Disentangling the prognostic heterogeneity of stage III colorectal cancer through histologic stromal categorization

Correlation analysis of interstitial maturity and prognosis of colorectal cancer: Meta-analysis

BACKGROUND

To investigate the relationship between interstitial maturity and prognosis of colorectal cancer.

AIM

To examine the correlation between interstitial maturity and the prognosis of colorectal cancer.

METHODS

The paper database PubMed, EMBASE, Cochranelibrary, Springerlink, CNKI, and Wanfang database were searched until December 2023. "tumor stroma maturity" "desmoplastic stroma reaction" "desmoplastic reaction" "stroma reaction" "degree of stroma reaction "" stroma classification" "stroma density" "colorectal cancer" "colon cancer" "rectal cancer" "prognosis" were searched for the search terms. Two system assessors independently screened the literature quality according to the inclusion exclusion criteria, Quality evaluation and data extraction were performed for the included literatures, and meta-analysis was performed for randomized control trials included at using Review Manager 5.2 software.

RESULTS

Finally, data of 9849 patients with colorectal cancer from 19 cosets in 15 literatures were included, including 4339 patients with mature type (control group), 3048 patients with intermediate type (intermediate group) and 2456 patients with immature type (immature group). The results of meta-analysis showed: Relapse-free survival [hazard ratio (HR) = 2.66, 95% confidence interval (CI): 2.30-3.08; P < 0.00001], disease-free survival (HR = 3.68, 95%CI: 2.33-5.81; P < 0.00001) and overall survival (HR = 1.70, 95%CI: 1.53-1.87; P < 0.00001) were significantly lower than those in mature group (control group); relapse-free survival (HR = 1.36, 95%CI: 1.17-1.59; P < 0.0001) and disease-free survival rate (HR = 1.85, 95%CI: 1.53-2.24; P < 0.0001) was significantly lower than the mature group (control group).

CONCLUSION

There is the correlation between tumor interstitial maturity and survival prognosis of colorectal cancer, and different degrees of tumor interstitial maturity have a certain impact on the quality of life of colorectal cancer patients.

Machine learning based local recurrence prediction in colorectal cancer using polarized light imaging

Significance

Current treatment for stage III colorectal cancer (CRC) patients involves surgery that may not be sufficient in many cases, requiring additional adjuvant systemic therapy. Identification of this latter cohort that is likely to recur following surgery is key to better personalized therapy selection, but there is a lack of proper quantitative assessment tools for potential clinical adoption.

Aim

The purpose of this study is to employ Mueller matrix (MM) polarized light microscopy in combination with supervised machine learning (ML) to quantitatively analyze the prognostic value of peri-tumoral collagen in CRC in relation to 5-year local recurrence (LR).

Approach

A simple MM microscope setup was used to image surgical resection samples acquired from stage III CRC patients. Various potential biomarkers of LR were derived from MM elements via decomposition and transformation operations. These were used as features by different supervised ML models to distinguish samples from patients that locally recurred 5 years later from those that did not.

Results

Using the top five most prognostic polarimetric biomarkers ranked by their relevant feature importances, the best-performing XGBoost model achieved a patient-level accuracy of 86%. When the patient pool was further stratified, 96% accuracy was achieved within a tumor-stage-III sub-cohort.

Conclusions

ML-aided polarimetric analysis of collagenous stroma may provide prognostic value toward improving the clinical management of CRC patients.

Mueller matrix polarization parameters correlate with local recurrence in patients with stage III colorectal cancer

The peri-tumoural stroma has been explored as a useful source of prognostic information in colorectal cancer. Using Mueller matrix (MM) polarized light microscopy for quantification of unstained histology slides, the current study assesses the prognostic potential of polarimetric characteristics of peri-tumoural collagenous stroma architecture in 38 human stage III colorectal cancer (CRC) patient samples. Specifically, Mueller matrix transformation and polar decomposition parameters were tested for association with 5-year patient local recurrence outcomes. The results show that some of these polarimetric parameters were significantly different (p value < 0.05) for the recurrence versus the no-recurrence patient cohorts (Mann-Whitney U test). MM parameters may thus be prognostically valuable towards improving clinical management/treatment stratification in CRC patients.

18F-Fluorodeoxyglucose Positron Emission Tomography/Magnetic Resonance Imaging-Defined Extramural Venous Invasion Predicts Distant Metastasis and Reflects Strong Tumor Invasiveness in Rectal Cancer

INTRODUCTION

Extramural vascular invasion in patients with rectal cancer is a poor prognostic factor associated with distant metastasis; thus, accurate preoperative diagnosis is important. However, the accurate detection of extramural vascular invasion using magnetic resonance imaging (MRI) is difficult, and an improved diagnostic modality is required. In addition, the factors involved in the formation of extramural venous invasion (EMVI) remain unclear. In this study, we aimed to examine the ability of 18F-fluorodeoxyglucose positron emission tomography/MRI ([18F] FDG PET/MRI) to detect EMVI and elucidate the factors involved in EMVI.

METHODS

Thirty-one patients with rectal cancer were enrolled in this study between 2017 and 2021. We preoperatively evaluated the pelvic [18F] FDG PET/MRI to detect extramural vascular invasion ([18F] FDG PET/MRI-defined EMVI: pmrEMVI). To investigate the factors related to pmrEMVI, we confirmed the desmoplastic reaction (DR) and TWIST expression in the primary lesions of rectal cancer and examined its relationship with pmrEMVI.

RESULTS

Six of the 31 patients were pmrEMVI positive. Four pmrEMVI-positive patients had distant metastases. The levels of immature DR and TWIST1 expression were significantly higher in cases with pmrEMVI positivity.

CONCLUSION

pmrEMVI is a useful biomarker for predicting distant metastasis. In addition, pmrEMVI was significantly correlated with factors related to tumor invasiveness.

Prognostic impact of desmoplastic reaction in esophageal squamous cell carcinoma patients with neoadjuvant therapy

AIM

This study aimed to examine the prognostic value of desmoplastic reaction (DR) in esophageal squamous cell carcinoma (ESCC), particularly in patients who received neoadjuvant therapy, such as chemotherapy (NAC) or chemoradiotherapy (NACRT).

METHOD

In total, 153 patients with pStage II/III ESCC were included in this study. Ninety-one patients received neoadjuvant therapy (NAC, 70; NACRT, 21). Patients were classified according to three DR categories based on the presence of keloid-like collagen and/or myxoid stroma.

RESULTS

In total, 50, 50, and 53 patients were classified as having mature, intermediate, and immature DR, respectively. The weighted kappa coefficient was 0.623 in the patients with preoperative treatments and 0.782, in those without. The 5-year disease-specific survival (DSS) rates in patients with intermediate/immature DR was significantly worse than those with mature DR (40.7% vs. 73.3%, p < 0.001). Similarly, the 5-year DSS rate in patients with intermediate/immature DR was significantly worse than those with mature DR in a study of patients who received neoadjuvant therapy (46.7% vs. 71.2%, p = 0.009). Multivariate analysis revealed that DR (hazard ratio [HR]: 3.15, 95% confidence interval [CI] 1.58-6.27, p = 0.001), along with N factors, was an independent risk factor for DSS. Moreover, multivariate analysis of patients who received neoadjuvant therapy revealed only DR (HR: 2.47, 95% CI 1.02-5.96, p = 0.045) as independent risk factors for DSS.

CONCLUSION

The DR classification was a valuable prognostic factor not only in the ESCC patients without neoadjuvant therapy but also in those with neoadjuvant therapy.

Polarimetric biomarkers of peri-tumoral stroma can correlate with 5-year survival in patients with left-sided colorectal cancer

Using a novel variant of polarized light microscopy for high-contrast imaging and quantification of unstained histology slides, the current study assesses the prognostic potential of peri-tumoral collagenous stroma architecture in 32 human stage III colorectal cancer (CRC) patient samples. We analyze three distinct polarimetrically-derived images and their associated texture features, explore different unsupervised clustering algorithm models to group the data, and compare the resultant groupings with patient survival. The results demonstrate an appreciable total accuracy of ~ 78% with significant separation (p < 0.05) across all approaches for the binary classification of 5-year patient survival outcomes. Surviving patients preferentially belonged to Cluster 1 irrespective of model approach, suggesting similar stromal microstructural characteristics in this sub-population. The results suggest that polarimetrically-derived stromal biomarkers may possess prognostic value that could improve clinical management/treatment stratification in CRC patients.

Cancer-associated fibroblasts at the unfavorable desmoplastic stroma promote colorectal cancer aggressiveness: potential role of ADAM9

The tumor microenvironment plays a key role in cancer aggressiveness. Desmoplastic reaction (DR), morphologically classified as Mature, Intermediate and Immature types, has previously been shown to be highly prognostic in colorectal cancer (CRC) and it consists to a large extent of cancer-associated fibroblasts (CAFs). The aim of this study was to characterize the molecular background of DR and understand the effects of CAFs in tumor aggressiveness. The prognostic significance of DR was initially examined in 1,497 patients. Then CAFs originating from patient tissues with different DR types were isolated and their impact on tumor growth was examined both in vitro and in vivo. DR was shown to be highly prognostic, with patients within the Immature DR group conferring the worst relapse-free survival. The conditioned media of CAFs from tumor with Immature-type DR (CAFs^Immature ) significantly increased proliferation and migration of CRC cell lines and growth of CRC-derived organoids compared to that of CAFs from Mature-type DR (CAFs^Mature ). Subcutaneous or orthotopic implantation of CRC cells together with CAFs^Immature in mice significantly promoted tumor growth and dissemination compared to implantation with CAFs^Mature . Systematic examination of the expression of "a disintegrin and metalloproteinases" (ADAMs) in CAFs isolated from CRC tissues showed that the secreted isoform of ADAM9 (ADAM9s) was significantly higher in CAFs^Immature than in CAFs^Mature . Knockdown of ADAM9s in CAFs^Immature abrogated the promoting effects on CRC cell proliferation and migration. CAFs-derived ADAM9s is implicated in deteriorating survival in CRC patients with Immature-type DR by increasing tumor cell proliferation and dissemination. This article is protected by copyright. All rights reserved.

Desmoplastic Reaction, Immune Cell Response, and Prognosis in Colorectal Cancer

Background

The relationships between tumor stromal features (such as desmoplastic reaction, myxoid stroma, and keloid-like collagen bundles) and immune cells in the colorectal carcinoma microenvironment have not yet been fully characterized.

Methods

In 908 tumors with available tissue among 4,465 incident colorectal adenocarcinoma cases in two prospective cohort studies, we examined desmoplastic reaction, myxoid stroma, and keloid-like collagen bundles. We conducted multiplex immunofluorescence for T cells [CD3, CD4, CD8, CD45RO (PTPRC), and FOXP3] and for macrophages [CD68, CD86, IRF5, MAF, and MRC1 (CD206)]. We used the inverse probability weighting method and the 4,465 incident cancer cases to adjust for selection bias.

Results

Immature desmoplastic reaction was associated with lower densities of intraepithelial CD3⁺CD8⁺CD45RO⁺ cells [multivariable odds ratio (OR) for the highest (vs. lowest) density category, 0.43; 95% confidence interval (CI), 0.29-0.62; P_trend <0.0001] and stromal M1-like macrophages [the corresponding OR, 0.44; 95% CI, 0.28-0.70; P_trend = 0.0011]. Similar relations were observed for myxoid stroma [intraepithelial CD3⁺CD8⁺CD45RO⁺ cells (P_trend <0.0001) and stromal M1-like macrophages (P_trend = 0.0007)] and for keloid-like collagen bundles (P_trend <0.0001 for intraepithelial CD3⁺CD8⁺CD45RO⁺ cells). In colorectal cancer-specific survival analyses, multivariable-adjusted hazard ratios (with 95% confidence intervals) were 0.32 (0.23-0.44; P_trend <0.0001) for mature (vs. immature) desmoplastic reaction, 0.25 (0.16-0.39; P_trend <0.0001) for absent (vs. marked) myxoid stroma, and 0.12 (0.05-0.28; P_trend <0.0001) for absent (vs. marked) keloid-like collagen bundles.

Conclusions

Immature desmoplastic reaction and myxoid stroma were associated with lower densities of tumor intraepithelial memory cytotoxic T cells and stromal M1-like macrophages, likely reflecting interactions between tumor, immune, and stromal cells in the colorectal tumor microenvironment.

Immunohistochemical Expression of “HCG-β” in Colorectal Carcinoma

BACKGROUND: Tumor budding is associated with adverse histology and is a predictor of lymph node metastasis. Human chorionic gonadotropin-beta (hCG-β) expression in non-trophoblastic tumors has been associated with aggressive behavior. AIM: Evaluation of tumor budding and hCG-β _immunohistochemical expression in colorectal carcinoma (CRC), and correlation of their expression with various clinicopathological parameters. MATERIALS AND METHODS: Immunohistochemical staining for hCG-β _was performed on paraffin-embedded sections of 60 cases of CRC. Tumors with cytoplasmic or membranous staining of more than five epithelial cell clusters were designated hCG-β _positive; otherwise, they were designated hCG-β _negative. Tumor budding was assessed in hematoxylin and eosin stained slides and was classified as; low: 0–4 buds, intermediate: 5–9 buds and high: ≥10 buds; with exclusion of pure mucoid or signet ring cell morphology cases from analysis. RESULTS: Tumor budding was low in (58.8%) of the cases, intermediate in (15.7%), and high in (25.5%). There was a statistically significant correlation between tumor budding and tumor histological grade (p = 0.011), lymph node metastasis (N) (p = 0.009), overall pathologic stage group (p = 0.009), modified Dukes’ stage (p = 0.009), lymphovascular invasion (p = 0.000), and desmoplastic reaction (p = 0.004). Positive hCG-β _alpha expression was detected in 12 (20%) of cases. There were statistically significant correlations between hCG-β _expression and each of lymphovascular invasion (p = 0.042) and tumor budding (p = 0.000). CONCLUSION: hCG-β _is a marker of aggressiveness that may have essential role in tumor invasion. Tumor budding is crucial event in tumor invasion and metastasis. Tumor budding with hCG-β _expression is a novel prognostic parameter and may represent a potential therapeutic target.

Prognostic significance of tumor budding, poorly differentiated cluster, and desmoplastic reaction in endometrioid endometrial carcinomas

AIMS

The tumor budding (TB); poorly differentiated cluster (PDC); desmoplastic reaction (DR); and microcystic, elongated, and fragmented (MELF) patterns of invasion are pathological findings at the tumor invasion front associated with epithelial-to-mesenchymal transition. This study aimed to clarify the clinical significance of the TB, PDC, DR, and MELF patterns in endometrioid endometrial carcinomas (EEC).

METHODS

Two hundred and eight cases of histologically proven EEC retrieved from the archives of the Department of Pathology, Fukui Prefectural Hospital, and diagnosed between January 2000 and August 2020 were retrospectively analyzed.

RESULTS

The TB, PDC, DR, and MELF patterns were identified in 29 (13.9%), 47 (22.6%), 45 (21.6%), and 23 (11.1%) cases, respectively. Kaplan-Meier curve analysis with log-rank test demonstrated that TB, PDC, and DR were associated with a lower progression-free survival (p = 0.010, 0.002, and <0.0001, respectively), whereas the MELF pattern did not show any association (p = 0.668). In multivariate analyses, only DR was significantly associated with lower progression-free survival (p = 0.034). Moreover, only PDC was associated with lower overall survival in univariate analysis (p = 0.018), but the association lost significance in multivariate analysis.

CONCLUSIONS

The present study revealed that the histological confirmation of TB, PDC, and DR at the tumor invasive front predicts poor prognosis in EEC. However, the MELF pattern was not a predictor of poor prognosis in EEC.

Histopathological atlas of desmoplastic reaction characterization in colorectal cancer

Emergent scientific evidence indicates the central role of cancer-associated fibroblasts in determining whether the microenvironment of cancer works as friend or foe of the host; however, there is no unified histological evaluation framework of fibrotic stroma in colorectal cancers. Myxoid stroma and keloid-like collagen are site-specific histopathological features generated by cancer-associated fibroblasts, which appear exclusively in the tumor front during desmoplastic reaction. On the basis of these two stromal components, desmoplastic reaction is categorized into three patterns-immature, intermediate and mature-using hematoxylin and eosin staining. In January 2020, a prospective randomized clinical trial, JCOG1805, to elucidate the value of adjuvant chemotherapy in stage II colorectal cancer patients with pathological risk factors of recurrence was launched in Japan, in which intermediate/immature desmoplastic reaction is one of the four risk factors selected as inclusion criteria. This paper covers the diagnostic criteria for the desmoplastic reaction classification being used in the JCOG1805 study.

Automated Detection and Classification of Desmoplastic Reaction at the Colorectal Tumour Front Using Deep Learning

The categorisation of desmoplastic reaction (DR) present at the colorectal cancer (CRC) invasive front into mature, intermediate or immature type has been previously shown to have high prognostic significance. However, the lack of an objective and reproducible assessment methodology for the assessment of DR has been a major hurdle to its clinical translation. In this study, a deep learning algorithm was trained to automatically classify immature DR on haematoxylin and eosin digitised slides of stage II and III CRC cases (n = 41). When assessing the classifier's performance on a test set of patient samples (n = 40), a Dice score of 0.87 for the segmentation of myxoid stroma was reported. The classifier was then applied to the full cohort of 528 stage II and III CRC cases, which was then divided into a training (n = 396) and a test set (n = 132). Automatically classed DR was shown to have superior prognostic significance over the manually classed DR in both the training and test cohorts. The findings demonstrated that deep learning algorithms could be applied to assist pathologists in the detection and classification of DR in CRC in an objective, standardised and reproducible manner.

Prognostic value of desmoplastic reaction characterisation in stage II colon cancer: prospective validation in a Phase 3 study (SACURA Trial)

BACKGROUND

The characterisation of desmoplastic reaction (DR) has emerged as a new, independent prognostic determinant in colorectal cancer. Herein, we report the validation of its prognostic value in a randomised controlled study (SACURA trial).

METHODS

The study included 991 stage II colon cancer patients. DR was classified by the central review as Mature, Intermediate or Immature based on the presence of hyalinised collagen bundles and myxoid stroma at the desmoplastic front. All clinical and pathological data, including DR characterisations, were prospectively recorded and analysed 5 years after the completion of the registration.

RESULTS

The five-year relapse-free survival (RFS) rate was the highest in the Mature group (N = 638), followed by the Intermediate (N = 294) and Immature groups (N = 59). Multivariate analysis revealed that DR classification was an independent prognostic factor, and based on Harrell's C-index, the Cox model for predicting RFS was significantly improved by including DR. In the conditional inference tree analysis, DR categorisation was the first split factor for predicting RFS, followed by T-stage, microsatellite instability status and budding.

CONCLUSIONS

Histological categorisation of DR provides important prognostic information that could contribute to the efficient selection of stage II colon cancer patients who would benefit from postoperative adjuvant therapy.

Periostin as a key molecule defining desmoplastic environment in colorectal cancer

Categorizing desmoplastic reaction (DR) based on the histological findings of cancer-associated fibroblasts is shown to be a promising novel method to predict prognosis of patients with colorectal cancer (CRC). Periostin (POSTN) in cancer-associated stroma is reportedly associated with poor clinical outcomes. Immunohistochemical staining with an anti-POSTN antibody was performed in 73 patients with pStage III CRC (cohort 1). In addition, to evaluate mRNA and protein expression levels of POSTN, we analyzed paired normal and invasive cancer frozen specimens by quantitative real-time polymerase chain reaction and western blot analysis in 41 patients (cohort 2). In cohort 1, according to the DR categorization, 18, 22, and 33 patients were classified as immature, intermediate, and mature, respectively. High immunoreactivity of POSTN was observed 100%, 68.2%, and 27.3%, respectively (p < 0.0001). The 5-year relapse-free survival rates were 56.8% and 82.7% in high and low POSTN expression subgroups, respectively (p = 0.015). In cohort 2, the POSTN mRNA and protein levels were significantly higher in the immature stroma as compared to the stroma characterized as other DR patterns. POSTN expression was closely associated with DR categorization. POSTN may be a key molecule that contributes to the malignant potential of CRC.

Novel Internationally Verified Method Reports Desmoplastic Reaction as the Most Significant Prognostic Feature For Disease-specific Survival in Stage II Colorectal Cancer

Multiple histopathologic features have been reported as candidates for predicting aggressive stage II colorectal cancer (CRC). These include tumor budding (TB), poorly differentiated clusters (PDC), Crohn-like lymphoid reaction and desmoplastic reaction (DR) categorization. Although their individual prognostic significance has been established, their association with disease-specific survival (DSS) has not been compared in stage II CRC. This study aimed to evaluate and compare the prognostic value of the above features in a Japanese (n=283) and a Scottish (n=163) cohort, as well as to compare 2 different reporting methodologies: analyzing each feature from across every tissue slide from the whole tumor and a more efficient methodology reporting each feature from a single slide containing the deepest tumor invasion. In the Japanese cohort, there was an excellent agreement between the multi-slide and single-slide methodologies for TB, PDC, and DR (κ=0.798 to 0.898) and a good agreement when assessing Crohn-like lymphoid reaction (κ=0.616). TB (hazard ratio [HR]=1.773; P=0.016), PDC (HR=1.706; P=0.028), and DR (HR=2.982; P<0.001) based on the single-slide method were all significantly associated with DSS. DR was the only candidate feature reported to be a significant independent prognostic factor (HR=2.982; P<0.001) with both multi-slide and single-slide methods. The single-slide result was verified in the Scottish cohort, where multivariate Cox regression analysis reported that DR was the only significant independent feature (HR=1.778; P=0.002) associated with DSS. DR was shown to be the most significant of all the analyzed histopathologic features to predict disease-specific death in stage II CRC. We further show that analyzing the features from a single-slide containing the tumor's deepest invasion is an efficient and quicker method of evaluation.

Morphological consistency of desmoplastic reactions between the primary colorectal cancer lesion and associated metastatic lesions

Some preceding studies show that a desmoplastic reaction (DR) at the invasive front of a primary tumor (DR^primary) is a promising prognostic indicator, and its histologic classification is an independent prognostic factor in patients with colorectal cancer (CRC). Although DR is observed in metastatic lesions, such as those in lymph nodes (DR^LN) and the liver (DR^liver), the association between DR^primary and DR of metastatic lesions is unclear. We investigated whether DR^LN and DR^liver could be categorized in the same manner as DR^primary and examined the features and prognostic implications of DR^LN and DR^liver. In this study, we evaluated 363 patients with metastases to lymph nodes and 45 patients with synchronous liver metastases who underwent curative resection. DR^LN and DR^liver statuses were classified as mature, intermediate, or immature, based on keloid-like collagen and myxoid stroma appearances in the metastatic lesions. Overall, 109, 106, and 148 patients had mature, intermediate, and immature DR^LN, respectively; in total, 5, 21, and 19 patients had mature, intermediate, and immature DR^liver, respectively. DR^LN and DR^primary (spearman's rho = 0.43, P < 0.0001) and DR^liver and DR^primary (spearman's rho = 0.40, P = 0.0069) were each significantly correlated. The 5-year relapse-free survival (RFS) after surgery was 67.7% for mature/intermediate DR^LN and 52.9% for immature DR^LN; the 5-year RFS after hepatectomy was 11.5% for mature/intermediate DR^liver and 5.6% for immature DR^liver. In conclusion, DR^LN and DR^liver may be classified in the same manner as DR^primary; morphological consistency of DR was observed between primary and metastatic lesions.

Uniform Noting for International Application of the Tumor-Stroma Ratio as an Easy Diagnostic Tool: Protocol for a Multicenter Prospective Cohort Study

Background

Colon cancer treatment is dependent on the stage at diagnosis. The current Tumor-Node-Metastasis (TNM) staging for the selection of patients for adjuvant chemotherapy needs additional prognostic and predictive biomarkers. Better decision making for chemotherapy will result in reducing over- and undertreatment. We developed a new, easy-to-apply, practice-changing method to select colon cancer patients for adjuvant chemotherapy: the tumor-stroma ratio (TSR). The TSR distinguishes within stage II-III patients who will likely benefit from adjuvant chemotherapy and those who will not.

Objective

The aim of the study was to add, in addition to the TNM classification, the TSR to current routine pathology evaluation. Pathologists will be instructed for scoring the TSR in combination with a quality assessment program. An international multicenter study will validate the parameter prospectively.

Methods

The study is designed for future implementation of the TSR to the current TNM guidelines, using routinely Haematoxylin- and Eosin-stained tumor tissue sections. In part 1 of the study, an electronic learning (e-learning) module with a quality assessment program using the European Society of Pathology framework will be developed. This module will be used to assess the reliability and reproducibility of the TSR, conducted by national and international pathologists. Part 2 will involve the validation of the TSR in a prospective cohort of colon cancer p-stage II-III patients in a multicenter setting. In total, 1500 patients will be included.

Results

The results of part 1 will be expected in the first half of 2019. For part 2, the inclusion of patients in the prospective study, which started at the end of 2018, will take 3 years with an additional follow-up after another 3 years.

Conclusions

The main endpoints of this study are as follows: in part 1, trained (international) pathologists who are able to reliably score the TSR, resulting in low intra- and interobserver variation; in part 2, confirmation of significant survival differences for patients with a stroma-high tumor versus patients with a stroma-low tumor. On the basis of these findings, a modification in current treatment guidelines will be suggested.

Trial Registration

Netherlands Trial Register NTR7270; https://www.trialregister.nl/trial/7072

International Registered Report Identifier (IRRID)

DERR1-10.2196/13464

Prognostic significance of histological categorization of desmoplastic reaction in colorectal liver metastases

Desmoplastic reaction (DR) involves the growth of fibrous or connective tissues around a tumor and has recently attracted attention as an indicator of malignant potential. Previous studies have confirmed that histological categorization of DR in the primary tumor is an independent prognostic factor in patients with colorectal liver metastases (CRLM). However, it remains unclear whether the DR status of the metastatic liver lesion (DR^liver) is a useful prognostic factor. This pathological review evaluated records from 204 patients who underwent hepatectomy for CRLM at the National Defense Medical College Hospital in Japan. Each case's DR^liver was classified as mature, intermediate, or immature based on the presence of keloid-like collagen and myxoid stroma in the metastatic liver lesion. This resulted in 12 cases of mature DR^liver, 101 cases of intermediate DR^liver, and 91 cases of immature DR^liver. There was a significant correlation between the DR statuses of the primary tumor and the metastatic liver lesion (Spearman's rho = 0.3, P = 0.0001). The 5-year relapse-free survival rates after hepatectomy were 33.8% for mature/intermediate DR^liver and 16.7% for immature DR^liver (P = 0.0021). The 5-year overall survival rate after hepatectomy was higher in the mature/intermediate DR^liver group (64.8%) than in the immature DR^liver group (35.0%; P = 0.0012). The multivariate analysis confirmed that DR^liver categorization could independently predict relapse-free survival and overall survival. In conclusion, DR^liver categorization may be valuable for predicting prognosis after hepatectomy among patients with CRLM.