Radiation therapy in young women with breast cancer

Breast cancer is the most common cause of cancer death in women aged 20–59 years [1]. Younger women with breast cancer are considered a unique group of patients, among other reasons because data from epidemiological, retrospective studies indicate that young women have worse clinical outcomes, increased rates of loco-regional recurrences (LRR), and a lower overall 5-year survival [2, 3]. The fact that young women are more likely to present higher grade tumors at diagnosis than their older counterparts is partly responsible for the poorer prognosis. Young women are not screened as rigorously as older women, and the anatomical characteristics of the breast tissue for that age group makes it difficult to differentiate between normal and tumor tissue in a mammogram [4]. Intrinsic tumor characteristics also contribute to the worse prognosis in young patients. Breast cancer in young women is considered a unique biologic and oncologic entity. Tumors in younger patients (less than 40–45 years old) are frequently estrogen receptorand progesterone receptor-negative, have an increased expression of Ki-67, human epidermal growth factor receptor-2 (HER-2/EGFR) and p53, and have greater lymphovascular invasion [4–6]. Young women are also considered to have a higher risk of developing LRR after breast-conserving surgery (BCS) than their older counterparts. Voogd et al. [7] reported that women younger than age 35 had a more than ninefold (hazard ratio: 9.24) greater risk of local recurrence after breast-conserving therapy than older women, but young women treated with mastectomy had a similar rate of chest wall recurrence compared with older patients. On the other hand, recent evidence suggests that, although still higher than would be expected for older women, the incidence of local breast tumor recurrences and failures may be substantially lower than previously [8]. This apparent risk reduction seems to stem from several factors, including the widespread use of systemic adjuvant therapy (endocrine and/or cytotoxic) and loco-regional treatments (surgery and/or radiotherapy) [4, 9]. Factors that significantly influence local control in young women treated with BCS include the presence of positive surgical margins, a negative lymph node status, and positive family history [10, 11]. Jobsen et al. [10] demonstrated that in women aged 40 years or less, the 5-year local recurrence rate was 8% in patients with negative margins and 37% in patients with positive margins. Also, the 5-year disease-free survival was 27% in patients with positive margins and 75% in those with negative margins [10].