Breast cancer in young women
Breast cancer diagnosed before 40 differs from the disease in older women in its biology, in what it does to quality of life and fertility, and in who is diagnosed late and who dies of it.
Definition and incidence
For breast cancer, young usually means diagnosed before 40. In the US breast cancer is the most commonly diagnosed cancer and the leading cause of death among women aged 20 to 49, and about 10% of new diagnoses occur in women under 45. Incidence can vary significantly between populations, mainly because of differences in risk factors and in access to screening programmes.
Breast cancer cases in young women are rising and becoming a health challenge. The challenges young women face differ from those of older women, and tumour characteristics, treatment options, fertility preservation and long-term quality of life differ profoundly in younger patients. Understanding those challenges is essential for providing better care and support.
Tumour biology and survival
Young women tend to develop more aggressive tumours than older women. Their tumours tend to be of higher grade, larger and more proliferative as marked by Ki-67 expression, and are often oestrogen receptor negative. They are also less differentiated and diagnosed at a more advanced stage. Young women are also more often diagnosed with triple-negative and basal-like breast cancer, which lead to worse outcomes. Together with lower survival rates, these characteristics make younger age a factor that worsens survival and a significant one for breast cancer deaths.
Quality of life
Beyond the biology, young women face physical and mental health problems, and when they decide on treatment and surgery they also weigh concerns about relationships, fertility, family planning, pregnancy, breastfeeding, returning to work, money and caring for children. They experience more fatigue, depression, and sexual and cognitive problems than older patients and healthy peers. Their quality of life falls to its lowest during treatment and recovers more slowly than in older patients. Even ten years after treatment it remains below that of the general population, so long-term follow-up is needed. Hair loss from chemotherapy is highly visible and brings emotional and social difficulty.
Fertility
At diagnosis some young women are still planning families, and about 40% want children of their own, yet only one in ten receives fertility preservation options and only 10% become pregnant within five years of diagnosis. Fertility can be preserved with medicines that suppress ovarian function, the gonadotropin-releasing hormone agonists, and by cryopreserving embryos, oocytes or ovarian tissue. Giving those agonists during chemotherapy is one strategy for increasing the chances of pregnancy by protecting ovarian function. Because young women worry about what treatment will do to their fertility, some may refuse chemotherapy, avoid endocrine therapy or shorten the recommended duration of therapy. Discussing fertility helps them make informed decisions, adhere to treatment and improve their outcomes without giving up their reproductive goals.
Disparities across populations
Incidence and death among young women vary with geography and ethnicity. Mortality (81.7%) and incidence (45.6%) rates vary significantly among countries and regions. The differences can be attributed to women under 40 not taking part in screening, the timing of diagnosis, awareness of symptoms and access to treatment. Therapeutic options may be limited in lower-income countries, but mortality also varies among high-income countries, so not only access to treatment but also how it is delivered influences outcomes. In wealthy countries fewer than one in 100,000 women die of breast cancer, against three in 100,000 in poorer regions, which means that young women in low-income countries face more than three times the risk of dying from it.
Delayed diagnosis is one of the main reasons for poorer outcomes and fewer early detections in young women. This is likely because patients and clinicians often have low suspicion of breast cancer, benign findings are common at that age, and women under 40 do not usually have mammograms.
In the US Surveillance, Epidemiology, and End Results Programme, Black women under 40 had a 16% higher diagnosis rate and more than double the mortality of their white peers. Patients aged 15 to 39 from African American and Hispanic backgrounds are more likely to have delays in starting treatment, which significantly worsens survival.
In several Latin American countries breast cancer incidence in young women reaches up to 20%, against 12% in high-income countries. Demographics, socioeconomic status, genetics, lifestyle and a younger age distribution may contribute to that higher incidence. Another explanation for the higher incidence there is that young women have delays in diagnosis, which worsen their survival. Shortages of healthcare staff, infrastructure and diagnostic equipment also make access to treatment difficult. Where healthcare coverage is limited, some patients have to pay for their own medicines to continue treatment. Young women in those regions have limited access to therapies and experience interruptions in treatment. Many must travel to specialist cancer referral centres, which adds travel and accommodation costs. About 26% of patients are forced to reduce their work, which worsens their financial burden.
Improving care
With its aggressive tumours and its mental, reproductive and quality-of-life challenges, breast cancer in young women is a public health concern. Patient education combined with the work of multidisciplinary teams can improve early diagnosis and treatment. Each woman should have the opportunity to receive adequate treatment tailored to her personal goals. Employers and policymakers must ensure adequate sick leave and create adaptable work settings for young women with breast cancer. Further research on breast cancer in young women will illuminate solutions to the main concerns of this age group.