Quantitative changes in hormone receptors expression level in breast cancer patients. A retrospective cohort study

KAMINSZCZIK, LUCÍA; VARGAS, JONATHAN; BUSTOS, BRUNO; DE RONATO, GABRIELA; TERRANOVA INTRIAGO, HUGO; BARDACH, ARIEL; ITKIN, BORIS; STRAMINSKY, SAMANTA; GONZÁLEZ ÁLVAREZ, DIANA

Oncología Clínica

Asociación Argentina de Oncología Clínica

Lugar: Buenos Aires; Año: 2019 vol. 24 p. 43 - 49

1669-6336

Although hormone receptors discordance in the evolution of breast cancer was extensively studied, it almost always has been treated as a dichotomous variable, disregarding their absolute values. The degree, the direction and the significance of quantitative variations in time in the level of expression of estrogen receptors (ER) and progesterone receptors (PR) are largely unknown.We performed a retrospective analysis of quantitative changes in the level of ER and PR in paired samples from either primary or recurrent lesion from the same patient in two separated points in time. ER and d PR expression was recorded as the percentage of staining cells. Subgroups analyses were not pre-planned.Sixty-eight females with breast cancer of any stage were included. Wilcoxon signed-rank test indicated a statistically significant reduction in the ER expression between first and second ER determination (Z=-2.75, r=-0.23, p=0.006). For PR, the difference was not statistically significant. In the subgroup analyses, after Bonferroni correction, only exposure to endocrine treatment, tissue obtained by surgery and age >40 years were significantly associated with the decrease in the ER expression level.Even though random error and technical issues are likely the main sources of the ER variability, the results of our study suggest a trend to a decrease in ER expression, in the relationship with tissue sampling methodology and/or exposure to endocrine therapy.