162P - Menopausal status on tumour biology in early breast cancer

Abstract

Breast cancer (BC) is primarily a disease of older or post menopausal women. It has been suggested that BC arising in young women is a unique biological subset characterized by less hormone sensitivity and higher HER2 (epidermal growth factor receptor) expression. This study was performed to compare the tumour biology between pre menopausal (PrM) and post menopausal (PoM) women. New diagnosis of early BC from 2011-2015 in the South East Cancer Centre were included. The patients were divided into PrM (<55 years) and PoM (≥55 years) groups. Information on pathology subtype (ductal carcinoma/lobular carcinoma), tumour grade, ki67, Tumour (T) stage, Nodal (N) stage and anatomical stage was obtained. Comparisons between these factors in the two groups were drawn using SPSS version 20.0. Data from 497 patients were obtained. 235 (47.3%) were PrM and 262 (52.7%) were PoM. Age range PrM group vs PoM group (29-54 vs 55-91). The differences between the groups was statistically significant on pathology subtype (p = 0.003), T stage (p = 0.033), and N stage (p = 0.008). Ki67 and grade were not statistically significant. The mean ki67 across biology subtypes (ER/PR/HER2/Ki67) in the PrM group was higher. PrM group had more grade III disease (33.2% vs 30.9%). Table 1: Distribution of tumour biology according to menopausal status.Tabled 1Pre Menopausal n = 235Post Menopausal n = 262P valueAge Range29-5455-91< 0.005Pathology IDC ILC214 21209 530.003Grade I II III4 153 787 174 810.481Size (mm)*25.927.20.396Ki67 (%)*21.819.40.083T stage 1 2 3 497 112 26 0103 131 21 70.033N stage 0 1 2 3129 79 22 5180 60 13 90.008 Open table in a new tab *mean, IDC: invasive ductal carcinoma, ILC: invasive lobular carcinoma. Pre menopausal women in this Irish population had poorer tumour biology compared to their Post menopausal counterpart. Aggressive measures should be taken in the treatment of these women to reduce the incidence of local recurrence and metastases.