Hegewisch-Becker S, et al. - Given that large retrospective studies have reported the major prognostic relevance of primary tumor location (LPT) in advanced colorectal cancer, researchers used mature survival data from the recent randomized AIO KRK0207 trial in order to analyze LPT relative to other clinical and molecular parameters. According to findings, in the prognostication of survival in advanced colorectal cancer cases, LPT showed relevance and importance within the framework of a uniform treatment strategy according to the current standards, although LPT was not identified as the sole dominating prognostic factor for survival in such cases. In tumors with a RAS mutation, its impact was low.

Methods

• This study included patients who uniformly received first-line induction treatment with a combination of bevacizumab, oxaliplatin and fluoropyrimidine.
• Researchers used surgical reports, pathology reports and endoscopy reports, to retrospectively determine LPT.
• They used Kaplan–Meier estimations and log-rank tests to perform prognostic analyses, while hazard ratios (HRs) and multivariable results were derived from Cox models.

Results

• Among 754 patients with unequivocal information on LPT, a median overall survival of 24.8 months was reported in patients with left-sided tumors vs 18.4 months in the right-sided cohort (HR: 1.54, 95% confidence interval: 1.30–1.81, P < 0.0001).
• In a multivariable model, performance status, number of metastatic sites, baseline carcinoembryonic antigen and platelets were shown to independently retain prognostic significance, but LPT was identified as the strongest prognosticator (HR 1.60).
• The greatest unfavorable impact (HR 3.16) was shown by a BRAF mutation in the subgroup of patients with known RAS/BRAF status (n = 567, 75%).
• Although findings revealed a strong correlation of BRAF with LPT, the latter continued to be a significant prognosticator in the BRAF wild-type subgroup.
• In contrast, tumors carrying RAS mutations were not found to be majorly influenced by LPT.