Colorectal carcinoma peritoneal metastases-derived organoids: results and perspective of a model for tailoring hyperthermic intraperitoneal chemotherapy from bench-to-bedside.

BACKGROUND: Peritoneal metastases from colorectal cancer (CRCPM) are related to poor prognosis. Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) have been reported to improve survival, but peritoneal recurrence rates are still high and there is no consensus on the drug of choice for HIPEC. The aim of this study was to use patient derived organoids (PDO) to build a relevant CRCPM model to improve HIPEC efficacy in a comprehensive bench-to-bedside strategy. METHODS: Oxaliplatin (L-OHP), cisplatin (CDDP), mitomycin-c (MMC) and doxorubicin (DOX) were used to mimic HIPEC on twelve PDO lines derived from twelve CRCPM patients, using clinically relevant concentrations. After chemotherapeutic interventions, cell viability was assessed with a luminescent assay, and the obtained dose-response curves were used to determine the half-maximal inhibitory concentrations. Also, induction of apoptosis by different HIPEC interventions on PDOs was studied by evaluating CASPASE3 cleavage. RESULTS: Response to drug treatments varied considerably among PDOs. The two schemes with better response at clinically relevant concentrations included MMC alone or combined with CDDP. L-OHP showed relative efficacy only when administered at low concentrations over a long perfusion period. PDOs showed that the short course/high dose L-OHP scheme did not appear to be an effective choice for HIPEC in CRCPM. HIPEC administered under hyperthermia conditions enhanced the effect of chemotherapy drugs against cancer cells, affecting PDO viability and apoptosis. Finally, PDO co-cultured with cancer-associated fibroblast impacted HIPEC treatments by increasing PDO viability and reducing CASPASES activity. CONCLUSIONS: Our study suggests that PDOs could be a reliable in vitro model to evaluate HIPEC schemes at individual-patient level and to develop more effective treatment strategies for CRCPM.

Biomimetic piezoelectric nanomaterial-modified oral microrobots for targeted catalytic and immunotherapy of colorectal cancer.

Lactic acid (LA) accumulation in the tumor microenvironment poses notable challenges to effective tumor immunotherapy. Here, an intelligent tumor treatment microrobot based on the unique physiological structure and metabolic characteristics of Veillonella atypica (VA) is proposed by loading Staphylococcus aureus cell membrane-coating BaTiO3 nanocubes (SAM@BTO) on the surface of VA cells (VA-SAM@BTO) via click chemical reaction. Following oral administration, VA-SAM@BTO accurately targeted orthotopic colorectal cancer through inflammatory targeting of SAM and hypoxic targeting of VA. Under in vitro ultrasonic stimulation, BTO catalyzed two reduction reactions (O2 → •O2- and CO2 → CO) and three oxidation reactions (H2O → •OH, GSH → GSSG, and LA → PA) simultaneously, effectively inducing immunogenic death of tumor cells. BTO catalyzed the oxidative coupling of VA cells metabolized LA, effectively disrupting the immunosuppressive microenvironment, improving dendritic cell maturation and macrophage M1 polarization, and increasing effector T cell proportions while decreasing regulatory T cell numbers, which facilitates synergetic catalysis and immunotherapy.

Role played by MDSC in colitis-associated colorectal cancer and potential therapeutic strategies.

Colitis-associated colorectal cancer has been a hot topic in public health issues worldwide. Numerous studies have demonstrated the significance of myeloid-derived suppressor cells (MDSCs) in the progression of this ailment, but the specific mechanism of their role in the transformation of inflammation to cancer is unclear, and potential therapies targeting MDSC are also unclear. This paper outlines the possible involvement of MDSC to the development of colitis-associated colorectal cancer. It also explores the immune and other relevant roles played by MDSC, and collates relevant targeted therapies against MDSC. In addition, current targeted therapies for colorectal cancer are analyzed and summarized.

Hyperthermic intraperitoneal chemotherapy in colorectal cancer.

BACKGROUND: This study evaluated the efficacy of hyperthermic intraperitoneal chemotherapy (HIPEC) in colorectal cancer with peritoneal metastases (pmCRC) in a large international data set of patients. PATIENTS AND METHODS: Patients with pmCRC from 39 centres who underwent cytoreductive surgery with HIPEC between 1991 and 2018 were selected and compared for the HIPEC protocols received-oxaliplatin-HIPEC versus mitomycin-HIPEC. Following analysis of crude data, propensity-score matching (PSM) and Cox-proportional hazard modelling were performed. Outcomes of interest were overall survival (OS), recurrence-free survival (RFS) and the HIPEC dose-response effects (high versus low dose, dose intensification and double drug protocols) on OS, RFS and 90-day morbidity. Furthermore, the impact of the treatment time period was assessed. RESULTS: Of 2760 patients, 2093 patients were included. Median OS was 43 months (95% c.i. 41 to 46 months) with a median RFS of 12 months (95% c.i. 12 to 13 months). The oxaliplatin-HIPEC group had an OS of 47 months (95% c.i. 42 to 53 months) versus 39 months (95% c.i. 36 to 43 months) in the mitomycin-HIPEC group (P = 0.002), aHR 0.77, 95% c.i. 0.67 to 0.90, P < 0.001. The OS benefit persisted after PSM of the oxaliplatin-HIPEC group and mitomycin-HIPEC group (48 months (95% c.i. 42 to 59 months) versus 40 months (95% c.i. 37 to 44 months)), P < 0.001, aHR 0.78 (95% c.i. 0.65 to 0.94), P = 0.009. Similarly, matched RFS was significantly higher for oxaliplatin-HIPEC versus others (13 months (95% c.i. 12 to 15 months) versus 11 months (95% c.i. 10 to 12 months, P = 0.02)). High-dose mitomycin-HIPEC protocols had similar OS compared to oxaliplatin-HIPEC. HIPEC dose intensification within each protocol resulted in improved survival. Oxaliplatin + irinotecan-HIPEC resulted in the most improved OS (61 months (95% c.i. 51 to 101 months)). Ninety-day mortality in both crude and PSM analysis was worse for mitomycin-HIPEC. There was no change in treatment effect depending on the analysed time period. CONCLUSIONS: Oxaliplatin-based HIPEC provided better outcomes compared to mitomycin-based HIPEC. High-dose mitomycin-HIPEC was similar to oxaliplatin-HIPEC. The 90-day mortality difference favours the oxaliplatin-HIPEC group. A trend for dose-response between low- and high-dose HIPEC was reported.

Missingness mechanisms and generalizability of patient reported outcome measures in colorectal cancer survivors - assessing the reasonableness of the "missing completely at random" assumption.

BACKGROUND: Patient-Reported Outcome Measures (PROM) provide important information, however, missing PROM data threaten the interpretability and generalizability of findings by introducing potential bias. This study aims to provide insight into missingness mechanisms and inform future researchers on generalizability and possible methodological solutions to overcome missing PROM data problems during data collection and statistical analyses. METHODS: We identified 10,236 colorectal cancer survivors (CRCs) above 18y, diagnosed between 2014 and 2018 through the Danish Clinical Registries. We invited a random 20% (2,097) to participate in a national survey in May 2023. We distributed reminder e-mails at day 10 and day 20, and compared Initial Responders (response day 0-9), Subsequent Responders (response day 10-28) and Non-responders (no response after 28 days) in demographic and cancer-related characteristics and PROM-scores using linear regression. RESULTS: Of the 2,097 CRCs, 1,188 responded (57%). Of these, 142 (7%) were excluded leaving 1,955 eligible CRCs. 628 (32%) were categorized as initial responders, 418 (21%) as subsequent responders, and 909 (47%) as non-responders. Differences in demographic and cancer-related characteristics between the three groups were minor and PROM-scores only marginally differed between initial and subsequent responders. CONCLUSION: In this study of long-term colorectal cancer survivors, we showed that initial responders, subsequent responders, and non-responders exhibit comparable demographic and cancer-related characteristics. Among respondents, Patient-Reported Outcome Measures were also similar, indicating generalizability. Assuming Patient-Reported Outcome Measures of subsequent responders represent answers by the non-responders (would they be available), it may be reasonable to judge the missingness mechanism as Missing Completely At Random.

Clinicopathologic Profile and Treatment Outcomes of Colorectal Cancer in Young Adults: A Multicenter Study From India.

PURPOSE: Colorectal cancer (CRC) in young adults is a rising concern in developing countries such as India. This study investigates clinicopathologic profiles, treatment patterns, and outcomes of CRC in young adults, focusing on adolescent and young adult (AYA) CRC in a low- and middle-income country (LMIC). METHODS: A retrospective registry study from January 2018 to December 2020 involved 126 young adults (age 40 years and younger) with CRC. Patient demographics, clinical features, tumor characteristics, treatment modalities, and survival outcomes were analyzed after obtaining institutional ethics committees' approval. RESULTS: Among 126 AYA patients, 62.70% had colon cancer and 37.30% had rectal cancer. Most patients (67%) were age 30-39 years, with no significant gender predisposition. Females had higher metastatic burden. Abdominal pain with obstruction features was common. Adenocarcinoma (65%) with signet ring differentiation (26%) suggested aggressive behavior. Limited access to molecular testing hindered mutation identification. Capecitabine-based chemotherapy was favored because of logistical constraints. Adjuvant therapy showed comparable recurrence-free survival in young adults and older patients. For localized colon cancer, the 2-year median progression-free survival was 74%, and for localized rectal cancer, it was 18 months. Palliative therapy resulted in a median overall survival of 33 months (95% CI, 18 to 47). Limited access to targeted agents affected treatment options, with only 27.5% of patients with metastatic disease receiving them. Chemotherapy was generally well tolerated, with hematologic side effect being most common. CONCLUSION: This collaborative study in an LMIC offers crucial insights into CRC in AYA patients in India. Differences in disease characteristics, treatment patterns, and limited access to targeted agents highlight the need for further research and resource allocation to improve outcomes in this population.

The double burden of severe mental illness and cancer: a population-based study on colorectal cancer care pathways from screening to end-of-life care.

AIMS: Cancer is one of the main causes of death in persons with severe mental illness (SMI). Although their cancer incidence is similar, or sometimes even potentially lower compared to the general population, their cancer mortality remains higher. The role of healthcare provision and care equity in this mortality is increasingly being addressed in research, but available studies are limited in their scope. In this context, our aim was to compare colorectal cancer (CRC) care pathways from screening to end-of-life care in patients with and without pre-existing SMI on a national scale. METHODS: This research leverages real-world data from the French national health claims database, covering the entire population, to assess cancer screening, diagnosis, treatment and post-treatment follow-up as well as quality of care (QOC) pathways among patients with incident CRC in 2015-2018, considering whether they had pre-existing SMI. We matched patients with SMI with three patients without - on age, sex, region of residence, year of cancer incidence and cancer type and location at presentation - as well as nationally established quality of CRC care indicators and regression models adjusting for relevant socio-economic, clinical and care provider-related covariates. RESULTS: Among patients with incident CRC, 1,532 individuals with pre-existing SMI were matched with individuals without SMI. After adjusting for covariates, both colon and rectal cancer patients with SMI were less likely to participate in the national CRC screening programme and to receive advanced diagnostic examinations (e.g., colonoscopies and several complementary diagnostic examinations). They also had lower odds of receiving combined treatments (e.g., neoadjuvant chemotherapy, radiotherapy and excision) and of having access to targeted therapy or capecitabine but higher odds for invasive care (e.g., stoma). Colon cancer patients with SMI were also more likely to have no treatment at all, and rectal cancer patients with SMI were less likely to receive post-treatment follow-up. Suboptimal QOC was observed for both groups of patients, but to a higher extent for patients with SMI, with statistically significant differences for indicators focusing on diagnosis and post-treatment follow-up. CONCLUSIONS: Our findings reveal discrepancies across the care continuum of CRC between individuals with and without SMI and provide initial avenues on where to focus future efforts to address them, notably at the entry and exit stages of cancer care pathways, while calling for further research on the mechanisms preventing equity of physical healthcare for individuals with SMI.

Colorectal cancer health and care quality indicators in a federated setting using the Personal Health Train.

OBJECTIVE: Hospitals and healthcare providers should assess and compare the quality of care given to patients and based on this improve the care. In the Netherlands, hospitals provide data to national quality registries, which in return provide annual quality indicators. However, this process is time-consuming, resource intensive and risks patient privacy and confidentiality. In this paper, we presented a multicentric 'Proof of Principle' study for federated calculation of quality indicators in patients with colorectal cancer. The findings suggest that the proposed approach is highly time-efficient and consume significantly lesser resources. MATERIALS AND METHODS: Two quality indicators are calculated in an efficient and privacy presevering federated manner, by i) applying the Findable Accessible Interoperable and Reusable (FAIR) data principles and ii) using the Personal Health Train (PHT) infrastructure. Instead of sharing data to a centralized registry, PHT enables analysis by sending algorithms and sharing only insights from the data. RESULTS: ETL process extracted data from the Electronic Health Record systems of the hospitals, converted them to FAIR data and hosted in RDF endpoints within each hospital. Finally, quality indicators from each center are calculated using PHT and the mean result along with the individual results plotted. DISCUSSION AND CONCLUSION: PHT and FAIR data principles can efficiently calculate quality indicators in a privacy-preserving federated approach and the work can be scaled up both nationally and internationally. Despite this, application of the methodology was largely hampered by ELSI issues. However, the lessons learned from this study can provide other hospitals and researchers to adapt to the process easily and take effective measures in building quality of care infrastructures.

[Sensitivity of colorectal cancer organoids to hyperthermic intraperitoneal chemotherapy with lobaplatin].

Objective: To investigate the sensitivity of tumor organoids derived from samples of colorectal cancer to lobaplatin and oxaliplatin hyperthermic perfusion in vitro and to assist clinical development of hyperthermic intraperitoneal chemotherapy. Method: Tumor samples and relevant clinical data were collected from patients with pathologically confirmed colorectal cancer in the Sixth Affiliated Hospital of Sun Yat-sen University from July 2021 to December 2022. Organoids were cultured and tumor tissue were passaged. In vitro hyperthermic perfusion experiments were performed on organoids with good viability. Firstly, 10 organoids were treated with oxaliplatin and lobaplatin at the following six concentrations: 1 000, 250, 62.5, 15.6, 3.9, and 0.98 µmol/L. The organoids were exposed to oxaliplatin at 42℃ for 30 minutes and to lobaplatin at 42℃ for 60 minutes. Dose-response curves of responses to in vitro hyperthermic perfusion with these two drugs were constructed and evaluated. Clinical doses of oxaliplatin and lobaplatin were further tested on 30 organoids. This testing revealed oxaliplatin was effective at 579 µmol/L at a hyperthermic perfusion temperature of 42℃ for 30 min and lobaplatin was effective at 240 µmol/L at a hyperthermic perfusion temperature of 42℃ for 60 minutes. Result: Thirty-two tumor organoids were cultured from samples of colorectal cancer. The median concentration required for oxaliplatin to eliminate 50% of tumor cells (IC50) was 577.45 µmol/L (IQR: 1846.09 µmol/L). The median IC50 for lobaplatin was 85.04 µmol/L (IQR: 305.01 µmol/L).The difference between the two groups was not statistically significant (Z=1.784, P=0.084). In seven of 10 organoids, lobaplatin showed a greater IC50 after in vitro hyperthermic perfusion than did oxaliplatin. Testing of 30 organoids with clinical doses of oxaliplatin and lobaplatin revealed that oxaliplatin achieved an average inhibition rate of 39.6% (95%CI: 32.1%‒47.0%), whereas the average rate of inhibition for lobaplatin was 89.7% (95%CI: 87.0%‒92.3%): this difference is statistically significant (t=‒15.282, P<0.001). Conclusion: The rate of inhibition achieved by hyperthermic perfusion of lobaplatin in vitro is better than that achieved by hyperthermic perfusion with oxaliplatin. Lobaplatin is more effective than oxaliplatin when administered by hyperthermic intraperitoneal perfusion and therefore has the potential to replace oxaliplatin in this setting.

[Research progress of diagnosis and treatment of early-onset colorectal cancer].

In recent years, the incidence rate of early-onset colorectal cancer (EOCRC) continues to rise, but its pathogenesis is still unclear. EOCRC is different from late-onset colorectal cancer in terms of the clinical and molecular pathological features, but their treatment strategies are the same, due to a lack of specific guidelines of screening, diagnosis and treatment for EOCRC. This article summarizes the research progress of epidemiological characteristics, risk factors, clinical features, molecular pathological features, pathogenesis, and prevention and screening strategies for EOCRC, in order to provide theoretical basis for the clinical treatment of patients with EOCRC.

Development of an anoikis-related gene signature and prognostic model for predicting the tumor microenvironment and response to immunotherapy in colorectal cancer.

The effect of anoikis-related genes (ARGs) on clinicopathological characteristics and tumor microenvironment remains unclear. We comprehensively analyzed anoikis-associated gene signatures of 1057 colorectal cancer (CRC) samples based on 18 ARGs. Anoikis-related molecular subtypes and gene features were identified through consensus clustering analysis. The biological functions and immune cell infiltration were assessed using the GSVA and ssGSEA algorithms. Prognostic risk score was constructed using multivariate Cox regression analysis. The immunological features of high-risk and low-risk groups were compared. Finally, DAPK2-overexpressing plasmid was transfected to measure its effect on tumor proliferation and metastasis in vitro and in vivo. We identified 18 prognostic ARGs. Three different subtypes of anoikis were identified and demonstrated to be linked to distinct biological processes and prognosis. Then, a risk score model was constructed and identified as an independent prognostic factor. Compared to the high-risk group, patients in the low-risk group exhibited longer survival, higher enrichment of checkpoint function, increased expression of CTLA4 and PD-L1, higher IPS scores, and a higher proportion of MSI-H. The results of RT-PCR indicated that the expression of DAPK2 mRNA was significantly downregulated in CRC tissues compared to normal tissues. Increased DAPK2 expression significantly suppressed cell proliferation, promoted apoptosis, and inhibited migration and invasion. The nude mice xenograft tumor model confirmed that high expression of DAPK2 inhibited tumor growth. Collectively, we discovered an innovative anoikis-related gene signature associated with prognosis and TME. Besides, our study indicated that DAPK2 can serve as a promising therapeutic target for inhibiting the growth and metastasis of CRC.

[Advances of CAR-T cell therapy in treating colorectal cancer].

Globally, colorectal cancer (CRC) ranks as the third most common cancer and the second leading cause of cancer-related fatalities. According to the World Health Organization, there are over 1.9 million annual cases of CRC diagnosed worldwide, resulting in more than 900 000 deaths. In recent years, chimeric antigen receptor T (CAR-T) cell therapy has shown clinical success in treating certain hematological malignancies and is now being explored for its potential in targeting solid tumors like CRC. Currently, CAR-T cell therapies targeting carcinoembryonic antigen (CEA), natural killer group 2, member D ligand (NKG2DL), and other markers have achieved remarkable results in clinical trials, albeit encountering significant challenges. This review summarizes the promising targets of CAR-T cell therapy for CRC and highlights progress made in clinical trials and preclinical studies. Additionally, the review discusses the challenges faced by CAR-T cell therapy in CRC treatment, including a shortage of tumor-specific antigens, cytokine release syndrome, adverse tumor microenvironment, and limited infiltration of CAR-T cells. In summary, this review provides an overview of the latest research progress and challenges in CAR-T cell therapy for CRC, aiming to contribute fresh insights for the clinical treatment of this disease.

State-of-the-Art Management of Colorectal Cancer: Treatment Advances and Innovation.

Colorectal cancer (CRC) remains a significant global health challenge, ranking among the leading causes of cancer-related morbidity and mortality worldwide. Recent advancements in molecular characterization have revolutionized our understanding of the heterogeneity within colorectal tumors, particularly in the context of tumor sidedness. Tumor sidedness, referring to the location of the primary tumor in either the right or left colon, has emerged as a critical factor influencing prognosis and treatment responses in metastatic CRC. Molecular underpinnings of CRC, the impact of tumor sidedness, and how this knowledge guides therapeutic decisions in the era of precision medicine have led to improved outcomes and better quality of life in patients. The emergence of circulating tumor DNA as a prognostic and predictive tool in CRC heralds promising advancements in the diagnosis and monitoring of the disease. This innovation facilitates better patient selection for exploration of additional treatment options. As the field progresses, with investigational agents demonstrating potential as future treatments for refractory metastatic CRC, new avenues for enhancing outcomes in this challenging disease are emerging.

Evolving Standards of Care in the Management of Localized Colorectal Cancer.

The treatment of patients with localized rectal cancer is complex and requires input from a multidisciplinary team. Baseline local staging and mismatch repair protein testing are vital to develop individualized treatment plans. There are multiple options in terms of treatment modalities and sequencing, including transanal excision, short-course radiation, long-course chemoradiation, chemotherapy doublet or triplet, nonoperative management, and immune checkpoint blockade for patients with mismatch repair deficient tumors. While localized colon cancer is typically treated with surgical resection and consideration of adjuvant chemotherapy, emerging data suggest that neoadjuvant chemotherapy may be beneficial in patients with higher-risk disease. Quality-of-life considerations are imperative to prevent potential chronic effects on psychosocial health, neuropathy, fertility, and bowel, bladder, and sexual function. The omission of radiation or surgery can mitigate these toxicities without diminishing oncologic outcomes. The optimal treatment plan and sequence is not a one-size-fits-all approach but rather should be personalized to the patient's disease burden, tumor location, comorbidities, and preferences.

Integrating artificial intelligence techniques for advancements in colorectal cancer management: navigating past and predicting future direction.

Artificial Intelligence (AI) in the last few years has emerged as a valuable tool in managing colorectal cancer, revolutionizing its management at different stages. In early detection and diagnosis, AI leverages its prowess in imaging analysis, scrutinizing CT scans, MRI, and colonoscopy views to identify polyps and tumors. This ability enables timely and accurate diagnoses, initiating treatment at earlier stages. AI has helped in personalized treatment planning because of its ability to integrate diverse patient data, including tumor characteristics, medical history, and genetic information. Integrating AI into clinical decision support systems guarantees evidence-based treatment strategy suggestions in multidisciplinary clinical settings, thus improving patient outcomes. This narrative review explores the multifaceted role of AI, spanning early detection of colorectal cancer, personalized treatment planning, polyp detection, lymph node evaluation, cancer staging, robotic colorectal surgery, and training of colorectal surgeons.

Laser-activable murine ferritin nanocage for chemo-photothermal therapy of colorectal cancer.

Chemotherapy, as a conventional strategy for tumor therapy, often leads to unsatisfied therapeutic effect due to the multi-drug resistance and the serious side effects. Herein, we genetically engineered a thermal-responsive murine Ferritin (mHFn) to specifically deliver mitoxantrone (MTO, a chemotherapeutic and photothermal agent) to tumor tissue for the chemotherapy and photothermal combined therapy of colorectal cancer, thanks to the high affinity of mHFn to transferrin receptor that highly expressed on tumor cells. The thermal-sensitive channels on mHFn allowed the effective encapsulation of MTO in vitro and the laser-controlled release of MTO in vivo. Upon irradiation with a 660 nm laser, the raised temperature triggered the opening of the thermal-sensitive channel in mHFn nanocage, resulting in the controlled and rapid release of MTO. Consequently, a significant amount of reactive oxygen species was generated, causing mitochondrial collapse and tumor cell death. The photothermal-sensitive controlled release, low systemic cytotoxicity, and excellent synergistic tumor eradication ability in vivo made mHFn@MTO a promising candidate for chemo-photothermal combination therapy against colorectal cancer.

Neoadjuvant treatment of colorectal cancer: comprehensive review.

BACKGROUND: Neoadjuvant therapy has an established role in the treatment of patients with colorectal cancer. However, its role continues to evolve due to both advances in the available treatment modalities, and refinements in the indications for neoadjuvant treatment and subsequent surgery. METHODS: A narrative review of the most recent relevant literature was conducted. RESULTS: Short-course radiotherapy and long-course chemoradiotherapy have an established role in improving local but not systemic disease control in patients with rectal cancer. Total neoadjuvant therapy offers advantages over short-course radiotherapy and long-course chemoradiotherapy, not only in terms of increased local response but also in reducing the risk of systemic relapses. Non-operative management is increasingly preferred to surgery in patients with rectal cancer and clinical complete responses but is still associated with some negative impacts on functional outcomes. Neoadjuvant chemotherapy may be of some benefit in patients with locally advanced colon cancer with proficient mismatch repair, although patient selection is a major challenge. Neoadjuvant immunotherapy in patients with deficient mismatch repair cancers in the colon or rectum is altering the treatment paradigm for these patients. CONCLUSION: Neoadjuvant treatments for patients with colon or rectal cancers continue to evolve, increasing the complexity of decision-making for patients and clinicians alike. This review describes the current guidance and most recent developments.

Gene mutation profiling in microsatellite instability colorectal cancer and its association with the efficacy of immunotherapy: A retrospective study.

BACKGROUND: Microsatellite instability-high (MSI-H) colorectal cancer (CRC) is known for its heightened responsiveness to immunotherapy. However, establishing robust predictive markers for immunotherapy efficacy remains imperative. This retrospective study aimed to elucidate the genetic landscape of MSI-H CRC and correlate these genetic alterations with immunotherapy outcomes in a cohort of 121 patients. METHODS: We analyzed clinical and molecular data from 121 patients with MSI-H CRC. We conducted a thorough genetic analysis of MSI-H CRC patients, with a specific emphasis on the APC, TP53, RAS, and MMR genes. We further analyzed the relationship between gene mutations and immunotherapy efficacy. The primary endpoints analyzed were objective response rate (ORR) and progression-free survival (PFS). All statistical analysis was conducted using SPSS26.0 and R 4.2.0 software. RESULTS: Our findings underscored the complexity of the genetic landscape in MSI-H CRC, shedding light on the intricate interplay of these genes in CRC development. Notably, mutations in MMR genes exhibited a distinctive pattern, providing insights into the underlying mechanisms of MSI-H. Furthermore, our results revealed correlations between specific genetic alterations and immunotherapy outcomes, with a particular focus on treatment response rates and progression-free survival. CONCLUSION: This study represents a significant step toward unraveling the genetic nuances of MSI-H CRC. The distinctive pattern of MMR gene mutations not only adds depth to our understanding of MSI-H CRC but also hints at potential avenues for targeted therapies. This research sets the stage for future investigations aimed at refining therapeutic strategies and improving outcomes for patients with MSI-H CRC.