5. Conclusions

vitro apoptosis or the programmed cell death of several varieties of cancer cells. On the other hand, the decrease of breast cancer risk due to prolonged lactation may be explained in part by the reduction of total number of ovulatory menstrual cycles and consequently cumulative ovarian hormone exposure [20]. Despite the scientific evidence available, there is an important controversy about the effect of hormones on the development of breast cancer. This is a complex task when we consider the complex etiopathogenic nature of breast tumors. Consequently,

Breastfeeding is still another research focus. An increasing number of studies have indicated that breastfeeding offers protection against breast cancer [22, 23]. In the long term, the protection offered by breastfeeding is greater for premenopausal women, but also persists for postmenopausal women even after 50 years since the first lactation [24]. These protective effects of breastfeeding appear to be stronger the longer a woman breastfeeds her first child, as well as cumulative, such that increased lifetime duration of lactation over multiple children confers greater protection against breast cancer [25]. From a biological perspective, there are various explanations why breastfeeding seems to prevent breast cancer and why it appears to significantly benefit female health. One mechanism may involve a markedly reduced susceptibility of the fully differentiated mammary gland to carcinogens due to, at least in part, a decrease in proliferative activity of parous epithelium [26]. Other important changes are estrogen reduction and elimination through mammary fluid and the excretion of carcinogenic agents through

According to a study carried out by Cancer Research UK, the short duration of breastfeeding typical of women in developed countries makes a major contribution to the high incidence of breast cancer in these countries. The results obtained showed that the relative risk of breast cancer decreased by 7.0% for each birth in addition to a decrease of 4.3% for every 12 months of breastfeeding [30]. Despite such studies, many researchers are still skeptical as to the protection against breast cancer potentially afforded by breastfeeding. They claim that the data obtained until now are both insufficient and in many cases, inconsistent. Therefore, the influence of each birth should be considered when the relationship between breastfeeding and breast cancer is studied. Likewise, the reported breastfeeding duration is not very trusty, with values generally rounded to multiples of 6 or 12 months, particularly among women who had

Nevertheless, a slightly lower rate of breast cancer was observed in women who breastfed their children for periods of over 12 months [32]. Of the women who had given birth, those who were cancer-free were more likely to have breastfed than those who subsequently developed breast cancer (79% as compared to 71%) [33]. However, a history of ever breast-feeding may be too crude an indicator, and it may be more important to demonstrate a dose–response association with increasing duration of breast-feeding in making causal inferences [34]. These results suggest an inverse relationship between breastfeeding duration and risk of developing breast cancer.

further studies are necessary in order to analyze this relationship [21].

the breast tissue during the breastfeeding process [27–29].

breastfed for long periods of time [31].

4. Breast milk

62 Selected Topics in Breastfeeding

Breastfeeding for periods of over 6 months results in statistically significant reductions in the risk of developing breast cancer, the most common gynecological tumor in young women. However, it remains to be studied further whether the observed risk reduction applies to women with inherited susceptibility to develop breast cancer. Further studies must be conducted to focus on populations in which breastfeeding was common for relatively long durations, and should attempt to collect information on the errors in the reporting of lifetime duration of breastfeeding and other forms of complementary feeding. Meanwhile, this potential beneficial effect of breastfeeding for the mother should lead health professionals to encourage prolonged breastfeeding in their clinical practice.

[10] Pathak DR, Osuch JR, He J. Breast carcinoma etiology: Current knowledge and new insights into the effects of reproductive and hormonal risk factors in black and white

Breastfeeding and Reduced Risk of Breast Cancer in Women: A Review of Scientific Evidence

[11] González-Jiménez E, García PA, Aguilar MJ, Padilla CA, Álvarez J. Breastfeeding and the prevention of breast cancer: A retrospective review of clinical histories. Journal of Clinical

[12] Clemon M, Goss P. Estrogen and the risk of breast cancer. The New England Journal of

[13] Chlebowski RT, Hendrix SL, Langer RD, Stefanick ML, Gass M, Lane D, Rodabough RJ, Gilligan MA, Cyr MG, Thomson CA, Khandekar J, Petrovitch H, McTiernan A, Investigators WHI. Influence of estrogen plus progestin on breast cancer and mammography in

[14] Umesh V. Risk of breast cancer due to hyperprolactinemia caused by antipsychotics

[15] Halbreich U, Kinon BJ, Gilmore JA, Kahn LS. Elevated prolactin levels in patients with schizophrenia: Mechanisms and related adverse effects. Psychoneuroendocrinology. 2003;

[16] Levine RS, Dolin P. Pregnancy and breast cancer: A possible explanation for the negative

[17] Alberktsen G, Heuch I, Kvale G. Multiple births, sex of children and subsequent breast cancer risk for the mothers: A prospective study in Norway. International Journal of

[18] Hakansson A, Zhivotovsky B, Orrenius S, Sabharwal H, Svanborg C. Apoptosis induced by a human milk protein. Proceedings of the National Academy of Sciences. 1995;92:8064-

[19] Rough SM, Sakamoto P, Fee CH, Hollenbeck CB. Qualitative analysis of cancer patients' experiences using donated human milk. Journal of Human Lactation. 2009;25:211-219 [20] Bernstein L. Epidemiology of endocrine-related risk factors for breast cancer. Journal of

[21] González-Jiménez E, Garcia-Lopez PA, Schmidt-Rio-Valle J, Valenza C. Influencia del estado nutricional, niveles hormonales e historia familiar de cancer en el desarrollo del

[22] Løland BF, Baerug AB, Nylander G. Human milk, immune responses and health effects.

s health initiative randomized trial. Journal

http://dx.doi.org/10.5772/intechopen.72688

65

populations. Cancer. 2000;88:1230-1238

healthy postmenopausal women: The women<sup>0</sup>

association. Medical Hypotheses. 1992;38:278-283

Mammary Gland Biology and Neoplasia. 2002;7:3-15

cancer de mama. Revista Médica de Chile. 2012;140:1263-1267

Tidsskrift for den Norske Lægeforening. 2007;127:2395-2398

of the American Medical Association. 2003;289:3243-3253

(neuroleptics). British Journal of Medical Practitioners. 2012;5(4):a534

Nursing. 2014;23(17–18):2397-2403

Medicine. 2001;344:276-285

28(Suppl 1):53-67

8068

Cancer. 1995;60(3):341-344

#### Author details

Emilio González-Jiménez

Address all correspondence to: emigoji@ugr.es

Department of Nursing, Faculty of Health Science, University of Granada, Spain

#### References


[10] Pathak DR, Osuch JR, He J. Breast carcinoma etiology: Current knowledge and new insights into the effects of reproductive and hormonal risk factors in black and white populations. Cancer. 2000;88:1230-1238

potential beneficial effect of breastfeeding for the mother should lead health professionals to

[1] Hery C, Ferlay J, Boniol M, Autier P. Changes in breast cancer incidence and mortality in middle–aged and elderly women in 28 countries with Caucasian majority populations.

[2] Amaral P, Miguel R, Mehdad A, Cruz C, Monteiro Grillo I, Camilo M, Ravasco P. Body fat and poor diet in breast cancer women. Nutrición Hospitalaria. 2010;25:456-461 [3] Jemal A, Bray F, Center MM, Ferlay J, Ward E, Forman D. Global cancer statistics. CA: A

[4] do Carmo França-Botelho A, Ferreira MC, França JL, França EL, Honório-França AC. Breastfeeding and its relationship with reduction of breast cancer: A review. Asian Pacific

[5] Ghoncheh M, Momenimovahed Z, Salehiniya H. Epidemiology, incidence and mortality of breast cancer in Asia. Asian Pacific Journal of Cancer Prevention. 2016;17:47-52 [6] Golubnitschaja O, Debald M, Yeghiazaryan K, Kuhn W, Pešta M, Costigliola V, Grech G. Breast cancer epidemic in the early twenty-first century: Evaluation of risk factors, cumulative questionnaires and recommendations for preventive measures. Tumour Biology.

[7] Tryggvadottir L, Tulinius H, Eyfjord JE, Sigurvinsson T. Breastfeeding and reduced risk of breast cancer in an Icelandic cohort study. American Journal of Epidemiology. 2001;154:37-42

[8] Vieira FGK, Di Pietro PF, Boaventura BCB, Ambrosi C, Rockenbach G, Fausto MA, Crippa CG, Da Silva EL. Factors associated with oxidative stress in women with breast

[9] Manrique Tejedor J, Figuerol Calderó MI, Cuéllar De Frutos A. Breastfeeding as a method

of breast cancer prevention. Revista de Enfermería. 2015;38(12):32-38

Department of Nursing, Faculty of Health Science, University of Granada, Spain

encourage prolonged breastfeeding in their clinical practice.

Address all correspondence to: emigoji@ugr.es

Annals of Oncology. 2008;19:1009-1018

Cancer Journal for Clinicians. 2011;61(2):69-90

2016;37(10):12941-12957. [Epub ahead of print]

cancer. Nutrición Hospitalaria. 2011;26:528-536

Journal of Cancer Prevention. 2012;13(11):5327-5332

Author details

64 Selected Topics in Breastfeeding

References

Emilio González-Jiménez


[23] Aguilar Cordero MJ, González Jiménez E, Alvarez Ferre J, Padilla Lopez CA, Mur Villar N, Garcia Lopez PA, Valenza Peñna MC. Breast feeding: An effective method to prevent breast cancer. Nutrición Hospitalaria. 2010;25:954-958

[36] Wang QS, Ross RK, MC Y, Ning JP, Henderson BE, Kimm HT. A case-control study of breast cancer in Tianjin, China. Cancer Epidemiology, Biomarkers & Prevention.

Breastfeeding and Reduced Risk of Breast Cancer in Women: A Review of Scientific Evidence

http://dx.doi.org/10.5772/intechopen.72688

67

[37] Michels KB, Willett WC, Rosner BA, Manson JE, Hunter DJ, Colditz GA, et al. Prospective assessment of breast-feeding and breast cancer incidence among 89,887 women. Lancet.

[38] Zheng T, Duan L, Liu Y, Zhang B, Wang Y, Chen Y, Zhang Y, Owens PH. Lactation reduces breast cancer risk in Shandong Province, China. American Journal of Epidemiology.

[39] Hajian-Tilaki KO, Kaveh-Ahangar T. Reproductive factors associated with breast cancer

[40] Awatef M, Olfa G, Imed H, Kacem M, Imen C, Rim C, Mohamed B, Slim BA. Breastfeeding reduces breast cancer risk: A case-control study in Tunisia. Cancer Causes

[41] Nagata C, Mizoue T, Tanaka K, Tsuji I, Tamakoshi A, Wakai K, Matsuo K, Ito H, Sasazuki S, Inoue M, Tsugane S; Research Group for the Development and Evaluation of Cancer Prevention Strategies in Japan. Breastfeeding and breast cancer risk: An evaluation based on a systematic review of epidemiologic evidence among the Japanese population. Japanese

[42] Galukande M, Wabinga H, Mirembe F, Karamagi C, Asea A. Breast cancer risk factors among Ugandan women at a tertiary hospital: A case-control study. Oncology. 2016;90(6):

risk in northern Iran. Medical Oncology. 2011;28(2):441-446

1992;1:435-439

1996;347:431-436

2000;152:1129-1135

356-362

& Control. 2010;21(3):393-397

Journal of Clinical Oncology 2012;42(2):124-130


[36] Wang QS, Ross RK, MC Y, Ning JP, Henderson BE, Kimm HT. A case-control study of breast cancer in Tianjin, China. Cancer Epidemiology, Biomarkers & Prevention. 1992;1:435-439

[23] Aguilar Cordero MJ, González Jiménez E, Alvarez Ferre J, Padilla Lopez CA, Mur Villar N, Garcia Lopez PA, Valenza Peñna MC. Breast feeding: An effective method to prevent

[24] Lee SY, Kim MT, Kim SW, Song MS, Yoon SJ. Effect of lifetime lactation on breast cancer risk: A Korean women's cohort study. International Journal of Cancer. 2003;105(3):

[25] Chang-Claude J, Eby N, Kiechle M, Bastert G, Becher H. Breastfeeding and breast cancer risk by age 50 among women in Germany. Cancer Causes & Control. 2000;11(8):687-695

[26] Dumitrescu RG, Cotarla I. Understanding breast cancer risk–Where do we stand in 2005?

[27] Freudenheim JL, Marshall JR, Vena JE, Moysich KB, Muti P, Laughlin R, Nemoto T, Graham S. Lactation history and breast cancer risk. American Journal of Epidemiology.

[28] Stuver SO, Hsieh CC, Bertone E, Trichopoulos D. The association between lactation and breast cancer in an international case–control study: A re–analysis by menopausal status.

[29] Loren L, Renee B, Dimitrios T. History of breast–feeding in relation to breast cancer risk: A review of the epidemiologic literature. Journal of the National Cancer Institute. 2000;92:

[30] Woodman I. Breast–feeding reduced risk of breast cancer, says study. BMJ. 2002;27:184 [31] Collaborative Group on Hormonal Factors in Breast Cancer. Breast cancer and breastfeeding: Collaborative reanalysis of individual data from 47 epidemiological studies in 30 countries, including 50302 women with breast cancer and 96973 women without the disease. Lancet.

[32] Chowdhury R, Sinha B, Sankar MJ, Taneja S, Bhandari N, Rollins N, Bahl R, Martines J. Breastfeeding and maternal health outcomes: A systematic review and meta-analysis.

[33] Islam T, Matsuo K, Ito H, Hosono S, Watanabe M, Iwata H, Tajima K, Tanaka H. Reproductive and hormonal risk factors for luminal, HER2-overexpressing, and triplenegative

[34] Lipworth L, Bailey LR, Trichopoulos D. History of breast-feeding in relation to breast cancer risk: A review of the epidemiologic literature. Journal of the National Cancer

[35] Yoo KY, Tajima K, Kuroishi T, Hirose K, Yoshida M, Miura S, et al. Independent protective effect of lactation against breast cancer: A case control study in Japan. American

breast cancer in Japanese women. Annals of Oncology. 2012;23:2435-2441

breast cancer. Nutrición Hospitalaria. 2010;25:954-958

Journal of Cellular and Molecular Medicine. 2005;9(1):208-221

International Journal of Cancer. 1997;71:166-169

390-393

66 Selected Topics in Breastfeeding

1997;146:932-938

2002;360(9328):187-195

Institute. 2000;92(4):302-312

Acta Paediatrica. 2015;104(467):96-113

Journal of Epidemiology. 1992;135:726-733

302-312

