Tumor Budding Assessment in Colorectal Carcinoma: Normalization Revisited.

Tumor budding (TB) is a powerful prognostic factor in colorectal cancer (CRC). An internationally standardized method for its assessment (International Tumor Budding Consensus Conference [ITBCC] method) has been adopted by most CRC pathology protocols. This method requires that TB counts are reported by field area (0.785 mm 2 ) rather than objective lens and a normalization factor is applied for this purpose. However, the validity of this approach is yet to be tested. We sought to validate the ITBCC method with a particular emphasis on normalization as a tool for standardization. In a cohort of 365 stage I-III CRC, both normalized and non-normalized TB were significantly associated with disease-specific survival and recurrence-free survival ( P <0.0001). Examining both 0.95 and 0.785 mm 2 field areas in a subset of patients (n=200), we found that normalization markedly overcorrects TB counts: Counts obtained in a 0.95 mm 2 hotspot field were reduced by an average of 17.5% following normalization compared with only 3.8% when counts were performed in an actual 0.785 mm 2 field. This resulted in 45 (11.3%) cases being downgraded using ITBCC grading criteria following normalization, compared with only 5 cases (1.3%, P =0.0007) downgraded when a true 0.785 mm 2 field was examined. In summary, the prognostic value of TB was retained regardless of whether TB counts in a 0.95 mm 2 field were normalized. Normalization resulted in overcorrecting TB counts with consequent downgrading of most borderline cases. This has implications for risk stratification and adjuvant treatment decisions, and suggests the need to re-evaluate the role of normalization in TB assessment.

Prognostic and Predictive Value of Tumor Budding in Colorectal Cancer.

BACKGROUND: Tumor budding (TB) is an adverse prognostic factor in colorectal cancer (CRC). International consensus on a standardized assessment method has led to its wider reporting. However, uncertainty regarding its clinical value persists. This study aimed to (1) confirm the prognostic significance of TB, particularly in stage II CRC; (2) to determine optimum thresholds for TB risk grouping; and (3) to determine whether TB influences responsiveness to chemotherapy. METHODS: TB was assessed in CRC sections from 1575 QUASAR trial patients randomized between adjuvant chemotherapy and observation. Optimal risk group cutoffs were determined by maximum likelihood methods, with their influence on recurrence and mortality investigated in stratified log-rank analyses on exploratory (n = 504), hypothesis-testing (n = 478), and final (n = 593) data sets. RESULTS: The optimal threshold for high-grade TB (HGTB) was ≥ 10 buds per 1.23 mm2. High-grade TB tumors had significantly worse outcomes than those with lower TB: 10-year recurrence 36% versus 22% (risk ratio, 2.00 [95% CI, 1.62-2.45]; 2P < .0001) and 10-year mortality 50% vs. 37% (risk ratio, 1.53 [95% CI, 1.34-1.76]; 2P < .0001). The prognostic significance remained equally strong after allowance for other pathological risk factors, including stage, grade, lymphovascular invasion, and mismatch repair status. There was a nonsignificant trend toward increasing chemotherapy efficacy with increasing bud counts. CONCLUSIONS: TB is a strong independent predictor of recurrence. Chemotherapy efficacy is comparable in patients with higher and lower TB; hence, absolute reductions in recurrence and death with chemotherapy should be about twice as large in patients with ≥ 10 than < 10 TB counts.

Cytokeratin-based assessment of tumour budding in colorectal cancer: analysis in stage II patients and prospective diagnostic experience.

Tumour budding in colorectal cancer is an important prognostic factor. A recent consensus conference elaborated recommendations and key issues for future studies, among those the use of pan-cytokeratin stains, especially in stage II patients. We report the first prospective diagnostic experience using pan-cytokeratin for tumour budding assessment. Moreover, we evaluate tumour budding using pan-cytokeratin stains and disease-free survival (DFS) in stage II patients. To this end, tumour budding on pan-cytokeratin-stained sections was evaluated by counting the number of tumour buds in 10 high-power fields (0.238 mm2), then categorizing counts as low/high-grade at a cut-off of 10 buds, in two cohorts. Cohort 1: prospective setting with 236 unselected primary resected colorectal cancers analysed by 17 pathologists during diagnostic routine. Cohort 2: retrospective cohort of 150 stage II patients with information on DFS. In prospective analysis of cohort 1, tumour budding counts correlated with advanced pT, lymph node metastasis, lymphovascular invasion, perineural invasion (all p < 0.0001), and distant metastasis (p = 0.0128). In cohort 2, tumour budding was an independent predictor of worse DFS using counts [p = 0.037, HR (95% CI): 1.007 (1.0-1.014)] and the low-grade/high-grade scoring approach [p = 0.02; HR (95% CI): 3.04 (1.2-7.77), 90.7 versus 73%, respectively]. In conclusion, tumour budding assessed on pan-cytokeratin slides is feasible in a large pathology institute and leads to expected associations with clinicopathological features. Additionally, it is an independent predictor of poor prognosis in stage II patients and should be considered for risk stratification in future clinical studies.

Collective migration of cancer-associated fibroblasts is enhanced by overexpression of tight junction-associated proteins claudin-11 and occludin.

It has been suggested that cancer-associated fibroblasts (CAFs) positioned at the desmoplastic areas of various types of cancer are capable of executing a migratory program, characterized by accelerated motility and collective configuration. Since CAFs are reprogrammed derivatives of normal progenitors, including quiescent fibroblasts, we hypothesized that such migratory program could be context-dependent, thus being regulated by specific paracrine signals from the adjacent cancer population. Using the traditional scratch assay setup, we showed that only specific colon cancer cell lines (i.e. HT29) were able to induce collective CAF migration. By performing quantitative proteomics (SILAC), we identified a 2.7-fold increase of claudin-11, a member of the tight junction apparatus, in CAFs that exerted such collectivity in their migratory pattern. Further proteomic investigations of cancer cell line secretomes revealed a specific signature, involving TGF-ß, as potential mediator of this effect. Normal colonic fibroblasts stimulated with TGF-ß exerted myofibroblastic differentiation, occludin (OCLN) and claudin-11 (CLDN11) overexpression and cohort formation. Subsequently, inhibition of TGF-ß attenuated all the previous effects. Immunohistochemistry of the universal tight junction marker occludin in a cohort of 30 colorectal adenocarcinoma patients defined a CAF subpopulation expressing tight junctions. Overall, these data suggest that cancer cells may induce CLDN11 overexpression and subsequent collective migration of peritumoral CAFs via TGF-ß secretion.

Tumor budding in colorectal carcinoma: time to take notice.

Tumor 'budding', loosely defined by the presence of individual cells and small clusters of tumor cells at the invasive front of carcinomas, has received much recent attention, particularly in the setting of colorectal carcinoma. It has been postulated to represent an epithelial-mesenchymal transition. Tumor budding is a well-established independent adverse prognostic factor in colorectal carcinoma that may allow for stratification of patients into risk categories more meaningful than those defined by TNM staging, and also potentially guide treatment decisions, especially in T1 and T3 N0 (Stage II, Dukes' B) colorectal carcinoma. Unfortunately, its universal acceptance as a reportable factor has been held back by a lack of definitional uniformity with respect to both qualitative and quantitative aspects of tumor budding. The purpose of this review is fourfold: (1) to describe the morphology of tumor budding and its relationship to other potentially important features of the invasive front; (2) to summarize current knowledge regarding the prognostic significance and potential clinical implications of this histomorphological feature; (3) to highlight the challenges posed by a lack of data to allow standardization with respect to the qualitative and quantitative criteria used to define budding; and (4) to present a practical approach to the assessment of tumor budding in everyday practice.

Determinants of repair type, reintervention, and mortality in 393 children with double-outlet right ventricle.

OBJECTIVE: We sought to define the prevalence of definitive end-states and their determinants in children with double-outlet right ventricle. METHODS: We performed a clinical record review of 393 children with double-outlet right ventricle presenting to our institution from 1980 to 2000. RESULTS: Double-outlet right ventricle classification was as follows: subaortic ventricular septal defect with or without pulmonary stenosis in 47%, subpulmonic ventricular septal defect in 23%, noncommitted ventricular septal defect in 26%, and doubly committed ventricular septal defect in 4%. Hypoplastic ventricles were present in 39%, pulmonary stenosis was present in 65%, and aortic arch obstruction was present in 24%. Biventricular repair was performed in 194 patients (55%) at a median age of 10 months (range: birth to 14.0 years), and the Fontan operation (n = 182; 23%) was performed at a median age of 3.7 years (range: 6 months to 14.9 years). Results improved over time (P < .001). Factors discriminating among end-states included younger patient age at presentation (P < .001), lower weight (P < .001), and adequacy of left-sided heart structures, especially the size of the left ventricle (P < .001), aortic arch (P < .001), and mitral valve (P = .004). For complex double-outlet right ventricle, Rastelli-type repair increased early reintervention risk (P = .04) and late post-repair mortality (P = .02), whereas the arterial switch operation increased early post-repair mortality (P = .02) with a benefit of improved late post-repair survival. CONCLUSIONS: Biventricular repair, especially Rastelli-type reconstruction, is associated with higher late mortality and reintervention than is Fontan repair. The wisdom of extending biventricular repair to borderline anatomic candidates with hypoplastic left-sided structures or a nonsubaortic ventricular septal defect is questionable.