The efficacy of anti-EGFR therapy in treating metastatic colorectal cancer differs between the middle/low rectum and the left-sided colon

Model-informed Evidence for Clinical Non-inferiority of Every-2-Weeks Versus Standard Weekly Dosing Schedule of Cetuximab in Metastatic Colorectal Cancer

Cetuximab was initially developed and approved as a first-line treatment in patients with unresectable metastatic colorectal cancer (mCRC) for weekly administration (250 mg/m2 Q1W with 400 mg/m2 loading dose). An every-2-weeks schedule (500 mg/m2 Q2W) was approved recently by several health authorities. Being synchronized with chemotherapy, Q2W administration should improve patients' convenience and healthcare resource utilization. Herein, we present evidence of non-inferiority of Q2W cetuximab, compared with Q1W dosing using pharmacometrics modeling and clinical trial simulation (CTS). Pooled data from five phase I-III clinical trials in 852 patients with KRAS wild-type mCRC treated with Q1W or Q2W cetuximab were modeled using a population exposure-tumor size (TS) model linked to overall survival (OS); exposure was derived from a previously established population pharmacokinetic model. A semi-mechanistic TS model adapted from the Claret model incorporated killing rate proportional to cetuximab area under the concentration-time curve over 2 weeks (AUC) with Eastern Cooperative Oncology Group (ECOG) status as covariate on baseline TS. The OS was modeled with Weibull hazard using ECOG, baseline TS, primary tumor location, and predicted percent change in TS at 8 weeks as covariates. Model-based simulations revealed indistinguishable early tumor shrinkage and survival between Q2W vs. Q1W cetuximab. CTS evaluated OS non-inferiority (predefined margin of 1.25) in 1,000 trials, each with 2,000 virtual patients receiving Q2W or Q1W cetuximab (1:1), and demonstrated non-inferiority in 94% of cases. Taken together, these analyses provide model-based evidence for clinical non-inferiority of Q2W vs. Q1W cetuximab in mCRC with potential benefits to patients and healthcare providers.

The survival outcome differs between left-sided colon cancer and middle/low rectal cancer after colorectal hepatic metastasectomy

BACKGROUND

The clinical outcomes between left-sided colon cancer and middle/low rectal cancer seem to be different. This study aimed to examine the effect of primary tumor location regarding the left-sided colon and middle/low rectum on the overall survival (OS) of patients who underwent colorectal hepatic metastasectomy.

METHODS

Patients who underwent colorectal hepatic metastasectomy were retrospectively enrolled. Patients were classified into 2 groups according to the primary tumor location (left-sided colon and middle/low rectum). Categorical variables were compared using the chi-square test or Fisher exact test, and continuous variables were analyzed using the Student t test. Survival was analyzed using the Kaplan-Meier method and log-rank test. The prognostic factors were analyzed by univariate and multivariate analyses using Cox proportional hazards regression models.

RESULTS

Overall, 365 patients were enrolled. Patients with left-sided colon cancer had significantly better OS than those with middle/low rectal cancer (hazard ratio [HR], 0.725; P = .018), with median OS estimates of 48 and 38 months, respectively. In the subgroup analysis of RAS mutations, patients with left-sided colon cancer had significantly prolonged OS compared with those with middle/low rectum cancer (HR, 0.608; P = .034), with median OS estimates of 49 and 26 months, respectively. This observation was limited to patients with RAS mutations.

CONCLUSION

According to our findings, patients with middle/low rectal cancer had poorer survival outcome and should not be categorized together with patients with left-sided colon cancer in terms of OS after colorectal hepatic metastasectomy.

Distinctive multicellular immunosuppressive hubs confer different intervention strategies for left- and right-sided colon cancers

Primary colon cancers arising from the left and right sides exhibit distinct clinical and molecular characteristics. Sidedness-associated heterogeneity relies intricately on the oncogenic properties of cancer cells and multicellular interactions in tumor microenvironments. Here, combining transcriptomic profiling of 426,863 single cells from 105 colon cancer patients and validation with spatial transcriptomics and large-scale histological analysis, we capture common transcriptional heterogeneity patterns between left- and right-sided malignant epithelia through delineating two side-specific expression meta-programs. The proliferation stemness meta-program is notably enriched in left-sided malignant epithelia that colocalize with Mph-PLTP cells, activated regulatory T cells (Tregs), and exhausted CD8-LAYN cells, constituting the glucose metabolism reprogramming niche. The immune secretory (IS) meta-program exhibits specific enrichment in right-sided malignant epithelia, especially in smoking patients with right-sided colon cancer. The IShigh malignant epithelia spatially localize in hypoxic regions and facilitate immune evasion through attenuating Mph-SPP1 cell antigen presentation and recruiting innate-like cytotoxicity-reduced CD8-CD161 cells.

Survival outcomes according to the tumor location and prognostic factor in metastatic rectal cancer: a multicenter retrospective cohort study

Background & aims

Prognostic factors of metastatic rectal cancer are not well known. We aim to determine prognostic factors affecting survival for metastatic rectal cancer patients and also to investigate the effect of tumor localization on overall survival.

Methods

Metastatic rectal cancer patients who received treatment in 5 different centers between 2012 and 2022 were included. Prognostic factors for survival were evaluated using univariate and multivariate analysis. The statistical methods included Pearson's chi-square test, Fisher exact test, Log-rank test, and Cox regression model.

Results

A total of 283 patients with metastatic rectal cancer were included in the study. The median OS was not significantly different among the three groups (upper rectum 30.1 months, middle rectum 28.3 months, and low rectum cancer 24.8 months; log-rank p = 0.25). In univariate analysis, Grade 3, ECOG performance status 2, the presence of multiple metastatic sites, the presence of KRAS mutation, the presence of liver metastases, the presence of nonregional lymph node metastases, and the presence of bone metastases were significant predictors of poor survival. In multivariate analysis, Grade 3, ECOG performance status 2, and the presence of multiple metastatic sites were determined as indicators of worse prognosis.

Conclusion

Our findings, primary tumor location did not affect survival in metastatic rectal cancer. The most important factors affecting survival were multiple metastatic sites, tumor grade, and ECOG performance status.

Impact of Primary Tumor Location on Demographics, Resectability, Outcomes, and Quality of Life in Finnish Metastatic Colorectal Cancer Patients (Subgroup Analysis of the RAXO Study)

The primary tumor location (PTL) is associated with the phenotype, metastatic sites, mutations, and outcomes of metastatic colorectal cancer (mCRC) patients, but this has mostly been studied according to sidedness (right vs. left sided). We studied right colon vs. left colon vs. rectal PTL in a real-life study population (n = 1080). Health-related quality of life (HRQoL) was assessed multi-cross-sectionally with QLQ-C30, QLQ-CR29, EQ-5D, and 15D. A chi-square, Kaplan-Meier, and Cox regression were used to compare the groups. The PTL was in the right colon in 310 patients (29%), the left colon in 396 patients (37%), and the rectum in 375 patients (35%). The PTL was associated with distinct differences in metastatic sites during the disease trajectory. The resectability, conversion, and resection rates were lowest in the right colon, followed by the rectum, and were highest in the left colon. Overall survival was shortest for right colon compared with left colon or rectal PTL (median 21 vs. 35 vs. 36 months), with the same trends after metastasectomy or systemic therapy only. PTL also remained statistically significant in a multivariable model. The distribution of symptoms varied according to PTL, especially between the right colon (with general symptoms of metastases) and rectal PTL (with sexual- and bowel-related symptoms). mCRC, according to PTL, behaves differently regarding metastatic sites, resectability of the metastases, outcomes of treatment, and HRQoL.

The Association of the Epidermal Growth Factor Receptor (EGFR) Immunoexpression With Prognostic Parameters in Adenocarcinoma Patients Receiving Neoadjuvant Treatment

The epidermal growth factor receptor (EGFR) expression is considered to play an essential role in the pathogenesis of colorectal adenocarcinoma. This study assessed the expression and predictive/prognostic value of EGFR expression in pre-op biopsy and post-op resection specimens in patients receiving neoadjuvant radiotherapy/neoadjuvant chemoradiotherapy (NRT/NCRT). Thirty-four consecutive patients were included in this study. The association between the prognostic features and EGFR immunohistochemical expression was analyzed in pre- (n=34) and post-treatment (n=22) tissue samples in cases with available tissue blocks. Of 34, 23 (67.6%) were men. The median age was 60.50 ± 10.69 (range, 31-84) years. EGFR expression was detected in 88.2% of biopsy specimens and in 91.2% of surgical specimens. There was only slight agreement between pre-op and post-op EGFR expression scores (kappa value 0.11). There was no significant correlation between pre-op and post-op EGFR expression scores (p>0.05). Although pre-op EGFR positivity and higher pre-op EGFR scores seemed to indicate a worse prognosis, this association between pre-op EGFR expression and overall survival (OS) or disease-specific survival (DSS) did not reach statistical significance (p>0.05). The only case with a post-op EGFR score of three who died of the disease experienced local recurrence and had distant metastasis. In conclusion, EGFR positivity in pre-op biopsy samples seems to be associated with shorter survival, and increased EGFR expression in post-treatment resection specimens predicts aggressive behavior in patients with rectal adenocarcinoma who received NRT/NCRT. However, due to the molecular heterogeneity, EGFR expression status should be evaluated in resection specimens rather than in pre-op biopsy samples for optimal prognosis prediction.

Bibliometric analysis and visualization of research trends in total mesorectal excision in the past twenty years

BACKGROUND

Rectal cancer leads a major disease burden worldwide. Total mesorectal excision (TME) is the standard treatment for locally advanced or node-positive rectal cancer, while attempts to improve the surgery such as laparoscopic and transanal TME are widely used but have their inherent limitations. This bibliometric study analyzed research trends, cooperation, and knowledge dissemination on TME over the past 20 years to inform future directions.

METHODS

Relevant literature from 2003 to 2023 was extracted from the Web of Science Core Collection and analyzed with VOSviewer, CiteSpace, and R for publication patterns, countries, institutions, authors, and research hotspots.

RESULTS

Five thousand three hundred forty-five related publications were included, with rising annual output and citations. The US and China contributed the most studies, while the Netherlands had greater influence. Leiden University ranked first in publications. The top authors were Heald, Kapiteijn, Sauer, Nagtegaal, and Peeters. Research shifted from cancer-focused to patient-centered care and from radiotherapy/chemotherapy to advanced surgery. Multicenter trials became more common.

CONCLUSION

Although the United States and China have the largest number of publications, it should be noted that the influence of these two countries in the field of TME research is not the highest, which does not match the number of publications. In addition, telemedicine, interdisciplinary, medical-industrial integration, etc. may be potential directions for future research in the field of TME.

Differential Efficacy of Targeted Monoclonal Antibodies in Left-Sided Colon and Rectal Metastatic Cancers

BACKGROUND

The recommended first-line chemotherapy for RAS/BRAF wild-type metastatic colorectal cancer (mCRC) is bevacizumab (BEV)-containing therapy for right-sided colon cancer (R) and antiepidermal growth factor receptor antibody (anti-EGFR)-containing therapy for left-sided colon cancer (L) or rectal cancer (RE). However, anatomical or biological heterogeneity reportedly exists between L and RE. Therefore, we aimed to compare the efficacies of anti-EGFR and BEV therapies for L and RE, respectively.

METHODS

We retrospectively reviewed 265 patients with KRAS (RAS)/BRAF wild-type mCRC treated with fluoropyrimidine-based doublet chemotherapy plus anti-EGFR or BEV as the first-line treatment at a single institution. They were divided into 3 groups: R, L, and RE. Overall survival (OS), progression-free survival (PFS), objective response rate, and conversion surgery rate were analyzed.

RESULTS

Forty-five patients had R (anti-EGFR/BEV: 6/39), 137 patients had L (45/92), and 83 patients had RE (25/58). In patients with R, both median (m) PFS and OS were superior with BEV therapy (mPFS, anti-EGFR vs. BEV: 8.7 vs. 13.0 months, hazard ratio [HR]: 3.90, P = .01; mOS, 17.1 vs. 33.9 months, HR: 1.54, P = .38). In patients with L, better mPFS and comparable mOS with anti-EGFR therapy were observed (mPFS, 20.0 vs. 13.4 months, HR: 0.68, P = .08; mOS, 44.8 vs. 36.0 months, HR: 0.87, P = .53), whereas, in patients with RE, comparable mPFS and worse mOS with anti-EGFR therapy were observed (mPFS, 17.2 vs. 17.8 months, HR: 1.08, P = .81; mOS, 29.1 vs. 42.2 months, HR: 1.53, P = .17).

CONCLUSIONS

Efficacies of anti-EGFR and BEV therapies may differ between patients with L and RE.

Enrichment of oral-derived bacteria in inflamed colorectal tumors and distinct associations of Fusobacterium in the mesenchymal subtype

While the association between colorectal cancer (CRC) features and Fusobacterium has been extensively studied, less is known of other intratumoral bacteria. Here, we leverage whole transcriptomes from 807 CRC samples to dually characterize tumor gene expression and 74 intratumoral bacteria. Seventeen of these species, including 4 Fusobacterium spp., are classified as orally derived and are enriched among right-sided, microsatellite instability-high (MSI-H), and BRAF-mutant tumors. Across consensus molecular subtypes (CMSs), integration of Fusobacterium animalis (Fa) presence and tumor expression reveals that Fa has the most significant associations in mesenchymal CMS4 tumors despite a lower prevalence than in immune CMS1. Within CMS4, the prevalence of Fa is uniquely associated with collagen- and immune-related pathways. Additional Fa pangenome analysis reveals that stress response genes and the adhesion FadA are commonly expressed intratumorally. Overall, this study identifies oral-derived bacteria as enriched in inflamed tumors, and the associations of bacteria and tumor expression are context and species specific.

NK Cell-Based Immunotherapy in Colorectal Cancer

Human Natural Killer (NK) cells are all round players in immunity thanks to their powerful and immediate response against transformed cells and the ability to modulate the subsequent adaptive immune response. The potential of immunotherapies based on NK cell involvement has been initially revealed in the hematological setting but has inspired the design of different immune tools to also be applied against solid tumors, including colorectal cancer (CRC). Indeed, despite cancer prevention screening plans, surgery, and chemotherapy strategies, CRC is one of the most widespread cancers and with the highest mortality rate. Therefore, further efficient and complementary immune-based therapies are in urgent need. In this review, we gathered the most recent advances in NK cell-based immunotherapies aimed at fighting CRC, in particular, the use of monoclonal antibodies targeting tumor-associated antigens (TAAs), immune checkpoint blockade, and adoptive NK cell therapy, including NK cells modified with chimeric antigen receptor (CAR-NK).

Exact Primary Tumor Location in mCRC: Prognostic Value and Predictive Impact on Anti-EGFR mAb Efficacy

Simple Summary

Sidedness of primary tumor is a well-established prognostic marker and is predictive for anti-EGFR efficacy in RAS/BRAF wild-type metastatic colorectal cancer (mCRC) patients. As molecular markers change rather continuously throughout the colon, we ask whether the exact primary tumor location (PTL) is a better prognostic marker than sidedness and predictive for anti-EGFR efficacy in RAS/BRAF wild-type mCRC. We retrospectively analyzed five studies containing various therapy protocols concerning primary tumor location, dividing the colorectal frame into six segments. In our cohort, PTL has a prognostic impact on disease spread and overall survival. Only distal segments benefitted when receiving anti-EGFR containing therapy regarding overall survival. Intermediate segments were indifferent and caecal primaries had a detrimental effect receiving anti-EGFR based therapy. Being a retrospective analysis and challenging the standard of basing anti-EGFR treatment on sidedness in RAS/BRAF wild-type mCRC, future studies are necessary to confirm and further investigate our hypothesis-generating results.

Abstract

Primary tumor sidedness (left vs. right) has prognostic and predictive impact on anti-EGFR agent efficacy and thus management of metastatic colorectal cancer (mCRC). This analysis evaluates the relevance of primary tumor location (PTL) in RAS/BRAF wild-type mCRC patients, when dividing the colorectal frame into six segments. This pooled analysis, performed on a single-patient basis of five randomized first-line therapy trials, evaluates the impact of exact PTL classification on baseline characteristics, prognosis and prediction of anti-EGFR antibody efficacy by chi-square and log-rank tests, the Kaplan–Meier method, Cox and logistic regressions. The PTL was significantly associated with metastatic spread: liver (p = 0.001), lung (p = 0.047), peritoneal (p < 0.001) and lymph nodes (p = 0.048). A multivariate analysis indicated an impact on anti-EGFR agent efficacy in terms of overall survival depending on the exact primary tumor location: from detrimental in caecal (HR 2.63), rather neutral effects in the ascending colon (HR 1.24), right flexure/transverse colon (HR 0.99) and left flexure/descending colon (HR 0.91) to clear benefit in sigmoid (HR 0.71) and rectal (HR 0.58) primaries. Exact primary tumor location affects anti-EGFR antibody efficacy in a rather continuous than a dichotomous fashion in RAS/BRAF wild-type mCRC patients. This perspective might help to support clinical decisions when anti-EGFR antibodies are considered.