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Association between tumor differentiation grade and TNM staging in colorectal cancer
Background
The tumor differentiation grade has been shown by several studies to be a stage-independent prognostic factor in colorectal cancer (CRC) 1. It is a factor that accounts for the tumor biology and is considered as an indicator of potential tumor growth and spread. The aim of this study was to analyze the importance of differentiation grade and how it relates to TNM staging system. 1. Mori T, Hirota T, Ohashi Y, Kodaira S. Significance of histologic type of primary lesion and metastatic lymph nodes as a prognostic factor in stage III colon cancer. Dis Colon Rectum 2006;49:982–92.
Methods
The study was a retrospective single-centre analysis conducted at the University Clinic of Gastroenterology, University Hospital Center Mother Teresa, Tirana, Albania during the period 2014-2017. The clinical parameters and pathology data of cancer stage and differentiation grade were included. Tumor staging was done according to TNM system, AJCC (American Joint Committee on Cancer) 7th edition. The differentiation grade was correlated with demography, tumor location and overall TNM stage. They were further divided into low tumor grade (G1+G2) and high tumor grade (G3+G4) according to tumor differentiation. Data analysis was performed using the SPSS statistical package version 23.0.
Results
A total number of 237 patients were included in the study, mean age 62.7 ± 11.0 years, 133 (56.1%) male and 104 (43.9%) female. The tumor differentiation grade correlated significantly with the overall TNM stage (p = 0.001). A higher grade was more likely to correspond with a worse overall stage. High tumor grade (G3+G4) was diagnosed more frequently in stage III-IV than in stage I-II (71.6% vs 9.6%). The grade significantly correlated with the risk of having lymph node metastasis where the high grade tumors (G3/4) had a markedly increased risk of having positive nodes (p < 0.001). There were found no correlations between the differentiation grade and age or gender.
Conclusions
Tumor differentiation grade is an important prognostic component, which correlates strongly with TNM classification system of CRC. Higher grade may have a higher malignant potential and be associated with worse clinical outcomes.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosures
All authors have declared no conflicts of interest.
