Routine Elastic Staining Helps Detection of Vascular Invasion in Colorectal Cancer: A Comprehensive Analysis of T3 or Higher Tumors Without Lymph Node Metastasis.

Background/aim: Vascular invasion (VI) in colorectal carcinoma (CRC) is an independent prognostic feature and a high-risk indicator for adjuvant chemotherapy in stage II CRC. This study evaluated the effect of elastic staining on VI detection.

Patients and methods: The VI was assessed using elastic staining in 154 patients with CRC. Based on hematoxylin and eosin (H&E) staining, cases were classified into three groups: absent (n=80), equivocal (n=23), and suspected (n=51). Two sections per case were evaluated for VI using elastic staining, and the presence of VI on one or both slides was confirmed. Finally, the correlation between the VI and other clinicopathological factors was analyzed.

Results: The overall detection rate of VI using elastic staining was 67/154 (51.4%). VI was detected in 17/80 (21.3%), 3/23 (13.0 %), and 47/51 (92.2%) patients in the absent, equivocal, and suspected groups, respectively. VI was detected in both sections of the elastic staining slides in 28 cases, and in only one section in 38 cases. The VI was significantly associated with perineural invasion, M stage, and synchronous metastasis.

Conclusion: VI detection using H&E staining alone is not reliable, emphasizing the importance of elastic staining in improving VI detection. Therefore, we recommend the incorporation of elastic staining into routine pathological practice for all pT3 and pT4 CRC cases.