factors tie in to a healthy childhood and adolescence.

The message about alcohol consumption is different. The incidence of heart disease in those who drink moderate amounts of alcohol is lower than in nondrinkers. People are going to get their heart disease at ages 50, 60, and 70 years, and it is what they are drinking at that age that modifies their platelet function, not what they drink at 18.

Alcohol is a known carcinogen[6] and yet we are not addressing that. The other factors do tie in to a healthy childhood and adolescence, and to me the question then becomes, how do we get mothers, grandmothers, aunts, fathers, and uncles to take this issue seriously? Obviously we have collectively avoided it to date and we now have a global epidemic of childhood obesity. Our campaign hasn't been effective, and the diet composition is continuing to move away from plant-based food.

Alcohol and Obesity: Not a Good Mix

Medscape: You recently published an infographic that showed that about half of breast cancers could be prevented, of which 5% could be avoided by alcohol restriction.[7]

Dr Colditz: Correct. Alcohol consumption is that big of a contributor to breast cancer, and yet we largely ignore it.

Medscape: According to your estimates, 32% of breast cancer cases could be prevented by avoidance of weight gain.

Dr Colditz: That may still be an underestimate, but yes—it is amazing how strong that association is.

Medscape: Isn't overweight/obesity usually regarded as a risk factor for postmenopausal breast cancer?

Dr Colditz: Evidence from the Nurses' Health Study,[8,9] and from women who have had bariatric surgery and major weight change,[10,11] show that weight loss after menopause lowers the risk for breast cancer. But obviously you are better off never having gained weight in the first place. There are continuing messages around weight, physical activity, and alcohol consumption that are all important after menopause.

But in premenopausal women, cancer is less responsive to treatment, and that is again where there has been a gap in the focus on prevention. There are data out of Europe showing that weight gain in premenopausal years actually increases premenopausal as well as postmenopausal breast cancer,[12,13] and that is why it is potentially an underestimate to say that 32% of breast cancer could be prevented by avoidance of weight gain. If the European data hold up in the United States, which I think they will, we will also be adding in some premenopausal breast cancer that is driven by weight gain through the 20s, 30s, and early 40s age groups.

Medscape: Do these factors affect women with and without inherited risk factors?

Dr Colditz: Yes. Lifestyle factors may work to the same collective benefit in women with BRCA 1 and 2 gene mutations and in women without mutations. Obviously, it is a more important focus in the women who have the genetic predisposition.

Breast Cancer Prevention Starts Young -- Really Young

Medscape: In a recent posting on the AACR blog, you indicated that prevention should begin as early as age 2,[7] but what can parents do for children of that age group?

Dr Colditz: Diet and physical activity are the key factors. A child doesn't end up obese at age 10 by starting to gain weight at age 9. Breast-feeding, avoiding drinking gallons of milk (which is associated with increased growth velocity),[14] and keeping kids active—those are the key features in early childhood, and then moving to avoiding alcohol in late adolescence. Parents' modeling healthy behaviors for their children is also important.

Medscape: Presumably, children are amenable to their parents' suggestions up to a certain age, but in adolescence they become less so.

Dr Colditz: I agree, but prevention efforts really work. We have had substantial changes in adolescent cigarette smoking. In the United States, 35% of adolescents surveyed in 1999 had smoked within the previous month; in 2013, it was down to 16%.[16] Over the same period, any alcohol consumption within the previous month decreased from 50% to 34.9%,[17] We are never going to go to zero alcohol consumption, but we shouldn't throw out the baby with the bath water and say there's no point in even thinking about it. In countries like China, alcohol consumption is rising rapidly[18]—maybe in men at the moment, but women will catch up. It's like tobacco use; women smokers have caught up with men all over the world.

Figure 1. Prevention strategies for breast cancer should begin in childhood.[15]

Medscape: Is there evidence that children who are taught good habits by their parents or caregivers at an early age continue those habits into adolescence and adulthood?

Dr Colditz: In children younger than 8 or 9 years, parents have influence over what their kids eat. After that, peer pressure can take over and affect eating habits, just as peer pressure can influence adolescent girls toward smoking or drinking. Some good behaviors are easier to sustain if they have been reinforced at home. And there is need for continuing reinforcement at home, at school, and in the workplace. At college and beyond, another set of dynamics influences behavior. Diet, access to alcohol, and other pressures change as young women move into the workforce.

Medscape: Young women can be very sensitive about weight gain, to the point of being underweight. Should weight advice take this into account to avoid too much emphasis on losing weight?

Dr Colditz: Dr Steven Gortmaker, at the Harvard School of Public Health, has done work in schools promoting increased physical activity and healthy diet. He studied the frequency of excess concern with weight and found that girls who underwent a program of increased activity had less concern about their weight than those who did not have activity intervention.[19,20]

While parents should certainly have a good idea of where their child falls in the weight range, when it comes to the children themselves, the focus should be on healthy eating and activity habits, rather than on weight per se.

I know the media see underweight as an issue. And concerns about body image are quite important, yet data show that only a small percentage of girls[21] and adult women[22] in the United States are underweight, while nearly two thirds of adult women are either overweight or obese. How do we make a healthy weight the norm without undue concern about underweight?

Figure 2. Strategies to prevent breast cancer.

Courtesy of Siteman Cancer Center at Barnes-Jewish Hospital and Washington University School of Medicine

Wanted: Nationwide Cancer Prevention Strategy

Medscape: In your publications you have implied that there isn't enough being done in the United States research and education about breast cancer prevention.

Dr Colditz: In the past there has been more emphasis on childhood and adolescent diet and physical activity to prevent diabetes and heart disease.[23] We have got to get cancer into that discussion as well. Cancer risk is accumulating from before the time a girl hits menarche. How quickly she grows impacts her lifetime risk for breast cancer, and if she drinks lots of milk she grows faster than if she doesn't drink lots of milk, and that raises her risk.[14,24] There is good evidence that an animal protein diet versus a vegetable protein diet results in earlier menarche and greater growth velocity.[25-27] If children eat a plant-based diet, they may still end up as tall as if they eat a diet high in animal protein; it just takes a little longer for them to get to full height, and that slower growth actually is beneficial for life.

Medscape: Do you think the National Institutes of Health or the Centers for Disease Control and Prevention should coordinate a campaign to raise awareness about breast cancer prevention?

Dr Colditz: We have got to build this in to a public health strategy. We need to better understand how to sustain the change to a healthier diet and activity level in childhood and adolescence, to have the benefit of lower risk for heart disease, diabetes, and cancer.

We do not do a good job of telling adolescents and women in their 20s about health trade-offs and the impact that their lifestyle behaviors will have on their current risk for diabetes and their future risk for cancer. The whole presentation and communication of wellness and long-term risk is not an area that has been studied.

Medscape: Is behavioral research needed as much as basic science or clinical research at the moment?

Dr Colditz: For the alcohol risk, if we actually knew how alcohol was damaging breast cells, eventually we could prevent that damage, even in adolescents and young women who are drinking. Maybe the damage is associated with folate intake.[28] Maybe the damage involves some pathway that you could inhibit, so that if a woman is going to drink, then she should be doing something that would counteract the negative effect of alcohol. At the moment, we don't know what the "something" is; there is clear potential for more study of mechanisms and pathways with the hope of prevention.

Primary Care for Primary Prevention

Medscape: Do we need a guideline on early prevention of breast cancer in children and adolescents that family practitioners and pediatricians can use as a reference when speaking to patients and their families?

Dr Colditz: If we don't have something that specifically addresses age, we end up not talking about prevention until people are in their 30s, 40s, and 50s. That is when, in a primary care visit, people ask what they should do about their weight or blood pressure, or changing their diet to lower their cholesterol. The point is that for breast cancer, that's starting late, given that the disease process and risk accumulation start early in life. With breast cells dividing with each menstrual cycle, there is risk accumulation. Alcohol in adolescents and before first pregnancy increases the DNA damage.

Yes, developing guidelines that are much more specific to the earlier ages feels like one step we are going to have to take to address prevention in the primary care visits of adolescents and young adults.

Medscape: Which organizations should be taking this on?

Dr Colditz: The US Preventive Services Task Force and the website Healthy People 2020, managed by the US Department of Health and Human Services—these are the avenues for getting recommendations on the radar. The American Academy of Pediatrics has taken on obesity, TV watching, and other messages as part of pediatrics care. We're not saying that just having your primary care provider talk to you about it is enough, but we know that a message from a provider is powerful reinforcement. We have to work at this initiative across multiple dimensions, but primary care providers are definitely one of the necessary components of a successful strategy.

Medscape: Is this included in any current guidelines?

Dr Colditz: Not yet. Not directly about early life and breast cancer prevention.

Medscape: Are there any relevant guidelines in development?

Dr Colditz: We're working on it. We've got to make providers aware that the evidence is strong enough to act on.

References

  1. Colditz GA, Bohlke K. Priorities for the prevention of breast cancer. CA Cancer J Clin. 2014;64:186-194. Abstract

  2. Colditz GA, Bohlke K, Berkey CS. Breast cancer risk accumulation starts early: prevention must also. Breast Cancer Res Treat. 2014;145:567-579. Abstract

  3. Breast cancer facts & figures 2013-2014. Atlanta, GA: American Cancer Society; 2013. http://www.cancer.org/research/cancerfactsstatistics/breast-cancer-facts-figures Accessed November 13, 2014.

  4. Jemal A, Bray F, Center MM, et al. Global cancer statistics.CA Cancer J Clin. 2011;61:69-90. Abstract

  5. Liu Y, Colditz GA, Cotterchio M, et al. Adolescent dietary fiber, vegetable fat, vegetable protein, and nut intakes and breast cancer risk. Breast Cancer Res Treat. 2014;145:461-470. Abstract

  6. International Agency for Research on Cancer (IARC) Working Group on the Evaluation of Carcinogenic Risks to Humans. Alcohol consumption and ethyl carbamate. Lyon, France: International Agency for Research on Cancer (distributed by WHO Press); 2010.

  7. Golditz GA. A youthful approach: expanding the reach of breast cancer prevention. Cancer Research Catalyst: The Official Blog of the American Association for Cancer Research. Posted on October 14, 2014 by AACR Press Office. http://blog.aacr.org/youthful-approach-expanding-reach-breast-cancer-prevention/ Accessed November 16, 2014.

  8. Eliassen AH, Colditz GA, Rosner B, et al. Adult weight change and risk of postmenopausal breast cancer. JAMA. 2006;296:193-201. Abstract

  9. Huang Z, Hankinson SE, Colditz GA, et al. Dual effects of weight and weight gain on breast cancer risk. JAMA. 1997;278:1407-1411. Abstract

  10. Christou NV, Lieberman M, Sampalis F, Sampalis JS. Bariatric surgery reduces cancer risk in morbidly obese patients. Surg Obes Relat Dis. 2008;4:691-695. Abstract

  11. Byers T, Sedjo RL. Does intentional weight loss reduce cancer risk? Diabetes Obes Metab. 2011;13:1063-1072.

  12. Emaus MJ, van Gils CH, Bakker MF, et al. Weight change in middle adulthood and breast cancer risk in the EPIC-PANACEA study. Int J Cancer. 2014; 135:2887-2899. Abstract

  13. Colditz GA, Eliaswsen H, Toriola AT, et al. Recent weight gain and increased breast cancer risk varies by receptor classification among pre- and postmenopausal women. Program and abstracts of the 2014 San Antonio Breast Cancer Symposium; December 9-13, 2014; San Antonio, Texas. Abstract: P6-09-01.

  14. De Beer. Dairy products and physical stature. Econ Hum Biol. 2012;299-309.

  15. Colditz GA, Bohlke K. Priorities for the primary prevention of breast cancer. CA Cancer J Clin. 2014;64:186-194. Abstract

  16. Trends in the prevalence of tobacco use National YRBS: 1991-2013. Atlanta, GA: Centers for Disease Control and Prevention: 2014. http://www.cdc.gov/healthyyouth/yrbs/factsheets/index.htm Accessed November 11, 2014.

  17. Trends in the prevalence of alcohol use National YRBS: 1991-2013. Atlanta, GA: Centers for Disease Control and Prevention: 2014. http://www.cdc.gov/healthyyouth/yrbs/factsheets/index.htm Accessed November 11, 2014.

  18. Tang YL, Xiang XJ, Wang XY, et al. Alcohol and alcohol-related harm in China: policy changes needed. Bull World Health Organ. 2013;91:270-276. Abstract

  19. Field AE, Cheung L, Wolf AM, et al. Exposure to the mass media and weight concerns among girls. Pediatrics. 1999;103:E36.

  20. Chavarro JE, Peterson KE, Sobol AM, et al. Effects of a school-based obesity-prevention intervention on menarche (United States). Cancer Causes Control. 2005;16:1245-1252. Abstract

  21. Fryar CD, Ogden CL. Prevalence of Underweight Among Children and Adolescents: United States, 2007-2008 Division of Health and Nutrition Examination Surveys. October 2010. National Centers for Health Statistics. Centers for Disease Control and Prevention. http://www.cdc.gov/nchs/data/hestat/underweight_child_07_08/underweight_child_07_08.pdf Accessed December 3, 2014.

  22. Fryar CD, Ogden CL. Prevalence of underweight among adults aged 20 years and over: United States, 1960-1962.Division of Health and Nutrition Examination Surveys. National Centers for Health Statistics. Centers for Disease Control and Prevention. http://www.cdc.gov/nchs/data/hestat/underweight_adult_07_10/underweight_adult_07_10.htm Accessed December 3, 2014.

  23. Nutrition and the health of young people. Centers for Disease Control and Prevention. http://www.cdc.gov/healthyyouth/nutrition/facts.htm Accessed November 29, 2014.

  24. Berkey CS, Colditz GA, Rockett HR, et al. Dairy consumption and female height growth: prospective cohort study. Cancer Epidemiol Biomarkers Prev. 2009;18:1881-1887. Abstract

  25. Ahlgren M, Melbye M, Wohlfahrt J, Sørensen TI. Growth patterns and the risk of breast cancer in women. N Engl J Med. 2004;351:1619-1626. Abstract

  26. Berkey CS, Gardner JD, Frazier AL, Colditz GA. Relation of childhood diet and body size to menarche and adolescent growth in girls. Am J Epidemiol. 2000;152:446-452. Abstract

  27. Berkey CS, Willett WC, Frazier AL, et al. Prospective study of growth and development in older girls and risk of benign breast disease in young women. Cancer. 2011;117:162-1620. Abstract

  28. Liu Y, Tamimi RM, Berkey CS, et al. Intakes of alcohol and folate during adolescence and risk of proliferative benign breast disease. Pediatrics. 2012;129:e1192-e1198. Abstract