Disease Free Survival among Molecular Subtypes of Early Stage Breast Cancer between 2001 and 2010 in Iran

Background: Breast cancer is the most common cancer among women. Molecular subtypes are important indetermining prognosis. This study evaluated five-year disease-free survival among four molecular subtypes inpatients with early stages of breast cancer. Materials and
Methods: In this retrospective descriptive-analyticalstudy, information on patients with breast cancer between 2001-2010 was evaluated. Five hundred ninety twopatients in the early stages of breast cancer (stages 1 and 2) were selected to undergo anthracycline-basedchemotherapy. Relapse, death or absence (censor) were considered as the end of the study. Patients based on ER,PR and HER-2 expression were divided into four subtypes (luminal A, luminal B, HER-2 enriched and triplenegative). Information based upon questionnaire was analysed. To show the patients survival rate, life table andKaplan-Meyer methods were used, and for comparing mean survival among different groups, the Log-Ranktest was utilized.
Results: Mean age at diagnosis was 47.9±9.6. Out of the 592 patients, 586 were female (99%)and 6 were male (1%). Considering breast cancer molecular subtypes, 361 patients were in the luminal A group(61%), 49 patients in the luminal B group (8.3%), 48 patients in the HER-2 enriched group (8.1%) and 134 in thetriple negative group (22.6%). Mean disease-free survival was 53.7 months overall, 55.4 months for the luminalA group, 48.3 months for the luminal B group, 43 months for the HER-2enriched group and 54.6 months forthe triple negatives. Disease free survival differed significantly among the molecular subtypes (p value=0.0001).
Conclusions: The best disease-free survival rate was among the luminal A subgroup and the worst disease-freesurvival rate was among the HER-2 enriched subgroup. Disease free survival rate in the HER-2 positive groups(luminal B and HER-2 enriched) was worse than the HER-2 negative groups (luminal A and triple negative).