Oncological outcomes by tumor biology in young women with breast cancer in a multiethnic middle-income setting: A multicenter study

Breast cancer in younger women has a poorer outcome due to lower disease-free survival than in old patients. One contributing factor to this poor survival rate could be related to more aggressive tumor biology. Research to date has focused on the biology of these tumors to refine prognosis and treatment strategies. This study aims to determine the 5-year overall survival of young breast cancer according to tumor biology in Malaysia. Multicenter retrospective study with convenience sampling method used to recruit the patients. All young women aged 50 years and below with breast cancer who underwent surgery/under follow up from January 1, 2014 to December 31, 2017 in Hospital Tengku Ampuan Rahimah (HTAR), Klang, Hospital Selayang and Hospital Putrajaya were in included. 5-year overall survival was calculated using Kaplan Meier. Cox Regression to estimate hazard ratio for mortality in patients with different tumor biology. Locoregional recurrence were analysed using Chi-Square analysis. A total of 360 patients were recruited predominantly within 41years–50years of age (63.9 %). The majority of the patients were Malays (66.4 %). Most of the patients were in Stage II (39.4 %) with a significant number of patients in Stage III and IV (25.0 % & 26.4 % respectively). 56.1 % had tumor biology of Luminal A followed by Triple negative (21.7 %), HER2 Enriched (12.2 %) and Luminal B (10 %). Kaplan Meier analysis showed that the 5-year overall survival was 58.3 %. There were no statistical significance across the tumor biology subtypes. Among the tumor biology groups, Triple Negative had the highest probability of survival with 54.5 %. Triple Negative had the highest probability of survival at 5-years while Luminal B (HER 2 Positive) had the lowest probability in young breast cancer. The 5-years overall survival was not statistically significant with accordance to locoregional recurrence rate and in different tumor biology.