Prognostic value of histological grading in ductal adenocarcinoma of the pancreas - Klöppel vs TNM grading

A new histological grading system with prognostic correlation for pancreatic cancer was proposed by Kloppel et al. in 1985. Histological sections from 60 ductal adenocarcinomas operated on between January 1980 and December 1990 were retrospectively reviewed in order to compare Kloppel's grading with standard TNM's grading and assess their prognostic value. Kloppel grading was determined through the following histologic and cytologic factors: number duct-like structures, mucus production, neoplastic epithelium, arrangement and pleomorphism of nuclei, and mitotic activity. A score from 0 (well differentiated) to 2 (poorly differentiated) was given to each factor. The mean value obtained dividing the sum of the different values by the number of parameters was used to construct a malignancy scale and therefore allocate each patient to his Kloppel grading. The concordance index K between the two grading systems was relevant (K=0.85p<0.001). There was no relation either between gradings (Kloppel or TNM) and preoperative duration of symptoms or between gradings and UICC stages. TNM's G2 grades of malignancy, N status, and tumor stage were significantly related to survival time (p<0.05). Kloppel's grading does not show any advantage over the classical and simpler TNM's grading, even though it can be considered more objective and therefore more easily reproducible. This characteristic further should be enhanced by the introduction of a malignancy scale such as the “mean value”.