Potential immune priming of the tumor microenvironment with FOLFOX chemotherapy in locally advanced rectal cancer

First in human intraarterial delivery of tislelizumab for the treatment of pMMR locally advanced rectal cancer: A single-arm, open label, phase II clinical trial

BACKGROUND

Intravenous immune checkpoint inhibitors (ICIs) have shown efficacy in treating locally advanced rectal cancer (LARC), but concerns about systemic toxicity persist. This study developed a unique approach termed chemo-immuno-embolization with transcatheter rectal arterial intervention (CIETAI), aiming to enhance the anti-tumor response while minimizing systemic toxicity.

METHOD

This is a prospective, single-arm, phase II clinical trial conducted in Daping hospital. Patients with previously untreated stage II/III LARC underwent preoperative CIETAI combined with PD-1 inhibitor tislelizumab plus oxaliplatin, followed by standard concomitant chemoradiotherapy (capecitabine and 50.4 Gy radiation). Intravenous tislelizumab was administered for an additional two cycles.

RESULTS

Between January 2023 and December 2023, a total of 38 patients were enrolled. As the primary endpoint, 17 (44.74 %) patients achieved pathological complete response (TRG0), with a major pathologic response (MPR) rate of 65.79 %. The anal preservation rate was 84.21 % (32/38), and importantly, 15 of 21 patients with low rectal cancer achieved organ preservation with functional maintenance. Eight patients experienced grade 3-4 adverse events (AEs). All immune-related AEs were grade 1-2, with the most common being endocrine toxicity (5/6, 83.33 %). No grade 5 AEs occurred.

CONCLUSION

This study provides preliminary evidence supporting the safety and efficacy of intraarterial tislelizumab delivery in the neoadjuvant setting for LARC. These promising results encourage further exploration in larger cohorts to validate the clinical impact of this novel CIETAI strategy.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05957016.

Advancements in nanomedicine: Precision delivery strategies for male pelvic malignancies - Spotlight on prostate and colorectal cancer

BACKGROUND

Pelvic malignancies consistently pose significant global health challenges, adversely affecting the well-being of the male population. It is anticipated that clinicians will continue to confront these cancers in their practice. Nanomedicine offers promising strategies that revolutionize the treatment of male pelvic malignancies by providing precise delivery methods that aim to improve the efficacy of therapeutic outcomes while minimizing side effects. Nanoparticles are designed to encapsulate therapeutic agents and selectively target cancer cells. They can also be loaded with theragnostic agents, enabling multifunctional capabilities.

OBJECTIVE

This review aims to summarize the latest nanomedicine research into clinical applications, focusing on nanotechnology-based treatment strategies for male pelvic malignancies, encompassing chemotherapy, radiotherapy, immunotherapy, and other cutting-edge therapies. The review is structured to assist physicians, particularly those with limited knowledge of biochemistry and bioengineering, in comprehending the functionalities and applications of nanomaterials.

METHODS

Multiple databases, including PubMed, the National Library of Medicine, and Embase, were utilized to locate and review recently published articles on advancements in nano-drug delivery for prostate and colorectal cancers.

CONCLUSION

Nanomedicine possesses considerable potential in improving therapeutic outcomes and reducing adverse effects for male pelvic malignancies. Through precision delivery methods, this emerging field presents innovative treatment modalities to address these challenging diseases. Nevertheless, the majority of current studies are in the preclinical phase, with a lack of sufficient evidence to fully understand the precise mechanisms of action, absence of comprehensive pharmacotoxicity profiles, and uncertainty surrounding long-term consequences.

Immunotherapy and radiotherapy for older patients with locally advanced rectal cancer unfit for surgery or decline surgery: a practical proposal by the International Geriatric Radiotherapy Group

The standard of care for locally advanced rectal cancer is total neoadjuvant therapy followed by surgical resection. Current evidence suggests that selected patients may be able to delay or avoid surgery without affecting survival rates if they achieve a complete clinical response (CCR). However, for older cancer patients who are too frail for surgery or decline the surgical procedure, local recurrence may lead to a deterioration of patient quality of life. Thus, for clinicians, a treatment algorithm which is well tolerated and may improve CCR in older and frail patients with rectal cancer may improve the potential for prolonged remission and potential cure. Recently, immunotherapy with check point inhibitors (CPI) is a promising treatment in selected patients with high expression of program death ligands receptor 1 (PD- L1). Radiotherapy may enhance PD-L1 expression in rectal cancer and may improve response rate to immunotherapy. We propose an algorithm combining immunotherapy and radiotherapy for older patients with locally advanced rectal cancer who are too frail for surgery or who decline surgery.

Evaluating morphological features for predicting microsatellite instability status in colorectal cancer

Background

Colorectal cancer (CRC) is one of the commonest cancers worldwide, with incidence rates in India being around 4%. It is a heterogeneous disease with multiple established prognostic factors. Ten to fifteen percent originate from microsatellite instability (MSI) pathway, characterized by defect in mismatch repair (MMR) gene. Identification of MMR defective protein is relevant for diagnosis, prognosis, and prediction. Certain clinical and histological features are known to be associated with defective MMR genes. The objectives of this study are to find the prevalence of MSI in CRC to identify features associated with MSI and assess the value of histopathology in predicting MSI.

Methods

We evaluated various clinical and histological parameters for identifying prognostically favorable colon cancers in a tertiary hospital. One hundred fifty colon cancers were evaluated, and MSI status was correlated with clinicopathologic variables.

Results

The prevalence of MSI in CRC was found to be 11.3%. The factors associated with MSI were tumor differentiation, stage, tumor site, tumor size, tumor-infiltrating lymphocytes, Crohn's-like lymphoid reaction, and dirty necrosis. We have defined a "P" score for prediction of MSI using the clinicohistological parameters, which could be used to select patients who are to be tested for MSI.

Conclusion

Assessment of clinical and histopathological features will help in patient stratification and selection of patients for MSI testing. The evaluation is economical, reproducible, and easy to apply.

The implications from the interplay of neoadjuvant chemoradiotherapy and the immune microenvironment in rectal cancer

Neoadjuvant chemoradiotherapy (nCRT) is recommended for the treatment of locally advanced rectal cancer. Even though the combination of nCRT and immune checkpoint inhibitors (ICIs) has received much attention, the specific combination modes and dose fractions in radiotherapy (RT) are still indistinct. This review focuses on the immunological mechanism involved in nCRT, the clinical efficacy, the immunological effect of different combined strategies, concurrent or sequential nCRT plus ICIs, long-course RT and short-course RT. This review discusses the impact of nCRT on tumor immunity and summarizes the availability of different dose fractions in RT and distinct combined strategies, aiming at providing clues for optimal neoadjuvant therapy options that maximize efficacy and minimize side effects.

Debating Pros and Cons of Total Neoadjuvant Therapy in Rectal Cancer

Simple Summary

Rectal cancers represent one third of all colorectal tumours. Patients diagnosed with localised colon cancer undergo surgery upfront, likely followed by adjuvant chemotherapy. Those diagnosed with localised rectal cancer, however, frequently benefit from neoadjuvant treatments with either radiotherapy or chemoradiotherapy before undergoing surgery. On the other hand, the benefit of adjuvant chemotherapy in this setting is more controversial. The main challenges in treating patients affected by rectal cancer encompass: decreasing the risks of local relapse and distant metastases, preserving the sphincter and minimising treatment-associated functional sequelae, and improving overall survival. Some of these fuelled the concept of total neoadjuvant therapy, namely giving all available treatments including radiotherapy and systemic chemotherapy before surgery. Here, we critically review the pros and cons of such a treatment strategy, but also discuss the biological rational to support neoadjuvant treatment intensification.

Abstract

Recently, two large, randomised phase III clinical trials of total neoadjuvant therapy (TNT) in locally advanced rectal cancer were published (RAPIDO and PRODIGE 23). These two trials compared short-course radiotherapy (SCRT) followed by chemotherapy with standard chemoradiotherapy (CRT) and chemotherapy followed by CRT with standard CRT, respectively. They showed improvement in some of the outcomes such as distant recurrence and pathological complete response (pCR). No improvement, however, was observed in local disease control or the de-escalation of surgical procedures. Although it seems lawful to integrate TNT within the treatment algorithm of localised stage II and III rectal cancer, many questions remain unanswered, including which are the optimal criteria to identify patients who are most likely to benefit from this intensive treatment. Instead of providing a sterile summary of trial results, we put these in perspective in a pros and cons manner. Moreover, we discuss some biological aspects of rectal cancer, which may provide some insights into the current decision-making process, and represent the basis for the future development of alternative, more effective treatment strategies.

The therapeutic and prognostic implications of immunobiology in colorectal cancer: a review

Colorectal cancer represents the second leading cause of cancer-related death worldwide. The therapeutic field of immuno-oncology has rapidly gained momentum, with strikingly promising results observed in clinical practice. Increasing emphasis has been placed on the role of the immune response in tumorigenesis, therapy and predicting prognosis. Enhanced understanding of the dynamic and complex tumour-immune microenvironment has enabled the development of molecularly directed, individualised treatment. Analysis of intra-tumoural lymphocyte infiltration and the dichotomisation of colorectal cancer into microsatellite stable and unstable disease has important therapeutic and prognostic implications, with potential to capitalise further on this data. This review discusses the latest evidence surrounding the tumour biology and immune landscape of colorectal cancer, novel immunotherapies and the interaction of the immune system with each apex of the tripartite of cancer management (oncotherapeutics, radiotherapy and surgery). By utilising the synergy of chemotherapeutic agents and immunotherapies, and identifying prognostic and predictive immunological biomarkers, we may enter an era of unprecedented disease control, survivorship and cure rates.

Relationship between stromal regulatory T cells and the response to neoadjuvant chemotherapy for locally advanced rectal cancer

BACKGROUND

In addition to the direct power of anticancer drugs, the effectiveness of anticancer therapy depends on the host immune function. The present study investigated whether or not the reduction rate and histological response of preoperative chemotherapy were related to the immune microenvironment surrounding a primary tumor of the rectum.

METHODS

Sixty-five patients received preoperative chemotherapy followed by resection from 2012 to 2014; all of these patients were retrospectively analyzed. CD3, CD8, and FoxP3 were immunohistochemically examined as markers for T lymphocytes, cytotoxic T lymphocytes, and regulatory T lymphocytes (Treg), respectively. The correlation between the tumor-infiltrating lymphocyte composition and the tumor reduction rate and histological response to neoadjuvant chemotherapy was investigated.

RESULTS

The average tumor reduction rate was 41.5% ± 18.8%. According to RECIST, 47 patients (72.3%) achieved a partial response (PR), and 1 patient (1.5%) achieved a complete response (CR). Eight patients (12.3%) showed a grade 2 histological response, and 2 (3.1%) showed a grade 3 response. A multivariate analysis demonstrated that a low Treg infiltration in stromal cell areas was significantly associated with the achievement of a PR or CR [odds ratio (OR) 7.69; 95% confidence interval (CI) 1.96-33.33; p < 0.01] and a histological grade 2 or 3 response (OR 11.11; 95% CI 1.37-98.04; p = 0.02).

CONCLUSION

A low Treg infiltration in the stromal cell areas may be a marker of a good response to neoadjuvant chemotherapy in patients with locally advanced rectal cancer.

Immunity, immunotherapy, and rectal cancer: A clinical and translational science review

Rectal cancer remains a challenging disease to treat. Therapy for locally advanced rectal cancer (LARC), the most frequent presentation, has evolved to include a multimodal approach of radiation, chemotherapy, and surgery. While this approach improves local disease control, the distant recurrence rate is nearly 30% and treatment-related morbidity is substantial, thus underscoring the need for new therapeutic approaches with better efficacy and lower side effects. Immunotherapy could potentially fill this need, but its promise is not yet realized in rectal cancer. In this translational science review, we address what is known about how cytotoxic therapies shape rectal cancer immunity and potentially prime the tumor microenvironment for response to immune checkpoint inhibitors and other immunotherapies. We also address the role of current immunotherapies in colorectal cancer and highlight where novel immunotherapy approaches are currently being evaluated in LARC. Finally, we address important future directions in LARC immunotherapy including the need to define optimal therapeutic sequencing, predictive biomarkers, strategies to limit treatment-related side effects and the potential of gut microbiome manipulation to improve outcomes. In summary, this review provides a framework to guide future research and inform immunotherapy trial design so as to advance rectal cancer care.

Immune Checkpoint Inhibition as a Strategy in the Neoadjuvant Treatment of Locally Advanced Rectal Cancer

The treatment of locally advanced rectal cancer (LARC) has seen major advances over the past 3 decades, with multimodality treatment now standard of care. Combining surgical resection with radiotherapy and/or chemotherapy can reduce local recurrence from around 20% to approximately 5%. Despite improvements in local control, distant recurrence and subsequent survival rates have not changed. Immune checkpoint inhibitors have improved patient outcomes in several solid tumor types in the neoadjuvant, adjuvant, and advanced disease setting; however, in colorectal cancer, most clinical trials have been performed in the metastatic setting and the benefits confined to microsatellite instability-high tumors. In this article, we review the current preclinical and clinical evidence for using immune checkpoint inhibition in the treatment of LARC and discuss the rationale for specifically exploring the use of this therapy in the neoadjuvant setting. We summarize and discuss relevant clinical trials that are currently in setup and recruiting to test this treatment strategy and reflect on unanswered questions that still need to be addressed within future research efforts.

Emerging Trends for Radio-Immunotherapy in Rectal Cancer

Rectal cancer is a heterogeneous disease at the genetic and molecular levels, both aspects having major repercussions on the tumor immune contexture. Whilst microsatellite status and tumor mutational load have been associated with response to immunotherapy, presence of tumor-infiltrating lymphocytes is one of the most powerful prognostic and predictive biomarkers. Yet, the majority of rectal cancers are characterized by microsatellite stability, low tumor mutational burden and poor T cell infiltration. Consequently, these tumors do not respond to immunotherapy and treatment largely relies on radiotherapy alone or in combination with chemotherapy followed by radical surgery. Importantly, pre-clinical and clinical studies suggest that radiotherapy can induce a complete reprograming of the tumor microenvironment, potentially sensitizing it for immune checkpoint inhibition. Nonetheless, growing evidence suggest that this synergistic effect strongly depends on radiotherapy dosing, fractionation and timing. Despite ongoing work, information about the radiotherapy regimen required to yield optimal clinical outcome when combined to checkpoint blockade remains largely unavailable. In this review, we describe the molecular and immune heterogeneity of rectal cancer and outline its prognostic value. In addition, we discuss the effect of radiotherapy on the tumor microenvironment, focusing on the mechanisms and benefits of its combination with immune checkpoint inhibitors.

Immunological impact of chemotherapy on the tumor microenvironment in gastric cancer

OBJECTIVE

This study aimed to investigate alterations in pre- and post-neoadjuvant chemotherapy (NACT) tumor-infiltrating immune cells and subsequent evaluation of the predictive and prognostic value of these changes in gastric cancer (GC).

METHODS

Fifty patients with GC underwent three cycles of S-1 and oxaliplatin (SOX regimen)-NACT. Paired samples from tumor lesions before and after NACT were available for all patients participating in the study. Immunohistochemistry was performed for T cell subsets (CD3⁺ and CD8⁺ ) and macrophages (CD68⁺ and CD163⁺ ).

RESULTS

After NACT, the average expression levels of CD3, CD8, CD68, and CD163 were significantly increased (p < .001). However, neither expression levels pre- nor post-chemotherapy correlated with treatment response. Multivariate Cox regression analysis demonstrated that upregulation of CD8/CD3 levels (hazard ratio [HR] = 0.117; 95% confidence interval [CI] = 0.031-0.446; p = 0.002) and CD163 levels after chemotherapy (HR = 2.258; 95% CI = 1.047-4.867; p = 0.038) were independent prognostic factors of overall survival.

CONCLUSION

Chemotherapy in GC is useful to induce CD3⁺ and CD8⁺ T lymphocytes as well as CD68⁺ and CD163⁺ macrophages in the tumor microenvironment in combination with its direct cytotoxic effects. These results indicate that chemotherapy may play a role in tumor immune microenvironment remodeling.

Immunotherapy for the treatment of colorectal cancer

Immune checkpoint inhibition (ICI) has transformed the management of metastatic colorectal cancer (mCRC) with mismatch-repair deficiency (dMMR) and microsatellite instability (MSI-H), though this constitutes on average less than 5% of mCRC, and ICI is ineffective in preserved MMR/microsatellite stable disease (pMMR/MSS). Here we review the efficacy of ICI in dMMR/MSI-H mCRC, poor response to ICI in pMMR/MSS mCRC, role for ICI in locally advanced disease, biomarkers of response, novel immunotherapies, and future directions in targeting resistance mechanisms.

Two nanoformulations induce reactive oxygen species and immunogenetic cell death for synergistic chemo-immunotherapy eradicating colorectal cancer and hepatocellular carcinoma

BACKGROUND

FOLFOX is a combinational regimen of folinic acid (FnA, FOL), fluorouracil (5-Fu, F) and oxaliplatin (OxP, OX), and has been long considered as the standard treatment of colorectal cancer (CRC) and hepatocellular carcinoma (HCC). Recent developments of nano delivery systems have provided profound promise for improving anticancer efficacy and alleviating side effects of FOLFOX. Previously, a nanoformulation (termed Nano-Folox) containing OxP derivative and FnA was developed in our laboratory using nanoprecipitation technique. Nano-Folox induced OxP-mediated immunogenic cell death (ICD)-associated antitumor immunity, which significantly suppressed tumor growth in the orthotopic CRC mouse model when administrated in combination with free 5-Fu.

METHODS

A nanoformulation (termed Nano-FdUMP) containing FdUMP (5-Fu active metabolite) was newly developed using nanoprecipitation technique and used in combination with Nano-Folox for CRC and HCC therapies.

RESULTS

Synergistic efficacy was achieved in orthotopic CRC and HCC mouse models. It resulted mainly from the fact that Nano-FdUMP mediated the formation of reactive oxygen species (ROS), which promoted the efficacy of ICD elicited by Nano-Folox. In addition, combination of Nano-Folox/Nano-FdUMP and anti-PD-L1 antibody significantly inhibited CRC liver metastasis, leading to long-term survival in mice.

CONCLUSION

This study provides proof of concept that combination of two nano delivery systems can result in successful FOLFOX-associated CRC and HCC therapies. Further optimization in terms of dosing and timing will enhance clinical potential of this combination strategy for patients.

Priming the tumor immune microenvironment with chemo(radio)therapy: A systematic review across tumor types

BACKGROUND

Chemotherapy (CT), radiotherapy (RT), and chemoradiotherapy (CRT) are able to alter the composition of the tumor immune microenvironment (TIME). Understanding the effect of these modalities on the TIME could aid in the development of improved treatment strategies. Our aim was to systematically review studies investigating the influence of CT, RT or CRT on different TIME markers.

METHODS

The EMBASE (Ovid) and PubMed databases were searched until January 2019 for prospective or retrospective studies investigating the dynamics of the local TIME in cancer patients (pts) treated with CT, RT or CRT, with or without targeted agents. Studies could either compare baseline and follow-up specimens - before and after treatment - or a treated versus an untreated cohort. Studies were included if they used immunohistochemistry and/or flow cytometry to assess the TIME.

RESULTS

In total we included 110 studies (n = 8850 pts), of which n = 89 (n = 6295 pts) compared pre-treatment to post-treatment specimens and n = 25 (n = 2555 pts) a treated versus an untreated cohort (4 studies conducted both comparisons). For several tumor types (among others; breast, cervical, esophageal, ovarian, rectal, lung mesothelioma and pancreatic cancer) remodeling of the TIME was observed, leading to a potentially more immunologically active microenvironment, including one or more of the following: an increase in CD3 or CD8 lymphocytes, a decrease in FOXP3 Tregs and increased PD-L1 expression. Both CT and CRT were able to immunologically alter the TIME.

CONCLUSION

The TIME of several tumor types is significantly altered after conventional therapy creating opportunities for concurrent or sequential immunotherapy.

Drug-Drug Interactions of Irinotecan, 5-Fluorouracil, Folinic Acid and Oxaliplatin and Its Activity in Colorectal Carcinoma Treatment

The combination of folinic acid, 5-fluorouracil, oxaliplatin and/or irinotecan (FOLFOXIRI) is the standard of care for metastatic colorectal cancer (CRC). This strategy inhibits tumor growth but provokes drug resistance and serious side effects. We aimed to improve FOLFOXIRI by optimization of the dosing and the sequence of drug administration. We employed an orthogonal array composite design and linear regression analysis to obtain cell line-specific drug combinations for four CRC cell lines (DLD1, SW620, HCT116, LS174T). Our results confirmed the synergy between folinic acid and 5-fluorouracil and additivity, or even antagonism, between the other drugs of the combination. The drug combination administered at clinical doses resulted in significantly higher antagonistic interactions compared to the low-dose optimized drug combination (ODC). We found that the concomitant administration of the optimized drug combination (ODC) was comparatively active to sequential administration. However, the administration of oxaliplatin or the active metabolite of irinotecan seemed to sensitize the cells to the combination of folinic acid and 5-fluorouracil. ODCs were similarly active in non-cancerous cells as compared to the clinically used doses, indicating a lack of reduction of side effects. Interestingly, ODCs were inactive in CRC cells chronically pretreated with FOLFOXIRI, suggesting the occurrence of resistance. We were unable to improve FOLFOXIRI in terms of efficacy or specificity. Improvement of CRC treatment should come from the optimization of targeted drugs and immunotherapy strategies.

Preoperative, biopsy-based assessment of the tumour microenvironment in patients with primary operable colorectal cancer

The tumour microenvironment (TME) is recognised as an important prognostic characteristic and therapeutic target in patients with colorectal cancer (CRC). However, assessment generally utilises surgically resected specimens, precluding neoadjuvant targeting. The present study investigated the feasibility of intra‐epithelial CD3⁺ T‐lymphocyte density and tumour stroma percentage (TSP) assessment using preoperative colonoscopic biopsies from 115 patients who had undergone resection of stages I–III CRC, examining the relationship between biopsy and surgically resected specimen‐based assessment, and the relationship with cancer‐specific survival (CSS). High biopsy CD3⁺ density was associated with high CD3⁺ density in the invasive margin, cancer stroma and intra‐epithelial compartments of surgically resected specimens (area under the curve > 0.62, p < 0.05 for all) and with high Immunoscore. High biopsy TSP predicted high TSP in resected specimens (p = 0.001). Intra‐class correlation coefficient for both measures was >0.7 (p < 0.001), indicating excellent concordance between individuals. Biopsy CD3⁺ density (hazard ratio [HR] 0.23, p = 0.002) and TSP (HR 2.23, p = 0.029) were independently associated with CSS; this was comparable to the prognostic value of full section assessment (HR 0.21, p = 0.004, and HR 2.25, p = 0.033 respectively). These results suggest that assessment of the TME is comparable in biopsy and surgically resected specimens from patients with CRC, and biopsy‐based assessment could allow for stratification prior to surgery or commencement of therapy targeting the TME.