Objective: To examine the prognostic implications of routine elastica staining for venous invasion on prediction of cancer-specific survival in colorectal cancer.
Summary background data: Venous invasion is an important high risk feature in colorectal cancer, although prevalence in published studies ranges from 10% to 90%. To resolve the disparity, elastica stains have been used in our institution to provide a more objective judgment since 2002.
Methods: The study included 419 patients undergoing curative elective colorectal cancer resection between 1997 and 2006. Patients were grouped prior to (1997-2001 [cohort 1]) and following the introduction of elastica staining (2003-2006 [cohort 2]).
Findings: Clinicopathologic characteristics and 3-year survival rates were similar in both groups. Rate of detected venous invasion increased from 18% to 58% following introduction of elastica staining (P < 0.001). The 3-year cancer-specific survival rate associated with the absence of venous invasion was 84% in cohort 1, compared with 96% in cohort 2 (P < 0.01). Elastica staining improved the prognostic value of venous invasion, showing the area under the receiver operator curve rising from 0.59 (P = 0.040; 1997-2001) to 0.68 (P < 0.001; 2003-2006), using cancer mortality as an end point. A direct comparison between H&E alone and elastica Hematoxylin and Eosin (H&E) was made in 53 patients. The area under the receiver operator curve increased from 0.58, P = 0.293 (H&E alone) to 0.74, P = 0.003 for venous invasion detected using the elastica method.
Conclusions: Increased detection of venous invasion with elastica staining, compared with H&E staining, provides superior prediction of cancer survival in colorectal cancer. This relationship was seen in the comparison of 2 consecutive cohorts and in a direct comparison in a single cohort. Based on these results, elastica staining should be incorporated into the routine pathologic assessment of venous invasion in colorectal cancer.