The impact of knowledge transfer on the detection of venous invasion in colorectal cancer.

Venous invasion (VI) is an independent predictor of hematogenous metastasis and mortality in colorectal cancer (CRC) yet remains widely underreported. Its detection may require recognition of subtle morphologic clues, which at times are only unmasked with an elastin stain. This study evaluates the impact of a knowledge transfer initiative (KTI) on VI detection in a "real-world" pathology practice setting. Following participation in an interobserver variability study of VI detection (Kirsch et al, 2013), 12 participants received educational materials highlighting key issues in VI detection. Eighteen months later, participants were invited to submit pathology reports from all CRC resections signed out 18 months prior to and 18 months following the KTI (n = 266 and n = 244, respectively). Nine pathologists participated. Reports were reviewed for VI and other established prognostic factors. Numbers of elastin stains and tumor-containing blocks were also recorded. Comparative analyses were adjusted for baseline differences in tumor, lymph node, and metastasis stage; tumor location; use of neoadjuvant therapy; and number of tumor-containing blocks. VI detection increased significantly post-KTI versus pre-KTI (39.3% versus 18.4%, adjusted odds ratio [OR] 2.86 [1.91-4.28], P < .001). Increased VI detection post-KTI was observed in both stage II (31.8% versus 12.5%, adjusted OR 3.27 [1.45-7.42], P = .004) and stage III CRC (62.4% versus 28.2%, adjusted OR 4.23 [2.37-7.55], P < .001). All pathologists demonstrated increased VI detection post-KTI. Use of elastin stains was significantly higher post-KTI versus pre-KTI (61.5% versus 5.3% of cases respectively, P < .001). This study demonstrates the effectiveness of knowledge transfer in increasing VI detection in routine pathology practice.

Venous invasion in colorectal cancer: impact of an elastin stain on detection and interobserver agreement among gastrointestinal and nongastrointestinal pathologists.

Venous invasion (VI) is an independent prognostic indicator in colorectal cancer and may prompt consideration for adjuvant chemotherapy in patients with stage II tumors. Recent evidence suggests that VI is underreported in colorectal cancer and that detection may be enhanced by an elastin stain. This study aimed (1) to determine the impact of an elastin stain on VI detection and on interobserver agreement between gastrointestinal (GI) and non-GI pathologists, and (2) to identify factors associated with increased VI detection. Forty hematoxylin and eosin (H&E)-stained slides were circulated to 6 GI and 6 non-GI pathologists who independently assessed the VI status as positive, negative, or equivocal. Six weeks later, 40 corresponding Movat-stained slides were recirculated together with the original H&E slides and reassessed for VI status. Detection of VI was >2-fold higher with a Movat stain compared with an H&E stain alone (46.4% vs. 19.6%, P=0.001). GI pathologists detected VI more frequently than non-GI pathologists on both H&E (30.0% vs. 9.2%, P=0.029) and Movat (58.3% vs. 34.6%, P=0.018) stains. There was higher interobserver agreement in the case of a Movat stain, particularly for extramural VI (H&E: κ=0.23 vs. Movat: κ=0.41). A poststudy survey indicated that GI pathologists and non-GI pathologists applied similar diagnostic criteria but that GI pathologists more frequently applied "orphan arteriole" and "protruding tongue" signs as diagnostic clues to VI. This study confirms that VI is underdetected on H&E and highlights the role of elastin staining in improving VI detection and interobserver agreement. Strategies to improve VI detection are warranted.