Prognostic value of Bax expression in the primary colon tumor of patients with metastatic colorectal cancer receiving first-line treatment with a triple combination of irinotecan + oxaliplatin + long-term infusion of 5-fluorouracil

Abstract

Objective: to evaluate the prognostic value of Bax expression in the primary colon tumor of patients with metastatic colorectal cancer (mCRC) receiving first-line treatment with a triple combination of irinotecan + oxaliplatin + long-term infusion of 5-fluorouracil.Materials and methods. The study included patients with mCRC (morphologically (histologically) verified diagnosis of colonic adenocarcinoma) that have never received treatment for disseminated disease. Study participants received a new first-line treatment regimen with a triple combination of irinotecan + oxaliplatin + long-term infusion of 5-fluorouracil. We evaluated both short-term and long-term treatment outcomes. We also assessed the level of Bax expression in primary tumor samples (biopsy/surgery specimens) collected prior to initiation of first-line treatment using immunohistochemical methods. We analyzed the correlation between the levels of Bax expression and short-term/long-term treatment outcomes.Results. Seventeen out of 20 mCRC patients included in the study were tested for Bax expression in the primary tumor using immunohistochemical staining. The analysis of correlation between Bax expression in tumor tissue and time-to-progression in patients with mCRC receiving first-line treatment with a triple combination of drugs demonstrated that high Bax expression was a favorable prognostic factor associated with longer time-to-progression. Median time-to-progression was significantly longer in patients with Bax overexpression than in those with low levels of Bax expression or no expression: 15.7 15,7 ± 3.38 months vs 8.6 15,7 ± 0.6 months, р = 0.012. When analyzing the impact of Bax expression on the overall survival (OS) in patients with mCRC, we found that patients with Bax overexpression demonstrated better OS (median follow-up time 17.3 15,7 ± 2.54; OS was not reached; mean value 31.26 15,7 ± 2.85 months) than patients with low Bax expression or no expression (median OS 13.60 15,7 ± 3.03 months), p = 0.021.Conclusion. Our results suggest that Bax overexpression in the primary colon tumor is a favorable prognostic factor associated with longer progression-free survival and OS in mCRC patients receiving first-line treatment with a triple combination of drugs.

Keywords

• molecular biomarkers
• вах
• metastatic colorectal cancer
• first-line treatment
• chemotherapy
• irinotecan
• oxaliplatin
• 5-fluoro-uracil