[OA-26] Prognostic significance of combined histologic factors, tumour budding and tumour-infiltrating lymphocyte, in patients with stage II colonic cancer

Prapatsorn Deelon and Sarawut Kongkanka

Department of Pathology, Facolty of Medicine, Chiang Mai University, Chiang Mai, Thailand

Colorectal cancer prognosis is based on conventional histologic factors, i.e. subtype, grade, size, lymphovascolar invasion, perineural invasion and margin status. The 5^th edition of WHO classification of digestive tumours newly updates histologic factors, i.e. growth pattern, tumour budding (TB), poorly differentiated clusters (PDC), tumour-infiltrating lymphocyte (TIL) and Crohn-like reaction (CLR). This study aimed to assess conventional histologic factors and newly updated histologic factors. Haematoxylin and eosin stained slides of 41 patients with stage II colonic adenocarcinoma at Maharaj Nakorn Chiang Mai hospital during 2014 to 2016 were evaluated. The combined histologic factors were grouped as low TB + high TIL (n = 18); low TB + low TIL (n = 11); high TB + high TIL (n = 2); and high TB + low TIL (n = 10). The combined histologic factors showed significant difference in overall survival (OS). Low TB + high TIL showed the best OS, followed by low TB + low TIL and high TB + high TIL. High TB + low TIL showed the worst OS. In conclusion, high-risk histologic factors are considered for the chosen treatment for stage II colonic cancer patients. The combined histologic factors may be usefol as high-risk histologic factors.

Keywords: colon cancer; tumour budding; tumour-infiltrating lymphocyte