Outcome of breast cancer in young women stratified by age at diagnosis: the younger, the worse? The Korean Breast Cancer Society registry program data.

Abstract

Abstract Abstract #2079 Introduction: In the previous studies investigating the relation between age of onset of breast cancer and disease outcome, the age cut-off for very young onset was usually under 35 or under 40. However, these cut-offs were set arbitrarily or empirically without sufficient outcome data on the detailed age strata. Hence we tried to compare breast cancer outcomes of premenopausal women (age ≤50)according to age groups of 5 year interval.
 Patients and Methods: We analyzed data of 9,885 breast cancer patients aged ≤50 years registered in the Korean Breast Cancer Society Registration Program between 1992 and 2001. The overall survivals were compared between age groups. The median follow-up for this cohort of patients was 74.4 months.
 Results: 351 patients were aged <30 years (Group I), 1,092 patients were 31-34 (Group II), 2,087 patients were 35-39 (Group III), and 6,354 patients were 40-50 years old (Group IV). Younger patients had significantly higher T-stage, higher lymph-node positivity, and lower hormone-receptor positiviy than older patients. In Univariate analysis, Group I patients showed worse outcome than Group II patients (p=0.03). Also, Group II patients showed worse outcome that Group III patients (p<0.0001). Interestingly, there was no significant difference in survival of Group III and Group IV patients. This survival trend according to age group was found only in hormone receptor positive or unknown patients, and not in hormone receptor negative patients. Multivariate analysis was performed using a Cox regression model including age groups, tumor size (2cm), lymph node involvement, hormone receptor, chemotherapy, and hormone therapy. Compared to the Group IV patients (reference), Group III patients had similar survival (hazard ratio (HR) = 1.06, 95% confidence interval (CI): 0.94-1.20). But, Group II and I patients had significantly worse survival (HR = 1.43 (95%CI: 1.24-1.64), HR = 2.09 (95%CI: 1.69-2.58), respectively). The HR was even higher in patients young than 25 (HR = 2.35, 95%CI: 1.35-4.06).
 Conclusions: Patients aged 35 to 39 showed similar overall survival compared to patients aged 40 to 50, whereas patients aged <35 showed significantly worse outcome than patients aged 35 to 39. Moreover, patients aged <30 showed significantly worse outcome than patients aged 31 to 34. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2079.