Association of tumor size in pathological T4 colorectal cancer with desmoplastic reaction and prognosis.

Background: Tumor size in pathological T4 (pT4) colorectal cancer (CRC) is associated with oncological prognosis; however, its relation to epithelial-mesenchymal transition (EMT)-associated histology is unclear. We aimed to investigate the association of tumor size with oncological prognosis and EMT.

Methods: We performed a retrospective analysis of 95 patients with primary CRC who underwent radical surgery and were consecutively diagnosed with pT4.

Results: Both 3-y disease-free survival (DFS) and cancer-specific survival (CSS) were significantly higher in patients with tumor size ≥50 mm than in those with tumor size <50 mm ( = .009 and  = .011, respectively). The independent factors identified in the multivariate analysis for DFS were pathological lymph node metastasis (hazard ratio [HR], 2.551; 95% confidence interval [CI], 1.031-6.315;  = .043), distant metastasis (HR, 2.511; 95% CI, 1.140-5.532;  = .022), tumor size (HR, 0.462; 95% CI, 0.234-0.913;  = .026), and adjuvant chemotherapy (HR, 0.357; 95% CI, 0.166-0.766;  = .008). The independent factors identified in multivariate analysis for CSS were tumor location (HR, 10.867; 95% CI, 2.539-45.518;  = .001) and tumor size (HR, 0.067; 95% CI, 0.014-0.321;  < .001). In pT4 CRC, smaller tumor size was associated with nonmature desmoplastic reaction and EMT-related histology.

Conclusions: Tumor size ≥50 mm was associated with a better DFS and CSS than that of <50 mm, in patients with pT4 CRC. Smaller tumor size with advanced invasion likely reflects a more biologically aggressive phenotype in pT4 CRC.