Molecular Subtypes and Prognostic Factors among Premenopausal and Postmenopausal Thai Women with Invasive Breast Cancer: 15 Years Follow-up Data

BACKGROUND AND PURPOSE: This study focused on molecular subtypes and prognostic factors for survival of pre- and post-menopausal breast cancer patients. METHODS: A retrospective cohort study was performed on 523 patients with invasive carcinoma of the breast treated at Ubon Ratchathani Cancer Hospital, Thailand from 2002 to 2016. Patient characteristics were collected based on a systematic chart audit from medical records. Prognostic factors were performed by observe survival analysis. A Cox regression model was used to calculate hazard ratios of death, taking into account the age and menopause status, molecular subtype, stage of disease, histological grade, lymphatic and vascular invasion, resection margin, hormone receptor expression, and treatment modality. RESULTS: The median time from the diagnosis of invasive breast cancer to the last follow-up or death was 10.2 [95% CI = 9.28-11.95] years in premenopausal women, and 7.4 [95% CI = 6.48-8.44] years in postmenopausal cases. The overall survival estimates at 5 and 10 years for younger woman of 71.2% and 51.8% respectively, appeared slightly better than the 68.3% and 40.9% for postmenopausal women [HRadj = 1.27, 95% CI =0.99-1.63]. In the multivariate analysis, 3 prognostic indicators significantly predicted a worse overall survival in premenopausal patients, triple negative subtype [HRadj = 6.03, 95% CI = 1.94-18.74], HER2-enriched status [HRadj = 4.11, 95% CI = 1.59-10.65] and stage III [HRadj = 2.73, 95% CI = 1.10-6.79]. Statistically significant increased risk of death in postmenopausal patients was noted for only chemotherapy after mastectomy [HRadj = 8.76, 95% CI = 2.88-26.61], and for a Luminal B status [HRadj = 3.55, 95% CI = 1.47-8.53]. CONCLUSION: Postmenopausal women with invasive breast cancer experience a significantly shorter survival than do their premenopausal counterparts. The predictors of worse overall survival were molecular subtype, stage of disease and type of treatment administered.