Prognostic relevance of low-grade versus high-grade FIGO IB1 squamous cell uterine cervical carcinomas

Tumor grade is one of the more controversial factors with limited prognostic information in squamous cell carcinomas (SCC) of the uterine cervix.

Histologic slides of 233 surgically treated cervical SCC (FIGO IB1) were re-examined regarding the prognostic impact of the WHO-based grading system, using the different degree of keratinization, categorizing the tumors in G1, G2 and G3 (conventional tumor grade).

45.1% presented with well-differentiated tumors (G1), 29.2% with moderate (G2) and 25.8% with poor differentiation (G3). Tumor grade significantly correlated with decreased recurrence-free and overall survival. However, detailed analyses between G1- and G2-tumors failed to show any correlation with either recurrence-free or overall survival. G1- and G2-tumors were therefore merged into low-grade tumors and were compared to the high-grade group (G3-tumors). This binary conventional grading system showed an improved 5-years recurrence-free (low-grade: 90.2% vs. high-grade: 71.6%; p = 0.001) and overall survival rates (low-grade: 89.9% vs. high-grade: 71.1%; p = 0.001) for low-grade tumors. On multivariate analysis adjusted for lymph node metastasis, high-grade tumors represented a hazard ratio of 2.4 (95% CI 1.3-4.7) for reduced recurrence-free and 2.4 (95% CI 1.2-4.6) for overall survival. High-grade tumors showed a significantly higher risk for pelvic lymph node involvement [OR 2.7 (95% CI 1.4-5.5); p = 0.003]. The traditional three-tiered grading system failed to predict pelvic lymph node metastases.

A binary grading model for the conventional tumor grade (based on the degree of keratinization) in SCC of the uterine cervix may allow a better prognostic discrimination than the traditionally used three-tiered system.