Benign Breast Disease

Benign Breast Disease

While there is a paucity of information regarding lactation in the setting of benign breast disease, lactation generally is possible and successful.  Non-proliferative benign breast disease that affects people of childbearing age includes but is not limited to fibroepithelial lesions, hamartomas, cysts, and idiopathic granulomatous mastitis (IGM).  Proliferative breast disease, both with atypia and without atypia, may also present in lactating people.  An example of proliferative breast disease without atypia is a radial scar or complex sclerosing lesion, while an example of a proliferative disease with atypia is atypical ductal hyperplasia (ADH).1

While these lesions themselves do not preclude lactation, those with atypia may sometimes need to use endocrine therapy (e.g. tamoxifen, a Selective Estrogen Receptor Modulator, or SERM) to reduce future risk of breast cancer development.  SERM’s are known to inhibit lactogenesis II.  There is no data regarding transfer into breastmilk and therefore they are not recommended during lactation.2 Patients should engage in shared decision making regarding the benefit of SERMs versus the risk-reducing benefits of breastfeeding, which is most significant in those with a first-degree relative with breast cancer3 and those with a BRCA I mutation.4

It should be noted that if a mass is in close proximity to the nipple areolar complex prior to pregnancy, it may present a challenge for lactation if it interferes with latch or obstructs the retroareolar region.  Therefore, we recommend these patients be referred for evaluation by a breast surgeon and breastfeeding and lactation medicine specialist to determine whether the risk of removal and potential damage to underlying parenchyma, lymphatics, and neurovascular structures outweighs the risk of the mass itself causing a significant breastfeeding complication.5 If the patient does undergo surgical excision, they should be referred to lactation during pregnancy and be monitored closely in the postpartum period for assistance with lactation.

For more detailed information and references on specific medications including specific SERMs, please refer to LactMede-lactanciaInfant Risk, or Mother to Baby.


  1. (1)          Dyrstad, S. W.; Yan, Y.; Fowler, A. M.; Colditz, G. A. Breast Cancer Risk Associated with Benign Breast Disease: Systematic Review and Meta-Analysis. Breast Cancer Res Treat 2015, 149 (3), 569–575.

    (2)          Masala, A.; Delitala, G.; Lo Dico, G.; Stoppelli, I.; Alagna, S.; Devilla, L. Inhibition of Lactation and Inhibition of Prolactin Release after Mechanical Breast Stimulation in Puerperal Women given Tamoxifen or Placebo. Br J Obstet Gynaecol 1978, 85 (2), 134–137.

    (3)          Stuebe, A. M.; Willett, W. C.; Xue, F.; Michels, K. B. Lactation and Incidence of Premenopausal Breast Cancer: A Longitudinal Study. Arch Intern Med 2009, 169 (15), 1364–1371.

    (4)          Kotsopoulos, J.; Lubinski, J.; Salmena, L.; Lynch, H. T.; Kim-Sing, C.; Foulkes, W. D.; Ghadirian, P.; Neuhausen, S. L.; Demsky, R.; Tung, N.; Ainsworth, P.; Senter, L.; Eisen, A.; Eng, C.; Singer, C.; Ginsburg, O.; Blum, J.; Huzarski, T.; Poll, A.; Sun, P.; Narod, S. A.; Hereditary Breast Cancer Clinical Study Group. Breastfeeding and the Risk of Breast Cancer in BRCA1 and BRCA2 Mutation Carriers. Breast Cancer Res 2012, 14 (2), R42.

    (5)          Ferre, R.; Pare, M.; Mesurolle, B. Ultrasound Features of Retroareolar Breast Carcinoma. Diagn Interv Imaging 2017, 98 (5), 409–413.