Phase II, single-arm trial of preoperative short-course radiotherapy followed by chemotherapy and camrelizumab in locally advanced rectal cancer

Randomized Phase II Trial of Immunotherapy-Based Total Neoadjuvant Therapy for Proficient Mismatch Repair or Microsatellite Stable Locally Advanced Rectal Cancer (TORCH)

PURPOSETo assess whether the integration of PD-1 inhibitor with total neoadjuvant therapy (iTNT) can lead to an improvement in complete responses (CRs) and favors a watch-and-wait (WW) strategy in patients with proficient mismatch repair or microsatellite stable (pMMR/MSS) locally advanced rectal cancer (LARC).PATIENTS AND METHODSWe conducted a prospective, multicenter, randomized, open-label, phase II trial using a pick-the-winner design. Eligible patients with clinical T3-4 and/or N+ rectal adenocarcinoma were randomly assigned to group A for short-course radiotherapy (SCRT) followed by six cycles of consolidation immunochemotherapy with capecitabine and oxaliplatin and toripalimab or to group B for two cycles of induction immunochemotherapy followed by SCRT and the rest four doses. Either total mesorectal excision or WW was applied on the basis of tumor response. The primary end point was CR which included pathological CR (pCR) after surgery and clinical CR (cCR) if WW was applicable, with hypothesis of an increased CR of 40% after iTNT compared with historical data of 25% after conventional TNT.RESULTSOf the 130 patients enrolled, 121 pMMR/MSS patients were evaluable (62 in group A and 59 in group B). At a median follow-up of 19 months, CR was achieved at 56.5% in group A and 54.2% in group B. Both groups fulfilled the predefined statistical hypothesis (P < .001). Both groups reported a pCR rate of 50%. Respectively, 15 patients in each group underwent WW and remained disease free. The most frequent grade 3 to 4 toxicities were thrombocytopenia and neutropenia. Patients in group A had higher rate of cCR (43.5% v 35.6%) at restaging and lower rate of grade 3 to 4 thrombocytopenia (24.2% v 33.9%) during neoadjuvant treatment.CONCLUSIONThe iTNT regimens remarkably improved CR rates in pMMR/MSS LARC compared with historical benchmark with acceptable toxicity. Up-front SCRT followed by immunochemotherapy was selected for future definitive study.

Neoadjuvant short-course radiotherapy followed by camrelizumab and chemotherapy in locally advanced rectal cancer (UNION): early outcomes of a multicenter randomized phase III trial

BACKGROUND

Neoadjuvant short-course radiotherapy (SCRT) followed by CAPOX and camrelizumab (a programmed cell death protein 1 monoclonal antibody) has shown potential clinical activity for locally advanced rectal cancer (LARC) in a phase II trial. This study aimed to further confirm the efficacy and safety of SCRT followed by CAPOX and camrelizumab compared to long-course chemoradiotherapy (LCRT) followed by CAPOX alone as neoadjuvant treatment for LARC.

PATIENTS AND METHODS

In this randomized, phase III trial, patients with T3-4/N+ rectal adenocarcinoma were randomly assigned (1 : 1) to receive SCRT or long-course chemoradiotherapy (LCRT), followed by two cycles of camrelizumab and CAPOX or CAPOX alone, respectively. After surgery, each arm underwent either six cycles of camrelizumab and CAPOX, followed by up to 17 doses of camrelizumab, or six cycles of CAPOX. The primary endpoint was pathological complete response (pCR) rate (ypT0N0) assessed by a blinded independent review committee. Key secondary endpoints tested hierarchically were 3-year event-free survival (EFS) rate and overall survival (OS).

RESULTS

Between July 2021 and March 2023, the intention-to-treat population comprised 113 patients in the experimental arm and 118 patients in the control arm, with surgery carried out in 92% and 83.9%, respectively. At data cut-off (11 July 2023), the pCR rates were 39.8% [95% confidence interval (CI) 30.7% to 49.5%] in the experimental arm compared to 15.3% (95% CI 9.3% to 23.0%) in the control arm (difference, 24.6%; odds ratio, 3.7; 95% CI 2.0-6.9; P < 0.001). In each arm, surgical complication rates were 40.0% and 40.8%, and grade ≥3 treatment-related adverse events were 29.2% and 27.2%. Three-year EFS rate and OS continue to mature.

CONCLUSIONS

In LARC patients, neoadjuvant SCRT followed by camrelizumab plus CAPOX demonstrated a significantly higher pCR rate than LCRT followed by CAPOX, with a well-tolerated safety profile. SCRT followed by camrelizumab and chemotherapy can be recommended as a neoadjuvant treatment modality for these patients.

Neoadjuvant immunotherapy for dMMR and pMMR colorectal cancers: therapeutic strategies and putative biomarkers of response

Approximately 15% of locally advanced colorectal cancers (CRC) have DNA mismatch repair deficiency (dMMR), resulting in high microsatellite instability and a high tumour mutational burden. These cancers are frequently sensitive to therapy with immune-checkpoint inhibitors (ICIs) in the metastatic setting. This sensitivity seems to be even more pronounced in locally advanced disease, and organ preservation has become a realistic aim in ongoing clinical trials involving patients with dMMR rectal cancer. By contrast, metastatic CRCs with proficient DNA mismatch repair (pMMR) are generally resistant to ICIs, although a proportion of locally advanced pMMR tumours seem to have a high degree of sensitivity to ICIs. In this Review, we describe the current and emerging clinical evidence supporting the use of neoadjuvant ICIs in patients with dMMR and pMMR CRC, and the potential advantages (based on a biological rationale) of such an approach. We discuss how neoadjuvant 'window-of-opportunity' trials are being leveraged to progress biomarker discovery and we provide an overview of potential predictive biomarkers of response to ICIs, exploring the challenges faced when evaluating such biomarkers in biopsy-derived samples. Lastly, we describe how these discoveries might be used to drive a rational approach to trialling novel immunotherapeutic strategies in patients with pMMR CRC, with the ultimate aim of disease eradication and the generation of long-term immunosurveillance.

Added value of histogram analysis of intravoxel incoherent motion and diffusion kurtosis imaging for the evaluation of complete response to neoadjuvant therapy in locally advanced rectal cancer

OBJECTIVE

To evaluate how intravoxel incoherent motion (IVIM) and diffusion kurtosis imaging (DKI) histogram analysis contribute to assessing complete response (CR) to neoadjuvant therapy (NAT) in locally advanced rectal cancer (LARC).

MATERIAL AND METHODS

In this prospective study, participants with LARC, who underwent NAT and subsequent surgery, with adequate MR image quality, were enrolled from November 2021 to March 2023. Conventional MRI (T2WI and DWI), IVIM, and DKI were performed before NAT (pre-NAT) and within two weeks before surgery (post-NAT). Image evaluation was independently performed by two experienced radiologists. Pathological complete response (pCR) was used as the reference standard. An IVIM-DKI-added model (a combination of IVIM and DKI histogram parameters with T2WI and DWI) was constructed. Receiver operating characteristic (ROC) curves were generated to evaluate the diagnostic performance of conventional MRI and the IVIM-DKI-added model.

RESULTS

A total of 59 participants (median age: 58.00 years [IQR: 52.00, 62.00]; 38 [64%] men) were evaluated, including 21 pCR and 38 non-pCR cases. The histogram parameters of DKI, including skewness of kurtosis post-NAT (post-KSkewness) and root mean squared of change ratio of diffusivity (Δ%DDKI-root mean squared), were entered into the IVIM-DKI-added model. The area under the ROC curve (AUC) of the IVIM-DKI-added model for assessing CR to NAT was significantly higher than that of conventional MRI (0.855 [95% CI: 0.749-0.960] vs 0.685 [95% CI: 0.565-0.806], p < 0.001).

CONCLUSION

IVIM and DKI provide added value in the evaluation of CR to NAT in LARC.

KEY POINTS

Question The current conventional imaging evaluation system lacks adequacy for assessing CR to NAT in LARC. Findings Significantly improved diagnostic performance was observed with the histogram analysis of IVIM and DKI in conjunction with conventional MRI. Clinical relevance IVIM and DKI provide significant value in evaluating CR to NAT in LARC, which bears significant implications for reducing surgical complications and facilitating organ preservation.

Significance of MRI-based radiomics in predicting pathological complete response to neoadjuvant chemoradiotherapy of locally advanced rectal cancer: A narrative review

Neoadjuvant chemoradiotherapy is the standard treatment for patients with locally advanced rectal cancers owing to its ability to downstage primary tumours. Some patients can achieve pathological complete response after neoadjuvant therapy, and can adopt a "watch and wait" treatment strategy to avoid overtreatment. Therefore, it is essential to develop strategies for predicting responses to neoadjuvant therapy. Radiomics has shown great potential in extracting tumour features from high-throughput medical images for the construction of mathematics models for predicting the effects of anticancerous therapies. Herein, we explored MRI-based radiomics and found that it can predict responses of locally advanced rectal cancers to chemoradiation. Efficient radiomics model allow early-stage prediction of the effect of neoadjuvant chemoradiotherapy on locally advanced rectal cancers. It helps clinicians to make informed therapeutic decisions. In this review, we discuss the workflow of radiomics, and summarize the clinical application of MRI-based radiomics in predicting pathological complete response to neoadjuvant chemoradiotherapy of locally advanced rectal cancer.

Neoadjuvant immunotherapy leads to complete pathologic response in locally advanced colon cancer

Immunotherapy is considered first line in patients with dMMR metastatic colorectal cancer (CRC). Recent studies have also shown promising results with neoadjuvant immunotherapy in locally advanced CRC. We report a case in which neoadjuvant immunotherapy with pembrolizumab resulted in complete pathologic response at time of resection as well as saved the patient the morbidity associated with a hepatectomy. We also completed a scoping review of the literature which suggests promising tumor responses with treatment in dMMR CRC. Further randomized control trials to determine the magnitude of response and optimal regimen are needed.

PD-L1 Expression in Paired Samples of Rectal Cancer

Immune checkpoint inhibitors and immune-related biomarkers are increasingly investigated in rectal cancer (RC). We retrospectively analysed PD-L1 expression in diagnostic biopsy and resection samples from RC patients treated at our centre between 2000 and 2020. PD-L1 immunostaining (22C3 clone) was evaluated according to tumour proportion (TPS), immune cell (ICS), and the combined positive score (CPS). Eighty-three patients were included. At diagnosis, PD-L1 expression ≥1%/≥5% was observed in 15.4%/0%, 80.7%/37.4%, and 69.2%/25.6% of patients based on TPS, ICS, and CPS, respectively. At surgery, the respective figures were 4.6%/1.5%, 60.2%/32.5%, and 50.7%/26.2%. Using the 1% cut-off and regardless of the scoring system, PD-L1 was less expressed in surgery than biopsy samples (p ≤ 0.04). In paired specimens, PD-L1-ICS reduction was especially observed following neoadjuvant long-course (chemo)radiotherapy (p = 0.03). PD-L1-ICS of ≥5% in surgical samples (HR: 0.17; p = 0.02), and a biopsy-to-surgery increase in PD-L1-ICS (HR: 0.19; p = 0.04) was predictive for longer disease-free survival, while the PD-L1-ICS of either ≥1% (HR 0.28; p = 0.04) or ≥5% (HR 0.19; p = 0.03) in surgical samples and the biopsy-to-surgery increase in PD-L1-ICS (HR: 0.20; p = 0.04) were associated with better overall survival. Our study suggests that PD-L1 expression in RC is largely reflective of immune cell infiltration, and its presence/increase in surgical samples predicts better outcomes.

Combining immunotherapy and radiation therapy in gastrointestinal cancers: A review

INTRODUCTION AND PURPOSE

With a significant global impact, treatment of gastrointestinal (GI) cancers still presents with challenges, despite current multimodality approaches in advanced stages. Clinical trials are expanding for checkpoint inhibition (ICI) combined with radiation therapy (RT). This review intends to offer a comprehensive image of the current data regarding the effectiveness of this association, and to reflect on possible directions to further optimize the results.

RESULTS

Several early phase studies demonstrated encouraging potential. However, translating preclinical outcomes to clinical settings proves challenging, especially in immunologically "cold" environments. GI cancers exhibit heterogeneity, requiring tailored approaches based on disease stage and patient characteristics. Current results, though promising, lack the power of evidence to influence the general practice.

CONCLUSIONS

Finding biomarkers for identifying or converting resistant cancers is essential for maximizing responses, moreover in this context strategic RT parameters need to be carefully considered. Our review emphasizes the significance of having a thorough grasp of how immunology, tumour biology, and treatment settings interact in order to propose novel research avenues and efficient GI cancer therapy.

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.

Treatment strategies and molecular mechanism of radiotherapy combined with immunotherapy in colorectal cancer

Radiotherapy (RT) remodels the tumor immune microenvironment (TIME) and modulates the immune response to indirectly destroy tumor cells, in addition to directly killing tumor cells. RT combined with immunotherapy may significantly enhance the efficacy of RT in colorectal cancer by modulating the microenvironment. However, the molecular mechanisms by which RT acts as an immunomodulator to modulate the immune microenvironment remain unclear. Further, the optimal modalities of RT combined with immunotherapy for the treatment of colorectal cancer, such as the time point of combining RT and immunization, the fractionation pattern and dosage of radiotherapy, and other methods to improve the efficacy, are also being explored parallelly. To address these aspects, in this review, we summarized the mechanisms by which RT modulates TIME and concluded the progress of RT combined with immunization in preclinical and clinical trials. Finally, we discussed heavy ion radiation therapy and the efficacy of prediction markers and other immune combination therapies. Overall, combining RT with immunotherapy to enhance antitumor effects will have a significant clinical implication and will help to facilitate individualized treatment modalities.

Immunotherapy in Colorectal Cancer - Finding the Achilles' Heel

AbstractColorectal cancer treatment has evolved considerably in the last decade with the development of immunotherapies. Immune checkpoint inhibitor therapies have brisk and durable responses in patients with advanced microsatellite instability-high colorectal cancer, both surgically resectable and unresectable; however, patients with microsatellite stable colorectal cancer in general do not respond to the same therapy. Emerging evidence shows that immune checkpoint inhibitors may elicit responses in subsets of patients with microsatellite stable colorectal cancer, especially when combined with other anticancer agents that can modulate the tumor microenvironment. Therefore, rationally designed therapeutic combinations involving immune checkpoint inhibitors, as well as the development of predictive biomarkers for optimal patient selection, have emerged as two key areas of active research. In addition, other immunotherapeutic agents such as cell-based therapies and bispecific T-cell engagers are beginning to be studied in preclinical and early-phase settings. Although by no means a universal treatment strategy, immunotherapy can elicit responses in microsatellite stable colorectal cancer and further research is needed to extend their benefit to patients with microsatellite stable colorectal cancer. Here, we review the current state of immunotherapeutic regimens for microsatellite stable colorectal cancer.

Immunotherapy in the neoadjuvant treatment of gastrointestinal tumors: is the time ripe?

Immune checkpoint inhibitors (ICIs) revolutionized the management of mismatch repair-deficient (dMMR)/microsatellite instability-high (MSI-H) gastrointestinal (GI) cancers. Based on notable results observed in the metastatic setting, several clinical trials investigated ICIs as neoadjuvant treatment (NAT) for localized dMMR/MSI-H GI cancers, achieving striking results in terms of clinical and pathological responses and creating the opportunity to spare patients from neoadjuvant chemotherapy and/or radiotherapy and even surgical resection. Nevertheless, these impressive findings are mainly derived from small proof of concept phase II studies and there are still several open questions to address. Moreover, dMMR/MSI-H represents a limited subgroup accounting for less than 10% of GI cancers. Consequently, many efforts have been produced to investigate neoadjuvant ICIs also in mismatch repair-proficient/microsatellite stable (MSS) cancers, considering the potential synergistic effect in combining immune-targeted agents with standard therapies such as chemo and/or radiotherapy. However, results for combining ICIs to the standard of care in the unselected population are still unsatisfactory, without improvements in event-free survival in esophago-gastric adenocarcinoma for the addition of pembrolizumab to chemotherapy, and sometimes limited benefit in patients with locally advanced rectal cancer. Therefore, a major challenge will be to identify among the heterogenous spectrum of this disease, those patients that could take advantage of neoadjuvant immunotherapy and deliver the most effective treatment. In this review we discuss the rationale of NAT in GI malignancies, summarize the available evidence regarding the completed trials that evaluated this treatment strategy in both MSI-H and MSS tumors. Finally, we discuss ongoing studies and future perspectives to render neoadjuvant immunotherapy another arrow in the quiver for the treatment of locally advanced GI tumors.

The efficacy and safety of neoadjuvant chemoradiotherapy combined with immunotherapy for locally advanced rectal cancer patients: a systematic review

Background

Several studies have explored the effectiveness of PD-1/PD-L1 inhibitors combined with neoadjuvant chemoradiotherapy (nCRT) in the treatment of locally advanced rectal cancer(LARC), particularly in microsatellite stable(MSS) or mismatch repair proficient(pMMR) LARC patients. We undertook a single-arm systematic review to comprehensively evaluate the advantages and potential risks associated with the use of PD-1/PD-L1 inhibitors in conjunction with nCRT for patients diagnosed with locally advanced rectal cancer.

Methods

The PubMed, Embase, Cochrane Library, ClinicalTrials.gov, ASCO and ESMO were searched for related studies. The main outcomes were pathologic complete response (pCR), major pathological response (MPR), anal preservation, and adverse effects (AEs).

Results

Fourteen articles including 533 locally advanced rectal cancer (LARC) patients were analyzed. The pooled pCR, MPR, and anal preservation rates were 36%, 66% and 86%. Grade ≥3 adverse events occurred in 20%. Subgroup analysis showed that; dMMR/MSI-H had a pooled pCR (100%) and MPR (100%), pMMR/MSS had a pooled pCR (38%) and MPR (60%); the short-course radiotherapy and long-course radiotherapy had pooled pCR rates of 51% and 30%, respectively. The rates of pCR for the concurrent and sequential immuno-chemoradiotherapy subgroups at 30% and 40%, mirroring pCR rates for the PD-L1 and PD-1 inhibitor subgroups were 32% and 40%, respectively.

Conclusion

In cases of locally advanced rectal cancer, PD-1/PD-L1 inhibitors combined with neoadjuvant chemoradiotherapy have shown promising response rates and acceptable toxicity profiles. PD-1/PD-L1 inhibitors combined with neoadjuvant chemoradiotherapy hence has a positive outcome even in MSS LARC patients.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/#myprospero, identifier CRD42023465380.

Total Neoadjuvant Therapy With PD-1 Blockade for High-Risk Proficient Mismatch Repair Rectal Cancer

Importance

Total neoadjuvant therapy (TNT) is the standard treatment for locally advanced rectal cancer, especially for patients with high-risk factors. However, the efficacy of TNT combined with immunotherapy for patients with proficient mismatch repair (pMMR) rectal cancer is unknown.

Objectives

To evaluate the safety and efficacy of TNT with induction chemoimmunotherapy followed by long-course chemoradiation in patients with high-risk, pMMR rectal cancer and to identify potential molecular biomarkers associated with treatment efficacy.

Design, Setting, and Participants

This cohort study was a single-arm phase 2 trial conducted at Gastrointestinal Cancer Center, Peking University Cancer Hospital & Institute, from June 2020 to October 2021. Biopsies and plasma were collected before treatment for whole-exome sequencing and cell-free DNA sequencing, respectively. Data were analyzed from May 2022 to September 2022.

Interventions

Participants received 3 cycles of induction oxaliplatin and capecitabine combined with camrelizumab and radiotherapy (50.6 Gy in 22 fractions) with concurrent capecitabine. Patients without disease progression received 2 cycles of consolidation oxaliplatin/capecitabine.

Main Outcomes and Measures

The primary end point was pathologic complete response rate.

Results

Of 25 patients enrolled (19 men [76%]; 6 women [24%]; median [IQR] age, 58 [48-64] years), 22 patients (88%) completed the TNT schedule. The pathologic complete response rate was 33.3% (7/21). Twelve patients (48%) achieved clinical complete response, and 4 patients (16%) chose to watch and wait. R0 resection was achieved in 21 of 21 patients, and the major pathologic response rate was 38.1% (8/21). The most common adverse event was nausea (80%, 20/25); grade 3 toxic effects occurred in 9 of 25 patients (36%). Patients with tumor shrinkage of 50% or greater after induction oxaliplatin/capecitabine and camrelizumab or clinical complete response had higher percentages of LRP1B mutation. Mutation of LRP1B was associated with high tumor mutation burden and tumor neoantigen burden. Patients with high tumor mutation burden all benefited from therapy.

Conclusions and Relevance

This study found that TNT with induction chemoimmunotherapy followed by long-course chemoradiation was safe and effective for patients with high-risk rectal cancer with pMMR status. Longer follow-up and larger clinical studies are needed to validate this innovative regimen. There is also an urgent need to further validate the predictive value of LRP1B and discover other novel biomarkers with potential predictive value for rectal cancer.

Advancing Personalized Medicine in the Treatment of Locally Advanced Rectal Cancer

Rectal cancer presents a significant burden globally, often requiring multimodal therapy for locally advanced cases. Long-course chemoradiotherapy (LCRT) and short-course radiotherapy (SCRT) followed by surgery have been conventional neoadjuvant approaches. Recent trials favor LCRT due to improved local control. However, distant tumor recurrence remains a concern, prompting the exploration of total neoadjuvant therapy (TNT) as a comprehensive treatment strategy. Immune checkpoint inhibitors (ICIs) show promise, particularly in mismatch repair-deficient (dMMR) or microsatellite instability-high (MSI-H) tumors, potentially revolutionizing neoadjuvant regimens. Nonoperative management (NOM) represents a viable alternative post-neoadjuvant therapy for selected patients achieving complete clinical response (cCR). Additionally, monitoring minimal residual disease (MRD) using circulating tumor DNA (ctDNA) emerges as a non-invasive method for the assessment of treatment response. This review synthesizes current evidence on TNT, ICIs, NOM, and ctDNA, elucidating their implications for rectal cancer management and highlighting avenues for future research and clinical application.

Novel radiation and targeted therapy combinations for improving rectal cancer outcomes

Neoadjuvant radiotherapy (RT) is commonly used as standard treatment for rectal cancer. However, response rates are variable and survival outcomes remain poor, highlighting the need to develop new therapeutic strategies. Research is focused on identifying novel methods for sensitising rectal tumours to RT to enhance responses and improve patient outcomes. This can be achieved through harnessing tumour promoting effects of radiation or preventing development of radio-resistance in cancer cells. Many of the approaches being investigated involve targeting the recently published new dimensions of cancer hallmarks. This review article will discuss key radiation and targeted therapy combination strategies being investigated in the rectal cancer setting, with a focus on exploitation of mechanisms which target the hallmarks of cancer.

Can rectal MRI and endorectal ultrasound accurately predict the complete response to neoadjuvant immunotherapy for rectal cancer?

Background

Standardized assessments of clinical complete response (cCR) to neoadjuvant chemoradiotherapy (nCRT) for rectal cancer have been established, but their utility and accuracy remain unclear. This study aimed to evaluate the clinical diagnostic value of rectal magnetic resonance imaging (MRI) and endorectal ultrasonography (ERUS) for the determination of cCRs after neoadjuvant immunotherapy and to investigate the concordance between cCR and pathological complete response (pCR).

Methods

Ninety-four patients with rectal cancer treated with neoadjuvant radiotherapy with or without immunotherapy were included. The sensitivity, specificity, and accuracy of each evaluation method were calculated.

Results

Combined MRI and ERUS assessments found cCR in seven of the 94 patients in our cohort. In the non-immunotherapy group, the sensitivity, specificity, and accuracy of MRI for diagnosing cCR were 50.0%, 85.2%, and 77.1%, respectively, whereas those of ERUS were 50.0%, 92.6%, and 82.9%, respectively; those of combined MRI and ERUS were 25.0%, 96.3%, and 87.5%, respectively. In the immunotherapy group, the sensitivity, specificity, and accuracy with which MRI identified CR were 51.7%, 76.7%, and 64.4%, respectively; those of ERUS were 13.8%, 90.0%, and 52.5%, respectively, and those of combined MRI and ERUS were 10.3%, 96.7%, and 54.2%, respectively. We also found that 32 of 37 patients with pCR did not meet the cCR evaluation criteria. Of these pCR patients, 78.4% (29/37) received immunotherapy. In the entire cohort, there were five pCRs among the seven cCRs. Of the four cCRs that occurred in the immunotherapy group, three were pCRs.

Conclusions

Rectal MRI and/or ERUS did not provide sufficiently accurate assessments of cCR in patients with rectal cancer receiving neoadjuvant therapy, especially immunotherapy, and cCR did not predict pCR.

Treatment Options for Distal Rectal Cancer in the Era of Organ Preservation

OPINION STATEMENT

The introduction of total mesorectal excision into the radical surgery of rectal cancer has significantly improved the oncological outcome with longer survival and lower local recurrence. Traditional treatment modalities of distal rectal cancer, relying on radical surgery, while effective, take their own set of risks, including surgical complications, potential damage to the anus, and surrounding structure owing to the pursuit of thorough resection. The progress of operating methods as well as the integration of systemic therapies and radiotherapy into the peri-operative period, particularly the exciting clinical complete response of patients after neoadjuvant treatment, have paved the way for organ preservation strategy. The non-inferiority oncological outcome of "watch and wait" compared with radical surgery underscores the potential of organ preservation not only to control local recurrence but also to reduce the need for treatments followed by structure destruction, hopefully improving the long-term quality of life. Radical radiotherapy provides another treatment option for patients unwilling or unable to undergo surgery. Organ preservation points out the direction of treatment for distal rectal cancer, while additional researches are needed to answer remaining questions about its optimal use.

Global research landscape and trends of cancer radiotherapy plus immunotherapy: A bibliometric analysis

The aim of this study was to present current research trends on the synergistic use of radiotherapy and immunotherapy (IRT) for cancer treatment. On March 1, 2023, we conducted a literature search for IRT papers using the Web of Science database. We extracted information and constructed two databases - the Core Database (CD) with 864 papers and Generalized Database (GD) with 6344 papers. A bibliometric analysis was performed to provide insights into the research landscape, to identify emerging trends and highly cited papers and journals in the field of IRT. The CD contained 864 papers that were collectively cited 31,818 times. Prominent journals in this area included the New England Journal of Medicine, Lancet Oncology, and the Journal of Clinical Oncology. Corresponding authors from the USA contributed the most publications. In recent years, lung cancer, melanoma, stereotactic radiotherapy, immune checkpoint inhibitors, and the tumor microenvironment emerged as hot research areas. This bibliometric analysis presented quantitative insights into research concerning IRT and proposed potential avenues for further exploration. Moreover, researchers can use our findings to select appropriate journals for publication or identify prospective collaborators. In summary, this bibliometric analysis provides a comprehensive overview of the historical progression and recent advancements in IRT research that may serve as inspiration for future investigations.

Efficacy and safety of PD-1 blockade plus long-course chemoradiotherapy in locally advanced rectal cancer (NECTAR): a multi-center phase 2 study

Adding PD-1 blockade in the neoadjuvant regimens for locally advanced rectal cancer (LARC) patients with microsatellite stable (MSS) / mismatch repair-proficient (pMMR) tumors is an attractive, but debatable strategy. This phase 2, multicenter, prospective, single-arm study enrolled patients from 6 centers from June 2021 to November 2022. Locally advanced rectal cancer (LARC, cT3-4aN0M0 and cT1-4aN1-2M0) patients aged ≥18 years with the distance from distal border of tumor to anal verge ≤10 cm (identified by Magnetic Resonance Imaging) were qualified for inclusion. The patients received long-course radiotherapy (50 Gy/25 fractions, 2 Gy/fraction, 5 days/week) and three 21-day cycles capecitabine (850-1000 mg/m2, bid, po, day1-14) and three 21-day cycles tislelizumab (200 mg, iv.gtt, day8) as neoadjuvant. Total mesorectal excision (TME) was 6-12 weeks after the end of radiotherapy to achieve radical resection. A total of 50 patients were enrolled in this study. The pathological complete response rate was 40.0% [20/50, 95% confidence interval (CI): 27.61-53.82%], while 15 (30.0%, 95% CI: 19.1-43.75%), 9 (18.0%, 95% CI: 9.77-30.8%), 2 (4.0%, 95% CI: 1.10-13.46%) patients respectively achieved grade 1, 2, and 3 tumor regression. Treatment-related adverse events (TRAEs) occurred in 28 (56.0%) LARC patients, including 26(52.0%) with grade I-II and 2 (4.0%) with grade III (1 with grade 3 immune-related colitis and 1 with grade 3 rash). PD-1 blockade plus long-course chemoradiotherapy (CRT) showed promising therapeutic effects according to pathological complete response rate and is well-tolerated in LARC patients. A larger randomized controlled study is desired to further validate the above findings.

Transforming the landscape of colorectal cancer treatment with immunotherapy: Evolution and future horizons

Colorectal cancer (CRC) continues to be one of the most prevalent and lethal cancers worldwide. Over the past decades, immune checkpoint inhibitors (ICIs) have shown to significantly improve patient outcomes in mismatch repair-deficient metastasized CRC. However, widening the scope of this novel treatment modality has been the object of growing interest. This article will review several landmark trials, while exploring various aspects of this rapidly evolving field, including potential neoadjuvant (or even entirely nonsurgical) and adjuvant indications in localized disease. We will also discuss differences between management of rectal and colon cancer, current and expected challenges (eg. resistance, toxicities, pseudoprogression, biomarkers) and other future opportunities including combinations with other therapeutic agents and the role of ICIs in the treatment of both deficient as well as proficient mismatch repair (dMMR and pMMR respectively) CRC.

Study protocol of short-course radiotherapy combined with CAPOX and PD-1 inhibitor for locally advanced colon cancer: a randomised, prospective, multicentre, phase II trial (TORCH-C)

INTRODUCTION

The preliminary result of the TORCH trial has shown a promising complete response (CR) for managing locally advanced rectal cancer with neoadjuvant short-course radiotherapy (SCRT) combined with chemotherapy and PD-1 inhibitor. For locally advanced colon cancer (LACC) with bulky nodal disease and/or clinically T4, neoadjuvant chemotherapy followed by colectomy with en bloc removal of regional lymph nodes is the suggested treatment. However, the CR rate is less than 5%. TORCH-C will aim to investigate neoadjuvant SCRT combined with chemotherapy and PD-1 inhibitor in LACC.

METHODS AND ANALYSIS

TORCH-C is a randomised, prospective, multicentre, double-arm, open, phase II trial of SCRT combined with chemotherapy and immunotherapy in LACC with microsatellite stable (MSS) patients and cT4 or bulky nodes. Eligible patients will be identified by the multidisciplinary team. 120 patients will be randomised 1:1 to the intervention or control arm. The patients in the control arm will receive four cycles of capecitabine plus oxaliplatin (CAPOX). The patients in the intervention arm will receive SCRT, followed by four cycles of CAPOX and PD-1 inhibitor (serplulimab). Both arms will receive curative surgery, followed by four cycles of CAPOX. The primary endpoint is pathological complete regression.TORCH-C (TORCH-colon) trial aims to investigate whether the combination of immunotherapy and chemoradiotherapy improves the treatment effect in LACC with MSS. TORCH-C will establish the TORCH platform, a key part of our long-term strategy to develop neoadjuvant treatment for colorectal cancer.

ETHICS AND DISSEMINATION

This study was approved by the Ethics Committee of Fudan University Shanghai Cancer Center (approval number: 2211265-12).

TRIAL REGISTRATION NUMBER

NCT05732493.

STING Agonist-Loaded Nanoparticles Promotes Positive Regulation of Type I Interferon-Dependent Radioimmunotherapy in Rectal Cancer

Hypoxia-associated radioresistance in rectal cancer (RC) has severely hampered the response to radioimmunotherapy (iRT), necessitating innovative strategies to enhance RC radiosensitivity and improve iRT efficacy. Here, a catalytic radiosensitizer, DMPtNPS, and a STING agonist, cGAMP, are integrated to overcome RC radioresistance and enhance iRT. DMPtNPS promotes efficient X-ray energy transfer to generate reactive oxygen species, while alleviating hypoxia within tumors, thereby increasing radiosensitivity. Mechanistically, the transcriptomic and immunoassay analysis reveal that the combination of DMPtNPS and RT provokes bidirectional regulatory effects on the immune response, which may potentially reduce the antitumor efficacy. To mitigate this, cGAMP is loaded into DMPtNPS to reverse the negative impact of DMPtNPS and RT on the tumor immune microenvironment (TiME) through the type I interferon-dependent pathway, which promotes cancer immunotherapy. In a bilateral tumor model, the combination treatment of RT, DMPtNPS@cGAMP, and αPD-1 demonstrates a durable complete response at the primary site and enhanced abscopal effect at the distant site. This study highlights the critical role of incorporating catalytic radiosensitizers and STING agonists into the iRT approach for RC.

Radiotherapy in the preoperative neoadjuvant treatment of locally advanced rectal cancer

Radiotherapy and chemotherapy are effective treatments for patients with locally advanced rectal cancer (LARC) and can significantly improve the likelihood of R0 resection. Radiotherapy can be used as a local treatment to reduce the size of the tumor, improve the success rate of surgery and reduce the residual cancer cells after surgery. Early chemotherapy can also downgrade the tumor and eliminate micrometastases throughout the body, reducing the risk of recurrence and metastasis. The advent of neoadjuvant concurrent radiotherapy (nCRT) and total neoadjuvant treatment (TNT) has brought substantial clinical benefits to patients with LARC. Even so, given increasing demand for organ preservation and quality of life and the disease becoming increasingly younger in its incidence profile, there is a need to further explore new neoadjuvant treatment options to further improve tumor remission rates and provide other opportunities for patients to choose watch-and-wait (W&W) strategies that avoid surgery. Targeted drugs and immunologic agents (ICIs) have shown good efficacy in patients with advanced rectal cancer but have not been commonly used in neoadjuvant therapy for patients with LARC. In this paper, we review several aspects of neoadjuvant therapy, including radiation therapy and chemotherapy drugs, immune drugs and targeted drugs used in combination with neoadjuvant therapy, with the aim of providing direction and thoughtful perspectives for LARC clinical treatment and research trials.

TORCH-R trial protocol: hypofractionated radiotherapy combined with chemotherapy and toripalimab for locally recurrent rectal cancer: a prospective, single-arm, two-cohort, phase II trial

For patients with locally recurrent rectal cancer (LRRC), the response rate to chemoradiotherapy is 40%-50%. Additionally, only approximately 40%-50% of patients with recurrent rectal cancer are able to undergo R0 resection. Recent studies in locally advanced rectal cancer (LARC) have shown promising synergistic effects when combining immunotherapy (PD-1/PD-L1 antibodies) with neoadjuvant chemoradiotherapy (nCRT). Therefore, incorporating immunotherapy into the treatment regimen for LRRC patients has the potential to further improve response rates and prognosis. To investigate this, the TORCH-R trial was conducted. This prospective, single-arm, two-cohort, phase II trial focuses on the use of hypofractionated radiotherapy, chemotherapy, and immunotherapy in LRRC patients without or with oligometastases. The trial will include two cohorts: cohort A consists of rectal cancer patients who are treatment-naive for local recurrence, and cohort B includes patients with progressive disease after first-line chemotherapy. Cohort A and cohort B patients will receive 25-40 Gy/5 Fx irradiation or 15-30 Gy/5 Fx reirradiation for pelvic recurrence, respectively. Subsequently, they will undergo 18 weeks of chemotherapy, toripalimab, and stereotactic ablative radiotherapy (SABR) for all metastatic lesions between chemoimmunotherapy cycles. Decisions regarding follow-up of complete response (CR), radical surgery, sustained treatment of non-resection, or exiting the trial are made by a multidisciplinary team (MDT). The primary endpoint of this study is the local objective response rate (ORR). The secondary endpoints include the extrapelvic response rate, duration of response, local recurrence R0 resection rate, progression-free survival (PFS), overall survival (OS), and safety and tolerability. Notably, this trial represents the first clinical exploration of inducing hypofractionated radiotherapy, chemotherapy, and immunotherapy in LRRC patients.

Clinical trial registration

https://clinicaltrials.gov/study/NCT05628038, identifier NCT05628038.

Perioperative immune checkpoint inhibition for colorectal cancer: recent advances and future directions

For colorectal cancer (CRC), surgical resection remains essential for achieving good prognoses. Unfortunately, numerous patients with locally advanced CRC and metastatic CRC failed to meet surgical indications or achieve pathological complete response after surgery. Perioperative therapy has been proven to effectively lower tumor staging and reduce recurrence and metastasis. Immune checkpoint inhibitors (ICIs) have shown unprecedented prolongation of survival time and satisfactory safety in patients with high microsatellite instability/deficient mismatch repair (MSI-H/dMMR), while the therapeutic effect obtained by patients with mismatch repair-proficient or microsatellite stable (pMMR/MSS) was considered minimal. However, recent studies found that certain CRC patients with dMMR/MSI-H presented intrinsic or acquired immune resistance, and pMMR/MSS CRC patients can also achieve better efficacy. Therefore, more predictors are required for screening patients with potential clinical benefits. Since the discovery of synergistic effects between immunotherapy, chemotherapy, and radiotherapy, different immunotherapy-based therapies have been applied to the perioperative therapy of CRC in an increasing number of research. This review comprehensively summarized the past and current progress of different combinations of immunotherapy in perioperative clinical trials for CRC, focusing on the efficacy and safety, and points out the direction for future development.

A Review of Scheduling Strategies for Radiotherapy and Immune Checkpoint Inhibition in Locally Advanced Rectal Cancer

Colorectal cancer (CRC) is the third most common malignancy across the globe and, despite advances in treatment strategies, survival rates remain low. Rectal cancer (RC) accounts for most of these cases, and traditional management strategies for advanced disease include total neoadjuvant therapy (TNT) with chemoradiotherapy followed by curative surgery. Unfortunately, approximately 10-15% of patients have no response to treatment or have recurrence at a short interval following radiotherapy. The introduction of immunotherapy in the form of immune checkpoint blockade (ICB) in metastatic colorectal cancer has improved clinical outcomes, yet most patients with RC present with microsatellite stable disease, which lacks the immune-rich microenvironment where ICB is most effective. There is evidence that combining radiotherapy with ICB can unlock the mechanisms that drive resistance in patients; however, the sequencing of these therapies is still debated. This review offers a comprehensive overview of clinical trials and preclinical models that use radiotherapy-immunotherapy combinations in RC in an attempt to extrapolate the ideal sequencing of the two treatment modalities. The results highlight the dearth of evidence to answer the question of whether ICB should be given before, during, or after radiotherapy, yet it is suggested that improving the relevance of our preclinical models will provide a platform with higher translational value and will lead to appropriate clinical trial designs.

Organ Preservation in MSS Rectal Cancer

Rectal cancer is a heterogeneous disease with complex genetic and molecular subtypes. Emerging progress of neoadjuvant therapy has led to increased pathological and clinical complete response (cCR) rates for microsatellite stable (MSS) rectal cancer, which responds poorly to immune checkpoint inhibitor alone. As a result, organ preservation of MSS rectal cancer as an alternative to radical surgery has gradually become a feasible option. For patients with cCR or near-cCR after neoadjuvant treatment, organ preservation can be implemented safely with less morbidity. Patient selection can be done either before the neoadjuvant treatment for higher probability or after with careful assessment for a favorable outcome. Those patients who achieved a good clinical response are managed with nonoperative management, organ preservation surgery, or radiation therapy alone followed by strict surveillance. The oncological outcomes of patients with careful selection and organ preservation seem to be noninferior compared with those of radical surgery, with lower postoperative morbidity. However, more studies should be done to seek better regression of tumor and maximize the possibility of organ preservation in MSS rectal cancer.

A Modified NAR Scoring Model Incorporating Immune Infiltration Characteristics to Better Predict Long-Term Survival Following Neoadjuvant Radiotherapy in Rectal Cancer

(1) Background: The neoadjuvant rectal (NAR) score has been developed as a prognostic tool for survival in locally advanced rectal cancer (LARC). However, the NAR score only incorporates weighted cT, ypT, and ypN categories. This long-term follow-up study aims to modify a novel prognostic scoring model and identify a short-term endpoint for survival. (2) Methods: The prognostic factors for overall survival (OS) were explored through univariate and multivariate analyses. Based on Cox regression modeling, nomogram plots were constructed. Area under the curve (AUC) and concordance indices were used to evaluate the performance of the nomogram. Receiver operating characteristic (ROC) analysis was conducted to compare the efficiency of the nomogram with other prognostic factors. (3) Results: After a long-term follow-up, the 5-year OS was 67.1%. The mean NAR score was 20.4 ± 16.3. Multivariate analysis indicated that CD8+ T-cell, lymphovascular invasion, and the NAR score were independent predictors of OS. The modified NAR scoring model, incorporating immune infiltration characteristics, exhibited a high C-index of 0.739 for 5-year OS, significantly outperforming any individual factor. Moreover, the predictive value of the nomogram was superior to the AJCC stage and pathological complete regression at 3-year, 5-year, and 10-year time points, respectively. Over time, the model's predictions of long-term survival remained consistent and improved in accuracy. (4) Conclusions: The modified NAR scoring model, incorporating immune infiltration characteristics, demonstrates high accuracy and consistency in predicting OS.

Implications of Rectal Cancer Radiotherapy on the Immune Microenvironment: Allies and Foes to Therapy Resistance and Patients' Outcome

Aside from surgical resection, locally advanced rectal cancer is regularly treated with neoadjuvant chemoradiotherapy. Since the concept of cancer treatment has shifted from only focusing on tumor cells as drivers of disease progression towards a broader understanding including the dynamic tumor microenvironment (TME), the impact of radiotherapy on the TME and specifically the tumor immune microenvironment (TIME) is increasingly recognized. Both promoting as well as suppressing effects on anti-tumor immunity have been reported in response to rectal cancer (chemo-)radiotherapy and various targets for combination therapies are under investigation. A literature review was conducted searching the PubMed database for evidence regarding the pleiotropic effects of (chemo-)radiotherapy on the rectal cancer TIME, including alterations in cytokine levels, immune cell populations and activity as well as changes in immune checkpoint proteins. Radiotherapy can induce immune-stimulating and -suppressive alterations, potentially mediating radioresistance. The response is influenced by treatment modalities, including the dosage administered and the highly individual intrinsic pre-treatment immune status. Directly addressing the main immune cells of the TME, this review aims to highlight therapeutical implications since efficient rectal cancer treatment relies on personalized strategies combining conventional therapies with immune-modulating approaches, such as immune checkpoint inhibitors.

Can neoadjuvant chemoradiotherapy combined with immunotherapy benefit patients with microsatellite stable locally advanced rectal cancer? a pooled and integration analysis

Objective

To assess the clinical efficacy of neoadjuvant chemoradiotherapy combined with immunotherapy for patients with microsatellite stable (MSS) locally advanced rectal cancer and provide evidence to support clinical decision-making.

Methods

A systematic search was conducted on the PubMed, Embase, Cochrane Collaboration databases, conference summaries, and Chinese databases for clinical studies that investigated neoadjuvant chemoradiotherapy combined with immunotherapy for the treatment of locally advanced rectal cancer with MSS status. The search spanned from the inception of each database through July 2023. Data from the identified studies were extracted using a pre-designed table, and efficacy outcomes were analyzed. An integrated analysis was conducted using Stata 12.0 software.

Results

Eight studies were included, comprising 204 patients with locally advanced MSS rectal cancer who received chemoradiotherapy combined with immunotherapy. The integrated analysis revealed a pathologic complete remission rate of 0.33, a sphincter preservation rate of 0.86, an R0 resection rate of 0.83, a major pathologic remission rate of 0.33, and a clinical complete remission rate of 0.30.

Conclusion

Neoadjuvant chemoradiotherapy combined with immunotherapy demonstrates significant short-term efficacy in MSS-type locally advanced rectal cancer, notably enhancing the pathologic complete remission and sphincter preservation rates. This combination is a recommended treatment for patients with MSS-type rectal cancer.

Propensity matched analysis of robotic and laparoscopic operations for mid-low rectal cancer: short-term comparison of anal function and oncological outcomes

Laparoscopic surgery for rectal cancer, while in some respects equivalent or even preferable to open surgery, is challenged in specific conditions where the tumor is located in the middle and lower third of the rectum. Robotic surgery equipped with a superior arm of machinery and gained better visualization can compensate for the deficiency of the laparoscopic approach. This study adopted a propensity matched analysis to compare the functional and oncological short-term outcomes of laparoscopic and robotic surgery. All patients who underwent proctectomy have been collected prospectively between December 2019 and November 2022. After censoring for inclusion criteria, we performed a propensity matching analysis. A detailed collection of post-operative examination indicators was performed, while the K-M survival curves were plotted to analyze post-operative oncology outcomes. The LARS scale was designed to evaluate the anal function of patients in the form of questionnaires. Totally, 215 patients underwent robotic operations while 1011 patients selected laparoscopic operations. Patients matched 1∶1 by propensity score were divided into the robotic and laparoscopic groups, 210 cases were included in each group. All patients underwent a follow-up for a median period of 18.3 months. Robotic surgery was connected with an enhanced recovery including the earlier time to first flatus passage without ileostomy (P = 0.050), the earlier time to liquid diet without ileostomy (P = 0.040), lower incidence of urinary retention (P = 0.043), better anal function 1 month after LAR without ileostomy (P < 0.001), longer operative time (\P = 0.042), compared with laparoscopic operations. The oncological outcomes and occurrence of other complications were comparable between the two approaches. For mid-low rectal cancer, robotic surgery could be recognized as an effective technique with identical short-term outcomes of oncology and better anal function in comparison to laparoscopic surgery. However, multi-center studies with larger samples are expected to validate the long-term outcomes of robotic surgery.

Clinical trials of neoadjuvant immune checkpoint inhibitors for early-stage operable colon and rectal cancer

BACKGROUND

Immune checkpoint inhibitors (ICI) have become first-line treatment for metastatic colorectal cancer (CRC) with deficient mismatch repair (dMMR). Despite the remarkable response reported in preliminary trials, the role of ICI in patients with early-stage, operable CRC remains unclear. The aim of this study was to investigate trials on neoadjuvant ICI in operable CRC.

MATERIALS AND METHODS

Scoping review of clinical trial registries (Clinicaltrials.gov and EU clinical trial registers) and PubMed/Medline database of trials on neoadjuvant ICI for operable CRC was done up to December 2022.

RESULTS

Some 40 trials investigating neoadjuvant ICI for early-stage, operable CRC were identified, including five published trials and three conference abstracts. Preclinical phase I/II trial predominated with only three clinical phase III trials. Few trials investigated neoadjuvant ICI as the only intervention (monotherapy). Trials in rectal cancer were designed for combined ICI with chemo(radio)therapy, only 8 trials stating an MSI/dMMR status for inclusion, one designed for MSS/pMMR only and, the rest agnostic for MMR status. Thirty-eight (95%) trials investigated programmed cell death protein 1 (PD-1) or programmed cell death ligand 1 (PD-L1) inhibitors. PD-1/PD-L1 inhibitors were combined with vascular endothelial growth factor (VEGF) inhibitor or with cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) inhibitor, in two trials each, respectively. Pathological complete response as primary outcome after surgery was the most frequently used study endpoint. In rectal cancer, six trials included a "watch and wait" strategy for patients with complete clinical response. No "watch and wait" study design for colon cancer after neoadjuvant ICI were identified.

CONCLUSION

High response rates from neoadjuvant ICI in early-stage colon and rectal cancer are reported in phase I/II studies. Contemporary trial designs are heterogeneous, with few comparable inclusion criteria, use of several drug combinations and durations and, wide variation of endpoints reported. Harmonizing clinical and translational aspects including survival data is needed for improved future trial designs with clinical impact.

Long-course chemoradiation plus concurrent/sequential PD-1 blockade as neoadjuvant treatment for MMR-status-unscreened locally advanced rectal cancer: protocol of a multicentre, phase 2, randomised controlled trial (the POLAR-STAR trial)

INTRODUCTION

Recent preclinical studies have discovered unique synergism between radiotherapy and immune checkpoint inhibitors, which has already brought significant survival benefit in lung cancer. In locally advanced rectal cancer (LARC), neoadjuvant radiotherapy plus immune checkpoint inhibitors have also achieved surprisingly high pathological complete response (pCR) rates even in proficient mismatch-repair patients. As existing researches are all phase 2, single-cohort trials, we aim to conduct a randomised, controlled trial to further clarify the efficacy and safety of this novel combination therapy.

METHODS AND ANALYSIS

Eligible patients with LARC are randomised to three arms (two experiment arms, one control arm). Patients in all arms receive long-course radiotherapy plus concurrent capecitabine as neoadjuvant therapy, as well as radical surgery. Distinguishingly, patients in arm 1 also receive anti-PD-1 (Programmed Death 1) treatment starting at Day 8 of radiation (concurrent plan), and patients in arm 2 receive anti-PD-1 treatment starting 2 weeks after completion of radiation (sequential plan). Tislelizumab (anti-PD-1) is scheduled to be administered at 200 mg each time for three consecutive times, with 3-week intervals. Randomisation is stratified by different participating centres, with a block size of 6. The primary endpoint is pCR rate, and secondary endpoints include neoadjuvant-treatment-related adverse event rate, as well as disease-free and overall survival rates at 2, 3 and 5 years postoperation. Data will be analysed with an intention-to-treat approach.

ETHICS AND DISSEMINATION

This protocol has been approved by the institutional ethical committee of Beijing Friendship Hospital (the primary centre) with an identifying serial number of 2022-P2-050-01. Before publication to peer-reviewed journals, data of this research will be stored in a specially developed clinical trial database.

TRIAL REGISTRATION NUMBER

NCT05245474.

Phase I/II clinical trial of nivolumab in combination with oligo-fractionated irradiation for unresectable advanced or recurrent gastric cancer

BACKGROUND

Although immune checkpoint inhibitors (ICI) targeting for PD-1 axis is a promising approach for advanced gastric cancer (GC) patients, the response rate is still limited. Induction of synergistic effect of irradiation with ICI targeting for the PD-1 axis can be an attractive strategy. The aim of this study was to assess the effect of the combination of irradiation with anti-PD-1 therapy for advanced GC.

METHODS

We conducted a single-arm, phase I/II trial in GC patients treated with a combination of nivolumab and oligo-fractionated irradiation (22.5 Gy/5 fractions/5 days) (NCT03453164). Eligible patients (n = 40) had unresectable advanced or recurrent GC which progressed after primary and secondary chemotherapy with more than one lesion. The primary endpoint is the disease control rate (DCR) of non-irradiated target lesions and the secondary endpoints are the median survival time (MST), safety, and DCR of irradiated lesions.

RESULTS

We observe that the DCR for the non-irradiated target as the abscopal effect is 22.5% (90% confidence interval (CI), 12.3-36.0), and the DCR for the irradiated lesion is 40.0% (90% CI, 26.9-54.2). The median survival time is 230 days (95% CI, 157-330), and grade 3 and higher adverse events (AEs) are observed in 16 patients (39 %) with no obvious additional AEs when adding irradiation.

CONCLUSIONS

The present study suggests that the combination of nivolumab with oligo-fractionated irradiation has the potential to induce a promising anti-tumor effect for advanced GC.

Carrilizumab for treatment of advanced colorectal cancer: Short-term efficacy and impact on immune function and PD-1/PD-L1 signaling pathway

BACKGROUND

Colorectal cancer is one of the most prevalent malignant tumours in China, and chemotherapy is the main treatment modality for patients with advanced colorectal cancer, which results in toxic side effects and reduces patients' quality of life. Since the occurrence of toxic side effects is related to patients' immunity and other factors, it is important to study whether the combined injection of carrilizumab with chemotherapy can positively affect patients' conditions by influencing the programmed cell death protein 1 (PD-1)/programmed death ligand 1 (PD-L1) signalling pathway.

AIM

To investigate the possible mechanism of carrilizumab for injection to improve immune function in advanced colorectal cancer, and to analyze its regulatory effect on the PD-1/ PD-L1 signaling pathway.

METHODS

A prospective randomised controlled study (RCT) was performed to include 127 patients with advanced colorectal cancer admitted to our hospital from January 2019 to October 2021, and they were divided into a control group (n = 63) and a study group (n = 64) using the computerised random number method. The control group was given oxaliplatin + capecitabine, and the study group was given oxaliplatin + capecitabine + carrilizumab for injection. The therapeutic effect, toxicity and side effects, survival status, PD-1/PD-L1 signaling pathway, tumor markers [carbohydrate antigen 125 (CA125), carbohydrate antigen 242 (CA242), thymidine kinase 1 (TK1), and carcinoembryonic antigen (CEA)], and nutritional status indicators [albumin (ALB), hemoglobin (HGB), prealbumin (PA), transferrin (TF), and patient-generated subjective global assessment (PG-SGA)] before and after treatment were compared between the two groups.

RESULTS

After four cycles of treatment, the disease control rate of the study group was higher than that of the control group (P < 0.05); the mRNA and protein levels of PD-1 and PD-L1 in the study group were lower than those in the control group (P < 0.05); serum ALB, PA, and TF levels and PG-SGA scores in the study group were higher than those in the control group (P < 0.05); and serum CA125, CA242, TK1, and CEA in the study group were lower than those in the control group (P < 0.05). There was no significant difference in the incidence of toxic and side effects or survival rate between the two groups (P > 0.05).

CONCLUSION

Camrelizumab for injection combined with oxaliplatin and capecitabine in the treatment of advanced colorectal cancer can improve the disease control rate, may reduce the impact of chemotherapy drugs on the nutritional status of the body by inhibiting the activation of PD-1/PD-L1 signal pathway, thus improving the immune function of the body, and has good safety.

Outcome of Patients With Early-Stage Mismatch Repair Deficient Colorectal Cancer Receiving Neoadjuvant Immunotherapy: A Systematic Review

PURPOSE

We conducted a systematic review to evaluate the outcome of patients with early-stage (stages I-III) mismatch repair deficient (dMMR) colorectal cancer (CRC) receiving neoadjuvant immunotherapy (NIT) with immune checkpoint inhibitor (ICI)-based regimens.

METHODS

MEDLINE, Scopus, Embase, Web of Science, and Cochrane Central Register of Controlled Trials were searched for publications reporting the outcome of patients with early-stage dMMR CRC receiving NIT. The primary outcome measures were the complete response (CR) rate (clinical CR [cCR] or pathologic CR [pCR]) and the incidence of grade 3 or higher toxicities.

RESULTS

The search identified 37 publications that included 423 patients with colon (n = 326, 77%) and rectal (n = 97,23%) cancers aged 19-82 years; most patients had stage III CRC (88%). Approximately 67% of patients received monotherapy with anti-PD-1 agents; the rest received dual ICIs (ipilimumab plus nivolumab). The CR rate (pCR + cCR) in the overall population was 72% (305 of 423). The R0 resection and pCR rates were 99.3% and 70% among the patients undergoing surgery, respectively. Only four (0.9%) patients had primary resistance to NIT. After median follow-up periods ranging from 4 to 27 months, 3 (0.7%) patients progressed after an initial response. Grade 3 or higher toxicities were uncommon (6.3%), rarely delaying planned surgery.

CONCLUSION

NIT in patients with early-stage dMMR CRC is associated with a high response rate, low primary resistance to immunotherapy and cancer recurrence rate, and an excellent safety profile. The findings of the present systematic review support further investigation of NIT in patients with early-stage dMMR CRC, with a particular emphasis on the organ-preserving potential of this strategy.

Neoadjuvant Immunotherapy: A Promising New Standard of Care

Neoadjuvant immunotherapy has emerged as a promising approach in the treatment of various malignancies, with preclinical studies showing improved immune responses in the preoperative setting. FDA-approved neoadjuvant-immunotherapy-based approaches include triple-negative breast cancer and early non-small cell lung cancer on the basis of improvement in pathological response and event free survival. Nevertheless, current trials have only shown benefits in a fraction of patients. It is therefore crucial to identify predictive biomarkers to improve patient selection for such approaches. This review aims to provide an overview of potential biomarkers of neoadjuvant immunotherapy in early triple-negative breast cancer, bladder cancer, melanoma, non-small cell lung cancer, colorectal cancer and gastric cancer. By the extrapolation of the metastatic setting, we explore known predictive biomarkers, i.e., PD-L1, mismatch repair deficiency and tumour mutational burden, as well as potential early-disease-specific biomarkers. We also discuss the challenges of identifying reliable biomarkers and the need for standardized protocols and guidelines for their validation and clinical implementation.

Harnessing the abscopal effect for gastrointestinal malignancies in the era of immunotherapy

Gastrointestinal (GI) cancers are among the leading causes of cancer-related mortality and have traditionally been treated using a combination of surgical resection and chemoradiotherapy (CRT). While the introduction of immunotherapies over the last decade have dramatically changed the treatment landscape for some GI malignancies, including esophageal, gastric, and colorectal cancer, treatment resistance remains a major unaddressed obstacle for many patients. There has thus been emerging interest in determining the optimal treatment strategy for the delivery of immunotherapy in combination with traditional therapies. In this regard, a growing number of preclinical and clinical studies have suggested that combining radiation therapy (RT) with immunotherapy may work synergistically to improve treatment response through amplification of the abscopal effect. In this review, we discuss the rationale for RT in combination with immunotherapy. We further discuss how this knowledge may lead to a paradigm shift in the application of RT and highlight remaining issues pertaining to the delivery of combination therapy.

New Opportunities for Minimizing Toxicity in Rectal Cancer Management

Advances in multimodal management of locally advanced rectal cancer (LARC), consisting of preoperative chemotherapy and/or radiotherapy followed by surgery with or without adjuvant chemotherapy, have improved local disease control and patient survival but are associated with significant risk for acute and long-term morbidity. Recently published trials, evaluating treatment dose intensification via the addition of preoperative induction or consolidation chemotherapy (total neoadjuvant therapy [TNT]), have demonstrated improved tumor response rates while maintaining acceptable toxicity. In addition, TNT has led to an increased number of patients achieving a clinical complete response and thus eligible to pursue a nonoperative, organ-preserving, watch and wait approach, thereby avoiding toxicities associated with surgery, such as bowel dysfunction and stoma-related complications. Ongoing trials using immune checkpoint inhibitors in patients with mismatch repair-deficient tumors suggest that this subgroup of patients with LARC could potentially be treated with immunotherapy alone, sparing them the toxicity associated with preoperative treatment and surgery. However, the majority of rectal cancers are mismatch repair-proficient and less responsive to immune checkpoint inhibitors and require multimodal management. The synergy noted in preclinical studies between immunotherapy and radiotherapy on immunogenic tumor cell death has led to the design of ongoing clinical trials that explore the benefit of combining radiotherapy, chemotherapy, and immunotherapy (mainly of immune checkpoint inhibitors) and aim to increase the number of patients eligible for organ preservation.

Radioimmunotherapy in colorectal cancer treatment: present and future

Colorectal cancer (CRC) is a deadly form of cancer worldwide. Patients with locally advanced rectal cancer and metastatic CRC have a poor long-term prognosis, and rational and effective treatment remains a major challenge. Common treatments include multi-modal combinations of surgery, radiotherapy, and chemotherapy; however, recurrence and metastasis rates remain high. The combination of radiotherapy and immunotherapy (radioimmunotherapy [RIT]) may offer new solutions to this problem, but its prospects remain uncertain. This review aimed to summarize the current applications of radiotherapy and immunotherapy, elaborate on the underlying mechanisms, and systematically review the preliminary results of RIT-related clinical trials for CRC. Studies have identified several key predictors of RIT efficacy. Summarily, rational RIT regimens can improve the outcomes of some patients with CRC, but current study designs have limitations. Further studies on RIT should focus on including larger sample sizes and optimizing the combination therapy regimen based on underlying influencing factors.

Management and prediction of immune-related adverse events for PD1/PDL-1 immunotherapy in colorectal cancer

Programmed cell death protein (PD-1) is an important immunosuppressive molecule, which can inhibit interaction between PD-1 and its ligand PD-L1, further enhancing the T cell response and anti-tumor activity, which is called immune checkpoint blockade. Immunotherapy, represented by immune checkpoint inhibitors, has opened up a new era of tumor treatment and is gradually being applied to colorectal cancer recently. Immunotherapy was reported could achieve a high objective response rate (ORR) for colorectal cancer with high microsatellite instability (MSI), thus opening up a new era of colorectal cancer immunotherapy. Along with the increasing use of PD1 drugs in colorectal cancer, we should pay more attention to the adverse effects of these immune drugs while seeing the hope. Immune-related adverse events (irAEs) caused by immune activation and immune homeostasis during anti-PD-1/PD-L1 therapy can affect multi-organ and even be fatal in serious cases. Therefore, understanding irAEs is essential for their early detection and appropriate management. In this article, we review the irAEs that occur during the treatment of colorectal cancer patients with PD-1/PD-L1 drugs, analyze the current controversies and challenges, and point out future directions that should be explored, including exploring efficacy predictive markers and optimizing the paradigm of individualized immunotherapy.

Current status of locally advanced rectal cancer therapy and future prospects

Rectal cancer treatment has been evolving ever since the beginning of the 20th century. Surgery was originally the only available method regardless of the extent of tumor invasion or nodal involvement status. Total mesorectal excision was established as the standard procedure in the early 1990s. Advances in the utilization of radiation for rectal cancer led to the addition of radiotherapy (RT) combined with chemotherapy to the postoperative treatment algorithm. The promising results of the Swedish short-course preoperative RT set the basis for a number of large randomized trials investigating the efficacy of neoadjuvant RT or chemoradiotherapy (CRT) for advanced rectal cancer. Both short-course RT and long-course preoperative CRT compared favorably to adjuvant treatment and became the standard of choice for patients with extramural invasion or lymph node involvement. Recently, the focus of clinical research has been shifted towards total neoadjuvant therapy (TNT), delivering the whole course of RT and chemotherapy before surgery, and showing good tolerance and encouraging efficacy. Although targeted therapies haven't displayed a benefit in the neoadjuvant setting, preliminary evidence suggests impressive efficacy of immunotherapy in rectal carcinomas with mismatch-repair deficiency. In this review, we provide an in-depth critical overview of all significant randomized trials that have shaped the current treatment guidelines for locally advanced rectal cancer and discuss future trends for the treatment of this common malignancy.

Total neoadjuvant treatment and organ preservation strategies in the management of localized rectal cancer: a narrative review and evidence-based algorithm

The multimodal approach with total mesorectal excision preceded by neoadjuvant (chemo)radiotherapy represented the mainstay treatment for locally advanced rectal cancer (LARC) for a long time. However, the benefit of adjuvant chemotherapy in terms of distant relapse reduction is limited. Recently, chemotherapy regimens administered before surgery and incorporated with (chemo)radiotherapy in total neoadjuvant treatment protocols have been established as new options in the management of LARC. Meanwhile, patients with clinical complete response to neoadjuvant treatment can benefit from organ preservation strategies, aimed at sparing surgery and long-term post-operative morbidities, while preserving an adequate disease control. However, the introduction of a non-operative management in clinical practice is a matter of debate with some concerns regarding the risk of local recurrence and long-term outcomes. In this review, we discuss how these recent advances are reshaping the multimodal management of localized rectal cancer and propose an algorithm to place them in the clinical practice.

Combining chemotherapy and tislelizumab with preoperative split-course hypofraction radiotherapy for locally advanced rectal cancer: study protocol of a prospective, single-arm, phase II trial

INTRODUCTION

Short-course radiotherapy (SCRT) with systemic therapy has the potential to further improve the long-term efficacy in patients with locally advanced rectal cancer (LARC). To maximise the benefits of neoadjuvant therapy for improved prognosis, it is important to determine the optimal mix of chemotherapy, immunotherapy and SCRT.

METHODS AND ANALYSIS

Fifty treatment-naïve patients with operable LARC (T3-4 and/or N+) will be recruited. Patients will be synchronously treated with capecitabine plus oxaliplatin (CAPOX) chemotherapy, tislelizumab and preoperative split-course hypofraction radiotherapy (SCHR) (5×7 Gy) before surgery. Chemotherapy for CAPOX starts on day 1 of every 21-day cycle: on day 1, oxaliplatin 130 mg/m² will be injected intravenously. On days 1-14, capecitabine 1000 mg/m² was ingested two times a day. Simultaneously, tocilizumab 200 mg will be given intravenously on the first day of every 21-day cycle. A single 7 Gy SCHR treatment (day 7 of each 21-day cycle) will be delivered five times during the seventh day of treatment. The primary endpoint will be pathological complete response. The secondary outcomes will be the 3-year disease-free survival, local recurrence rate, overall survival, sphincter-sparing surgery rate, R0 resection rate, predictive biomarkers and quality of life.

ETHICS AND DISSEMINATION

The study protocol was approved by the Ethics Committee of Xiehe Affiliated Hospital of Fujian Medical University (XAHFMU) (No. 2021YF025-01). Results from our study will be disseminated in international peer-reviewed journals. All study procedures were developed in order to assure data protection and confidentiality.

TRIAL REGISTRATION NUMBER

NCT05176964.

Safety and efficacy of radiotherapy/chemoradiotherapy combined with immune checkpoint inhibitors for non-small cell lung cancer: A systematic review and meta-analysis

Background

It is now widely accepted that radiotherapy (RT) can provoke a systemic immune response, which gives a strong rationale for the combination of RT and immune checkpoint inhibitors (ICIs). However, RT is a double-edged sword that not only enhances systemic antitumor immune response, but also promotes immunosuppression to some extent. Nevertheless, many aspects regarding the efficacy and safety of this combination therapy remain unknown. Therefore, a systematic review and meta-analysis was performed in order to assess the safety and efficacy of RT/chemoradiotherapy (CRT) and ICI combination therapy for non-small cell lung cancer (NSCLC) patients.

Methods

PubMed and several other databases were searched (according to specific criteria) to find relevant studies published prior to the 28th of February 2022.

Results

3,652 articles were identified for screening and 25 trials containing 1,645 NSCLC patients were identified. For stage II-III NSCLC, the one- and two-year overall survival (OS) was 83.25% (95% confidence interval (CI): 79.42%-86.75%) and 66.16% (95% CI: 62.3%-69.92%), respectively. For stage IV NSCLC, the one- and two-year OS was 50% and 25%. In our study, the pooled rate of grade 3-5 adverse events (AEs) and grade 5 AEs was 30.18% (95% CI: 10.04%-50.33%, I2: 96.7%) and 2.03% (95% CI: 0.03%-4.04%, I2: 36.8%), respectively. Fatigue (50.97%), dyspnea (46.06%), dysphagia (10%-82.5%), leucopenia (47.6%), anaemia (5%-47.6%), cough (40.09%), esophagitis (38.51%), fever (32.5%-38.1%), neutropenia (12.5%-38.1%), alopecia (35%), nausea (30.51%) and pneumonitis (28.53%) were the most common adverse events for the combined treatment. The incidence of cardiotoxicity (0%-5.00%) was low, but it was associated with a high mortality rate (0%-2.56%). Furthermore, the incidence of pneumonitis was 28.53% (95% CI: 19.22%-38.88%, I2: 92.00%), grade ≥ 3 pneumonitis was 5.82% (95% CI: 3.75%-8.32%, I2: 57.90%) and grade 5 was 0%-4.76%.

Conclusion

This study suggests that the addition of ICIs to RT/CRT for NSCLC patients may be both safe and feasible. We also summarize details of different RT combinations with ICIs to treat NSCLC. These findings may help guide the design of future trials, the testing of concurrent or sequential combinations for ICIs and RT/CRT could be particularly useful to guide the treatment of NSCLC patients.

Identification of hub genes and potential molecular mechanisms related to radiotherapy sensitivity in rectal cancer based on multiple datasets

BACKGROUND

Radiotherapy resistance is the main cause of low tumor regression for locally advanced rectum adenocarcinoma (READ). The biomarkers correlated to radiotherapy sensitivity and potential molecular mechanisms have not been completely elucidated.

METHODS

A mRNA expression profile and a gene expression dataset of READ (GSE35452) were acquired from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Differentially expressed genes (DEGs) between radiotherapy responder and non-responder of READ were screened out. Gene ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis for DEGs were performed. Random survival forest analysis was used to identified hub genes by randomForestSRC package. Based on CIBERSORT algorithm, Genomics of Drug Sensitivity in Cancer (GDSC) database, Gene set variation analysis (GSVA), enrichment analysis (GSEA), nomogram, motif enrichment and non-coding RNA network analyses, the associations between hub genes and immune cell infiltration, drug sensitivity, specific signaling pathways, prognosis prediction and TF - miRNA regulatory and ceRNA network were investigated. The expressions of hub genes in clinical samples were displayed with the online Human Protein Atlas (HPA).

RESULTS

In total, 544 up-regulated and 575 down-regulated DEGs in READ were enrolled. Among that, three hubs including PLAGL2, ZNF337 and ALG10 were identified. These three hub genes were significantly associated with tumor immune infiltration, different immune-related genes and sensitivity of chemotherapeutic drugs. Also, they were correlated with the expression of various disease-related genes. In addition, GSVA and GSEA analysis revealed that different expression levels of PLAGL2, ZNF337 and ALG10 affected various signaling pathways related to disease progression. A nomogram and calibration curves based on three hub genes showed excellent prognosis predictive performance. And then, a regulatory network of transcription factor (ZBTB6) - mRNA (PLAGL2) and a ceRNA network of miRNA (has-miR-133b) - lncRNA were established. Finally, the results from HPA online database demonstrated the protein expression levels of PLAGL2, ZNF337 and ALG10 varied widely in READ patients.

CONCLUSION

These findings indicated that up-regulation of PLAGL2, ZNF337 and ALG10 in READ associated with radiotherapy response and involved in multiple process of cellular biology in tumor. They might be potential predictive biomarkers for radiotherapy sensitivity and prognosis for READ.

Implications of recent neoadjuvant clinical trials on the future practice of radiotherapy in locally advanced rectal cancer

Over the last two decades, the standard treatment for locally advanced rectal cancer (LARC) has been neoadjuvant chemoradiotherapy plus total mesorectal excision followed by adjuvant chemotherapy. Total neoadjuvant treatment (TNT) and immunotherapy are two major issues in the treatment of LARC. In the two latest phase III randomized controlled trials (RAPIDO and PRODIGE23), the TNT approach achieved higher rates of pathologic complete response and distant metastasis-free survival than conventional chemoradiotherapy. Phase I/II clinical trials have reported promising response rates to neoadjuvant (chemo)-radiotherapy combined with immunotherapy. Accordingly, the treatment paradigm for LARC is shifting toward methods that increase the oncologic outcomes and organ preservation rate. However, despite the progress of these combined modality treatment strategies for LARC, the radiotherapy details in clinical trials have not changed significantly. To guide future radiotherapy for LARC with clinical and radiobiological evidence, this study reviewed recent neoadjuvant clinical trials evaluating TNT and immunotherapy from a radiation oncologist’s perspective.

Interim result of phase II, prospective, single-arm trial of long-course chemoradiotherapy combined with concurrent tislelizumab in locally advanced rectal cancer

Background

Neoadjuvant chemoradiotherapy is the standard treatment for locally advanced rectal cancer, with modest benefits on tumor regression and survival. Since chemoradiotherapy combined with immune checkpoint inhibitors has been reported to have synergic effects. This study aims to explore the safety and efficacy of long-course chemoradiotherapy combined with concurrent tislelizumab as a neoadjuvant treatment regimen for patients with locally advanced rectal cancer.

Methods

This manuscript reported the interim result of a prospective, multicenter, single-arm, phase II trial. Patients with mid-to-low locally advanced rectal cancer with clinical stages of cT3-4a N0M0 or cT1-4a N1-2M0 were included. The patients received long-course radiotherapy (50 Gy/25 f, 2 Gy/f, 5 days/week) and three 21-day cycles of capecitabine (1000 mg/m2, bid, day1-14) plus concurrent three 21-day cycles of tislelizumab (200 mg, day8), followed by a radical surgery 6-8 weeks after radiotherapy. The primary endpoint was the pathological complete response rate. (Clinical trial number: NCT04911517).

Results

A total of 26 patients completed the treatment protocol between April 2021 and June 2022. All patients completed chemoradiotherapy, 24 patients received three cycles of tislelizumab, and 2 patients received two cycles. The pathological complete remission (ypT0N0) was achieved in 50% (13/26) of the patients with all proficient mismatch repair tumors. The immune-related adverse event occurred in 19.2% (5/26) of patients. Patients with no CEA elevation or age less than 50 were more likely to benefit from this treatment regimen.

Conclusion

Long-course chemoradiotherapy combined with concurrent tislelizumab in patients with locally advanced low rectal cancer had favorable safety and efficacy, and does not increase the complication rate of surgery. Further study is needed to confirm these results.

Evaluating the Magnolol Anticancer Potential in MKN-45 Gastric Cancer Cells

Background and Objectives: Combination therapy improves the effect of chemotherapy on tumor cells. Magnolol, used in treating gastrointestinal disorders, has been shown to have anti-cancer properties. We investigated the synergistic effect of cisplatin and magnolol on the viability and maintenance of MKN-45 gastric cancer cells. Materials and Methods: The toxicity of magnolol and/or cisplatin was determined using the MTT technique. The trypan blue method was used to test magnolol and/or cisplatin's effect on MKN-45 cell growth. Crystal violet staining was used to assess the treated cells' tendency for colony formation. The expression of genes linked to apoptosis, cell cycle arrest, and cell migration was examined using the qPCR method. Results: According to MTT data, using magnolol and/or cisplatin significantly reduced cell viability. The ability of the treated cells to proliferate and form colonies was also reduced considerably. Magnolol and/or cisplatin treatment resulted in a considerable elevation in Bax expression. However, the level of Bcl2 expression was dramatically reduced. p21 and p53 expression levels were significantly increased in the treated cells, while MMP-9 expression was significantly reduced. Conclusions: These findings show that magnolol has a remarkable anti-tumor effect on MKN-45 cells. In combination with cisplatin, magnolol may be utilized to overcome cisplatin resistance in gastric cancer cells.