Predictive factors of tumor regression grading after neoadjuvant chemoradiotheraphy in locally advanced rectal cancer

Abstract

Objective To explore the predictive factors of tumor regression grading (TRG) after neoadjuvant chemoradiotheraphy of patients with locally advanced rectal cancer. Methods A retrospective analysis was performed on clinical and molecular biological data of 68 patients with rectal cancer, who underwent neoadjunant chemoradiotheraphy followed by radical surgery from April 2007 to December 2016. The clinical factors associated with TRG were analyzed by Logistic regression. Results Overall, there were 3 cases of TRG 0 (4.4%), 14 cases of TRG 1 (20.1%), 30 cases of TRG 2 (44.1%), 13 cases of TRG 3 (19.1 %), and 8 cases of TRG 4 (11.8%). Univariate analysis showed pre-neoadjuvant chemoradiotheraphy stage cT3 (P=0.008), cN0 (P=0.000), and the K-ras mutation status of wide-type (P=0.007) were significantly correlated with TRG after neoadjuvant chemoradiotheraphy. Logistic regression revealed that cT, cN and K-ras were independent predictive factors of TRG after neoadjuvant chemoradiotheraphy in rectal cancer. Conclusion Early stage of T and N, and the K-ras mutation status of wide-type may be predictive factors of high degree of TRG for rectal cancer after neoadjuvant chemoradiotherapy. Key words: Rectal cancer; Neoadjuvant chemoradiotherapy; Tumor regression grading