Histological growth patterns of colorectal cancer liver metastases: a strong prognostic marker associated with invasive patterns of the primary tumor and p53 alteration

Critical appraisal of surgical margins according to KRAS status in liver resection for colorectal liver metastases: Should surgical strategy be influenced by tumor biology?

BACKGROUND

KRAS mutation is a negative prognostic factor for colorectal liver metastases. Several studies have investigated the resection margins according to KRAS status, with conflicting results. The aim of the study was to assess the oncologic outcomes of R0 and R1 resections for colorectal liver metastases according to KRAS status.

METHODS

All patients who underwent resection for colorectal liver metastases between 2010 and 2015 with available KRAS status were enrolled in this multicentric international cohort study. Logistic regression models were used to investigate the outcomes of R0 and R1 colorectal liver metastases resections according to KRAS status: wild type versus mutated. The primary outcomes were overall survival and disease-free survival.

RESULTS

The analysis included 593 patients. KRAS mutation was associated with shorter overall survival (40 vs 60 months; P = .0012) and disease-free survival (15 vs 21 months; P = .003). In KRAS-mutated tumors, the resection margin did not influence oncologic outcomes. In multivariable analysis, the only predictor of disease-free survival and overall survival was primary tumor location (P = .03 and P = .03, respectively). In KRAS wild-type tumors, R0 resection was associated with prolonged overall survival (74 vs 45 months, P < .001) and disease-free survival (30 vs 17 months, P < .001). The multivariable model confirmed that R0 resection margin was associated with prolonged overall survival (hazard ratio = 1.43, 95% confidence interval: 1.01-2.03) and disease-free survival (hazard ratio = 1.42; 95% confidence interval: 1.06-1.91).

CONCLUSIONS

KRAS-mutated colorectal liver metastases showed more aggressive tumor biology with inferior overall survival and disease-free survival after liver resection. Although R0 resection was not associated with improved oncologic outcomes in the KRAS-mutated tumors group, it seems to be of paramount importance for achieving prolonged long-term survival in KRAS wild-type tumors.

Cancer spreading patterns based on epithelial-mesenchymal plasticity

Introduction: Metastasis is a major cause of cancer-related deaths, underscoring the necessity to discern the rules and patterns of cancer cell spreading. Epithelial-mesenchymal plasticity contributes to cancer aggressiveness and metastasis. Despite establishing key determinants of cancer aggressiveness and metastatic ability, a comprehensive understanding of the underlying mechanism is unknown. We aimed to propose a classification system for cancer cells based on epithelial-mesenchymal plasticity, focusing on hysteresis of the epithelial-mesenchymal transition and the hybrid epithelial/mesenchymal phenotype. Methods: We extensively reviewed the concept of epithelial-mesenchymal plasticity, specifically considering the hysteresis of the epithelial-mesenchymal transition and the hybrid epithelial/mesenchymal phenotype. Results: In this review and hypothesis article, based on epithelial-mesenchymal plasticity, especially the hysteresis of epithelial-mesenchymal transition and the hybrid epithelial/mesenchymal phenotype, we proposed a classification of cancer cells, indicating that cancer cells with epithelial-mesenchymal plasticity potential could be classified into four types: irreversible hysteresis, weak hysteresis, strong hysteresis, and hybrid epithelial/mesenchymal phenotype. These four types of cancer cells had varied biology, spreading features, and prognoses. Discussion: Our results highlight that the proposed classification system offers insights into the diverse behaviors of cancer cells, providing implications for cancer aggressiveness and metastasis.

Association between primary tumor characteristics and histopathological growth pattern of liver metastases in colorectal cancer

INTRODUCTION

The microarchitecture of liver metastases (LMs), or histopathological growth pattern (HGP), has been demonstrated to be a significant prognostic factor in patients undergoing resection of colorectal liver metastases (CRLMs). Currently, however, HGP can be only determined on the operative specimen. Therefore, the development of new tools to predict the HGP of CRLMs before surgery and to understand the mechanisms that drive these patterns is important for improving individualization of therapeutic management. In this study, we analyzed data from a retrospective series of patients who underwent surgery for CRLMs to compare primary tumor characteristics, including markers of local aggressiveness and migratory capacity, and HGP of liver metastases.

METHODS

Data from a retrospective series of 167 patients who underwent curative-intent resection of CRLMs and in whom pathological samples from both primary tumor and liver metastases were available were reviewed. At the primary tumor level, KRAS mutational status, grade of differentiation, and tumor budding were assessed. HGP was scored in each resected CRLM, according to consensus guidelines, and classified as desmoplastic (dHGP) or non-desmoplastic (non-dHGP). Associations between primary tumor characteristics and HGP of CRLMs were evaluated using a binary logistic regression model. Overall survival and disease-free survival were evaluated using Kaplan-Meier and multivariable Cox regression analyses.

RESULTS

CRLMs were classified as dHGP in 36% of the patients and as non-dHGP in 64%. Higher rates of moderately or poorly differentiated primary tumors were observed in the non-dHGP CRLM group (80%), as compared with the dHGP group (60%) (OR = 3.6; 95%CI: 1.6-7.05; p = 0.001). Higher rates of tumor budding were observed in the non-dHGP CRLM group, with a median tumor budding value of 4 as compared with 2.5 in the dHGP group (p = 0.042). In the entire series, 5-year overall and disease-free survival were 43% and 32.5%, respectively. The non-dHGP CRLM group had worse post-hepatectomy survival, with 5-year overall and disease-free survival of 32.2% and 24.6%, respectively, as compared with 60.8% and 45.9%, respectively, for the dHGP group (p = 0.02).

CONCLUSION

Colorectal tumors with moderate or poor differentiation and those with high tumor budding are more frequently associated with CRLMs with a non-dHGP. This suggests that primary tumor characteristics of local aggressiveness and migratory capacity could preferentially promote the development of CRLMs with an infiltrating pattern and that these parameters should be considered as part of new scores for predicting HGP before surgery. This finding may stimulate new lines of research for more individualized therapeutic decision in patients with CRLM candidate to surgery.

Circulating tumour cells are associated with histopathological growth patterns of colorectal cancer liver metastases

Histopathological Growth Patterns (HGPs) have prognostic and predictive value in patients with Colorectal Liver Metastases (CRLM). This study examined whether preoperative measurement of Circulating Tumour Cells (CTCs) is associated with HGP. CTCs were prospectively enumerated in 7.5 ml of blood using the FDA-approved CellSearch system in patients who underwent local treatment of CRLM with curative intent between 2008 and 2021. All CTC samples were collected on the day of local treatment. Patients treated with neoadjuvant chemotherapy for CRLM or with extrahepatic disease at the time of CTC sampling were excluded. HGP was scored retrospectively following the current consensus guidelines. The association between CTCs and HGP was investigated through multivariable logistic regression. Data were available for 177 patients, desmoplastic HGP (dHGP) was observed in 34 patients (19%). There were no statistically significant differences in patient and tumour characteristics between dHGP and non-dHGP at baseline. Patients with dHGP had longer overall - and disease-free survival (logrank p = 0.003 and 0.003, respectively) compared to patients with non-dHGP. CTCs were not detected in 25(74%) of dHGP patients and in 68(48%) of non-dHGP patients (chi-squared p = 0.006). Preoperative absence of CTCs was the only significant predictor for dHGP in multivariable logistic regression (Odds Ratio 2.7, 95%CI 1.1-6.8, p = 0.028), Table 3. Preoperative absence of CTCs is associated with dHGP in chemo naive CRLM patients without extrahepatic disease. Based on our results, CTC count alone is not sufficient to preoperatively identify HGPs, but integration of CTC count in multivariable prediction models may aid the preoperative identification of HGPs of CRLM.

Histopathological Growth Pattern in Colorectal Liver Metastasis and The Tumor Immune Microenvironment

Almost half of all patients with colorectal cancer present with or eventually develop metastasis, most frequently in the liver. Understanding the histopathological growth patterns and tumor immune microenvironment of colorectal liver metastases may help determine treatment strategies and assess prognosis. A literature search was conducted to gather information on cancer biology, histopathological growth patterns, and the tumor immune microenvironment in colorectal liver metastases, including their mechanisms and their impact on clinical outcomes. A first consensus on histopathological growth patterns emerged in 2017, identifying five growth patterns. Later studies found benefits from a two-tier system, desmoplastic and non-desmoplastic, incorporated into the updated 2022 consensus. Furthermore, the tumor immune microenvironment shows additional characteristic features with relevance to cancer biology. This includes density of T-cells (CD8+), expression of claudin-2, presence of vessel co-option versus angiogenesis, as well as several other factors. The relation between histopathological growth patterns and the tumor immune microenvironment delineates distinct subtypes of cancer biology. The distinct subtypes are found to correlate with risk of metastasis or relapse, and hence to clinical outcome and long-term survival in each patient. In order to optimize personalized and precision therapy for patients with colorectal liver metastases, further investigation into the mechanisms of cancer biology and their translational aspects to novel treatment targets is warranted.

Prognostic Significance of the Histopathological Growth Pattern and Tumor-Infiltrating Lymphocytes in Stratifying Survival After Hepatectomy for Colorectal Liver Metastases

BACKGROUND

A histopathological growth pattern (HGP) occurs at the interface between tumor cells and the surrounding liver parenchyma. Desmoplastic HGP (dHGP) is associated with a favorable prognosis and shows denser infiltration of lymphocytes than other HGPs. Tumor-infiltrating lymphocytes (TILs) exert antitumor immunity, nonetheless, their prognostic significance in patients with dHGP is unknown. This study aimed to identify the prognostic significance of HGP and TILs in colorectal liver metastasis (CRLM).

METHODS

The study analyzed 140 patients who underwent hepatectomy for CRLM. Depending on the type of HGP and TIL, the patients were categorized into four groups (dHGP/high TIL, dHGP/low TIL, non-dHGP/high TIL, and non-dHGP/low TIL) for a comparison of their recurrence-free survival (RFS) and overall survival (OS). Uni- and multivariate analyses were performed using a Cox proportional hazards model.

RESULTS

The RFS and OS curves differed significantly between the groups. The multivariate analysis showed that a combination of HGP and TIL could stratify the recurrence and survival outcomes.

CONCLUSION

This study indicated that a combination of HGP and TIL can stratify the risk of survival after hepatectomy in patients with CRLM.

CT, MRI, and radiomics studies of liver metastasis histopathological growth patterns: an up-to-date review

The histopathological growth patterns (HGPs) of liver metastases (LMs) are independently associated with the long-term prognosis of the primary tumor, with different HGPs predicting different patient outcomes and clinical treatment decisions. Non-invasive imaging biomarkers for stratification of HGPs are beneficial for treatment monitoring, evaluation of efficacy, and prognosis prediction of LMs. This review describes the state of research regarding computed tomography (CT), magnetic resonance imaging (MRI), and radiomics imaging biomarkers for LM-HGPs; discusses the advantages of CT, MRI, and radiomics for classification of LM-HGPs; and provides a reference for the stratification of LM-HGPs. Finally, the difficulties and deficiencies of CT, MRI, and radiomics in LM-HGP research are summarized along with the proposed directions for future research.