Breast cancer in women younger than 50 makes up about 25 % of the incident breast cancer cases each year (Desantis et al. 2014) (see Table 2.2). Fewer numbers of incident cases occur if one uses earlier age cut-points, as noted previously. In a recent systematic review of the unique psychosocial needs of younger women with breast cancer, we used age 50 years as the cut-point for the review due to the paucity of literature focused solely on very young women (Howard-Anderson et al. 2012). 45 years is probably a more appropriate age to use as a cut point for linking to other studies of young adults with cancer, which use 39 years as the upper age limit (Brinton et al. 2008; Tricoli et al. 2011). However, in detailed interviews with younger women with breast cancer, classification of “young” was more often associated with life stage and challenges, rather than chronological age (Dunn and Steginga 2000). While there is no official definition of “young breast cancer patient” we will focus on the diversity of clinical and psychosocial features of women with breast cancer who are less than 50 years at diagnosis. However, a CDC program and federal legislation that has called attention to this group of patients using an age of less than 45 years at diagnosis (http://​www.​cdc.​gov/​cancer/​breast/​young_​women/​index.​htm) Although we acknowledge that younger men may be affected by breast cancer, this is such a small group, for which even less is known, that we confine our discussion to women.

The complexity of discussing this special population relates foremost to the diversity of life stage of development interacting with chronological age. The experience of the rare young woman diagnosed with breast cancer while in college is extremely different from the mother of teenage children who is in her early 40s. However, within these several decades of risk that these two women mark, the emotional, educational, professional and reproductive issues may be similar and be independent of chronological age. The ability to accept the cancer diagnosis, complete treatment, remain adherent to endocrine therapy if required, and continue with education or work, may be more tied to emotional maturity and financial resources, which may or may not be related to chronological age. Also, younger women with breast cancer have a higher likelihood of hereditary breast cancer, where knowledge of the potential risk for the disease is known (i.e., by family history if not by established mutation); however, many women diagnosed at a young age may first learn of having a germ line mutation for breast cancer at the time of cancer diagnosis, without prior knowledge of the disease in any relatives, especially if this is passed through the paternal line. The rate of germ line mutations of BRCA1 are considerably higher in younger women than in older women, and TP53 mutations may also be responsible for breast cancer in these women (Gabriel and Domchek 2010) (Table 2.3). Increasingly, breast cancer gene panels are being used to assess these younger women, and in the future, we may have a better explanation for the occurrence of cancer at such a young age. Also, among these women may be survivors of a prior childhood cancer in which radiation treatment to the thorax or total body was included (Moskowitz et al. 2014). Such women are also among the younger breast cancer patients and survivors.

One of the other challenges among younger women is the co-occurrence of breast cancer and pregnancy—largely due to the later age of marriage and childbearing among well-educated women (Litton et al. 2013; Partridge et al. 2004; Theriault and Litton 2013). Deferring pregnancy until an older age is a recent phenomenon in Western industrialized countries. These breast cancers may be diagnosed during pregnancy or in the first years after childbirth. Large tumors and delays in diagnosis are common due to the natural changes that occur in the breast as part of pregnancy and lactation. Clearly, these cancers are already present in the breast prior to the pregnancy, but come to clinical recognition with the stimulation of hormones during pregnancy. The increased challenge of delivering antineoplastic treatments during pregnancy, as well as the high risk management of the mother and fetus, can add to the stress of the cancer diagnosis and treatment for young women. And of course, for most young women of reproductive age who are diagnosed with breast cancer, the concerns about preserving fertility may influence decision-making about treatments, (Ruddy et al. 2014) including finding clinicians to provide these services in a timely manner, as well as having the financial resources to pay for these services.

Genetic and genomic discoveries during the past 15 years have allowed us to subtype breast cancer molecularly and develop classifications that are useful with regard to biology and therapy. Survival outcomes for women younger than 35 have been historically poor (Keegan et al. 2013), although most of the improvements related to introduction of adjuvant chemotherapy were most apparent in younger women. For some time, it has been known that the frequency distribution of hormone receptor positive breast cancer is lower in younger women than post-menopausal women, but recent gene expression studies have more extensively characterized the distribution of hormone receptor positive, triple negative, double negative and HER2 positive tumors (Keegan et al. 2012) (Fig. 2.1). Also, some of these subtypes vary by race/ethnicity, most notably the high proportion of triple negative and basal cell phenotypes in African American and Latino women, as well as the higher rates of incident breast cancer in African American women before age 40 compared to other ethnic groups (Brinton et al. 2008). In addition, the higher rate of incident stage IV metastatic breast cancer among younger age women compared to older women complicates the initial treatment and management (Johnson et al. 2013).

All of the age and life stage variables described earlier will influence the treatment of young women, beyond the tumor stage and biological features, which would be the dominant consideration in older women. If the younger woman carries a deleterious BRCA1/2 mutation, she may opt for bilateral mastectomy at the time of initial surgery, even though breast conservation could be considered. The young woman’s treatment decision-making may also be influenced by her marital status and whether she has completed childbearing. In addition, we see some women opting for very aggressive chemotherapy regimens, even in the setting of small tumors with favorable characteristics, due to their desire to stay alive to raise children or pursue other meaningful goals. Other younger women may avoid treatments because they fear their toxicity, such as infertility. Because younger women often have more advanced stage disease at diagnosis, they will more likely be subjected to post-mastectomy or axillary radiation, which may contribute to the burden of survivorship symptoms. In our experience, younger women opt for disability during treatment more frequently than older women. The experience can be physically and emotionally overwhelming.

The psychosocial challenges of getting young women through treatment may be considerable. As alluded to earlier, the emotional and financial resources needed to cope with treatments which often last more than a year, are substantial. Finally, adherence to endocrine therapy is a particularly challenging problem, as often chemotherapy has induced transient or permanent amenorrhea, and the addition of tamoxifen increases the likelihood of greater vasomotor symptoms (Ganz et al. 2011), as well as sexual dysfunction in some. Several studies document a relationship between younger age and nonadherence to endocrine therapy. Factors such as low social support, a perceived lack of understanding of endocrine therapy and lack of the opportunity to ask questions at diagnosis, and a greater number of menopausal symptoms are associated with nonadherence [e.g., (Cluze et al. 2012)].

Premature menopause and infertility are a frequent consequence of treatments in young women, and prolonged treatments may also interfere with the timing of subsequent childbearing. Specifically, the 5 years of endocrine therapy with tamoxifen may make it difficult to fit in a pregnancy, especially if a woman is in her late 30s. Although recent data do not suggest increased risk for breast cancer recurrence with childbearing, (Azim et al. 2012, 2013) this is still a major concern for some women. This is especially an issue for women with DCIS for whom treatment decisions may be quite difficult. We discuss fertility and reproductive concerns in greater detail in the Chap. 10. Premature menopause may lead to other health consequences such as weight gain and menopause-related symptoms.

Breast cancer is the leading cause of death among women 40–59 years (Siegel et al. 2014) so that fear of recurrence and death from cancer is a reality for younger women with breast cancer. This is in spite of the significant advances in treatment with chemotherapy and targeted therapies. Many of the women living for long periods of time with metastatic breast cancer are younger women (see Chap. 15 on metastatic breast cancer survivors). Younger women are also at greatest risk for experiencing the long-term and late effects of cancer treatment, similar to childhood cancer survivors, as they have a long time horizon of survival in which these long-term and late effects may occur. For example, fractures from early osteoporosis, cardiac failure, and second cancers (breast and non-breast) can occur. The extent to which the breast cancer treatments received as a young woman may accelerate various aspects of organ aging is uncertain at this time. Clearly, some of the manifestations of cognitive difficulties may portend accelerated brain aging, and both structural and functional brain changes have been observed in breast cancer survivors several decades later (Koppelmans et al. 2012a, b). Thus, younger women need to be viewed as a high-risk population at risk for future health events, and should be considered for systematic cancer prevention and control interventions. This is particularly true for BRCA1/2 carriers in whom second cancers of the breast and Fallopian tubes/ovaries can be prevented or their risk reduced.

Breast cancer has a more negative impact on quality of life among younger women, particularly in the psychosocial and emotional domains (Cimprich et al. 2002; Ganz et al. 2003; Howard-Anderson et al. 2012; Mor et al. 1994). Younger women with breast cancer report worse mental health-related quality of life than both age-matched women without breast cancer and older women with breast cancer (Howard-Anderson et al. 2012). Younger women also report elevated levels of distress and depressive symptoms following cancer diagnosis, which may persist into survivorship (Avis et al. 2012, 2013). Higher levels of depressive symptoms in younger women are due to a variety of factors, including more aggressive treatment (though differences remain after controlling for type of treatment), a lower sense of peace and meaning in life, and particularly greater illness intrusiveness (Avis et al. 2012, 2013). Indeed, younger women report higher levels of illness intrusiveness in all domains of life, including health, diet, work, recreation, financial situation, relationships, and sex life, which are closely tied to depression. Further, younger women perceive cancer as more threatening (Vinokur et al. 1990) and report greater fear of cancer recurrence (Lebel et al. 2013) than older women.