Tumour budding as prognostic factor in stage I/II colorectal carcinoma

Immunohistochemical analysis of tumor budding in stage II colon cancer: exploring zero budding as a prognostic marker

Tumor budding, a biomarker traditionally evaluated using hematoxylin and eosin (H&E) staining, has gained recognition as a prognostic biomarker for stage II colon cancer. Nevertheless, while H&E staining offers valuable insights, its limitations prompt the utilization of pan-cytokeratin immunohistochemistry (IHC). Consequently, this study seeks to evaluate the prognostic significance of tumor budding using IHC in a contemporary cohort of stage II colon cancer patients, aiming to deepen our understanding of this critical facet in cancer prognosis. We conducted a retrospective, population-based cohort study including 493 patients with stage II colon cancer and evaluated tumor budding using IHC, following the H&E-based guidelines proposed by the International Tumor Budding Consensus Conference Group. Correlation between H&E-based and IHC-based tumor budding was assessed using a four-tiered scoring system that included a zero budding (Bd0) category. Survival analyses explored the prognostic significance of tumor budding assessed by IHC and H&E. As expected, IHC-based tumor budding evaluation yielded significantly higher bud counts compared to H&E (p < 0.01). Interestingly, 21 patients were identified with no tumor budding using IHC. This was associated with significantly improved recurrence-free survival (HR = 5.19, p = 0.02) and overall survival (HR = 4.47, p = 0.04) in a multivariate analysis when compared to tumors with budding. The Bd0 category demonstrated a 100% predictive value for the absence of recurrence. In conclusion, IHC-based tumor budding evaluation in stage II colon cancer provides additional prognostic information. The absence of tumor budding is associated with a favorable prognosis and may serve as a potential marker for identifying patients with no risk of recurrence.

Tumor Budding as a Prognostic Marker in Primary Colon Cancer - A Single Center Experience

Introduction: Tumor budding (TB) is considered to be a morphological and prognostic factor relevant to colon cancer (CC). The aim of our study is to assess the TB and to evaluate its relationship to clinicopathological findings within stage II and III CC patients as a single center experience. Materials and methods: A total of 120 CC patients operated between 2018 and 2021 at the University Clinic of Digestive Surgery in Skopje, the Republic of North Macedonia were included in this retrospective, single center study. TB was evaluated by the magnification of 200x along the invasive front of the primary tumor on H&E and CKAE1/AE3 immunohistochemically stained sections. Two grades were used: low grade (TB1, 0-4 TBs) and high-grade, which includes intermediate (TB2, 5-9 TBs) and high grade (TB3 ≥10TBs) of TBs. Results: A statistically significant correlation has been identified between high-grade TB and age (p=0.05) of the patients. There was also a significantly higher occurrence of high-grade TB in patients within stage III CC. Statistically significant correlations were also found in lymph node status (p<0.01), vascular invasion (p<0.05), lymphatic invasion (p<0.01), postoperative relapse (p<0.01), and death (p<0.01). Tumor relapse and death were significantly more frequent in patients with high-grade TB than those with low-grade TB. Patients with registered high-grade TB demonstrated significantly lower relapse-free survival (RFS) and overall survival (OS) rates than patients with low-grade TB over the observation period (RFS: 53.8% vs. 98.5%, p<0.001; OS: 65.4% vs. 97.1%, p<0.001, respectively). Patients with lung and liver postoperative relapses had higher percentage of cases with high-grade TB (94.1%). Conclusion: Our results are highly suggestive that TB should be included as a histological biomarker in the pathology report of patients with stage II and stage III CC, because of its prognostic value.

Establishment of a tissue-engineered colon cancer model for comparative analysis of cancer cell lines

To overcome the limitations of in vitro two-dimensional (2D) cancer models in mimicking the complexities of the native tumor milieu, three-dimensional (3D) engineered cancer models using biomimetic materials have been introduced to more closely recapitulate the key attributes of the tumor microenvironment. Specifically, for colorectal cancer (CRC), a few studies have developed 3D engineered tumor models to investigate cell-cell interactions or efficacy of anti-cancer drugs. However, recapitulation of CRC cell line phenotypic differences within a 3D engineered matrix has not been systematically investigated. Here, we developed an in vitro 3D engineered CRC (3D-eCRC) tissue model using the natural-synthetic hybrid biomaterial PEG-fibrinogen and three CRC cell lines, HCT 116, HT-29, and SW480. To better recapitulate native tumor conditions, our 3D-eCRC model supported higher cell density encapsulation (20 × 106  cells/mL) and enabled longer term maintenance (29 days) as compared to previously reported in vitro CRC models. The 3D-eCRCs formed using each cell line demonstrated line-dependent differences in cellular and tissue properties, including cellular growth and morphology, cell subpopulations, cell size, cell granularity, migration patterns, tissue growth, gene expression, and tissue stiffness. Importantly, these differences were found to be most prominent from Day 22 to Day 29, thereby indicating the importance of long-term culture of engineered CRC tissues for recapitulation and investigation of mechanistic differences and drug response. Our 3D-eCRC tissue model showed high potential for supporting future in vitro comparative studies of disease progression, metastatic mechanisms, and anti-cancer drug candidate response in a CRC cell line-dependent manner.

Tumor budding as an indicator for lymph node metastasis and prognosis of early gastric cancer

BACKGROUND

Tumor budding, considered as an independent risk factor reflecting prognosis of some malignant tumors, has been recognized as an important clinicopathological indicator of colorectal carcinoma. However, the evaluation of tumor budding and its clinicopathological significance in gastric cancer remain controversial.

AIM

To investigate the relationship between tumor budding and clinical biological behavior of early gastric cancer (EGC) and assess the predictive value of tumor budding for lymph node metastasis as well as its impact on prognosis of EGC patients.

METHODS

Tissue specimens of 164 EGC patients who underwent radical gastrectomy between June 2011 and January 2017 from a single center were selected to carry out HE and CK staining respectively, so as to evaluate tumor budding under light microscopy. Clinicopathological data and follow-up results of all EGC patients were collected for statistical analysis among tumor budding, EGC clinicopathological factors and prognosis.

RESULTS

Of all 164 EGC patients, there were 84 (51.2%) cases with mucosal invasion and 80 (48.8%) cases with submucosal invasion. Meanwhile, 32 cases (19.5%) had lymph node metastasis, 19 (11.6%) had lympho-vascular invasion and 4 (2.4%) had early recurrence. Tumor budding were observed in 90 (54.9%) patients, with low-grade budding 68 (41.5%) cases and high-grade budding 22 (13.4%) cases. Tumor budding was closely correlated with tumor size (c² = 6.609, P = 0.037), tumor histologic differentiation (c² = 10.522, P = 0.032), depth of invasion (c² = 8.787, P = 0.012), lymph node metastasis (c² = 24.226, P < 0.01), TNM stage (c² = 24.226, P < 0.01), lympho-vascular invasion (c² = 8.225, P = 0.016) and early recurrence (c² = 6.462, P = 0.040). Additionally, tumor budding was correlated with postoperative survival rate as well. Multiple regression analysis revealed that tumor budding was an independent influencing factor of postoperative 3-year survival rate, 5-year survival rate, OS, DFS and DSS (P < 0.05). Furthermore, tumor budding was an independent risk factor of lymph node metastasis of EGC patients, and high-grade budding was a high-risk indicator of lymph node metastasis.

CONCLUSION

Tumor budding is related to tumor size, tumor histologic differentiation, depth of invasion, lymph node metastasis, lympho-vascular invasion and early recurrence of EGC. Tumor budding, especially high-grade budding can serve as an indicator for predicting lymph node metastasis of EGC, and high-grade budding could be an important parameter for evaluating prognosis of EGC patients.

Evaluation of the Cellular Dissociation Grading, Based on Tumor Budding and Cell Nest Size, in Squamous Cell Carcinoma of the Penis

The "Cellular Dissociation Grade" (CDG) is based on tumor cell budding and cell nest size. Many studies have examined the CDG in squamous cell carcinomas of other organs such as the lungs, oral cavity, pharynx, larynx, cervix and esophagus. In this study, the CDG was examined in 109 cases of invasive penile squamous cell carcinoma that were treated at the University Medicine Rostock between 2014 and 2022. Furthermore, its correlation with the pathologic status of regional lymph nodes (pN) as the main prognostic factor was verified. Finally, cellular dissociation grading was compared with classic WHO grading. The results showed that pN in penile squamous cell carcinoma showed a highly significant association with the CDG and no statistically significant association with WHO grading. These results support the notion that cellular dissociation grading is an important prognostic factor for squamous cell carcinoma.

Tumor budding as a prognostic indicator in colorectal carcinoma: a retrospective study of primary colorectal carcinoma cases in a tertiary care center

Colorectal carcinoma (CRC) is the third most common cancer worldwide. Along with many established prognostic factors, tumor budding is emerging as a valuable marker of prognosis. Tumor budding is not yet universally reported but it has recently been suggested in guidelines by ITBCC (International Tumor Budding Consensus Conference). Our aim is to study prognostic implications of tumor budding in CRC. Hundred cases of primary CRC specimens were retrospectively studied from January, 2016, to February, 2017. Tumor bud count and other histopathological parameters were evaluated from hematoxyline and eosin (H & E) stained slides. Survival analysis was done using Cox proportional hazards model. Association of tumor budding and cancer-specific survival was found to be statistically significant (P = 0.018 for average tumor budding and P = 0.035 for highest tumor budding) Tumor budding was found to be significantly associated with other clinicopathological parameters such as T stage, N stage, TNM stage, and lymphovascular invasion with p value < 0.05. Tumor budding is a valuable prognostic indictor for primary CRC and also significantly associated with other prognostic parameters. It should be reported routinely as a guide to prognosis and further management of patients.

Identification of high-risk stage I colon and rectal cancer patients: a retrospective analysis of a large Japanese cohort

PURPOSE

Data regarding risk factors for recurrence in stage I colorectal cancer patients are limited. The aim of this study was to clarify the existence of a high-recurrence-risk population among stage I colorectal cancer patients.

METHODS

This analysis included 7,539 stage I colorectal cancer patients treated between 1997 and 2012 at 24 leading hospitals in Japan. Risk factors for time to recurrence were evaluated using a Cox proportional hazards model, and a high-risk group for recurrence was identified. Prognostic outcomes of high-risk stage I colorectal cancer patients were compared with those of low-risk stage I and stage II patients.

RESULTS

Multivariable analyses identified left-sided location (hazard ratio [HR]: 1.65, 95% confidence interval [CI]: 1.09-2.58), T2 tumors (HR: 1.80, 95% CI: 1.21-2.66), and lymphatic invasion (HR: 1.55, 95% CI: 1.05-2.28) as risk factors for recurrence in stage I colon cancer, and patients with these three risk factors were classified as high risk. For stage I rectal cancer, patients with poor differentiation (HR: 2.86, 95% CI: 1.21-5.69), T2 tumors (HR: 1.53, 95% CI: 1.07-2.23), and venous invasion (HR: 1.51, 95% CI: 1.08-2.13) were identified as high risk. The Kaplan-Meier analysis of cumulative recurrence rate and recurrence-free survival revealed that the high-risk stage I colorectal cancer patients have poorer clinical outcomes than the low-risk patients.

CONCLUSION

Although stage I colorectal cancer patients generally have a favorable prognosis after curative surgery, poorer prognosis was observed in high-risk stage I colorectal cancer patients than in low-risk patients.

Potential key roles of tumour budding: a representative malignant pathological feature of non-small cell lung cancer and a sensitive indicator of prognosis

OBJECTIVES

To investigate the relationship between tumour budding, clinicopathological characteristics of patients and prognosis in non-small cell lung cancer.

STUDY DESIGN

A retrospective study was used.

PARTICIPANTS

We selected 532 patients with non-small cell lung cancer from China, including 380 patients with adenocarcinoma and 152 with squamous cell carcinoma.

PRIMARY AND SECONDARY OUTCOME MEASURES

Tumour budding was visible using H&E staining as well as pancytokeratin staining. The count data and measurement data were compared using the χ² test and the t-test, respectively. The overall survival rate was the follow-up result. The survival curves were drawn using the Kaplan-Meier method, and the differences between groups were analysed using the log-rank method. The independent prognostic factor of patients with lung cancer was determined using a multivariate Cox proportional hazard model.

RESULTS

In patients with lung adenocarcinoma, there was a correlation between tumour budding and spread through air spaces (OR 36.698; 95% CI 13.925 to 96.715; p<0.001), and in patients with squamous cell carcinoma, tumour budding state was closely related to the peritumoural space (OR 11.667; 95% CI 4.041 to 33.683; p<0.001). On Cox regression analysis, multivariate analysis showed that tumour budding, pleural and vascular invasion, spread through air spaces, tumour size, lymph node metastasis, and tumour node metastasis stage were independent risk factors of prognosis for patients with non-small cell lung cancer.

CONCLUSIONS

As an effective and simple pathological diagnostic index, it is necessary to establish an effective grading system in the clinical diagnosis of lung cancer to verify the value of tumour budding as a prognostic indicator. We hope that this analysis of Chinese patients with non-small cell lung cancer can provide useful reference material for the continued study of tumour budding.

Novel Criteria for Intratumoral Budding with Prognostic Relevance for Colon Cancer and Its Histological Subtypes

Peritumoral budding and intratumoral budding (ITB) are important prognostic factors for colorectal cancer patients. Scientists worldwide have investigated the role of budding in tumor progression and its prognosis, but guidelines for reliably identifying tumor buds based on morphology are lacking. In this study, next-generation tissue microarray (ngTMA^®) construction was used for tumor bud evaluation, and highly detailed rule-out annotation was used for tumor definition in pancytokeratin-stained tissue sections. Initially, tissues of 245 colon cancer patients were evaluated with high interobserver reliability, and a concordance of 96% was achieved. It was shown that high ITB scores were associated with poor distant metastasis-free survival (p = 0.006 with a cut-off of ≥10 buds). This cut-off was defined as the best maximum value from one of two/three ngTMA^® cores (0.6 mm diameter). ITB in 30 cases of mucinous, medullary, and signet ring cell carcinoma was analyzed for the subsequent determination of differences in tumor bud analyses between those subtypes. In conclusion, blinded randomized punched cores in the tumor center can be useful for ITB detection. It can be assumed that this method is suitable for its adoption in clinical routines.

A novel self-learning framework for bladder cancer grading using histopathological images

In recent times, bladder cancer has increased significantly in terms of incidence and mortality. Currently, two subtypes are known based on tumour growth: non-muscle invasive (NMIBC) and muscle-invasive bladder cancer (MIBC). In this work, we focus on the MIBC subtype because it has the worst prognosis and can spread to adjacent organs. We present a self-learning framework to grade bladder cancer from histological images stained by immunohistochemical techniques. Specifically, we propose a novel Deep Convolutional Embedded Attention Clustering (DCEAC) which allows for the classification of histological patches into different levels of disease severity, according to established patterns in the literature. The proposed DCEAC model follows a fully unsupervised two-step learning methodology to discern between non-tumour, mild and infiltrative patterns from high-resolution 512 × 512 pixel samples. Our system outperforms previous clustering-based methods by including a convolutional attention module, which enables the refinement of the features of the latent space prior to the classification stage. The proposed network surpasses state-of-the-art approaches by 2-3% across different metrics, reaching a final average accuracy of 0.9034 in a multi-class scenario. Furthermore, the reported class activation maps evidence that our model is able to learn by itself the same patterns that clinicians consider relevant, without requiring previous annotation steps. This represents a breakthrough in MIBC grading that bridges the gap with respect to training the model on labelled data.

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.

Matrix adhesion and remodeling diversifies modes of cancer invasion across spatial scales

The metastasis of malignant epithelial tumors begins with the egress of transformed cells from the confines of their basement membrane (BM) to their surrounding collagen-rich stroma. Invasion can be morphologically diverse: when breast cancer cells are separately cultured within BM-like matrix, collagen I (Coll I), or a combination of both, they exhibit collective-, dispersed mesenchymal-, and a mixed collective-dispersed (multimodal)- invasion, respectively. In this paper, we asked how distinct these invasive modes are with respect to the cellular and microenvironmental cues that drive them. A rigorous computational exploration of invasion was performed within an experimentally motivated Cellular Potts-based modeling environment. The model comprised of adhesive interactions between cancer cells, BM- and Coll I-like extracellular matrix (ECM), and reaction-diffusion-based remodeling of ECM. The model outputs were parameters cognate to dispersed- and collective- invasion. A clustering analysis of the output distribution curated through a careful examination of subsumed phenotypes suggested at least four distinct invasive states: dispersed, papillary-collective, bulk-collective, and multimodal, in addition to an indolent/non-invasive state. Mapping input values to specific output clusters suggested that each of these invasive states are specified by distinct input signatures of proliferation, adhesion and ECM remodeling. In addition, specific input perturbations allowed transitions between the clusters and revealed the variation in the robustness between the invasive states. Our systems-level approach proffers quantitative insights into how the diversity in ECM microenvironments may steer invasion into diverse phenotypic modes during early dissemination of breast cancer and contributes to tumor heterogeneity.

Prognostic value of tumor budding in gallbladder cancer: application of the International Tumor Budding Consensus Conference scoring system

Tumor budding (TB), a histopathological manifestation of epithelial-mesenchymal transition, is an important step in cancer invasion and metastasis development. TB has been considered a strong prognostic indicator in colorectal cancer. The International Tumor Budding Consensus Conference (ITBCC) scoring system is the standardized method used for patient outcome prediction in several human tumors. We investigated the clinicopathological implications and applicability of TB measured using the ITBCC scoring system in gallbladder cancer (GBC). The TB grades assigned to the 78 GBC patients were as follows: Bd1 (low TB), 41 (52.6%) patients; Bd2 (intermediate TB), 22 (28.2%) patients; and Bd3 (high TB), 15 (19.2%) patients. A higher TB grade correlated with a poorer histological differentiation (P < 0.000), higher pT category (P < 0.000), the involvement of surgical resection margin (P = 0.005), presence of nodal metastasis (P < 0.000), lymphatic and venous invasion (P < 0.000), and perineural invasion (P = 0.004). Univariate Cox regression analysis revealed that a poor histological grade, high pT category, lymphatic invasion, perineural invasion, and intermediate to high TB grades were associated with worse 5-year overall survival and disease-free survival. TB was not significantly associated with death or recurrence risk in multivariate Cox analysis. The interobserver agreement of TB grading was substantial. This study is the first to apply the ITBCC scoring system and suggest the prognostic value of TB in GBC.

Tumor Budding and Poorly Differentiated Clusters in Small Intestinal Adenocarcinoma

The clinicopathologic and prognostic significances of tumor budding (TB) and poorly-differentiated clusters (PDC) have not been investigated in small intestinal adenocarcinomas (SIACs). In 236 surgically-resected SIACs, we counted TB (single cells or clusters ≤4 tumor cells) and PDC (clusters ≥5 tumor cells) at the peritumoral-invasive front (p) and in the intratumoral area (i) independently to classify as grade-1 (≤4), grade-2 (5–9), or grade-3 (≥10). Consequently, grades-2 and -3 were considered high-grade. High-pTB, -iTB, -pPDC, and -iPDC were observed in 174 (73.7%), 129 (54.7%), 118 (50.0%), and 85 (36.0%) cases, respectively. High-TB/PDCs were more frequently observed in tumors with high-grade, higher T- and N-categories and stage grouping, and perineural or lymphovascular invasion. Patients with high-TB/PDC had a shorter survival than those with low-TB/PDC. In a multivariate analysis, high-pTB, nonintestinal type, high N-category, retroperitoneal seeding, and microsatellite-stable were worse independent-prognostic predictors. Subgroup analysis demonstrated that patients with high-pTB showed worse survival (median: 42.5 months) than those with low-pTB (133.7 months; p = 0.007) in the lower stage (stages I–II) group. High-TB/PDC, both in peritumoral and intratumoral localizations, were associated with aggressive behaviors in SIACs. High-pTB can be used as an adverse prognostic indicator in SIAC patients, especially when patients are in early disease stages.

Lymphovascular invasion, perineural invasion, and tumor budding are prognostic factors for stage I colon cancer recurrence

BACKGROUND

The diagnostic impact of lymphovascular invasion (LVI), perineural invasion (PNI), and tumor budding in stage I colon cancer is currently unknown. This study was conducted to evaluate the prognostic impact of LVI, PNI, and tumor budding in stage I colon cancer.

METHODS

From January 2008 to December 2013, 720 patients who underwent curative surgery and were diagnosed with stage I colon cancer were reviewed retrospectively. These patients were categorized into two groups based on LVI, PNI, and tumor budding: the no risk group (n = 566) and risk group (n = 154).

RESULTS

Median follow-up period was 103.5 months, and the 5-year disease-free survival rate of the risk group was significantly lower than that of the no risk group (p = 0.025). In multivariate analysis, only the risk group had prognostic factors for 5-year disease-free survival (p = 0.036). In addition, only differentiation was an independent predictor in the risk group (p = 0.009).

CONCLUSION

LVI, PNI, and tumor budding are strong prognostic factors for stage I colon cancer. Therefore, patients with positive LVI, PNI, or tumor budding should receive close follow-up and potentially be considered for chemotherapy.

The Relationship Between Tumor Budding, Tumor Microenvironment, and Survival in Patients with Primary Operable Colorectal Cancer

Background

Tumor budding is an independent prognostic factor in colorectal cancer (CRC) and has recently been well-defined by the International Tumour Budding Consensus Conference (ITBCC).

Objective

The aim of the present study was to use the ITBCC budding evaluation method to examine the relationship between tumor budding, tumor factors, tumor microenvironment, and survival in patients with primary operable CRC.

Methods

Hematoxylin and eosin-stained slides of 952 CRC patients diagnosed between 1997 and 2007 were evaluated for tumor budding according to the ITBCC criteria. The tumor microenvironment was evaluated using tumor stroma percentage (TSP) and Klintrup–Makinen (KM) grade to assess the tumor inflammatory cell infiltrate.

Results

High budding (n = 268, 28%) was significantly associated with TNM stage (p < 0.001), competent mismatch repair (MMR; p < 0.05), venous invasion (p < 0.001), weak KM grade (p < 0.001), high TSP (p < 0.001), and reduced cancer-specific survival (CSS) (hazard ratio 8.68, 95% confidence interval 6.30–11.97; p < 0.001). Tumor budding effectively stratifies CSS stage T1 through to T4 (all p < 0.05) independent of associated factors.

Conclusions

Tumor budding effectively stratifies patients’ survival in primary operable CRC independent of other phenotypic features. In particular, the combination of T stage and budding should form the basis of a new staging system for primary operable CRC.

Tumour budding predicts increased recurrence after curative resection for T2N0 colorectal cancer

Background

Tumour budding is defined as the presence of a cluster of fewer than 5 cells along the invasive margin. It may confer a worse prognosis in colorectal cancer, but its importance in pT2N0 colorectal cancer is unknown. This study aimed to determine the prognostic value of tumour budding in pT2N0 colorectal cancer.

Methods

This was a retrospective cohort study with prospective assessment of tumour budding by 2 pathologists. We included all patients who underwent elective curative resection for pT2N0 colorectal cancer except those with hereditary colorectal cancer syndromes, inflammatory bowel disease or positive resection margins, those who received neoadjuvant or adjuvant therapy and those who died within 90 days of operation. Patients were classified as having high-grade tumour budding (≥ 10 budding foci per high-power field) or low-grade tumour budding (< 9 budding foci per high-power field). The main outcome measure was locoregional or distant recurrence.

Results

Of 85 patients, 36 had high-grade tumour budding and 49 had low-grade tumour budding. The overall recurrence rate was 11% (9/85) and median follow-up was 41.0 months (interquartile range 22.0–68.0). Interrater reliability for tumour budding assessment was excellent (κ = 0.86, 95% confidence interval [CI] 0.76–0.96). There were more recurrences in patients with high-grade tumour budding (7/36, 19.4% v. 2/49, 4.1%; p = 0.020). On multivariate analysis, after we adjusted for confounders, the presence of high-grade tumour budding was independently associated with recurrence (hazard ratio 5.11, 95% CI 1.01–25.9).

Conclusion

Tumour budding was independently associated with increased recurrence after pT2N0 colorectal cancer resection. It offers additional prognostic information that may affect treatment strategy.

Improving tumour budding evaluation in colon cancer by extending the assessment area in colectomy specimens

AIMS

It is recommended that tumour budding in colon cancer be counted on haematoxylin and eosin-stained sections in a hotspot area of 0.785 mm² with a ×20 microscope objective. However, tumour buds may be difficult to visualise on haematoxylin and eosin-stained sections, and counting in such a limited area may result in overestimation in cases with focal budding. The aim of this study was to assess the contributions of various factors to improving tumour budding risk stratification: increasing the number of fields counted, using cytokeratin immunostaining, and recording proliferation, the apoptotic index and the emperipoletic index in tumour buds.

METHODS AND RESULTS

We created an exploratory series composed of 172 cases of colon cancer in all stages, and we analysed the survival probability in a second cohort of 158 stage I-II patients. According to our results, counting of budding in 10 fields was the only factor that was significantly correlated with disease-free survival probability in stage I-II patients [hazard ratio (HR) for high versus low grade of 7.64, 95% confidence interval (CI) 5.54-27.92, P = 0.01; HR for intermediate versus low grade of 3.02, 95% CI 1.54-26.72, P = 0.04). Emperipolesis was frequently observed in tumour buds, whereas the mitotic index and the apoptotic index were extremely low. Although cytokeratin immunostaining increased interobserver concordance, it did not improve the accuracy of tumour budding grading.

CONCLUSIONS

According to our results, counting in 10 fields significantly enhanced the budding grade risk stratification in colon cancer patients, and cytokeratin immunostaining could be reserved as a complementary technique for challenging cases with an inflammatory infiltrate and/or striking fibrosis.

Prospective Multicenter Study on the Prognostic and Predictive Impact of Tumor Budding in Stage II Colon Cancer: Results From the SACURA Trial

PURPOSE

The International Union Against Cancer highlighted tumor budding as a tumor-related prognostic factor. International assessment criteria for tumor budding were recently defined by the 2016 International Tumor Budding Consensus Conference (ITBCC2016). This study aimed to clarify the prognostic and predictive values of tumor budding in a randomized controlled trial evaluating the superiority of adjuvant chemotherapy with oral tegafur-uracil over surgery alone for stage II colon cancer (SACURA trial; ClinicalTrials.gov identifier: NCT00392899).

PATIENTS AND METHODS

Between 2006 and 2010, we enrolled 991 patients from 123 institutions with stage II colon cancer. Tumor budding was diagnosed by central review on the basis of the criteria adopted in the ITBCC2016. We prospectively recorded all clinical and pathologic data, including the budding grade, and performed prognostic analyses after 5 years of completing the patients' registration.

RESULTS

Of 991 tumors, 376, 331, and 284 were classified as BD1, BD2, and BD3, respectively; the 5-year relapse-free survival (RFS) rate was 90.9%, 85.1%, and 74.4%, respectively (P < .001), and ranged widely in T4 tumors (86.6% to 53.3%). The budding grade significantly correlated with recurrence in the liver, lungs, lymph nodes, and peritoneum (P < .001 to .01). Multivariable analysis revealed that budding and T stage exerted an independent impact on RFS, and on the basis of the Harrell concordance index, these two factors substantially contributed to the improvement of the Cox model for predicting RFS. Both the BD2 and BD3 groups demonstrated greater improvement in the 5-year recurrence rate in the adjuvant chemotherapy group than the surgery-alone group by approximately 5%, but the difference was statistically nonsignificant.

CONCLUSION

Tumor budding grade on the basis of the ITBCC2016 criteria should be routinely evaluated in pathologic practice and could improve the benefit of adjuvant chemotherapy for stage II colon cancer.

ROCK2 inhibition triggers the collective invasion of colorectal adenocarcinomas

The metastatic progression of cancer is a multi-step process initiated by the local invasion of the peritumoral stroma. To identify the mechanisms underlying colorectal carcinoma (CRC) invasion, we collected live human primary cancer specimens at the time of surgery and monitored them ex vivo. This revealed that conventional adenocarcinomas undergo collective invasion while retaining their epithelial glandular architecture with an inward apical pole delineating a luminal cavity. To identify the underlying mechanisms, we used microscopy-based assays on 3D organotypic cultures of Caco-2 cysts as a model system. We performed two siRNA screens targeting Rho-GTPases effectors and guanine nucleotide exchange factors. These screens revealed that ROCK2 inhibition triggers the initial leader/follower polarization of the CRC cell cohorts and induces collective invasion. We further identified FARP2 as the Rac1 GEF necessary for CRC collective invasion. However, FARP2 activation is not sufficient to trigger leader cell formation and the concomitant inhibition of Myosin-II is required to induce invasion downstream of ROCK2 inhibition. Our results contrast with ROCK pro-invasive function in other cancers, stressing that the molecular mechanism of metastatic spread likely depends on tumour types and invasion mode.

Tumor Budding in Colorectal Carcinoma: Translating a Morphologic Score Into Clinically Meaningful Results

CONTEXT

- Tumor budding has received increasing recognition as an important independent prognostic factor in colorectal carcinoma. Prominent tumor budding in adenocarcinoma arising in a polyp has been shown to be a risk factor for lymph node involvement. The variability in methods used for evaluating tumor budding in different studies and lack of standardized guidelines have impeded routine inclusion of tumor budding in pathology reports. This changed last year with consensus guidelines based on the International Tumor Budding Consensus Conference (ITBCC). These guidelines have been included in the recent College of American Pathologists (CAPs) Colorectal Cancer Protocol. The consensus methodology will allow uniform reporting of this finding, but challenges in interpretation in the setting of intense inflammation, fibrosis, or gland fragmentation need to be addressed in future guidelines.

OBJECTIVE

- To provide a brief overview of the known clinical significance of tumor budding in colorectal carcinoma and discuss the practical aspects of its implementation on a routine basis.

DATA SOURCES

- English-language pathology literature.

CONCLUSIONS

- Tumor budding has been shown to be an independent prognostic marker in colorectal carcinomas and the routine reporting of tumor buds is now advocated by using the approach outlined by the ITBCC guidelines. Tumor budding is included in the CAP protocol as a recommended element. Presence of prominent tumor budding in an adenocarcinoma in a polyp may have implications for management, such as additional resection, while it serves as a prognostic factor in other settings.

Poorly Differentiated Clusters Predict a Poor Prognosis for External Auditory Canal Carcinoma

Squamous cell carcinoma (SCC) of the external auditory canal (EAC) is rare and offers a poor prognosis; more accurate prognostic biomarkers are required. Our laboratory recently demonstrated that tumor budding, characterized by tumor cell clusters (< 5 cells), and laminin 5-γ2 staining of SCC of the EAC are associated with shorter survival. However, clusters composed of ≥ 5 tumor cells are also found in the stroma. Previous reports of colorectal cancer suggest that poorly differentiated clusters (PDCs) are a negative prognostic indicator. Here, we report on the association between PDCs and prognosis in SCC of the EAC. PDCs and tumor budding were histopathologically and immunohistochemically (cytokeratin AE1/AE3) analyzed in 31 cases of pre-treatment biopsy SCC of the EAC. Clusters in the stroma composed of < or ≥ 5 cancer cells were defined as tumor budding or PDCs, respectively. Entire tumors were initially scanned to identify greatest PDC density. Tumors with low or high PDC density were classified as low- and high-grade, respectively. Patients with high-grade PDCs had a significantly poorer outcome than those with low-grade. Even in cases of low-grade tumor budding, those with high-grade PDCs had a poor prognosis. Multivariate analysis results indicated that high-grade PDCs were associated with poor prognosis. PDC grade can provide a more accurate prognosis than tumor budding in SCC of the EAC.

Immunohistochemical evaluation of tumor budding for stratifying T1 colorectal cancer: optimal cut-off value and a novel computer-assisted semiautomatic method

High-grade tumor budding is an adverse prognostic factor for submucosal invasive (T1) colorectal cancer used to predict the risk for lymph node metastasis in endoscopically resected specimens. Cytokeratin immunohistochemistry is a potential option for evaluating tumor budding. The optimal cut-off value between low- and high-grade budding has not yet been determined, however, and the high inter-observer variability in selecting budding foci remains problematic. We explored the optimal cut-off value for predicting lymph node metastasis using cytokeratin immunohistochemistry, and developed a novel computer-assisted semiautomatic quantification method to reduce inter-observer variability. A retrospective single-institution study of 463 T1 colorectal cancer cases was conducted. Cases were split into derivation and validation datasets. Tumor budding foci were counted manually and semiautomatically using Image J software on cytokeratin immunohistochemistry-stained specimens. We determined the cut-off values and compared inter-observer variability among pathologists between the two methods. Univariate and multivariate analyses of the derivation dataset were performed to select the risk factors for lymph node metastasis. Predictive simulation for the validation dataset was conducted. The optimal cut-off values for the manual and semiautomatic methods were ≥10 and ≥12, respectively. For both methods, multivariate analyses revealed that venous invasion, lymphatic invasion, and high-grade tumor budding were independent risk factors for lymph node metastasis. The semiautomatic method provided significantly better inter-observer agreement. The predictive and observed lymph node metastasis frequencies were highly correlated in the validation dataset.

Differential clinical impacts of tumour budding evaluated by the use of immunohistochemical and haematoxylin and eosin staining in stage II colorectal cancer

AIMS

The aim of this study was to clarify the quantitative and qualitative differences in tumour budding identification between haematoxylin and eosin (H&E) staining and immunohistochemical (IHC) staining for cytokeratin, and to estimate the respective clinical impacts in stage II colorectal cancer.

METHODS AND RESULTS

We retrospectively examined 314 surgically resected cases of stage II colorectal cancer, and assessed tumour budding on serial section slides with H&E staining and IHC staining for cytokeratin. Tumour budding counts based on cytokeratin-stained slides were strongly correlated with those based on H&E-stained slides, and had higher detection and reproducibility. On the basis of receiver operating characteristic analyses, the optimal cut-off values of budding counts for relapse-free survival (RFS) were 7 and 16 in a ×200 microscopic field with H&E and IHC staining, respectively. With these cut-off values, tumour budding based on H&E staining had a significant correlation with RFS (80.3% and 93.2% of 5-year RFS in the high-budding group and the low-budding group, respectively), and similar results were observed for IHC staining (79.9% and 91.7%, respectively). The Akaike Information Criterion value for RFS with H&E staining was favourable as compared with that with IHC staining.

CONCLUSIONS

Tumour budding counts based on cytokeratin-stained slides showed higher detection and better reproducibility, but did not have as satisfactory clinical impacts as those based on H&E staining.

Automated tumour budding quantification by machine learning augments TNM staging in muscle-invasive bladder cancer prognosis

Tumour budding has been described as an independent prognostic feature in several tumour types. We report for the first time the relationship between tumour budding and survival evaluated in patients with muscle invasive bladder cancer. A machine learning-based methodology was applied to accurately quantify tumour buds across immunofluorescence labelled whole slide images from 100 muscle invasive bladder cancer patients. Furthermore, tumour budding was found to be correlated to TNM (p = 0.00089) and pT (p = 0.0078) staging. A novel classification and regression tree model was constructed to stratify all stage II, III, and IV patients into three new staging criteria based on disease specific survival. For the stratification of non-metastatic patients into high or low risk of disease specific death, our decision tree model reported that tumour budding was the most significant feature (HR = 2.59, p = 0.0091), and no clinical feature was utilised to categorise these patients. Our findings demonstrate that tumour budding, quantified using automated image analysis provides prognostic value for muscle invasive bladder cancer patients and a better model fit than TNM staging.

A Review of Current Challenges in Colorectal Cancer Reporting

Context.—

Pathologic assessment of colorectal cancer resection specimens plays an important role in postsurgical management and prognostication in patients with colorectal cancer. Challenges exist in the evaluation and reporting of these specimens, either because of difficulties in applying existing guidelines or related to newer concepts.

Objective.—

To address challenging areas in colorectal cancer pathology and to provide an overview of the literature, current guidelines, and expert recommendations for the handling of colorectal cancer resection specimens in everyday practice.

Data Sources.—

PubMed (US National Library of Medicine, Bethesda, Maryland) literature review; reporting protocols of the College of American Pathologists, the Royal College of Pathologists of the United Kingdom, and the Japanese Society for Cancer of the Colon and Rectum; and classification manuals of the American Joint Committee on Cancer and the Union for International Cancer Control.

Conclusions.—

This review has addressed issues and challenges affecting quality of colorectal cancer pathology reporting. High-quality pathology reporting is essential for prognostication and management of patients with colorectal cancer.

Reporting of tumor budding in colorectal adenocarcinomas using ×40 objective: A practical approach for resource constrained set-ups

CONTEXT

Tumor budding (TBud) is recognized as a poor prognostic marker in colorectal cancer (CRC) with important treatment implications in Stage II cancers and malignant polyps. There are multiple propositions for bud count reporting but without an uniformly accepted system. The International TBud consensus conference (ITBCC) proposed mandatory reporting of budding on the single worst ×20 high power field (0.785 mm² area) with a 3-tier scoring system (low/intermediate/high for 0-4, 5-9, and ≥10 buds/×20 field).

AIMS

Due to the lack of availability of ×20 objective, we aimed to validate a simple ×40 field count (0.236 mm² area) for wider applicability.

METHODS

Bud count was done on hematoxylin and eosin-stained slides of 92 archived cases of colon cancer on the worst ×20 and ×40 fields (0.95 mm² and 0.236 mm² area) (hotspot method). Count for 0.785 mm² area was calculated using ITBCC normalization factor of 1.2. Interobserver variability between two observers was assessed. Score groups for ×20 field and proposed score groups for 40× field (low/intermediate/high for 0-1, 2-4 and ≥5 buds) were compared with disease-free survival.

RESULTS

High bud score was seen in 20.6% and 31.5% cases, respectively, using the ×20 and ×40 methods. High interobserver concordance was noted (ICC 0.95). Both the ITBCC bud score and our proposed 40× scoring correlated significantly with prognosis (P = 0.030, log-rank test).

CONCLUSIONS

: In centers lacking 20× objective, we propose using the worst 40× hotspot method for reporting of budding for all CRCs as a simple, reproducible and prognostically significant scoring system.

Automatic evaluation of tumor budding in immunohistochemically stained colorectal carcinomas and correlation to clinical outcome

Background

Tumor budding, meaning a detachment of tumor cells at the invasion front of colorectal carcinoma (CRC) into single cells or clusters (<=5 tumor cells), has been shown to correlate to an inferior clinical outcome by several independent studies. Therefore, it has been discussed as a complementary prognostic factor to the TNM staging system, and it is already included in national guidelines as an additional prognostic parameter. However, its application by manual evaluation in routine pathology is hampered due to the use of several slightly different assessment systems, a time-consuming manual counting process and a high inter-observer variability. Hence, we established and validated an automatic image processing approach to reliably quantify tumor budding in immunohistochemically (IHC) stained sections of CRC samples.

Methods

This approach combines classical segmentation methods (like morphological operations) and machine learning techniques (k-means and hierarchical clustering, convolutional neural networks) to reliably detect tumor buds in colorectal carcinoma samples immunohistochemically stained for pan-cytokeratin. As a possible application, we tested it on whole-slide images as well as on tissue microarrays (TMA) from a clinically well-annotated CRC cohort.

Results

Our automatic tumor budding evaluation tool detected the absolute number of tumor buds per image with a very good correlation to the manually segmented ground truth (R2 value of 0.86).

Furthermore the automatic evaluation of whole-slide images from 20 CRC-patients, we found that neither the detected number of tumor buds at the invasion front nor the number in hotspots was associated with the nodal status. However, the number of spatial clusters of tumor buds (budding hotspots) significantly correlated to the nodal status (p-value = 0.003 for N0 vs. N1/N2). TMAs were not feasible for tumor budding evaluation, as the spatial relationship of tumor buds (especially hotspots) was not preserved.

Conclusions

Automatic image processing is a feasible and valid assessment tool for tumor budding in CRC on whole-slide images. Interestingly, only the spatial clustering of the tumor buds in hotspots (and especially the number of hotspots) and not the absolute number of tumor buds showed a clinically relevant correlation with patient outcome in our data.

Electronic supplementary material

The online version of this article (10.1186/s13000-018-0739-3) contains supplementary material, which is available to authorized users.

Tumour budding in rectal cancer. A comprehensive review

A unique and fundamental characteristic of malignant neoplastic cells is their ability to invade other tissues and metastasise. The first step in this process is the dissociation of some of these cells from the tumour invasion front, named tumour budding (TB). This phenomenon has become increasingly relevant in recent years due to its association with adverse clinicopathological characteristics and with the epithelial-mesenchymal transition. TB has been studied by mixing colon with rectal tumours, but it is clinically important to differentiate these types of tumours. A review in two databases without language restriction was performed from 1950 to 2017 about TB with an emphasis on rectal cancer. We present various aspects of TB, from its terminology and evaluation to its molecular aspects, through its clinical associations. TB is associated with adverse clinicopathological features, like lymphovascular invasion, lymph node metastasis, and decreased survival. More studies of the clinicopathological, molecular, and epidemiological characteristics of TB in rectal cancer are needed.

Interobserver variability in the H&E-based assessment of tumor budding in pT3/4 colon cancer: does it affect the prognostic relevance?

Tumor budding is a mostly accepted adverse prognostic factor in colorectal carcinoma. It is on the cusp of a widespread use after agreement was reached recently on uniform assessment criteria. We investigated whether the interobserver variability has a direct influence on the prognostic relevance in pT3/4 colon cancer in the background of different levels of experience of the investigators. In total, six investigators with different levels of experience evaluated tumor budding on H&E slides in 244 cases with primary diagnosed (2002-2011) colon carcinoma (pT3/4, N+/-, M0). High-grade tumor budding/budding grade 3 (defined as majority assessment among the investigators) was significantly associated with an adverse outcome (overall survival p = 0.03, cancer-specific survival p = 0.08) and the occurrence of distant metastasis (p = 0.009). However, a detailed analysis of the rating results of the individual investigators revealed that only ratings of one investigator (advanced resident) were associated with an adverse outcome (p = 0.01 cancer-specific survival, overall survival p = 0.09, distant metastasis p = 0.002). The results of another investigator (consultant) were significantly associated with distant metastasis (p = 0.007). The kappa values among the investigators have a range between 0.077 and 0.357 (median 0.166). Total agreement of all investigators existed in 109 cases (44.7%). Our results demonstrate that the evaluation of tumor budding on H&E slides in pT3/4 colon cancer goes along with a considerable interobserver variability among investigators of different levels of experience. Furthermore, our results reveal that these findings directly influence the prognostic value.

The 9p21 locus as a potential therapeutic target and prognostic marker in colorectal cancer

Colorectal cancer (CRC) is a major cause of cancer-related-death worldwide. Despite extensive efforts to identify valid biomarkers for the risk stratification of CRC patients, there are few of proven clinical utility. It is recognized that genetic factors play a major role in determining susceptibility to CRC. Recent genome-wide association studies have demonstrated common genetic variants in a region on chromosome 9p21 associated with an increased risk of CRC. Several genetic polymorphisms have been identified in this region that are associated with CRC. Three genes are located at this locus; CDKN2B(encoding-p15ink4b), CDKN2A (encoding-p16ink4a/p14ARF) and 3′ end of CDKN2BAS (termed-antisense-noncoding-RNA in the INK4-locus [ANRIL]). ANRIL has a post-transcriptional modulatory activity, which has been shown to perturb the expression of nearby genes. It also plays an important role in coordinating tissue remodeling through regulation of cell proliferation, apoptosis, aging, extra-cellular matrix remodeling and inflammatory response. However, the role of ANRIL is not well understood in CRC. Hypermethylation of the p14ARF and p16INK4a genes is often found in some tumors, including CRC. However, further studies are necessary to explore the clinical utility of these putative markers in risk stratification, and in the assessment of prognosis. In this review, we have summarized the prognostic and therapeutic potential of the p14ARF and p16INK4a genes in patients with colorectal cancer.

Tumor-associated macrophages remodeling EMT and predicting survival in colorectal carcinoma

The immune contexture, a composition of the tumor microenvironment, plays multiple important roles in cancer stem cell (CSC) and epithelial-mesenchymal transition (EMT), and hence critically influences tumor initiation, progression and patient outcome. Tumor-associated macrophages (TAMs) are abundant in immune contexture, however their roles in CSC, EMT and prognosis of colorectal cancer (CRC) have not been elucidated. In 419 colorectal carcinomas, immune cell types (CD68⁺ macrophages, CD3⁺, CD4⁺ or CD8⁺ T lymphocytes, CD20⁺ B lymphocytes), EMT markers (E-cadherin and Snail) as well as the stem cell marker (CD44v6) were detected in tumor center (TC) and tumor invasive front (TF) respectively by immunohistochemistry. Tumor buds, that represent EMT phenotype, were also counted. It was found CD68⁺ macrophages were the most infiltrating immune cells in CRC. By correlation analysis, more CD68⁺_TF macrophages were associated with more CD44v6 expression (p < 0.001), lower Snail_TF expression (p = 0.08) and fewer tumor buds (p < 0.001). More CD68⁺_TF macrophages were significantly related to more CD3⁺_TF T lymphocytes (p = 0.002), CD8⁺_TF T lymphocytes (p < 0.001) and CD20⁺_TF B lymphocytes counts (p = 0.004). Strong CD68⁺_TF macrophages infiltration also predicted long term overall survival. CRC patients with more tumor buds had worse survival. However, strong CD68⁺_TF macrophages infiltration could reverse the unfavorable results since patients with more tumor buds but increasing CD68⁺_TF macrophages infiltration had the favorable outcome, similar to lower tumor buds groups. This study provided direct morphological evidence that tumor-associated macrophages in the invasive front play critical roles in fighting with the unfavorable results of tumor buds, thus resulting favorable outcomes for CRC patients.

Construction of a pathological risk model of occult lymph node metastases for prognostication by semi-automated image analysis of tumor budding in early-stage oral squamous cell carcinoma

It is challenging to identify at diagnosis those patients with early oral squamous cell carcinoma (OSCC), who have a poor prognosis and those that have a high risk of harboring occult lymph node metastases. The aim of this study was to develop a standardized and objective digital scoring method to evaluate the predictive value of tumor budding. We developed a semi-automated image-analysis algorithm, Digital Tumor Bud Count (DTBC), to evaluate tumor budding. The algorithm was tested in 222 consecutive patients with early-stage OSCC and major endpoints were overall (OS) and progression free survival (PFS). We subsequently constructed and cross-validated a binary logistic regression model and evaluated its clinical utility by decision curve analysis. A high DTBC was an independent predictor of both poor OS and PFS in a multivariate Cox regression model. The logistic regression model was able to identify patients with occult lymph node metastases with an area under the curve (AUC) of 0.83 (95% CI: 0.78–0.89, P <0.001) and a 10-fold cross-validated AUC of 0.79. Compared to other known histopathological risk factors, the DTBC had a higher diagnostic accuracy. The proposed, novel risk model could be used as a guide to identify patients who would benefit from an up-front neck dissection.

Recommendations for reporting tumor budding in colorectal cancer based on the International Tumor Budding Consensus Conference (ITBCC) 2016

Tumor budding is a well-established independent prognostic factor in colorectal cancer but a standardized method for its assessment has been lacking. The primary aim of the International Tumor Budding Consensus Conference (ITBCC) was to reach agreement on an international, evidence-based standardized scoring system for tumor budding in colorectal cancer. The ITBCC included nine sessions with presentations, a pre-meeting survey and an e-book covering the key publications on tumor budding in colorectal cancer. The 'Grading of Recommendation Assessment, Development and Evaluation' method was used to determine the strength of recommendations and quality of evidence. The following 10 statements achieved consensus: tumor budding is defined as a single tumor cell or a cell cluster consisting of four tumor cells or less (22/22, 100%). Tumor budding is an independent predictor of lymph node metastases in pT1 colorectal cancer (23/23, 100%). Tumor budding is an independent predictor of survival in stage II colorectal cancer (23/23, 100%). Tumor budding should be taken into account along with other clinicopathological features in a multidisciplinary setting (23/23, 100%). Tumor budding is counted on H&E (19/22, 86%). Intratumoral budding exists in colorectal cancer and has been shown to be related to lymph node metastasis (22/22, 100%). Tumor budding is assessed in one hotspot (in a field measuring 0.785 mm2) at the invasive front (22/22, 100%). A three-tier system should be used along with the budding count in order to facilitate risk stratification in colorectal cancer (23/23, 100%). Tumor budding and tumor grade are not the same (23/23, 100%). Tumor budding should be included in guidelines/protocols for colorectal cancer reporting (23/23, 100%). Members of the ITBCC were able to reach strong consensus on a single international, evidence-based method for tumor budding assessment and reporting. It is proposed that this method be incorporated into colorectal cancer guidelines/protocols and staging systems.

TAP1 down-regulation elicits immune escape and poor prognosis in colorectal cancer

The anti-tumor immune response has been shown to be of great prognostic importance in colorectal cancer (CRC) and so has the tumors ability for immune evasion. Our aim of this study was to investigate tumor factors that influence immunity. We used a gene expression array to search for potential mechanisms of tumor immune escape. One candidate gene identified was TAP1, involved in antigen presentation by MHC class I. TAP1 protein expression was evaluated by immunohistochemistry in 436 CRC patients of the Colorectal Cancer in Umeå Study cohort. We found a significant association between a downregulated expression of TAP1 and low infiltration of various subtypes of lymphocytes as well as macrophages. A downregulated expression of TAP1 was further found to be independent of molecular characteristics, suggesting TAP1 down-regulation to reach beyond the well described highly immunogenic MSI CRCs. A low expression of TAP1 was also significantly associated with poor prognosis in patients with CRC, a result that stayed significant in tumor front of early stage tumors (stage I-II) through multivariable analyses. Furthermore, we found that TAP1 expression was inversely correlated with methylation at sites in close proximity to the promoter region. In summary, our results show down-regulation of TAP1 to be a general mechanism of tumor immune escape in CRC and a poor prognostic factor in stage I-II CRC patients. We also suggest that methylation of the TAP1 gene may be a putative mechanism for TAP1 downregulation.

Use of a combination of CEA and tumor budding to identify high-risk patients with stage II colon cancer

BACKGROUND

High-risk patients with stage II colon cancer may benefit from adjuvant chemotherapy, but identifying this patient population can be difficult. We assessed the prognosis value for predicting tumor progression in patients with stage II colon cancer, of a panel of 2 biomarkers for colon cancer: tumor budding and preoperative carcinoembryonic antigen (CEA).

METHODS

Consecutive patients (N = 134) with stage II colon cancer who underwent curative surgery from 2000 to 2007 were included. Multivariate analysis was used to evaluate the association of CEA and tumor budding grade with 5-year disease-free survival (DFS). The prognostic accuracy of CEA, tumor budding grade and the combination of both (CEA-budding panel) was determined.

RESULTS

The study found that both CEA and tumor budding grade were associated with 5-year DFS. The prognostic accuracy for disease progression was higher for the CEA-budding panel (82.1%) than either CEA (70.9%) or tumor budding grade (72.4%) alone.

CONCLUSIONS

The findings indicate that the combination of CEA levels and tumor budding grade has greater prognostic value for identifying patients with stage II colon cancer who are at high-risk for disease progression, than either marker alone.

Tumor deposits: markers of poor prognosis in patients with locally advanced rectal cancer following neoadjuvant chemoradiotherapy

Background

Tumor deposits (TDs) were reported to be poor prognoses in colorectal carcinoma, but the significance in locally advanced rectal cancer (LARC) (T3-4/N+) following neoadjuvant chemoradiotherapy (neo-CRT) and surgery is unclear. Since adjuvant chemotherapy showed no benefit for LARC following neo-CRT, it is of great value to investigate whether TDs can identify the subgroup of patients who may benefit from adjuvant chemotherapy.

Methods

Between 2004 and 2012, 310 LARC patients following neo-CRT and surgery were retrospectively reviewed. Overall survival (OS), disease-free survival (DFS), distant metastasis free survival (DMFS) and local recurrence free survival (LRFS) were evaluated by Kaplan-Meier method, log-rank test and Cox models.

Results

TDs-positive patients showed adverse OS, DFS and DMFS (all P≤0.001), but not LRFS (P = 0.273). In multivariate analysis, TDs continued to be associated with poor OS (HR = 2.44, 95% CI 1.32-4.4, P = 0.004) and DFS (HR = 1.99, 95% CI 1.21-3.27, P = 0.007), but not DMFS (HR = 1.77, 95% CI 0.97-3.20, P = 0.061) or LRFS (HR = 1.85, 95% CI 0.58-5.85, P = 0.298). Among TDs-positive patients, adjuvant chemotherapy significantly improved OS (P = 0.045) and DMFS (P = 0.026), but not DFS (P = 0.127) or LRFS (P = 0.862).

Conclusions

TDs are predictive of poor survival in LARC after neo-CRT. Fortunately, TDs-positive patients appear to benefit from adjuvant chemotherapy.

S100A8+ stroma cells predict a good prognosis and inhibit aggressiveness in colorectal carcinoma

Gene microarray and bioinformatic analysis showed that S100A8 was more abundant in the stroma surrounding tumor buddings (TBs) than in the stroma surrounding primary tumor cells in colorectal carcinomas. Here, S100A8⁺ cells in 419 colorectal carcinoma samples were stained by immunohistochemistry and counted using Image-pro plus 6.0. TBs were also counted and biomarkers associated with the epithelial-mesenchymal transition and apoptosis were assessed by immunohistochemistry. We evaluated the association between S100A8⁺ cells and clinico-pathological variables as well as survival. Migration and invasion as well as biomarkers of the epithelial-mesenchymal transition and apoptosis were tested in CRC cells, treated with graded concentrations of recombinant human S100A8 protein. We found that the density of S100A8⁺ cells in the tumor invasive front (S100A8⁺_TIF) clearly distinguished patients with 5-y survival from those who did not survive (p = 0.01). The S100A8⁺-associated tumor budding (SATB) index determined by the S100A8⁺_TIF and TB was an independent predictor of overall survival (p = 0.001) other than the S100A8⁺_TIF or TB alone. Migration and invasion properties of CRC cells were inhibited by recombinant human S100A8 treatment. The particular S100A8⁺ cells in the stroma were associated with important biomarkers of the epithelial-mesenchymal transition (E-cadherin and SNAIL) and apoptosis (BCL2). In conclusion, S100A8⁺ cells in the stroma predict a good prognosis in colorectal carcinoma. An index combining S100A8⁺ cells and TB independently predicts survival. Recombinant human S100A8 inhibited CRC cell migration and invasion, which was involved in epithelial-mesenchymal transition (E-cadherin and SNAIL) and apoptosis (BCL2).

Modes of invasion during tumour dissemination

Cancer cell migration and invasion underlie metastatic dissemination, one of the major problems in cancer. Tumour cells exhibit a striking variety of invasion strategies. Importantly, cancer cells can switch between invasion modes in order to cope with challenging environments. This ability to switch migratory modes or plasticity highlights the challenges behind antimetastasis therapy design. In this Review, we present current knowledge on different tumour invasion strategies, the determinants controlling plasticity and arising therapeutic opportunities. We propose that targeting master regulators controlling plasticity is needed to hinder tumour dissemination and metastasis.

High-Grade Tumor Budding Stratifies Early-Stage Cervical Cancer with Recurrence Risk

OBJECTIVES

This study investigated prognostic significance of tumor budding in early-stage cervical cancer (ESCC) following radical surgery and its contribution to improve the stratification of patients with recurrence risk.

METHODS

The archival medical records and H&E-stained slides of 643 patients with IA2-IIA stage cervical cancer who underwent radical surgery were retrospectively reviewed. Clinicopathological parameters were noted, and tumor buds were counted using immunohistochemistry for each case. The prognostic significance of tumor budding was analyzed. Prediction models that comprised tumor budding were established, and the performance was compared between the novel models and classic criteria via log-rank test and receiver operating characteristic analysis.

RESULTS

Tumors with high-grade tumor budding (HTB) exhibited a substantially increased risk of recurrence (hazard ratio = 4.287, P < 0.001). Nine predictive models for recurrence were established, in which HTB was combined with recognized risk factors. The model using of at least two risk factors of HTB, tumor size ≥ 4 cm, deep stromal invasion of outer 1/3, and lymphovascular space invasion to stratify patients with an intermediate risk was most predictive of recurrence compared with the classic criteria.

CONCLUSIONS

Tumor budding is an independent, unfavorable, prognostic factor for ESCC patients following radical surgery and holds promise for improved recurrence risk stratification.

Systematic review and meta-analysis of the impact of tumour budding in colorectal cancer

Background:

Tumour budding is a histological finding in epithelial cancers indicating an unfavourable phenotype. Previous studies have demonstrated that it is a negative prognostic indicator in colorectal cancer (CRC), and has been proposed as an additional factor to incorporate into staging protocols.

Methods:

A systematic review of papers until March 2016 published on Embase, Medline, PubMed, PubMed Central and Cochrane databases pertaining to tumour budding in CRC was performed. Study end points were the presence of lymph node metastases, recurrence (local and distal) and 5-year cancer-related death.

Results:

A total of 7821 patients from 34 papers were included, with a mean rate of tumour budding of 36.8±16.5%. Pooled analysis suggested that specimens exhibiting tumour budding were significantly associated with lymph node positivity (OR 4.94, 95% CI 3.96–6.17, P<0.00001), more likely to develop disease recurrence over the time period (OR 5.50, 95% CI 3.64–8.29, P<0.00001) and more likely to lead to cancer-related death at 5 years (OR 4.51, 95% CI 2.55–7.99, P<0.00001).

Conclusions:

Tumour budding in CRC is strongly predictive of lymph node metastases, recurrence and cancer-related death at 5 years, and its incorporation into the CRC staging algorithm will contribute to more effective risk stratification.

Diagnostic reproducibility of tumour budding in colorectal cancer: a multicentre, multinational study using virtual microscopy

AIMS

Despite the established prognostic relevance of tumour budding in colorectal cancer, the reproducibility of the methods reported for its assessment has not yet been determined, limiting its use and reporting in routine pathology practice.

METHODS AND RESULTS

A morphometric system within telepathology was devised to evaluate the reproducibility of the various methods published for the assessment of tumour budding in colorectal cancer. Five methods were selected to evaluate the diagnostic reproducibility among 10 investigators, using haematoxylin and eosin (H&E) and AE1-3 cytokeratin-immunostained, whole-slide digital scans from 50 pT1-pT4 colorectal cancers. The overall interobserver agreement was fair for all methods, and increased to moderate for pT1 cancers. The intraobserver agreement was also fair for all methods and moderate for pT1 cancers. Agreement was dependent on the participants' experience with tumour budding reporting and performance time. Cytokeratin immunohistochemistry detected a higher percentage of tumour budding-positive cases with all methods compared to H&E-stained slides, but did not influence agreement levels.

CONCLUSION

An overall fair level of diagnostic agreement for tumour budding in colorectal cancer was demonstrated, which was significantly higher in early cancer and among experienced gastrointestinal pathologists. Cytokeratin immunostaining facilitated detection of budding cancer cells, but did not result in improved interobserver agreement.

The relationship between tumour budding, the tumour microenvironment and survival in patients with primary operable colorectal cancer

Background:

Tumour budding has been reported to reflect invasiveness, metastasis and unfavourable prognosis in colorectal cancer. The aim of the study was to examine the relationship between tumour budding and clinicopathological characteristics, tumour microenvironment and survival in patients with primary operable colorectal cancer.

Methods:

A total of 303 patients from a prospective data set of patients with primary operable colorectal cancer were included in the study. The presence of budding was determined through assessment of all tumour-containing H&E slides and the number of tumour buds was counted using a 10 high-powered field method. Routine pathologic sections were used to assess: tumour necrosis, the tumour inflammatory cell infiltrate using Klintrup–Makinen (KM) grade and tumour stroma percentage (TSP) combined as the Glasgow Microenvironment Score (GMS).

Results:

High-grade tumour budding was present in 39% of all tumours and in 28% of node-negative tumours respectively. High-grade budding was significantly associated with T stage (P<0.001), N stage (P<0.001), TNM stage (P<0.001), serosal involvement (P<0.001), venous invasion (P<0.005), KM grade (P=0.022), high tumour stroma (P<0.001) and GMS (P<0.001). Tumour budding was associated with reduced cancer-specific survival (CSS) (HR=4.03; 95% confidence interval (CI), 2.50–6.52; P<0.001), independent of age (HR=1.47; 95% CI, 1.13–1.90; P=0.004), TNM stage (HR=1.52; 95% CI, 1.02–2.25; P=0.040), venous invasion (HR=1.73; 95% CI, 1.13–2.64; P=0.012) and GMS (HR=1.54; 95% CI, 1.15–2.07; P=0.004).

Conclusions:

The presence of tumour budding was associated with elements of the tumour microenvironment and was an independent adverse prognostic factor in patients with primary operable colorectal cancer. Specifically high tumour budding stratifies effectively the prognostic value of tumour stage, venous invasion and GMS. Taken together, tumour budding should be assessed routinely in patients with primary operable colorectal cancer.

Tumour Budding and Survival in Stage II Colorectal Cancer: a Systematic Review and Pooled Analysis

PURPOSE

Tumour budding is defined as the presence of isolated or small clusters of malignant cells at the invasive edge of the tumour. It is considered a negative prognostic factor in colorectal cancer (CRC) and is associated with a poor outcome and adverse pathological features. Here, we report a meta-analysis of the association of tumour budding and survival in stage II CRC patients.

METHODS

PubMed, EMBASE, Web of Science and SCOPUS were searched for studies that assessed the relationship between tumour budding and 5-year overall survival (OS) in stage II CRC patients. Published data were extracted and used to compute odds ratios (ORs) for death at 5 years and hazard ratios (HRs) for survival amongst patients with respect to the extent of tumour budding, using multivariate analysis. Data were pooled using the Mantel-Haenszel random effect model.

RESULTS

We analysed 12 studies that included a total of 1652 patients. High-grade budding was associated with worse OS at 5 years (OR for death, 6.25; 95 % confidence interval [CI], 4.04-9.67; P < 0.00001). The absolute difference in 5-year OS was -25 % (95 % CI, -18- - 33 %, P < 0.00001). It was particularly noteworthy that the presence of high-grade budding was associated with an increased risk of death (HR for death, 3.68; 95 % CI, 2.16-6.28, P < 0.00001).

CONCLUSIONS

Tumour budding is associated with worse survival in stage II CRC, in particular in pT3N0M0 patients. It could therefore potentially be used when deciding whether to administer adjuvant chemotherapy in high-risk node negative CRC patients.

Tumor Budding: The Name is EMT. Partial EMT

Tumor budding is a histological phenomenon encountered in various cancers, whereby individual malignant cells and/or small clusters of malignant cells are seen in the tumor stroma. Postulated to be mirror epithelial-mesenchymal transition, tumor budding has been associated with poor cancer outcomes. However, the vast heterogeneity in its exact definition, methodology of assessment, and patient stratification need to be resolved before it can be routinely used as a standardized prognostic feature. Here, we discuss the heterogeneity in defining and assessing tumor budding, its clinical significance across multiple cancer types, and its prospective implementation in clinical practice. Next, we review the emerging evidence about partial, rather than complete, epithelial-mesenchymal phenotype at the tumor bud level, and its connection with tumor proliferation, quiescence, and stemness. Finally, based on recent literature, indicating a co-expression of epithelial and mesenchymal markers in many tumor buds, we posit tumor budding to be a manifestation of this hybrid epithelial/mesenchymal phenotype displaying collective cell migration.

Tumor Budding in Colorectal Carcinoma: Confirmation of Prognostic Significance and Histologic Cutoff in a Population-based Cohort

Tumor budding in colorectal carcinoma has been associated with poor outcome in multiple studies, but the absence of an established histologic cutoff for "high" tumor budding, heterogeneity in study populations, and varying methods for assessing tumor budding have hindered widespread incorporation of this parameter in clinical reports. We used an established scoring system in a population-based cohort to determine a histologic cutoff for "high" tumor budding and confirm its prognostic significance. We retrieved hematoxylin and eosin-stained sections from 553 incident colorectal carcinoma cases. Each case was previously characterized for select molecular alterations and survival data. Interobserver agreement was assessed between 2 gastrointestinal pathologists and a group of 4 general surgical pathologists. High budding (≥ 10 tumor buds in a ×20 objective field) was present in 32% of cases, low budding in 46%, and no budding in 22%. High tumor budding was associated with advanced pathologic stage (P < 0.001), microsatellite stability (P = 0.005), KRAS mutation (P = 0.010), and on multivariate analysis with a > 2 times risk of cancer-specific death (hazard ratio = 2.57 [1.27, 5.19]). After multivariate adjustment, by penalized smoothing splines, we found increasing tumor bud counts from 5 upward to be associated with an increasingly shortened cancer-specific survival. By this method, a tumor bud count of 10 corresponded to approximately 2.5 times risk of cancer-specific death. The interobserver agreement was good with weighted κ of 0.70 for 2 gastrointestinal pathologists over 121 random cases and 0.72 between all 6 pathologists for 20 random cases. Using an established method to assess budding on routine histologic stains, we have shown that a cutoff of 10 for high tumor budding is independently associated with a significantly worse prognosis. The reproducibility data provide support for the routine widespread implementation of tumor budding in clinical reports.

Tumour budding in colorectal cancer: what do we know and what can we do?

Budding is a process during which individual or small clusters of up to five tumour cells detach from the main tumour mass and invade into the surrounding stroma. In colorectal cancer, this feature is observed in 20-40% of cases and is associated with lymphovascular invasion, lymph node and distant metastases, and poor prognosis. A variety of scoring systems for budding have been proposed but so far a gold standard is lacking, hampering implementation of a budding score in guidelines for pathological examination of colorectal cancer. Furthermore, little is known about the mechanisms which cause tumour cells to detach from the main tumour mass and obtain increased invasive potential. In this review, we present an overview of tumour budding including its definition, scoring systems, prognostic relevance and biological mechanisms involved.

Tumor budding in colorectal cancer--ready for diagnostic practice?

Tumor budding is an important additional prognostic factor for patients with colorectal cancer (CRC). Defined as the presence of single tumor cells or small clusters of up to 5 cells in the tumor stroma, tumor budding has been likened to an epithelial-mesenchymal transition. Based on well-designed retrospective studies, tumor budding is linked to adverse outcome of CRC patients in 3 clinical scenarios: (1) in malignant polyps, detection of tumor buds is a risk factor for lymph node metastasis indicating the need for colorectal surgery; (2) tumor budding in stage II CRC is a highly adverse prognostic indicator and may aid patient selection for adjuvant therapy; (3) in the preoperative setting, presence of tumor budding in biopsy material may help to identify high-risk rectal cancer patients for neoadjuvant therapy. However, lack of consensus guidelines for standardized assessment still limits reporting in daily diagnostic practice. This article provides a practical and comprehensive overview on tumor budding aimed at the practicing pathologist. First, we review the prognostic value of tumor budding for the management of colon and rectal cancer patients. Second, we outline a practical, evidence-based proposal for the assessment of tumor budding in the daily sign-out. Last, we summarize the current knowledge of the molecular characteristics of high-grade budding tumors in the context of personalized treatment approaches and biomarker discovery.