Long-term prognostic effect of hormone receptor subtype on breast cancer

Abstract

Purpose To determine the long-term prognostic role of hormone receptor subtype in breast cancer using surveillance, epidemiology, and end results (SEER) database. Methods Data of 810,587 female operable invasive breast cancer patients from SEER database with a mean follow-up period of 94.2 months (range, 0-311 months) were analyzed. Hormone receptor subtype was classified into four groups based on estrogen receptor (ER) and progesterone receptor (PR) statuses: ER(+)/PR(+), ER(+)/PR(-), ER(-)/PR(+), and ER(-)/PR(-). Results Numbers of subjects with ER(+)/PR(+), ER(+)/PR(-), ER(-)/PR(+), ER(-)/PR(-), and unknown were 496,279 (61.2%), 86,858 (10.7%), 11,545 (1.4%), 135,441 (16.7%), and 80,464 (9.9%), respectively. The ER(+)/PR(+) subtype showed the best breast-cancer-specific survival, followed by ER(+)/PR(-), ER(-)/PR(+), and ER(-)/PR(-) subtypes in the respective order (all p < 0.001). Survival difference among hormone receptor subtypes was maintained in subgroup analysis according to anatomic stage, race, age group, and year of diagnosis. Hormone receptor subtype was a significant independent prognostic factor in multivariable analyses (p < 0.001). Hazard ratios of ER(+)/PR(-), ER(-)/PR(+), and ER(-)/PR(-) for breast-cancer-specific mortality risk were 1.419 (95% confidence interval [CI] 1.383-1.456), 1.630 (95% CI 1.537-1.729), and 1.811 (95% CI 1.773-1.848), respectively, with ER(+)/PR(+) as reference. Conclusion Hormone receptor subtype is a significant independent prognostic factor in female operable invasive breast cancer patients with long-term effect. The ER(+)/PR(+) subtype shows the most favorable prognosis, followed by ER(+)/PR(-), ER(-)/PR(+), and ER(-)/PR(-) subtypes in the respective order. Prognostic impacts of hormone receptor subtypes are also maintained in subgroup analysis according to anatomic stage, race, age, and year of diagnosis.