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

Introducing Neoadjuvant Immunotherapy for Colorectal Cancer: Advancing the Frontier

OBJECTIVE

To give surgeons a review of the current and future use of neoadjuvant immunotherapy in patients with localized colorectal cancer (CRC).

BACKGROUND

Immunotherapy has revolutionized the standard of care in oncology and improved survival outcomes in several cancers. However, the applicability of immunotherapy is still an ongoing challenge. Some cancer types are less responsive to immunotherapy, and the heterogeneity in responses within cancer types is poorly understood. Clinical characteristics of the patient, the timing of immunotherapy in relation to surgery, diversities in the immune responses, clonal heterogeneity, different features of the tumor microenvironment, and genetic alterations are some factors among many that may influence the efficacy of immunotherapy.

RESULTS

In this narrative review, we describe the major types of immunotherapy used to treat localized CRC. Furthermore, we discuss the prediction of response to immunotherapy in relation to biomarkers and radiologic assessment. Finally, we consider the future perspectives of clinical implications and response patterns, as well as the potential and challenges of neoadjuvant immunotherapy in localized CRC.

CONCLUSIONS

Establishing mismatch repair (MMR) status at the time of diagnosis is central to the potential use of neoadjuvant immunotherapy, in particular immune checkpoint inhibitors, in localized CRC. To date, efficacy is primarily seen in patients with deficient MMR status and polymerase epsilon mutations, although a small group of patients with proficient MMR does respond. In conclusion, neoadjuvant immunotherapy shows promising complete response rates, which may open a future avenue of an organ-sparing watch-and-wait approach for a group of patients.

Pathological response following neoadjuvant immunotherapy and imaging characteristics in dMMR/MSI-H locally advanced colorectal cancer

Background

In recent years, there has been significant research interest in immunotherapy for colorectal cancer (CRC). Specifically, immunotherapy has emerged as the primary treatment for patients with mismatch repair gene defects (dMMR) or microsatellite highly unstable (MSI-H) who have colorectal cancer. Yet, there is currently no data to support the practicality and safety of neoadjuvant immunotherapy for colorectal cancer with dMMR or MSI-H. Therefore, a study was conducted to identify the postoperative pathology, safety profile, and imaging features of patients with dMMR or MSI-H CRC following neoadjuvant immunotherapy.

Methods

The retrospective study was carried out on patients with locally advanced or metastatic CRC who received immunotherapy at Sichuan Cancer Hospital, with approval from the hospital's ethics committee. The study aimed to assess the short-term effectiveness of immunotherapy by focusing on pathological complete response (pCR) as the primary outcome, while also considering secondary endpoints such as objective response rate, disease-free survival, and safety profile.

Results

Twenty patients with dMMR/MSI-H CRC who underwent neoadjuvant immunotherapy as part of the treatment were enrolled between May 2019 and February 2024 at Sichuan Cancer Hospital. Out of these patients, eight patients received PD-1 blockade monotherapy as neoadjuvant treatment, while 12 were administered a combined therapy of anti-CTLA-4 and anti-PD-1. 12 patients received Nivolumab plus Ipilimumab regimen and 8 patients received PD-1 blockades (2 patients were Pembrolizumab, 2 patients were Sintilimab, 4 patients were Tislelizumab) monotherapy. Additionally, 19 patients underwent surgery after immunotherapy and of these, 15 (75.0%) achieved complete pathological response (pCR), 8 (66.7%) achieved the same on Nivolumab plus Ipilimumab immunotherapy while 7 (87.5%) achieved on PD-1 antibody monotherapy. The overall response rate (ORR) was 75%, with 45.0% of patients experiencing grade I/II immunotherapy-related adverse events. The most frequent adverse event observed was increased ALT i.e. 20%. Notably, no postoperative complications were observed.

Conclusion

Based on the findings, neoadjuvant immunotherapy for colorectal cancer may be both safe and effective in clinical practice. Furthermore, the study suggested that dual immunotherapy could potentially increase the immunotherapy cycle and contribute to a superior pCR rate. However, the conclusion emphasized the need for further prospective clinical trials to validate these results.

Clinical status and future prospects of neoadjuvant immunotherapy for localized mismatch repair-deficient cancers: a review

Frameshift mutations accumulate in cancers related to mismatch repair deficiency (dMMR), which has the potential to produce various neoantigens, representing a distinct subset of cancers that respond considerably to immunotherapy. In recent years, robust evidence has supported the first-line application of immunotherapy for patients with metastatic dMMR cancers, which provoked extensive investigations of the feasibility and efficacy of immunotherapy in up-front settings, including neoadjuvant therapy. Several completed trials with small sample sizes suggested that neoadjuvant immunotherapy can achieve an impressively high complete response rate, for the first time offering the potential of systemic therapy to cure cancer without the need for surgical resection. However, a difficult dilemma emerges: clinicians are now facing a selection between the standard of care with good evidence for proficient MMR but suboptimal for dMMR cancers and the emerging immunotherapy with promising results but only based on a limited number of patients with shorter duration of follow-up. This review aims to provide a comprehensive summary of the biological rationale and clinical status of neoadjuvant immunotherapy in patients with dMMR cancers. Furthermore, I elaborate on particular issues that must be taken into consideration for further advancement in the field.

Efficacy and Safety of Neoadjuvant Subcutaneous Envafolimab in dMMR/MSI-H Locally Advanced Colon Cancer

BACKGROUND

Neoadjuvant immunotherapy with programmed death-ligand 1 blockade for colon cancer, especially for mismatch repair-deficient (dMMR)/high microsatellite instability (MSI-H) colon cancer, has gained considerable attention recently.

OBJECTIVE

This study aimed to assess the safety and efficacy of neoadjuvant subcutaneous envafolimab in patients with dMMR/MSI-H locally advanced colon cancer.

METHODS

Patients with dMMR/MSI-H locally advanced colon cancer treated with envafolimab at Sun Yat-sen University Cancer Center and Yunnan Cancer Hospital from October 2021 to July 2023 were retrospectively reviewed and analyzed. The primary endpoint was the pathological complete response (CR) rate, and secondary endpoints were treatment-related adverse events and complete clinical response rate.

RESULTS

Overall, 15 patients were analyzed. After neoadjuvant immunotherapy with envafolimab, six patients achieved a CR, with five partial responses, and four stable disease. Three patients achieving a complete clinical response chose to accept a "watch and wait" strategy, and surgery was performed in 12 patients. Postoperative pathology results revealed seven patients achieved pathological CRs, and five patients achieved tumor regression grade 2, with 66.7% of the total CR rate. The most common treatment-related adverse events were pruritus and rash (40%), with no severe cases. No recurrences occurred over a 7.9-month follow-up.

CONCLUSIONS

Envafolimab yielded promising surgical outcomes and safety in dMMR/MSI-H locally advanced colon cancer, representing a promising treatment modality for this population.

An SNP Marker Predicts Colorectal Cancer Outcomes with 5-Fluorouracil-Based Adjuvant Chemotherapy Post-Resection

Colorectal cancer (CRC) is a global health concern, necessitating adjuvant chemotherapy post-curative surgery to mitigate recurrence and enhance survival, particularly in intermediate-stage patients. However, existing therapeutic disparities highlight the need for biomarker-guided adjuvant chemotherapy to achieve better CRC inhibition. This study explores the molecular mechanisms underlying the inhibition of CRC through a genome-wide association study (GWAS) focused on 5-fluorouracil (5-FU)-based adjuvant therapy in intermediate-stage CRC patients, a domain previously unexplored. We retrospectively included 226 intermediate-stage CRC patients undergoing surgical resection followed by 5-FU-based adjuvant chemotherapy. The exploration cohort comprised 31 patients, and the validation cohort included 195 individuals. Genotyping was carried out using either Axiom Genome-Wide TWB 2.0 Array Plate-based or polymerase chain reaction-based methods on genomic DNA derived from collected tissue samples. Statistical analyses involved descriptive statistics, Kaplan-Meier analyses, and Cox proportional hazard analyses. From the GWAS, potential genetic predictors, GALNT14-rs62139523 and DNMBP-rs10786578 genotypes, of 5-FU-based adjuvant therapy following surgery in intermediate-stage CRC patients were identified. Validation in a larger cohort of 195 patients emphasized the predictive significance of GALNT14-rs62139523 genotypes, especially the "A/G" genotype, for improved overall and progression-free survival. This predictive association remained robust across various subgroups, with exceptions for specific demographic and clinical parameters such as age < 58 years old, CEA ≤ 2.5 ng/mL, tumor diameter > 44.0 mm, and tumor-free margin ≥ 50 mm. This study identifies that the GALNT14-rs62139523 "A/G" genotype modulates therapeutic outcomes, establishing it as a promising biomarker for predicting favorable responses to 5-FU-based adjuvant chemotherapy in intermediate-stage CRC patients, although further investigations are needed to detail these mechanisms.

Neoadjuvant envafolimab in a patient with MSI-H/dMMR colon cancer: a case report and literature review

Clinical evidences of neoadjuvant immunotherapy in patients with mismatch repair deficient/microsatellite instability-high status (dMMR/MSI-H) colorectal cancer have not been well received. A 36-year-old man complained of recurrent right upper quadrant pain for more than 1 year, and the symptoms were not significantly relieved after 10 days of oral Changyanning tablet. The patient was finally diagnosed as dMMR/MSI-H colon cancer. Tumor regression was achieved after seven cycles of envafolimab treatment, and the patient obtained postoperative pathological complete response (pCR). Here, we report a case of MSI-H/dMMR transverse colon cancer, who obtained pCR after neoadjuvant envafolimab (a novel subcutaneous single-domain anti-PD-L1 antibody) with a favorable safety profile, aiming to enhance the experiences of comprehensive diagnosis and treatment of colon cancer.

Current landscape of preoperative neoadjuvant therapies for initial resectable colorectal cancer liver metastasis

Colorectal cancer liver metastasis (CRLM) presents a clinical challenge, and optimizing treatment strategies is crucial for improving patient outcomes. Surgical resection, a key element in achieving prolonged survival, is often linked to a heightened risk of recurrence. Acknowledging the potential benefits of preoperative neoadjuvant chemotherapy in managing resectable liver metastases, this approach has gained attention for its role in tumor downsizing, assessing biological behavior, and reducing the risk of postoperative recurrence. However, the use of neoadjuvant chemotherapy in initially resectable CRLM sparks ongoing debates. The balance between tumor reduction and the risk of hepatic injury, coupled with concerns about delaying surgery, necessitates a nuanced approach. This article explores recent research insights and draws upon the practical experiences at our center to address critical issues regarding considerations for initially resectable cases. Examining the criteria for patient selection and the judicious choice of neoadjuvant regimens are pivotal areas of discussion. Striking the right balance between maximizing treatment efficacy and minimizing adverse effects is imperative. The dynamic landscape of precision medicine is also reflected in the evolving role of gene testing, such as RAS/BRAF and PIK3CA, in tailoring neoadjuvant regimens. Furthermore, the review emphasizes the need for a multidisciplinary approach to navigate the complexities of CRLM. Integrating technical expertise and biological insights is crucial in refining neoadjuvant strategies. The management of progression following neoadjuvant chemotherapy requires a tailored approach, acknowledging the diverse biological behaviors that may emerge. In conclusion, this review aims to provide a comprehensive perspective on the considerations, challenges, and advancements in the use of neoadjuvant chemotherapy for initially resectable CRLM. By combining evidence-based insights with practical experiences, we aspire to contribute to the ongoing discourse on refining treatment paradigms for improved outcomes in patients with CRLM.

Causal linkage between type 2 diabetes mellitus and inflammatory bowel disease: an integrated Mendelian randomization study and bioinformatics analysis

Background

Observational studies have indicated associations between type 2 diabetes mellitus (T2DM) and both colorectal cancer (CRC) and inflammatory bowel disease (IBD). However, the underlying causality and biological mechanisms between these associations remains unclear.

Methods

We conducted a bidirectional Mendelian randomization (MR) analysis employing summary statistics from genome-wide association studies involving European individuals. The inverse variance weighting (IVW) method was the primary method used to assess causality. Additionally, we applied MR Egger, Weighted median, Simple mode, and Weighted mode to evaluate the robustness of the results. Outliers were identified and eliminated using the MR-PRESSO, while the MR-Egger intercept was used to assess the horizontal pleiotropic effects of single nucleotide polymorphisms (SNPs). The heterogeneity was evaluated using the Cochrane Q test, and sensitivity analysis was performed using leave-one-out method. The F statistic was calculated to evaluate weak instrumental variable bias. Finally, a pilot bioinformatics analysis was conducted to explore the underlying biological mechanisms between T2DM and IBD/UC.

Results

The IVW results demonstrated that T2DM significantly reduced risks of IBD (OR=0.885, 95% CI: 0.818-0.958, P=0.002) and ulcerative colitis (UC) (OR=0.887, 95% CI: 0.812-0.968, P=0.007). Although the 95% CIs of MR Egger, Weighted median, Simple mode, and Weighted mode were broad, the majority of their estimates were consistent with the direction of IVW. Despite significant heterogeneity among SNPs, no horizontal pleiotropy was observed. The leave-one-out analysis showed that the causality remained consistent after each SNP was removed, underscoring the reliability of the results. Reverse MR analysis indicated that genetic susceptibility to both CRC and IBD had no significant effect on the relative risk of T2DM. Ten hub genes were identified, which mainly enriched in pathways including maturity onset diabetes of the young, thyroid cancer, gastric acid secretion, longevity regulating pathway, melanogenesis, and pancreatic secretion.

Conclusion

The presence of T2DM does not increase the risk of CRC or IBD. Moreover, T2DM might reduce risk of IBD, including UC. Conversely, the occurrence of CRC or IBD does not influence the risk of T2DM. The association between T2DM and IBD/UC may be related to the changes in multiple metabolic pathways and CTLA-4-mediated immune response.

Mismatch repair deficiency and microsatellite instability in urothelial carcinoma: a systematic review and meta-analysis

Background

Mismatch repair deficiency (dMMR) and microsatellite instability-high (MSI-H) occur in a subset of cancers and have been shown to confer sensitivity to immune checkpoint inhibition (ICI); however, there is a lack of prospective data in urothelial carcinoma (UC).

Methods and analysis

We performed a systematic review to estimate the prevalence of dMMR and MSI-H in UC, including survival and clinical outcomes. We searched for studies published up to 26 October 2022 in major scientific databases. We screened 1745 studies and included 110. Meta-analyses were performed if the extracted data were suitable.

Results

The pooled weighted prevalences of dMMR in bladder cancer (BC) and upper tract UC (UTUC) were 2.30% (95% CI 1.12% to 4.65%) and 8.95% (95% CI 6.81% to 11.67%), respectively. The pooled weighted prevalences of MSI-H in BC and UTUC were 2.11% (95% CI 0.82% to 5.31%) and 8.36% (95% CI 5.50% to 12.53%), respectively. Comparing localised versus metastatic disease, the pooled weighted prevalences for MSI-H in BC were 5.26% (95% CI 0.86% to 26.12%) and 0.86% (95% CI 0.59% to 1.25%), respectively; and in UTUC, they were 18.04% (95% CI 13.36% to 23.91%) and 4.96% (95% CI 2.72% to 8.86%), respectively. Cumulatively, the response rate in dMMR/MSI-H metastatic UC treated with an ICI was 22/34 (64.7%) compared with 1/9 (11.1%) with chemotherapy.

Conclusion

Both dMMR and MSI-H occur more frequently in UTUC than in BC. In UC, MSI-H occurs more frequently in localised disease than in metastatic disease. These biomarkers may predict sensitivity to ICI in metastatic UC and resistance to cisplatin-based chemotherapy.