Applied Evidence

Breast cancer prevention and Tx: An evidence-based guide

J Fam Pract. 2010 October;59(10):575-581a

References

1. US Preventive Services Task Force Screening for breast cancer. Available at: http://www.uspreventiveservicestaskforce.org/uspstf/uspsbrca.htm. Accessed September 2, 2010.

2. American Cancer Society. American Cancer Society guidelines for the early detection of cancer. Available at: http://www.cancer.org/Healthy/FindCancerEarly/CancerScreeningGuidelines/american-cancer-society-guidelines-for-the-early-detection-of-cancer. Accessed September 2, 2010.

3. American College of Obstetricians and Gynecologists. Response of the American College of Obstetricians and Gynecologists to the new breast cancer screening recommendations from the US Preventive Services Task Force. Available at: http://www.acog.org/from_home/misc/uspstfresponse.cfm. Accessed September 2, 2010.

4. National Comprehensive Cancer Network. Breast cancer screening and diagnosis. Clinical Practice Guidelines in Oncology-V.1.2010. Fort Washington, Pa: National Comprehensive Cancer Network: November 3, 2009. Available at: http://www.nccn.org/professionals/physician_gls/f_guidelines.asp. Accessed September 17 , 2010.

5. National Cancer Institute. Breast cancer risk assessment tool. Available at: http://www.cancer.gov/bcrisktool/. Accessed September 2, 2010

6. Robson M, Offit K. Clinical practice. Management of an inherited predisposition to breast cancer. N Engl J Med. 2007;357:154-162.

7. Fisher B, Costantino JP, Wickerham DL, et al. Tamoxifen for prevention of breast cancer: report of the National Surgical Adjuvant Breast and Bowel Project P-1 Study. J Natl Cancer Inst. 1998;90:1371-1388.

8. Cummings SR, Tice JA, Bauer S, et al. Prevention of breast cancer in postmenopausal women: approaches to estimating and reducing risk. J Natl Cancer Inst. 2009;18:101,-384-398.

9. Prentice RL, Caan B, Chlebowski RT, et al. Low-fat dietary pattern and risk of invasive breast cancer: the Women’s Health Initiative Randomized Controlled Dietary Modification Trial. JAMA. 2006;295:629-642.

10. Pierce JP, Natarajan L, Caan BJ, et al. Influence of a diet very high in vegetables, fruit, and fiber and low in fat on prognosis following treatment for breast cancer: the Women’s Healthy Eating and Living (WHEL) randomized trial. JAMA. 2007;298:289-298.

11. Chlebowski RT, Blackburn GL, Thomson CA, et al. Dietary fat reduction and breast cancer outcome: interim efficacy results from the Women’s Intervention Nutrition Study (WINS). J Natl Cancer Inst. 2006;98:1767-1776.

12. PDQ Cancer Information Summary. Breast Cancer Prevention (PRQ) – Health Professional. Date last modified April 30, 2009. Available at: http://www.cancer.gov/cancertopics/pdq/prevention/breast/healthprofessional. Accessed May 12, 2009.

13. Hulka BS, Moorman PG. Breast cancer: hormones and other risk factors. Maturitas. 2001;38:103-113.

14. Rossouw JE, Anderson GL, Prentice RL, et al. Risks and benefits of estrogen plus progestin in healthy postmenopausal women: principal results From the Women’s Health Initiative randomized controlled trial. JAMA. 2002;288:321-333.

15. Ravdin PM, Cronin KA, Howlader N, et al. The decrease in breast-cancer incidence in 2003 in the United States. N Engl J Med. 2007;356:1670-1674.

16. Chlebowski RT, Kuller LH, Prentice RL, et al. WHI Investigators. Breast cancer after use of estrogen plus progestin in postmenopausal women. N Engl J Med. 2009;360:573-587.

17. Kosters JP, Gotzsche PC. Regular self-examination or clinical examination for early detection of breast cancer. Cochrane Database Syst Rev. 2003;(2):CD003373.-

18. Canadian Task Force on the Periodic Health Examination Ottawa, Canada: Health Canada; 1994:788-795 (reaffirmed by the Canadian Task Force on the Periodic Health Examination 1999, 2001).Available at: http://www.ctfphc.org/index/html. Accessed August 12, 2009.

19. Green BB, Taplin SH. Breast cancer screening controversies. J Am Board Fam Pract. 2003;16:233-241.

20. Berry DA, Cronin KA, Plevritis SK, et al. Effect of screening and adjuvant therapy on mortality from breast cancer. N Engl J Med. 2005;353:1784-1792.

21. Tice JA, Kerlikowske K. Screening and prevention of breast cancer in primary care. Prim Care. 2009;36:533-558.

22. US Preventive Services Task Force. Screening for breast cancer. Systematic evidence review update for the US Preventive Services Task Force. Available at: http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=es74. Accessed September 2, 2010.

23. Pisano ED, Gatsonis C, Hendrick E, et al. Digital Mammographic Imaging Screening Trial (DMIST) Investigators Group. Diagnostic performance of digital versus film mammography for breast-cancer screening. N Engl J Med. 2005;353:1773-1783.

24. Saslow D, Boetes C, Burke W, et al. American Cancer Society Breast Cancer Advisory Group. American Cancer Society guidelines for breast screening with MRI as an adjunct to mammography. CA Cancer J Clin. 2007;57:75-89.

25. Berg W, Blume J, Cormack J, et al. Combined screening with ultrasound and mammography vs mammography alone in women at elevated risk of breast cancer. JAMA. 2008;299:2151-2163.

26. King M, Wieand S, Hale K, et al. Tamoxifen and breast cancer incidence among women with inherited mutations in BRCA1 and BRCA2: National Surgical Adjuvant Breast and Bowel Project (NSABP-P1) Breast Cancer Prevention Trial. JAMA. 2001;286:2251-2256.

27. Vogel VG, Costantino JP, Wickerham DL, et al. Effects of tamoxifen vs raloxifene on the risk of developing invasive breast cancer and other disease outcomes: the NSABP Study of Tamoxifen and Raloxifene (STAR) P-2 trial. JAMA. 2006;295:2727-2741.

28. Berg AO. US Preventive Services Task Force. Chemoprevention of breast cancer: recommendations and rationale. Am J Nurs. 2003;103:107-113.

29. National Comprehensive Cancer Network. Breast cancer risk reduction. Clinical Practice Guidelines in Oncology-V.2.2010. Fort Washington, Pa: National Comprehensive Cancer Network; August 7, 2010. Available at: http://www.nccn.org/professionals/physician_gls/f_guidelines.asp. Accessed September 17, 2010.

30. Sickles EA, Filly RA, Cllen PW. Benign breast lesions: ultrasound detection and diagnosis. Radiology. 1984;151:467.-

31. Beavers TB, Anderson BO, Bonaccio E, et al. NCCN clinical practice guidelines in oncology: breast cancer screening and diagnosis. J Natl Compr Canc Netw. 2009;7:1060-1096.

32. Mansel RE, Fallowfield L, Kissin M, et al. Randomized multicenter trial of sentinel node biopsy versus standard axillary treatment in operable breast cancer: the ALMANAC trial. J Natl Canc Inst. 2006;98:599-609

33. Lyman GH, Guiliano AE, Somerfield MR, et al. American Society of Clinical Oncology guideline recommendations for sentinel lymph node biopsy in early- stage breast cancer. J Clin Oncol. 2005;23:7703-7720.

34. Turner N, Jones A. Management of breast cancer-Part II. BMJ. 2008;337:a540.-

35. Harris L, Fritsche H, Mennel R, et al:. American Society of Clinical Oncology 2007 update of recommendations for the use of tumor markers in breast cancer J Clin Oncol. 2007;25:5287-5312.

36. Piccart-Gebhart MJ, Procter M, Leyland-Jones B, et al. Herceptin adjuvant (HERA) Trial Study Team. Trastuzumab after adjuvant chemotherapy in HER2-positive breast cancer. N Engl J Med. 2005;353:1659-1672.

37. PDQ Cancer Information Summary Breast cancer treatment– health professional. Available at: http://www.cancer.gov/cancertopics/pdq/treatment/breast/HealthProfessional. Accessed May 12, 2009.

38. Anderson BL, Yang HC, Farrar WB, et al. Psychologic intervention improves survival for breast cancer patients: a randomized clinical trial. Cancer. 2008;113:3450-3458.

39. Jin Y, Desta Z, Stearns V, et al. CYP2D6 genotype, antidepressant use, and tamoxifen metabolism during adjuvant breast cancer treatment. J Natl Cancer Inst. 2005;97:30-39.

The association between oral contraceptives (OCs) and breast cancer is more controversial. Some studies have found an increased breast cancer risk among OC users, but both the relative risk and absolute risk were found to be very small and to dissipate 10 years after stopping OC use. More recent studies with newer formulations containing lower doses of estrogen have failed to show an increased risk.⁸

Breast cancer screening: The parameters have changed

Various organizations have published guidelines for breast cancer screening (TABLE 2), and all are somewhat different. Here’s what you need to know.

Breast self-examination (BSE), which women were previously advised to perform monthly, has not been shown to improve mortality in any age group, and is no longer routinely recommended.¹⁷ While both the USPSTF and the Canadian Task Force on Preventive Health Care recommend against teaching women BSE, the ACS, ACOG, and NCCN encourage self-examination—particularly among women older than 40 years.^1-4,17,18

Clinical breast examination has an average sensitivity of 50% and detects approximately 5% of mammographically occult cancers.¹⁹ It is still not clear whether clinical breast exams save lives, however—a finding that is reflected in the USPSTF’s “I” (insufficient evidence to assess the benefits and harms) recommendation.¹ Other consensus guidelines still recommend clinical breast examination, albeit at varying frequencies.

FAST TRACK

AT PRESSTIME, a new study reported that screening mammography in women 50 and older did little to reduce breast cancer deaths. See the September 23 edition of The New England Journal of Medicine for more.

Screening mammography decreases mortality rates by anywhere from 28% to 65%, depending on the statistical model used.²⁰ The benefit is greatest in women between the ages of 50 and 69 years, however, and most groups agree that mammography every 1 to 2 years is advisable for this age group. (There is limited data on the value of mammography for women 70 years of age and older, and no consensus on the age at which to stop screening.^1,21) But because the mortality benefit from screening mammography is lower for women aged 40 to 49, guidelines for this age group are more controversial.

Mammography’s sensitivity is affected by a variety of factors, including age and menopausal status, prior breast surgery or radiation, breast density, and the experience of the radiologist. Women in their 40s have denser breast tissue than older women, making mammography less sensitive for this age group. Because of that, and because the overall incidence of breast cancer is lower for women younger than 50, some argue that screening mammography for women between the ages of 40 and 49 years leads to unacceptably high false-positive rates (9.8% annually²²) and that the harm associated with mammography may outweigh the benefit. Others counter that tumors in younger women tend to be more aggressive and faster growing, making early detection even more critical than for older women.

What should you advise women in this age group? You might point out that the USPSTF recommends against routine screening, but indicates that the decision to begin (or defer) routine mammography before age 50 should be individualized, based on the needs and values of each patient.¹

FAST TRACK

Digital mammography is more accurate than film—but only for women <50 years of age, women with dense breasts, and pre- and perimenopausal women.

Digital mammography. A recent study of more than 43,000 women demonstrated that digital mammography is more accurate than film—but only for certain groups: These include women <50 years of age, women with dense breasts, and pre- and perimenopausal women. ²³ Because it is still not clear whether the increased accuracy will translate into a mortality benefit, more research is needed before digital mammography is widely adopted. The USPSTF maintains that there is insufficient evidence to assess the benefits and harms of using either digital mammography or magnetic resonance imaging (MRI) rather than film mammography to screen for breast cancer.¹

MRI. In 2007, the ACS published guidelines on the use of MRI as an adjunct to mammography for breast cancer screening in high-risk women.²⁴ According to ACS guidelines, screening MRI should be offered to patients with a known BRCA 1 or 2 mutation (5%-10% of all breast cancers are associated with a mutation in the BRCA 1 or BRCA 2 gene, which is transmitted in an autosomal dominant pattern⁶). It also should be offered to those with a strong family history, or a lifetime risk of developing breast cancer that is >20% to 25%. And finally, MRI should be offered to women who had chest wall radiation when they were between the ages of 10 and 30 years—another significant risk factor for breast cancer—and those with other genetic syndromes that increase their lifetime risk of breast cancer.²⁴