Gallbladder adenocarcinoma: The prognostic significance of histologic grade

Gallbladder adenocarcinoma (GBA) postresection 5‐year survival rates are less than 5%, but when histologically confined to the mucosa or submucosa, survival rates of 64% (5 years) and 44% (10 years) have been reported. Whether any other histologic features of GBA have prognostic significance is unknown. This investigation was conducted to determine if GBA histologic grade correlates with survival. Thirty patients with advanced stage GBA participating in Eastern Cooperative Oncology Group (ECOG) treatment protocol EST‐2273 served as the study material. Using glandular tumor grade criteria recommended by others, a panel of 7 ECOG pathologists categorized the GBA as either predominantly low or high histologic grade. Each patient's GBA histologic section measured no less than 1.0 × 1.0 cm. Predominant grade was defined as being that grade present in > 75% of the histologic section. Patient survival times by grade were calculated from date of initiation of chemotherapy until date of death. The 13‐week low grade GBA patient survival was significantly longer than the 7‐week high grade GBA patient survival (p < 0.01). Stratification of patients by either high or low predominant histologic grade is recommended in future GBA treatment studies.