KRAS Mutation as Predictor Factor in Locally Advanced Rectal Cancer

Introduction: Standard treatment of locally advanced rectal cancer (LARC) includes neoadjuvant chemo-radiotherapy followed by total mesorectal excision (TME). The role of KRAS as a biomarker in rectal cancer remains equivocal. We evaluate the Tumor Regression Grade (TRG), Relapse-Free Survival (RFS) and Overall Survival (OS) according to the KRAS oncogene status in LARC. Material and Method: We evaluated the KRAS status in 23 patients with LARC. Tumor DNA was obtained from pretreatment biopsy tissues. Results: KRAS mutation was found in 30,4% of the patients. TRG (1-2) after CRT were 56,2% and 42,8%, for wild-type and mutant KRAS groups (p= NS). After a median follow-up of 31 months, there was no difference in RFS (47,7 vs 23,3 months) or OS (51,5 vs 30 months) between wild-type and mutant-type KRAS groups, respectively. Conclusions: Although KRAS status seems to have slightly better prognosis in LARC, it does not reach significant results (probably due to insufficient sample) in TRG, RFS or OS.