A visual classification method for tumor growth patterns at the invasive front—specifically the tumor growth pattern method—was the only scoring system independently associated with colon cancer–specific survival in multivariable analysis, according to a recent study.
The researchers conducted a retrospective cohort study to evaluate the reproducibility and prognostic utility of three histopathological scoring methods at the invasive tumor front in stage I to III colorectal cancer (CRC). Published in The Journal of Pathology Clinical Research, the study analyzed hematoxylin and eosin–stained sections from 538 patients treated at Glasgow Royal Infirmary between 1997 and 2013.
The scoring systems assessed were the Karamitopoulou method (percentage-based infiltration in 5 percent increments), the Taskin method (five-point scale evaluating tumor demarcation and infiltrative clusters), and the tumor growth pattern (TGP) classification (categorizing patterns as pushing, intermediate, or infiltrative). Interobserver reproducibility was highest for the Karamitopoulou and TGP methods, with intraclass correlation coefficients of 0.63 and 0.79 for Karamitopoulou and weighted kappa of 0.78 for TGP. The Taskin method demonstrated lower agreement (weighted kappa of 0.31 and 0.27).
Among the 538 patients, 65 percent were classified with high infiltrative scores by the Karamitopoulou method (greater than 50 percent), and 67 percent received scores of 4 to 5 using the Taskin method. The TGP classification identified 44 percent of tumors as infiltrative, 31 percent as pushing, and 25 percent as intermediate. Higher scores across all methods were associated with adverse clinicopathological features, including advanced T stage, N stage, venous invasion, and peritoneal involvement.
In Kaplan–Meier analysis, infiltrative tumors classified via the TGP method were associated with reduced CRC-specific survival. On multivariable Cox regression, the TGP method independently predicted colon cancer–specific survival, while the Karamitopoulou and Taskin methods did not retain statistical significance after adjusting for tumor budding and other variables.
The TGP method demonstrated additional prognostic value among patients with low tumor budding and was reported by the researchers as practical, reproducible, and prognostically relevant for colon cancer.
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