Pembrolizumab for previously treated, microsatellite instability–high/mismatch repair–deficient advanced colorectal cancer: final analysis of KEYNOTE-164

Combination therapy with immune checkpoint inhibitors in colorectal cancer: Challenges, resistance mechanisms, and the role of microbiota

Colorectal cancer (CRC) is still one of the leading causes of cancer deaths worldwide. Even though there has been progress in cancer immunotherapy, the results of applying immune checkpoint inhibitors (ICIs) have been unsatisfactory, especially in microsatellite stable (MSS) CRC. Single-agent ICIs that target programmed cell death-1 (PD-1)/ PD-L1, cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), T cell Ig- and mucin-domain-containing molecule-3 (TIM-3), and lymphocyte activation gene (LAG)-3 have emerged as having specific benefits. However, many primary and secondary resistance mechanisms are available in the tumor microenvironment (TME) that prevent it from happening. Combination strategies, such as the use of anti-PD-1 and anti-CTLA-4, can be effective in overcoming these resistance pathways, but toxicities remain a significant concern. Moreover, ICIs have been integrated with various treatment modalities, including chemotherapy, radiotherapy, antibiotics, virotherapy, polyadenosine diphosphate-ribose polymerase (PARP) inhibitors, and heat shock protein 90 (HSP90) inhibitors. The outcomes observed in both preclinical and clinical settings have been encouraging. Interestingly, manipulating gut microbiota via fecal microbiota transplantation (FMT) has been identified as a new strategy to increase the efficacy of immunotherapy in CRC patients. Therefore, integrating ICIs with other treatment approaches holds promise in enhancing the prognosis of CRC patients. This review focuses on the unmet need for new biomarkers to select patients for combination therapies and the ongoing work to overcome resistance and immune checkpoint blockade.

Inflammation, Immunosuppression, and Immunotherapy in Pancreatic Cancer-Where Are We Now?

Pancreatic cancer (PC) is one of the most commonly diagnosed and deadliest neoplasms in the modern world. Over the past few years, the incidence of PC has risen with only a slight improvement in overall survival. Moreover, the improvement in survival is primarily driven by diagnoses in the localized stage of the disease, rather than by new treatment methods. The inflammatory process is a key mediator of PC development, yet PC is also one of the most immune-resistant tumors. Patients rarely benefit from monotherapy with immune checkpoint inhibitors; nevertheless, the latest biological findings on the complexity of the pancreatic tumor microenvironment might be translated into designing new clinical studies that combine various approaches to overcome single-agent immunotherapy resistance. On the other hand, focusing on inflammation may lead to the development of new inflammation-based prognostic markers for patients. This review aims to describe the current state of knowledge regarding the complex relationships between systemic and local inflammation, immune response, immunosuppression, and therapeutic options in PC.

Precision treatment for human epidermal growth factor receptor 2-amplified advanced rectal cancer: A case report

BACKGROUND

Although targeted therapy provides survival benefits for patients with metastatic colorectal cancer, some patients develop resistance to these treatments. Human epidermal growth factor receptor 2 (HER2) is overexpressed in a subset of patients with colorectal cancer and has been established as a therapeutic target.

CASE SUMMARY

This case report describes a Chinese patient with HER2-amplified advanced rectal cancer who showed no response to chemotherapy and targeted therapies against epidermal growth factor receptor and vascular endothelial growth factor but achieved a remarkable response following treatment with immune checkpoint inhibitors (ICIs) in combination with pyrotinib. The combination of oxaliplatin and ICIs with pyrotinib demonstrates synergistic effects after late-stage disease progression.

CONCLUSION

ICIs and pyrotinib may be effective in treating HER2-amplified advanced rectal cancer. Chemotherapy following disease progression could enhance efficacy synergistically.

Navigating established and emerging biomarkers for immune checkpoint inhibitor therapy

Immune checkpoint inhibitors (ICIs) have improved outcomes of patients with many different cancers. These antibodies target molecules such as programmed cell death 1 (PD-1) or cytotoxic T lymphocyte associated protein 4 (CTLA-4) which normally function to limit immune activity. Treatment with ICIs reactivates T cells to destroy tumor cells in a highly specific manner, which in some patients, results in dramatic remissions and durable disease control. Over the last decade, much effort has been directed at characterizing factors that drive efficacy and resistance to ICI therapy. Food and Drug Administration (FDA)-approved biomarkers for ICI therapy have facilitated more judicious treatment of cancer patients and transformed the field of precision oncology. Yet, adaptive immunity against cancers is complex, and newer data have revealed the potential utility of other biomarkers. In this review, we discuss the utility of currently approved biomarkers and highlight how emerging biomarkers can further improve the identification of patients who benefit from ICIs.

Pembrolizumab versus bevacizumab plus modified FOLFOX6 in metastatic MSI-H/dMMR colorectal cancer: a multicenter retrospective study with CT evaluation

Objective

The optimal therapeutic strategy for metastatic microsatellite instability-high/mismatch repair-deficient (MSI-H/dMMR) colorectal cancer (CRC) remains uncertain. This multicenter retrospective study compared the efficacy and safety of pembrolizumab monotherapy versus bevacizumab combined with modified FOLFOX6 (mFOLFOX6) in this molecularly defined population.

Methods

Consecutive patients with metastatic MSI-H/dMMR CRC treated with pembrolizumab or bevacizumab plus mFOLFOX6 at two tertiary centers (2017-2024) were analyzed. Dual primary endpoints included overall survival (OS) and progression-free survival (PFS); secondary endpoints encompassed incidence of grade ≥3 treatment-emergent adverse events (AEs).

Results

Among 58 eligible patients (PE: n=30; BF: n=28), the PE cohort demonstrated a significantly higher objective response rate (ORR) compared to the BF cohort (XX% vs XX%, p=0.030) after a median follow-up of 18.0 months (IQR: 1.0-24.0). Survival analyses revealed superior outcomes in the PE cohort, with a median OS of 12.0 months (95% CI: 10.2-14.1) versus 8.8 months (95% CI: 7.1-9.6) in the BF cohort (HR=0.55, 95% CI: 0.29-0.56; p=0.02). Similarly, median PFS was prolonged in the PE cohort (7.0 months, 95% CI: 5.3-9.3) relative to the BF cohort (3.7 months, 95% CI: 2.2-5.4; HR=0.46, 95% CI: 0.24-0.89; p<0.001). No statistically significant intergroup differences were observed in grade ≥3 treatment-emergent AE rates.

Conclusion

Pembrolizumab monotherapy significantly improved survival over bevacizumab-based chemotherapy in metastatic MSI-H/dMMR CRC, with a manageable safety profile. These results reinforce PD-1 inhibitors as first-line therapy for this population, while highlighting tumor mutation burden (TMB) and tumor burden as critical biomarkers for personalized strategies.

What Is Next for Refractory Colorectal Cancer CRC? Looking Beyond SUNLIGHT, FRESCO2, RECURSE and CORRECT

The treatment landscape of metastatic colorectal cancer (mCRC) has undergone significant evolution, with the introduction of targeted therapies and immunotherapy dramatically altering the management of microsatellite instability-high (MSI-H) tumors. However, the majority of patients, particularly those with microsatellite-stable (MSS) disease, remain refractory to immunotherapy, necessitating the exploration of alternative therapeutic strategies. This review summarizes the current treatment options for heavily pretreated mCRC patients who are not eligible for targeted therapies or clinical trials. Approved therapies for refractory mCRC, including regorafenib, trifluridine/tipiracil (FTD/TPI), and fruquintinib, demonstrate modest survival benefits but are often associated with significant toxicities. Additionally, innovative approaches targeting specific mutations such as KRAS G12C, HER2 amplification, and BRAF V600E are discussed, highlighting emerging combination regimens with immune checkpoint inhibitors and other agents to overcome resistance mechanisms. The potential of rechallenge strategies using previously administered therapies, such as oxaliplatin and anti-EGFR agents, is examined, supported by retrospective and prospective studies. Furthermore, the role of older drugs like mitomycin C in combination with capecitabine is revisited, offering insights into their viability in advanced treatment settings. Ongoing clinical trials with novel agents and combinations are expected to provide further clarity on optimizing sequential treatment regimens and personalizing therapy for mCRC patients. This review emphasizes the need for comprehensive molecular profiling and shared decision-making to improve outcomes and quality of life in this challenging patient population.

Pan-Cancer Molecular Biomarkers: Practical Considerations for the Surgical Pathologist

Traditional anatomic pathologic classification of cancer is based on tissue of origin and morphologic and immunohistochemical characterization of the malignant cells. With the technological improvements of massively parallel or next-generation sequencing, oncogenic drivers that are shared across different tumor types are increasingly being identified and used as pan-cancer biomarkers. This approach is reflected in the growing list of Food and Drug Administration-approved tumor-agnostic therapies, including pembrolizumab in the setting of microsatellite instability and high tumor mutational burden, larotrectinib and entrectinib for solid tumors with NTRK fusions, and combined dabrafenib-trametinib for BRAF V600E-mutated neoplasms. Several other biomarkers are currently under investigation, including fibroblast growth factor receptor (FGFR), RET, and ROS1 fusions; ERBB2 amplification; and mutations in the AKT1/2/3, NF1, RAS pathway and (mitogen-activated protein kinase (MAPK) pathway. As molecular assays are increasingly incorporated into routine tumor workup, the emergence of additional pan-cancer biomarkers is likely to be a matter more of "when" than "if." In this review, we first explore some of the conceptual and technical considerations at the intersection of surgical and molecular pathology, followed by a brief overview of both established and emerging molecular pan-cancer biomarkers and their diagnostic and clinical applications.

Ultrasound genomics related mitochondrial gene signature for prognosis and neoadjuvant chemotherapy resistance in triple negative breast cancer

Background

Neoadjuvant chemotherapy (NAC) significantly enhances clinical outcomes in patients with triple-negative breast cancer (TNBC); however, chemoresistance frequently results in treatment failure. Consequently, understanding the mechanisms underlying resistance and accurately predicting this phenomenon are crucial for improving treatment efficacy.

Methods

Ultrasound images from 62 patients, taken before and after neoadjuvant therapy, were collected. Mitochondrial-related genes were extracted from a public database. Ultrasound features associated with NAC resistance were identified and correlated with significant mitochondrial-related genes. Subsequently, a prognostic model was developed and evaluated using the GSE58812 dataset. We also assessed this model alongside clinical factors and its ability to predict immunotherapy response.

Results

A total of 32 significant differentially expressed genes in TNBC across three groups indicated a strong correlation with ultrasound features. Univariate and multivariate Cox regression analyses identified six genes as independent risk factors for TNBC prognosis. Based on these six mitochondrial-related genes, we constructed a TNBC prognostic model. The model's risk scores indicated that high-risk patients generally have a poorer prognosis compared to low-risk patients, with the model demonstrating high predictive performance (p = 0.002, AUC = 0.745). This conclusion was further supported in the test set (p = 0.026, AUC = 0.718). Additionally, we found that high-risk patients exhibited more advanced tumor characteristics, while low-risk patients were more sensitive to common chemotherapy drugs and immunotherapy. The signature-related genes also predicted immunotherapy response with a high accuracy of 0.765.

Conclusion

We identified resistance-related features from ultrasound images and integrated them with genomic data, enabling effective risk stratification of patients and prediction of the efficacy of neoadjuvant chemotherapy and immunotherapy in patients with TNBC.

Dynamics of blood microsatellite instability (bMSI) burden predicts outcome of a patient treated with immune checkpoint inhibitors: a case report of hyperprogressive disease

Microsatellite instability (MSI) is a widely studied molecular signature, which is associated with long-term benefit in patients treated with immune checkpoint inhibitor therapy. This approach has been proven to be effective in the treatment of patients with MSI-positive colorectal cancer (CRC). Analysis of serial liquid biopsy samples allows to detect changes in the tumor in response to therapy. Typically, somatic mutations are used for tracing the dynamics of the tumor, and the assessment of DNA signatures such as MSI is not currently used for these purposes. Here, we describe a case of a MSI-positive CRC, who received nivolumab monotherapy. Sequential sampling of the patient's plasma demonstrated an increase in MSI burden (bMSI), which was found to correlate with the increase of driver mutation burden one month after starting nivolumab, and hyperprogressive disease. Thus, analysis of bMSI in liquid biopsy via NGS may be a promising method for timely assessment of the treatment effectiveness received by patients with MSI-positive CRC.

Fruquintinib Combined With PD-1 Inhibitors for the Treatment of the Patients With Microsatellite Stability Metastatic Colorectal Cancer: Real-World Data

AIMS

Programmed death-1 (PD-1) or programmed death-ligand 1 (PD-L1) inhibitors have shown limited effectiveness in patients with microsatellite stable (MSS) metastatic colorectal cancer (mCRC). Combining anti-angiogenesis inhibitors with PD-1 inhibitors has the potential to reverse the immunosuppressive tumour microenvironment, synergistically enhancing the anti-tumour immune response in MSS mCRC. The goal is to present real-world data that prove the clinical efficacy and safety of fruquintinib combined with PD-1 inhibitors in MSS mCRC.

MATERIALS AND METHODS

We conducted a real-world retrospective study in patients with MSS mCRC who received treatment with fruquintinib combined with PD-1 inhibitors between May 2019 and March 2023 in our centre.

RESULTS

Seventy seven patients with MSS mCRC received fruquintinib combined with PD-1 inhibitors. In total, 5.2% of patients (4/77) achieved a partial response (PR), while 50.6% (39/77) had a stable disease (SD). Notably, three lesions achieving PR were all lung metastases and the overall disease control rate (DCR) reached 55.8% (43/77). Median progression-free survival (PFS) and overall survival (OS) reached 5.1 months (95% CI: 3.6-6.7) and 14.6 months (95% CI: 9.6-15.6), respectively. Multivariate Cox analysis showed that prior treatment without vascular endothelial growth factor (VEGF) inhibitors was significantly associated with PFS and OS (p < 0.05). Further analysis indicated that total- or polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) significantly decreased after treatment (P = 0.039), especially in the PR/SD group (P = 0.003). Most adverse events included abdominal pain, rash, oedema, diarrhoea, and immunotherapy-associated hypothyroidism, yet symptoms were controllable.

CONCLUSION

Our results provided additional evidence that patients with MSS mCRC could benefit from the combination of fruquintinib and PD-1 inhibitors, especially those with lung metastases or without prior treatment with VEGF inhibitors. The detection of MDSCs may be an immune indicator for predicting of the combined therapy.

Integrative analysis of ferroptosis in the hypoxic microenvironment of gastric cancer unveils the immune landscape and personalized therapeutic strategies

Background

Ferroptosis is a cell death mode caused by excessive accumulation of lipid peroxides caused by disturbance of intracellular metabolic pathway, which is closely related to iron and cholesterol metabolism homeostasis. Its regulation within the hypoxic metabolic tumor microenvironment (TME) has the potential to improve the effectiveness of tumor immunotherapy. The predictive role of ferroptosis in gastric cancer (GC) hypoxia TME, particularly in relation to TME immune cell infiltration, has not been fully explained.

Methods

By analyzing the mRNA expression data of ferroptosis and hypoxia-related genes, a prediction model was constructed to evaluate further the predictive value of immune cell infiltration, clinical characteristics, and immunotherapy efficacy of gastric cancer, and the essential genes were validated.

Results

Two distinct molecular states of ferroptosis-hypoxia were identified in GC. Notably, patients with high ferroptosis-hypoxia risk scores (FHRS) displayed significant levels of hypoxia and epithelial-mesenchymal transition (EMT), which were associated with unfavorable prognosis, increased chemoresistance, and heightened immunosuppression.

Conclusions

This study demonstrates that ferroptosis under hypoxic conditions significantly affects the modulation of the tumor immune microenvironment. The FHRS can independently predict prognosis in gastric cancer. Assessing the molecular status of ferroptosis-hypoxia in individual patients will help in selecting more suitable immunotherapy regimens by providing a better understanding of TME characteristics and predicting immunotherapeutic outcomes.

Late-line options for patients with metastatic colorectal cancer: a review and evidence-based algorithm

Over the past few years, several novel systemic treatments have emerged for patients with treatment-refractory metastatic colorectal cancer, thus making selection of the most effective later-line therapy a challenge for medical oncologists. Over the past decade, regorafenib and trifluridine-tipiracil were the only available drugs and often provided limited clinical benefit compared to best supportive care. Results from subsequent practice-changing trials opened several novel therapeutic avenues, both for unselected patients (such as trifluridine-tipiracil plus bevacizumab or fruquintinib) and for subgroups defined by the presence of actionable alterations in their tumours (such as HER2-targeted therapies or KRASG12C inhibitors) or with no acquired mechanisms of resistance to the previously received targeted agents in circulating tumour DNA (such as retreatment with anti-EGFR antibodies). In this Review, we provide a comprehensive overview of advances in the field over the past few years and offer a practical perspective on translation of the most relevant results into the daily management of patients with metastatic colorectal cancer using an evidence-based algorithm. Finally, we discuss some of the most appealing ongoing areas of research and highlight approaches with the potential to further expand the therapeutic armamentarium.

Dostarlimab: A promising new PD-1 inhibitor for cancer immunotherapy

OBJECTIVE

Dostarlimab, a humanized monoclonal PD-1 blocking antibody, is being tested as a cancer therapy in this review. Specifically, it addresses mismatch repair failure in endometrial cancer and locally progressed rectal cancer patients.

DATA SOURCES

A thorough database search found Dostarlimab clinical trials and studies. Published publications and ongoing clinical trials on Dostarlimab's efficacy as a single therapy and in conjunction with other medicines across cancer types were searched.

DATA SUMMARY

The review recommends Dostarlimab for endometrial cancer mismatch repair failure, as supported by GARNET studies. The analysis also highlights locally advanced rectal cancer findings. In the evolving area of cancer therapy, immune checkpoint inhibitors including pembrolizumab, avelumab, atezolizumab, nivolumab, and durvalumab were discussed.

CONCLUSIONS

Locally advanced rectal cancer patients responded 100% to Dostarlimab. Many clinical trials, including ROSCAN, AMBER, IOLite, CITRINO, JASPER, OPAL, PRIME, PERLA, and others, are investigating Dostarlimab in combination treatment. This research sheds light on Dostarlimab's current and future possibilities, in improving cancer immunotherapy understanding.

Newer Biomarkers in Gallbladder Carcinoma: A Scoping Review

Biomarkers have the potential to play a crucial role in managing gallbladder cancer post-surgery. They can identify patients more likely to experience a recurrence, allowing oncologists to tailor a more intensive surveillance plan and consider additional therapies. Some biomarkers can even predict how well a patient will respond to specific chemotherapy or targeted treatments. By monitoring these biomarkers, clinicians can track how effective the ongoing treatment is and detect any signs of early recurrence. Various biomarkers, like tumor markers, genetic markers, and genomic and epigenetic markers, are being investigated. The goal is to find the most reliable and accurate biomarkers to enhance patient care and outcomes. Integrating biomarker data into treatment plans can help personalize therapy and make better informed decisions. By identifying which patients are likely to benefit from specific treatments, biomarkers have the potential to improve long-term survival rates significantly. This scoping review discusses newer biomarkers in gallbladder carcinoma; some of them are in clinical use, while most of them are used in research settings. This provides a broad insight to practicing clinicians about the present biomarkers and the futuristic biomarkers.

Colorectal cancer with BRAF V600E mutation: Trends in immune checkpoint inhibitor treatment

Colorectal cancer (CRC) with BRAF V600E mutation presents a formidable scientific and clinical challenge due to its aggressive nature and poor response to standard therapeutic approaches. BRAF V600E mutation-induced conspicuous activation of the MAPK pathway contributes to the relentless tumor progression. Nevertheless, the efficacy of multi-targeted MAPK pathway inhibition remains suboptimal in clinical practice. Patients with high microsatellite instability (MSI-H) have shown favorable results with immune checkpoint inhibitors (ICIs). The combination of the MAPK pathway inhibition with ICIs has recently emerged as a promising regimen to improve clinical outcomes in the microsatellite stable (MSS) subgroup of BRAF V600E-mutant metastatic CRC patients. In this review, we elucidate the unique tumor biology of BRAF V600E-mutant CRC, with a particular focus on the immune features underlying the rationale for ICI treatments in the MSI-H and MSS subpopulations, then highlight the trends in clinical trials of the ICI therapy for BRAF V600E-mutant metastatic CRC.

A new strategy for immunotherapy of microsatellite-stable (MSS)-type advanced colorectal cancer: Multi-pathway combination therapy with PD-1/PD-L1 inhibitors

Colorectal cancer (CRC) is a frequent gastrointestinal malignancy with high rates of morbidity and mortality; 85% of these tumours are proficient mismatch repair (pMMR)-microsatellite instability-low (MSI-L)/microsatellite stable (MSS) CRC known as 'cold' tumours that are resistant to immunosuppressive drugs. Monotherapy with programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) inhibitors is ineffective for treating MSS CRC, making immunotherapy for MSS CRC a bottleneck. Recent studies have found that the multi-pathway regimens combined with PD-1/PD-L1 inhibitors can enhance the efficacy of anti-PD-1/PD-L1 in MSS CRC by increasing the number of CD8+ T cells, upregulating PD-L1 expression and improving the tumour microenvironment. This paper reviews the research progress of PD-1/PD-L1 inhibitors in combination with cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) inhibitors, oncolytic virus, intestinal flora, antiangiogenic agents, chemotherapy, radiotherapy and epigenetic drugs for the treatment of pMMR-MSI-L/MSS CRC.

Personalised medicine based on host genetics and microbiota applied to colorectal cancer

Colorectal cancer (CRC) ranks second in incidence and third in cancer mortality worldwide. This situation, together with the understanding of the heterogeneity of the disease, has highlighted the need to develop a more individualised approach to its prevention, diagnosis and treatment through personalised medicine. This approach aims to stratify patients according to risk, predict disease progression and determine the most appropriate treatment. It is essential to identify patients who may respond adequately to treatment and those who may be resistant to treatment to avoid unnecessary therapies and minimise adverse side effects. Current research is focused on identifying biomarkers such as specific mutated genes, the type of mutations and molecular profiles critical for the individualisation of CRC diagnosis, prognosis and treatment guidance. In addition, the study of the intestinal microbiota as biomarkers is being incorporated due to the growing scientific evidence supporting its influence on this disease. This article comprehensively addresses the use of current and emerging diagnostic, prognostic and predictive biomarkers in precision medicine against CRC. The effects of host genetics and gut microbiota composition on new approaches to treating this disease are discussed. How the gut microbiota could mitigate the side effects of treatment is reviewed. In addition, strategies to modulate the gut microbiota, such as dietary interventions, antibiotics, and transplantation of faecal microbiota and phages, are discussed to improve CRC prevention and treatment. These findings provide a solid foundation for future research and improving the care of CRC patients.

The evolving landscape of tissue-agnostic therapies in precision oncology

Tumor-agnostic therapies represent a paradigm shift in oncology by altering the traditional means of characterizing tumors based on their origin or location. Instead, they zero in on specific genetic anomalies responsible for fueling malignant growth. The watershed moment for tumor-agnostic therapies arrived in 2017, with the US Food and Drug Administration's historic approval of pembrolizumab, an immune checkpoint inhibitor. This milestone marked the marriage of genomics and immunology fields, as an immunotherapeutic agent gained approval based on genomic biomarkers, specifically, microsatellite instability-high or mismatch repair deficiency (dMMR). Subsequently, the approval of NTRK inhibitors, designed to combat NTRK gene fusions prevalent in various tumor types, including pediatric cancers and adult solid tumors, further underscored the potential of tumor-agnostic therapies. The US Food and Drug Administration approvals of targeted therapies (BRAF V600E, RET fusion), immunotherapies (tumor mutational burden ≥10 mutations per megabase, dMMR) and an antibody-drug conjugate (Her2-positive-immunohistochemistry 3+ expression) with pan-cancer efficacy have continued, offering newfound hope to patients grappling with advanced solid tumors that harbor particular biomarkers. In this comprehensive review, the authors delve into the expansive landscape of tissue-agnostic targets and drugs, shedding light on the rationale underpinning this approach, the hurdles it faces, presently approved therapies, voices from the patient advocacy perspective, and the tantalizing prospects on the horizon. This is a welcome advance in oncology that transcends the boundaries of histology and location to provide personalized options.

Oncological characteristics, treatments and prognostic outcomes in MMR-deficient colorectal cancer

Colorectal cancer (CRC) ranks as the third most prevalent cancer globally. It's recognized that the molecular subtype of CRC, characterized by mismatch repair deficiency (dMMR) or microsatellite instability-high (MSI-H), plays a critical role in determining appropriate treatment strategies. This review examines the current molecular classifications, focusing on dMMR/MSI-H CRC and its subtypes: Lynch syndrome (LS), Lynch-like syndrome (LLS), and sporadic cases. Despite advances in understanding of these genetic backgrounds, clinical trials have not conclusively differentiated the efficacy of immune checkpoint inhibitors among these subgroups. Therefore, while this review details the molecular characteristics and their general implications for treatment and prognosis, it also highlights the limitations and the need for more refined clinical studies to ascertain tailored therapeutic strategies for each subtype. Furthermore, this review summarizes completed and ongoing clinical studies, emphasizing the importance of developing treatments aligned more closely with molecular profiles. By discussing these aspects, the review seeks to provide a comprehensive analysis of oncological characteristics, presenting a detailed understanding of their implications for treatment and prognosis in dMMR/MSI-H CRC.

Recent developments in immunotherapy for gastrointestinal tract cancers

The past few decades have witnessed the rise of immunotherapy for Gastrointestinal (GI) tract cancers. The role of immune checkpoint inhibitors (ICIs), particularly programmed death protein 1 (PD-1) and PD ligand-1 antibodies, has become increasingly pivotal in the treatment of advanced and perioperative GI tract cancers. Currently, anti-PD-1 plus chemotherapy is considered as first-line regimen for unselected advanced gastric/gastroesophageal junction adenocarcinoma (G/GEJC), mismatch repair deficient (dMMR)/microsatellite instability-high (MSI-H) colorectal cancer (CRC), and advanced esophageal cancer (EC). In addition, the encouraging performance of claudin18.2-redirected chimeric antigen receptor T-cell (CAR-T) therapy in later-line GI tract cancers brings new hope for cell therapy in solid tumour treatment. Nevertheless, immunotherapy for GI tumour remains yet precise, and researchers are dedicated to further maximising and optimising the efficacy. This review summarises the important research, latest progress, and future directions of immunotherapy for GI tract cancers including EC, G/GEJC, and CRC.

Exploring Predictive and Prognostic Biomarkers in Colorectal Cancer: A Comprehensive Review

Colorectal cancer (CRC) remains the second leading cause of cancer-related mortality worldwide. While immune checkpoint inhibitors have significantly improved patient outcomes, their effectiveness is mostly limited to tumors with microsatellite instability (MSI-H/dMMR) or an increased tumor mutational burden, which comprise 10% of cases. Advancing personalized medicine in CRC hinges on identifying predictive biomarkers to guide treatment decisions. This comprehensive review examines established tissue markers such as KRAS and HER2, highlighting their roles in resistance to anti-EGFR agents and discussing advances in targeted therapies for these markers. Additionally, this review summarizes encouraging data on promising therapeutic targets and highlights the clinical utility of liquid biopsies. By synthesizing current evidence and identifying knowledge gaps, this review provides clinicians and researchers with a contemporary understanding of the biomarker landscape in CRC. Finally, the review examines future directions and challenges in translating promising biomarkers into clinical practice, with the goal of enhancing personalized medicine approaches for colorectal cancer patients.

Non-operative management after immune checkpoint inhibitors for early-stage, dMMR/MSI-H gastrointestinal cancers

Surgery is a standard treatment for early-stage gastrointestinal cancers, often preceded by neoadjuvant chemo(radio)therapy or followed by adjuvant therapy. While leading to cure in a proportion of patients, it has some drawbacks such as intra/post-operative complications, mutilation and life-long functional sequelae. Further to the unprecedented efficacy data from studies of immune checkpoint inhibitors for advanced mismatch repair deficient/microsatellite instable (dMMR/MSI-H) tumours, a strong interest has recently emerged for the investigation of such agents in the neoadjuvant setting. Although limited by the exploratory design and small sample size, trials of neoadjuvant immune checkpoint inhibitors for early-stage dMMR/MSI-H gastrointestinal cancers have consistently reported complete response rates ranging from 70 % to 100 %. As a result, the question has arisen as to whether surgery is still needed or organ-preserving strategies should be offered to this especially immuno-sensitive population. In this article, we discuss the available evidence for neoadjuvant immune checkpoint inhibitors in dMMR/MSI-H gastrointestinal cancers and analyse opportunities and challenges to the implementation of non-operative management approaches in this setting.

Conversion therapy with pembrolizumab for a peritoneal metastasis of rectal cancer causing hydronephrosis in a patient with Lynch syndrome

A 44-year-old woman with Lynch syndrome was referred to our hospital for treatment of recurrence of microsatellite instability-high rectal cancer. [18F]Fluorodeoxyglucose (18FDG)-positron emission tomography revealed a peritoneal metastasis with invasion to the small intestine and left ureter. The peritoneal metastasis was diagnosed initially as unresectable because of extensive invasion to the left ureter requiring nephrectomy. Hence, first-line treatment with pembrolizumab was started. After the first course of pembrolizumab, she developed hydronephrosis and a resulting urinary tract infection (UTI). A percutaneous nephrostomy was performed to control the UTI. After six courses of pembrolizumab, 18FDG-positron emission tomography showed that the peritoneal metastasis was smaller with significantly reduced 18FDG uptake, and it was then diagnosed as resectable without nephrectomy. She underwent R0 resection of the peritoneal metastasis with partial resection of the small intestine. Intraoperatively, the peritoneal metastasis showed no invasion of the left ureter, allowing its preservation. The percutaneous nephrostomy was removed postoperatively, and she has not developed any subsequent UTIs. Histopathologically, the tumor showed a pathological complete response to pembrolizumab. To the best of our knowledge, this is the first case of conversion therapy with pembrolizumab for peritoneal metastasis with hydronephrosis.

Advances in Precision Medicine Approaches for Colorectal Cancer: From Molecular Profiling to Targeted Therapies

Precision medicine is transforming colorectal cancer treatment through the integration of advanced technologies and biomarkers, enhancing personalized and effective disease management. Identification of key driver mutations and molecular profiling have deepened our comprehension of the genetic alterations in colorectal cancer, facilitating targeted therapy and immunotherapy selection. Biomarkers such as microsatellite instability (MSI) and DNA mismatch repair deficiency (dMMR) guide treatment decisions, opening avenues for immunotherapy. Emerging technologies such as liquid biopsies, artificial intelligence, and machine learning promise to revolutionize early detection, monitoring, and treatment selection in precision medicine. Despite these advancements, ethical and regulatory challenges, including equitable access and data privacy, emphasize the importance of responsible implementation. The dynamic nature of colorectal cancer, with its tumor heterogeneity and clonal evolution, underscores the necessity for adaptive and personalized treatment strategies. The future of precision medicine in colorectal cancer lies in its potential to enhance patient care, clinical outcomes, and our understanding of this intricate disease, marked by ongoing evolution in the field. The current reviews focus on providing in-depth knowledge on the various and diverse approaches utilized for precision medicine against colorectal cancer, at both molecular and biochemical levels.

Colon cancer: the 2023 Korean clinical practice guidelines for diagnosis and treatment

Colorectal cancer is the third most common cancer in Korea and the third leading cause of death from cancer. Treatment outcomes for colon cancer are steadily improving due to national health screening programs with advances in diagnostic methods, surgical techniques, and therapeutic agents.. The Korea Colon Cancer Multidisciplinary (KCCM) Committee intends to provide professionals who treat colon cancer with the most up-to-date, evidence-based practice guidelines to improve outcomes and help them make decisions that reflect their patients' values and preferences. These guidelines have been established by consensus reached by the KCCM Guideline Committee based on a systematic literature review and evidence synthesis and by considering the national health insurance system in real clinical practice settings. Each recommendation is presented with a recommendation strength and level of evidence based on the consensus of the committee.

Combination of mutations in genes controlling DNA repair and high mutational load plays a prognostic role in pancreatic ductal adenocarcinoma (PDAC): a retrospective real-life study in Sardinian population

BACKGROUND

Patients with pancreatic ductal adenocarcinoma (PDCA) carrying impaired mismatch repair mechanisms seem to have an outcome advantage under treatment with conventional chemotherapy, whereas the role for the tumor mutation burden on prognosis is controversial. In this study, we evaluated the prognostic role of the mutated genes involved in genome damage repair in a real-life series of PDAC patients in a hospital-based manner from the main Institution deputed to surgically treat such a disease in North Sardinia.

METHODS

A cohort of fifty-five consecutive PDAC patients with potentially resectable/border line resectable PDAC (stage IIB-III) or oligometastatic disease (stage IV) and tumor tissue availability underwent next-generation sequencing (NGS)-based analysis using a panel containing driver oncogenes and tumor suppressor genes as well as genes controlling DNA repair mechanisms.

RESULTS

Genes involved in the both genome damage repair (DR) and DNA mismatch repair (MMR) were found mutated in 17 (31%) and 15 (27%) cases, respectively. One fourth of PDAC cases (14/55; 25.5%) carried tumors presenting a combination of mutations in repair genes (DR and MMR) and the highest mutation load rates (MLR-H). After correction for confounders (surgery, adjuvant therapy, stage T, and metastasis), multivariate Cox regression analysis indicated that mutations in DR genes (HR = 3.0126, 95% CI 1.0707 to 8.4764, p = 0.0367) and the MLR (HR = 1.0018, 95%CI 1.0005 to 1.0032, p = 0.009) were significantly related to worse survival.

CONCLUSIONS

The combination of mutated repair genes and MLR-H, which is associated with a worse survival in our series of PDAC patients treated with conventional chemotherapy protocols, might become a predictive biomarker of response to immunotherapy in addition to its prognostic role in predicting survival.

Molecular tumour boards - current and future considerations for precision oncology

Over the past 15 years, rapid progress has been made in developmental therapeutics, especially regarding the use of matched targeted therapies against specific oncogenic molecular alterations across cancer types. Molecular tumour boards (MTBs) are panels of expert physicians, scientists, health-care providers and patient advocates who review and interpret molecular-profiling results for individual patients with cancer and match each patient to available therapies, which can include investigational drugs. Interpretation of the molecular alterations found in each patient is a complicated task that requires an understanding of their contextual functional effects and their correlations with sensitivity or resistance to specific treatments. The criteria for determining the actionability of molecular alterations and selecting matched treatments are constantly evolving. Therefore, MTBs have an increasingly necessary role in optimizing the allocation of biomarker-directed therapies and the implementation of precision oncology. Ultimately, increased MTB availability, accessibility and performance are likely to improve patient care. The challenges faced by MTBs are increasing, owing to the plethora of identifiable molecular alterations and immune markers in tumours of individual patients and their evolving clinical significance as more and more data on patient outcomes and results from clinical trials become available. Beyond next-generation sequencing, broader biomarker analyses can provide useful information. However, greater funding, resources and expertise are needed to ensure the sustainability of MTBs and expand their outreach to underserved populations. Harmonization between practice and policy will be required to optimally implement precision oncology. Herein, we discuss the evolving role of MTBs and current and future considerations for their use in precision oncology.

DNA mismatch repair deficient cancer - Emerging biomarkers of resistance to immune checkpoint inhibition

The DNA mismatch repair pathway is involved in the identification, excision, and repair of base-base mismatches and indel loops in the genome. Mismatch repair deficiency occurs in approximately 20% of all cancers and results in a type of DNA damage called microsatellite instability. In 2017, the immune checkpoint inhibitor, Pembrolizumab, an anti-PD-1 therapy, was approved for use in all unresectable or metastatic tumours that were mismatch repair deficient or had high microsatellite instability regardless of tissue origin. This landmark approval was the first time a drug had been approved in a site agnostic way, but accumulating data has revealed that up to 50% of mismatch repair deficient tumours are refractory to treatment and there is a huge amount of variability in the therapeutic benefit amongst responders. Several mechanisms of resistance to immune checkpoint blockade for mismatch repair deficient cancers have been identified but our understanding of what is driving resistance in a proportion of patients remains lacking. In this review article, we discuss the emerging mechanisms of resistance which may enable optimal stratification of patients for treatment with immune checkpoint inhibitors in the future.

Clinical research progress on BRAF V600E-mutant advanced colorectal cancer

Colorectal cancer is one of the malignant tumors that pose a serious threat to human health. A particularly bad prognosis might be expected for colorectal tumors with the unique molecular subtype BRAF V600E mutation. With the development of precision therapy, the advent of molecularly targeted therapies and immune checkpoint inhibitors has improved the outcome of intermediate to advanced colorectal cancer. However, the duration of drug benefit is usually short, and overall survival and progression-free survival remain suboptimal. Therefore, investigators are exploring more rational, safe, and effective drug combination regimens through clinical trials to provide longer survival for patients with such genetic mutations with metastatic colorectal cancer (mCRC). This article reviews the progress of clinical research on molecularly targeted drugs, immune checkpoint inhibitors, first-line chemotherapeutic agents, and different combination therapy regimens (including different targeted drug combinations, immune combination targeting, and chemotherapy combination targeting) for colorectal cancer patients with BRAF V600E mutation, which provides a reference for further in-depth clinical exploration of the treatment of colorectal cancer patients with BRAF V600E mutation.

Presentation, Molecular Characteristics, Treatment, and Outcomes of Colorectal Cancer in Patients Older than 80 Years Old

Background: An increasing proportion of the population of patients with cancer presents at an advanced age, increasing the challenges of successful and well-tolerated treatments. In the older spectrum of the geriatric cancer patients, those older than 80 years old, challenges are even higher because of increasing comorbidities and decreasing organ function reserves. Methods: Studies regarding colorectal cancer presentation, treatment, and prognosis in patients older than 80 years old available in the literature were evaluated and were compiled within a narrative review. Molecular attributes of colorectal cancer in the subset of patients older than 80 years old in published genomic cohorts were also reviewed and were compared with similar attributes in younger patients. Results: Characteristics of colorectal cancer in octogenarians are in many aspects similar to younger patients, but patients older than 80 years old present more often with right colon cancers. Surgical treatment of colorectal cancer in selected patients over 80 years old is feasible and should be pursued. Adjuvant chemotherapy is under-utilized in this population. Although combination chemotherapy is in most cases not advisable, monotherapy with fluoropyrimidine derivatives is feasible and efficacious. Conclusions: Outcomes of colorectal cancer patients over the age of 80 years old may be optimized with a combination of standard treatments adjusted to the individual patient's functional status and organ reserves. Increased support for the older age group during their colorectal cancer treatment modalities would improve oncologic outcomes with decreasing adverse outcomes of therapies.

Immunotherapy for Colorectal Cancer with High Microsatellite Instability: The Ongoing Search for Biomarkers

Microsatellite instability (MSI) is a biological condition associated with inflamed tumors, high tumor mutational burden (TMB), and responses to immune checkpoint inhibitors. In colorectal cancer (CRC), MSI tumors are found in 5% of patients in the metastatic setting and 15% in early-stage disease. Following the impressive clinical activity of immune checkpoint inhibitors in the metastatic setting, associated with deep and long-lasting responses, the development of immune checkpoint inhibitors has expanded to early-stage disease. Several phase II trials have demonstrated a high rate of pathological complete responses, with some patients even spared from surgery. However, in both settings, not all patients respond and some responses are short, emphasizing the importance of the ongoing search for accurate biomarkers. While various biomarkers of response have been evaluated in the context of MSI CRC, including B2M and JAK1/2 mutations, TMB, WNT pathway mutations, and Lynch syndrome, with mixed results, liver metastases have been associated with a lack of activity in such strategies. To improve patient selection and treatment outcomes, further research is required to identify additional biomarkers and refine existing ones. This will allow for the development of personalized treatment approaches and the integration of novel therapeutic strategies for MSI CRC patients with liver metastases.

Treatment outcome comparisons of first-line targeted therapy in patients with KRAS wild-type metastatic colorectal cancer: A nationwide database study

BACKGROUND

The first-line systemic therapy for metastatic colorectal cancer (mCRC) is a combination of one targeted therapy agent and a chemotherapy doublet. Whether bevacizumab or anti-epidermal growth factor receptor (anti-EGFR) monoclonal antibody (mAb) is the more effective addition to a chemotherapy doublet as the first-line treatment for inoperable KRAS wild-type mCRC remains controversial in prior clinical trials. Moreover, the association between the sidedness of primary tumors and the efficacy of anti-EGFR mAb needs to be addressed.

METHODS

We established a cohort of patients with KRAS wild-type mCRC who were treated with first-line targeted therapy plus doublet chemotherapy between 2013 and 2018 using Taiwan's National Health Insurance Research Database. Secondary surgery was defined as either resection of primary tumors, liver metastases, lung metastases, or radiofrequency ablation.

RESULTS

A total of 6482 patients were included; bevacizumab and anti-EGFR mAb were the first-line targeted therapies in 3334 (51.4%) and 3148 (48.6%) patients, respectively. Compared with those who received bevacizumab, patients who received anti-EGFR mAb exhibited significantly longer overall survival (OS; median, 23.1 vs. 20.2 months, p = 0.012) and time to treatment failure (TTF; median, 11.3 vs. 10 months, p < 0.001). Among left-sided primary tumors, the OS and TTF benefits of anti-EGFR mAb remained. Among right-sided primary tumors, the OS and TTF were similar regardless of the type of targeted therapy. In multivariate analyses, first-line anti-EGFR mAb therapy remained an independent predictor of longer OS and TTF for left-sided primary tumors. Patients who received anti-EGFR mAb were more likely to receive secondary surgery (29.6% vs. 22.6%, p < 0.0001) than patients who received bevacizumab.

CONCLUSION

For patients who received first-line doublet chemotherapy for KRAS wild-type mCRC, adding anti-EGFR mAb was associated with significantly longer OS and TTF, especially for left-sided primary tumors.

Crosstalk between ILC3s and Microbiota: Implications for Colon Cancer Development and Treatment with Immune Check Point Inhibitors

Type 3 innate lymphoid cells (ILC3s) are primarily tissue-resident cells strategically localized at the intestinal barrier that exhibit the fast-acting responsiveness of classic innate immune cells. Populations of these lymphocytes depend on the transcription factor RAR-related orphan receptor and play a key role in maintaining intestinal homeostasis, keeping host-microbial mutualism in check. Current evidence has indicated a bidirectional relationship between microbiota and ILC3s. While ILC3 function and maintenance in the gut are influenced by commensal microbiota, ILC3s themselves can control immune responses to intestinal microbiota by providing host defense against extracellular bacteria, helping to maintain a diverse microbiota and inducing immune tolerance for commensal bacteria. Thus, ILC3s have been linked to host-microbiota interactions and the loss of their normal activity promotes dysbiosis, chronic inflammation and colon cancer. Furthermore, recent evidence has suggested that a healthy dialog between ILC3s and gut microbes is necessary to support antitumor immunity and response to immune checkpoint inhibitor (ICI) therapy. In this review, we summarize the functional interactions occurring between microbiota and ILC3s in homeostasis, providing an overview of the molecular mechanisms orchestrating these interactions. We focus on how alterations in this interplay promote gut inflammation, colorectal cancer and resistance to therapies with immune check point inhibitors.