Prognostic and predictive factors in metastasic colorectal cancer.

Abstract

690 Background: In recent years, prognostic and predictive factors in mCRC are becoming more important, outstanding the tumor and metastasic location, the primary tumor and/or metastasis resections as well as molecular biomarkers (KRAS, NRAS, BRAF and PIK3CA). Methods: We conducted a retrospective study of 334 patients with mCRC diagnosticated between January 2010 and June 2015 in the Oncology Service from HGUGM. The objective of our study was to evaluate the overall survival (OS) relating to each of these settings. We also evaluated OS considering the biological treatment received in first line. Multivariant analysis was performed with independence of tumor and metastasic location, metastasectomies, no primary tumor resection, biological treatment used in first line, age, sex and moleculars biomarkers. Results: Median OS was 24,34m. The advantageous prognostic factors which statistically significant impact on the median OS have been triple (RAS and BRAF) (n = 86) and quadruple (RAS, BRAF and PIK3CA) (n = 76) wild-type (wt 36,6m vs mut 23m, p = 0,02; wt 37,6m vs mut 23,38m, p = 0.02, respectively), left tumor location with rectum (left 25,55m vs right 19,44m, p = 0,001) and isolated hepatic and pulmonary metastasic location (30,32 vs 23 m, p = 0,03; 45,32m vs 23,38 m, p = 0,004, respectively). The main disadvantageous prognostic factor has been the no primary tumor resection (13,75m vs 31,61m, p = 0,00001) with independence of synchronous presentation of the disease as well as biomarkers mutational status. Median OS in first line was 30.13 m with bevacizumab (n = 54) vs 16,18m with antiEGFR (n = 28) (p = 0.02) in extended RAS wild-type patients (n = 101). Considering the multivariate analysis, the independent prognostic factors have been the isolated pulmonary metastasis (HR = 0,46; CI 95% 0,30-0,73;p = 0,001), quadruple wild-type (HR = 0,69;CI 95% 0,49-0,97; p = 0,031), metastasectomies (HR = 0,29; CI 95% 0,21-0,4; p = 0,000), right location (HR = 1,43; CI 95% 1,08-1,9;p = 0,014) and no primary tumor resection (HR = 2,06; CI 95% 1,49-2,86; p = 0,000). Conclusions: Isolated pulmonary metastasis, quadruple wild-type, metastasectomies, left location and primary tumor resection have independent positive prognostic value, according to our retrospective study.