Background: Prognostic assessment is crucial for optimal treatment. The aim of our study was to investigate the potential impact of estrogen receptor-α (ER-α) and progesterone receptor (PR) on the prognosis of colorectal cancer (CRC) patients who received curative resection.
Methods: Retrospective evaluation of two independent cohorts of CRC patients maintained prospectively in 2009-2010 (training set) (n = 148) and 2007-2009 (internal validation set) (n = 485). Furthermore, we used an external independent CRC cohort from The Cancer Genome Atlas (TCGA) (n = 511) for further validation. ER-α and PR expression as well as other potential prognostic factors were retrospectively evaluated in training set with respect to overall survival (OS), local relapse free survival (LRFS) and distant metastasis free survival (DMFS). The prognostic factors found in training set will be validated in two validation cohorts.
Results: On univariate analysis for the training set, OS, LRFS and DMFS were not associated with PR expression. While patients with ER-αexpression were found to have poor prognosis. In addition, multivariate analysis showed that ER-αexpression maintained significance with respect to OS (HR, 5.06; p = 0.002), LRFS (HR, 8.81; p = 0.002) and DMFS (HR, 8.07; p = 0.004). Similarly, ER-α expression showed prognostic significance with respect to OS with hazard ratios (HRs) of 1.572 (95% CI: 1.001-2.467, p = 0.049) and 1.624 (95% CI: 1.047-2.520, p = 0.031) for the internal and external validation cohort, respectively.
Conclusion: ER-α expression was a biomarker of poor prognosis and it might inform treatment decision for high risk CRC patients. However, PR expression was not associated with survival outcomes.
Keywords: Colorectal cancer; Curative resection; Estrogen receptor-α; Progesterone receptor; Prognosis.