Cohort study on the treatment of BRAF V600E mutant metastatic colorectal cancer with integrated Chinese and western medicine

BACKGROUND Patients with BRAF V600E mutant metastatic colorectal cancer(mCRC)have a low incidence rate,poor biological activity,suboptimal response to conventional treatments,and a poor prognosis.In the previous cohort study on mCRC conducted by our team,it was observed that integrated Chinese and Western medicine treatment could significantly prolong the overall survival(OS)of patients with colorectal cancer.Therefore,we further explored the survival benefits in the population with BRAF V600E mutant mCRC.AIM To evaluate the efficacy of integrated Chinese and Western medicine in the treatment of BRAF V600E mutant metastatic colorectal cancer.METHODS A cohort study was conducted on patients with BRAF V600E mutant metastatic colorectal cancer admitted to Xiyuan Hospital of China Academy of Chinese Medical Sciences and Traditional Chinese Medicine Hospital of Xinjiang Uygur Autonomous Region from January 2016 to December 2022.The patients were divided into two cohorts.RESULTS A total of 34 cases were included,with 23 in Chinese-Western medicine cohort(cohort A)and 11 in Western medicine cohort(cohort B).The median overall survival was 19.9 months in cohort A and 14.2 months in cohort B,with a statistically significant difference(P=0.038,hazard ratio=0.46).The 1-3-year survival rates were 95.65%(22/23),39.13%(9/23),and 26.09%(6/23)in cohort A,and 63.64%(7/11),18.18%(2/11),and 9.09%(1/11)in cohort B,respectively.Subgroup analysis showed statistically significant differences in median OS between the two cohorts in the right colon,liver metastasis,chemotherapy,and first-line treatment subgroups(P<0.05).CONCLUSION Integrated Chinese and Western medicine can prolong the survival and reduce the risk of death in patients with BRAF V600E mutant metastatic colorectal cancer,with more pronounced benefits observed in patients with right colon involvement,liver metastasis,combined chemotherapy,and first-line treatment.

Overall survival with frontline vs subsequent anti-epidermal growth factor receptor therapies in unresectable,RAS/BRAF wild-type,leftsided metastatic colorectal cancer

BACKGROUND The combination of anti-epidermal growth factor receptor(EGFR)therapy and chemotherapy is currently a preferred first-line treatment for patients with unre-sectable,RAS and BRAF wild-type,left-sided metastatic colorectal cancer(mCRC).Several studies have also demonstrated the benefit of anti-EGFR therapy in sub-sequent line settings for this patient population.However,direct evidence com-paring the effectiveness of frontline vs subsequent anti-EGFR therapy remains limited,leaving a crucial gap in guiding optimal treatment strategies.AIM To compare overall survival(OS)between frontline and subsequent anti-EGFR treatment in patients with unresectable,RAS and BRAF wild-type,left-sided mCRC.METHODS We retrospectively reviewed the medical records of mCRC patients treated at The King Chulalongkorn Memorial Hospital and Songklanagarind Hospital,Thailand,between January 2013 and April 2023.Patients were classified into two groups based on the sequence of their anti-EGFR treatment.The primary endpoint was OS.RESULTS Among 222 patients with a median follow-up of 29 months,no significant difference in OS was observed between the frontline and subsequent-line groups(HR 1.03,95%CI:0.73-1.46,P=0.878).The median OS was 35.53 months(95%CI:26.59-44.47)for the frontline group and 31.60 months(95%CI:27.83-35.37)for the subsequent-line group.In the subsequent-line group,71 patients(32.4%)who ultimately never received anti-EGFR therapy had a significantly worse median OS of 19.70 months(95%CI:12.87-26.53).CONCLUSION Frontline and subsequent-line anti-EGFR treatments provide comparable OS in unresectable,RAS/BRAF wild-type,left-sided mCRC patients,but early exposure is vital for those unlikely to receive subsequent therapy.

Efficacy of disitamab vedotin-containing therapy in metastatic colorectal cancer: A case report

BACKGROUND Colorectal cancer(CRC)is a leading cause of cancer-related mortality worldwide.In cases of metastatic CRC(mCRC)that are resistant to conventional chemo-therapy-based treatments,the efficacy of available therapeutic options is typically low.CRC exhibiting overexpression or amplification of the human epidermal growth factor receptor 2(HER2)gene has shown responsiveness to HER2-targeted therapies.CASE SUMMARY We present the case of a 69-year-old woman diagnosed with mCRC with an NRAS p.G12V mutation and microsatellite stability,identified through tumor sequencing,along with HER2 overexpression detected by immunohistochemistry.She exhibited an excellent response to disitamab vedotin-containing therapy.To our knowledge,this is the first reported case of mCRC with HER2 overexpression and an NRAS p.G12V mutation achieving a remarkable clinical response to anti-HER2 therapy.CONCLUSION Disitamab vedotin demonstrates promising anti-tumor effects in HER2-overex-pressing mCRC,offering patients an additional treatment option.

Efficacy of chemotherapy containing bevacizumab in patients with metastatic colorectal cancer according to programmed cell death ligand 1

BACKGROUND Bevacizumab,an anti-vascular endothelial growth factor(VEGF)monoclonal antibody,inhibits angiogenesis and reduces tumor growth.Serum VEGF-C,lactate dehydrogenase,and inflammatory markers have been reported as predictive markers related to bevacizumab treatment.Programmed cell death ligand 1(PD-L1)could act upon VEGF receptor 2 to induce cancer cell angiogenesis and metastasis.AIM To investigate the efficacy of bevacizumab-containing chemotherapy in patients with metastatic colorectal cancer(CRC)according to the expression of PD-L1.METHODS This analysis included CRC patients who received bevacizumab plus FOLFOX or FOLFIRI as first-line therapy between June 24,2014 and February 28,2022,at Samsung Medical Center(Seoul,South Korea).Analysis of patient data included evaluation of PD-L1 expression by the combined positive score(CPS).We analyzed the efficacy of bevacizumab according to PD-L1 expression status in patients with CRC.RESULTS A total of 124 patients was included in this analysis.Almost all patients were treated with bevacizumab plus FOLFIRI or FOLFOX as the first-line chemotherapy.While 77%of patients received FOLFOX,23%received FOLFIRI as backbone first-line chemotherapy.The numbers of patients with a PD-L1 CPS of 1 or more,5 or more,or 10 or more were 105(85%),64(52%),and 32(26%),respectively.The results showed no significant difference in progression-free survival(PFS)and overall survival(OS)with bevacizumab treatment between patients with PDL1 CPS less than 1 and those with PD-L1 CPS of 1 or more(PD-L1<1%vs PD-L1≥1%;PFS:P=0.93,OS:P=0.33),between patients with PD-L1 CPS less than 5 and of 5 or more(PD-L1<5%vs PD-L1≥5%;PFS:P=0.409,OS:P=0.746),and between patients with PD-L1 CPS less than 10 and of 10 or more(PD-L1<10%vs PD-L1≥10%;PFS:P=0.529,OS:P=0.568).CONCLUSION Chemotherapy containing bevacizumab can be considered as first-line therapy in metastatic CRC irrespective of PD-L1 expression.

Emerging role of liquid biopsy in rat sarcoma virus mutated metastatic colorectal cancer:A case report

BACKGROUND In patients with metastatic colorectal cancer(mCRC),the treatment options are limited and have been proved to be affected by rat sarcoma virus(RAS)mutational status.In RAS wild-type(wt)patients,the combination of antiepidermal growth factor receptor(EGFR)monoclonal antibodies with chemotherapy(CT)is more effective than CT alone.On the other hand,RAS-mutated patients are not eligible for treatment with anti-EGFR antibodies.CASE SUMMARY Eleven patients with initially RAS-mutated mCRC were followed from diagnosis to May 2022.At the time of cell-free DNA determination,five patients had undergone one CT line,five patients had undergone two CT lines,and one patient had undergone three CT lines(all in combination with bevacizumab).At the second and third treatment lines[second line(2L),third line(3L)],patients with neo-RAS wt received a combination of CT and cetuximab.In neo-RAS wt patients treated with anti-EGFR,our findings indicated an increase in progression-free survival for both 2L and 3L(14.5 mo,P=0.119 and 3.9 mo,P=0.882,respectively).Regarding 2L overall survival,we registered a slight increase in neo-RAS wt patients treated with anti-EGFR(33.6 mo vs 32.4 mo,P=0.385).At data cut-off,two patients were still alive:A RAS-mutated patient undergoing 3L treatment and a neo-RAS wt patient who received 2L treatment with anti-EGFR(ongoing).CONCLUSION Our case series demonstrated that monitoring RAS mutations in mCRC by liquid biopsy may provide an additional treatment line for neo-RAS wt patients.

Vascular endothelial growth factor pathway’s influence on bevacizumab efficacy in metastatic colorectal cancer treatment

In this article,an article published in the World Journal of Gastrointestinal Oncology,which focuses on whether the expression of programmed death-ligand 1(PD-L1)affects the effectiveness of chemotherapy regimens,including bevacizumab,in treating patients with colorectal cancer(CRC).Through neutralization of vascular endothelial growth factor(VEGF),bevacizumab inhibits tumor angiogenesis,impairing neovascularization and thereby depriving the tumor of essential nutrients and oxygen.Conversely,PD-L1 binding to VEGF receptor 2 promotes angiogenesis,supporting tumor vasculature.The interplay between these pathways complicates the assessment of bevacizumab’s efficacy in cancer therapy,notably in CRC,where VEGF and PD-L1 significantly affect treatment response.This review examines metastatic CRC treatment strategies,focusing on bevacizumab’s mechanism of action and the role of PD-L1 in this therapeutic context.

Comparative effectiveness of immunotherapy and chemotherapy in patients with metastatic colorectal cancer stratified by microsatellite instability status

BACKGROUND Immunotherapy have demonstrated promising outcomes in patients with high microsatellite instability(MSI)(MSI-H)metastatic colorectal cancer.However,the comparative effectiveness of Immunotherapy and chemotherapy for patients with low MSI(MSI-L),and microsatellite stable(MSS)metastatic colorectal cancer remains unclear.AIM To investigate immunotherapy vs chemotherapy for treatment of MSI-L/MSS metastatic colorectal cancer,and to evaluate the success of immunotherapy against chemotherapy in managing MSI-H metastatic colorectal cancer during a follow-up of 50 months.METHODS We conducted a retrospective cohort study using the National Cancer Database(NCDB)to evaluate the overall survival(OS)of patients with metastatic colorectal cancer treated with immunotherapy or chemotherapy.The study population was stratified by MSI status(MSI-H,MSI-L,and MSS).Multivariable Cox proportional hazard models were used to assess the association between treatment modality and OS,adjusting for potential confounders.RESULTS A total of 21951 patients with metastatic colorectal cancer were included in the analysis,of which 2358 were MSI-H,and 19593 were MSI-L/MSS.In the MSI-H cohort,immunotherapy treatment(n=142)was associated with a significantly improved median OS compared to chemotherapy(n=860).After adjusting for potential confounders,immunotherapy treatment remained significantly associated with better OS in the MSI-H cohort[adjusted hazard ratio(aHR):0.57,95%confidence interval(95%CI):0.43-0.77,P<0.001].In the MSS cohort,no significant difference in median OS was observed between immunotherapy treatment and chemotherapy(aHR:0.94,95%CI:0.69-1.29,P=0.715).CONCLUSION In this population-based study using the NCDB,immunotherapy treatment was associated with significantly improved OS compared to chemotherapy in patients with MSI-H metastatic colorectal cancer,but not in those with MSI-L/MSS metastatic colorectal cancer.Further studies are warranted to determine the optimal therapeutic approach for patients with MSI-L/MSS metastatic colorectal cancer.

Successful cetuximab rechallenge in metastatic colorectal cancer:A case report

BACKGROUND Metastatic colorectal cancer(mCRC)treatment has been evolving and increasingly driven by tumor biology and gene expression analysis.Rechallenge with epidermal growth factor receptor(EGFR)inhibitors(anti-EGFR)represents a promising strategy for patients with RAS wild-type(RAS-wt)mCRC and circulating tumor DNA has emerged as a potential selection strategy.Herein,we report the case of a RAS-wt mCRC patient who had a successful response to cetuximab rechallenge.CASE SUMMARY Our patient was diagnosed with stage IV RAS-wt,microsatellite-stable rectosigmoid junction adenocarcinoma.He was started on first-line treatment with FOLFIRI and cetuximab and achieved partial response,allowing for a left hepatectomy(R0),followed by post-operative chemotherapy and an anterior resection;progression-free survival(PFS)of 16 months was obtained.Due to hepatic and nodal relapse,second-line treatment with FOLFOX and bevacizumab was started with partial response;metastasectomy was performed(R0),achieving a PFS of 11 months.After a 15 months anti-EGFR-free interval,FOLFIRI and cetuximab were reintroduced upon disease progression,again with partial response and a PFS of 16 months.Following extensive hepatic relapse,cetuximab was reintroduced and a marked clinical and analytical improvement was seen,after only one cycle.RASwt status was confirmed on circulating tumor DNA.The patient’s overall survival exceeded 5 years.CONCLUSION Our case provides real-world data to support cetuximab rechallenge in later lines of RAS-wt mCRC treatment.

Therapeutic strategies targeting the epidermal growth factor receptor signaling pathway in metastatic colorectal cancer

More than 1.9 million new colorectal cancer(CRC)cases and 935000 deaths were estimated to occur worldwide in 2020,representing about one in ten cancer cases and deaths.Overall,colorectal ranks third in incidence,but second in mortality.More than half of the patients are in advanced stages at diagnosis.Treatment options are complex because of the heterogeneity of the patient population,including different molecular subtypes.Treatments have included conventional fluorouracil-based chemotherapy,targeted therapy,immunotherapy,etc.In recent years,with the development of genetic testing technology,more and more targeted drugs have been applied to the treatment of CRC,which has further prolonged the survival of metastatic CRC patients.

Current and future perspectives in the management and treatment of colorectal cancer

In this editorial,we reviewed the article by Fadlallah et al that was recently published in the World Journal of Clinical Oncology.The article provided a comprehensive and in-depth view of the management and treatment of colorectal cancer(CRC),one of the leading causes of cancer-related morbidity and mortality worldwide.The article analyzed the therapeutic modalities and their sequencing,focusing on total neoadjuvant therapy for locally advanced rectal cancer.It highlighted the role of immunotherapy in tumors with high microsatellite instability or deficient mismatch repair,addressing recent advances that have improved prognosis and therapeutic response in localized and metastatic CRC.Innovations in surgical techniques,advanced radiotherapy,and systemic agents targeting specific mutational profiles are also discussed,reflecting on how they revolutionized clinical management.Circulating tumor DNA has emerged as a promising tool for detecting minimal residual disease,prognosis,and therapeutic monitoring,solidifying its role in precision oncology.This review emphasized the importance of technological and therapeutic advancements in improving clinical outcomes and personalizing CRC treatment.

Transcriptomic Analysis of Metastatic Colorectal Tumor with Low Mutational Burden

Objective:To identify potential drug targets for metastasis colorectal cancer(CRC)patients with low mutational burden by examining differences in immune-related gene expression.Methods:For this study,623 samples were collected from The Cancer Genome Atlas(TCGA)database,comprising tumor mutational burden(TMB),RNA sequencing(RNA-Seq),and clinical data.Differential gene expression analysis,Gene Ontology(GO),and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analysis of the identified genes were conducted using the R package.Additionally,a comparative analysis of immune infiltrating cell composition in metastatic and non-metastatic groups was performed.Hub genes,exhibiting high levels of interaction,were selected using the Search Tool for the Retrieval of Interacting Genes/Proteins(STRING)database.The Drug Gene Interaction Database(DGIdb)was then utilized to estimate drugs targeting the identified hub genes.Results:The transcriptome data of 326 colorectal cancer patients with low TMB were analyzed,comprising 58 patients with metastasis and 268 patients without metastasis.Among the differential expression in 1,111 genes for patients with metastasis compared to those without metastasis,733 genes were upregulated,and 378 genes were downregulated.KEGG and GO enrichment analysis indicated significant differences in gene expression in CRC metastatic patients with low TMB compared to non-metastasis patients with low TMB.Enriched pathways included humoral immune response,immunoglobulin production,and regulation of AMPA receptor activity.Two genes related to interleukin-12 were identified through secondary enrichment for immune-related genes.Analysis of tumor-infiltrating immune cell data revealed significant differences in memory-activated T cell CD4 and T cell CD8.Conclusions:This analysis of RNA sequencing data and immune-filtrating cell data revealed significant differences between metastatic colorectal cancer patients with low TMB and their non-metastatic counterparts.These distinctions suggest the possibility of identifying more effective drugs or therapies for metastatic colorectal cancer patients with low TMB.

Irinotecan, a key chemotherapeutic drug for metastatic colorectal cancer

Irinotecan hydrochloride is a camptothecin derivative that exerts antitumor activity against a variety of tumors. SN-38 produced in the body by carboxylesterase is the active metabolite of irinotecan. After irinotecan was introduced for the treatment of metastatic colorectal cancer(CRC) at the end of the last century,survival has improved dramatically. Irinotecan is now combined with 5-fluorouracil,oxaliplatin and several molecularly-targeted anticancer drugs,resulting in the extension of overall survival to longer than 30 mo. Severe,occasionally life-threatening toxicity occurs sporadically,even in patients in relatively good condition who have a low risk of chemotherapyinduced toxicity,often causing the failure of irinotecanbased chemotherapy. Clinical pharmacological studies have revealed that such severe toxicity is related to exposure to SN-38 and genetic polymorphisms in UDPglucuronosyltransferase 1A1 gene. The large interand intra-patient variability in systemic exposure to SN-38 is determined not only by genetic factors but also by physiological and environmental factors. This review first summarizes the roles of irinotecan in chemotherapy for metastatic CRC and then discusses the optimal dosing of irinotecan based on the aforementioned factors affecting systemic exposure to SN-38,with the ultimate goal of achieving personalized irinotecan-based chemotherapy.

Expert consensus on maintenance treatment for metastatic colorectal cancer in China

The impact of maintenance therapy on progression-free survival and overall survival as well as quality of life of Chinese patients with metastatic colorectal cancer has long been under discussion.Recently,some phase III clinical trials have revealed that maintenance therapy can significantly prolong the progression-free survival while maintain an acceptable safety profile.Based on this evidence and common treatment practice in China,we now generated one Expert Consensus on Maintenance Treatment for Metastatic Colorectal Cancer in China to further specify the necessity of maintenance therapy,suitable candidates for such treatment,and appropriate regimens.

Prognostic significance of the pre-chemotherapy lymphocyte-to-monocyte ratio in patients with previously untreated metastatic colorectal cancer receiving FOLFOX chemotherapy

Background:As a surrogate marker of systemic inflammation,the lymphocyte-to-monocyte ratio(LMR) is an independent prognostic factor for various malignancies.This study investigated the prognostic significance of the pre-chemotherapy LMR in patients with previously untreated metastatic colorectal cancer(mCRC) receiving chemotherapy.Methods:The present study included newly diagnosed mCRC patients treated between January 2005 and December 2013 with FOLFOX chemotherapy,specifically oxaliplatin 180 mg/m^2 on day 1,with leucovorin 400 mg/m^2administered as a 2-hour infusion before the administration of 5-fluorouracil 400 mg/m^2 as an intravenous bolus injection,and 5-fluorouracil 2400 mg/m^2 as a 46-h infusion immediately after 5-fluorouracil bolus injection.The LMR was calculated as the absolute count of lymphocytes divided by the absolute count of monocytes.COX proportional hazards analysis was performed to evaluate the association of LMR with survival outcomes.Results:A total of 488 patients were included.Patients with high pre-chemotherapy LMR experienced significant improvements in progression-free survival(PFS,9.2 vs.7.6 months,P < 0.001) and overall survival(OS,19.4 vs.16.6 months,P < 0.001) compared with patients with low pre-chemotherapy LMR.Subsequent COX multivariate analysis showed that high pre-chemotherapy LMR(>3.11) was an independent favorable prognostic factor for PFS and OS.Additionally,patients whose LMR remained high(high-high subgroup),increased(low-high subgroup),or decreased(high-low subgroup) following chemotherapy showed better results in terms of PFS and OS than patients whose LMR remained low(low-low subgroup) after chemotherapy.Conclusions:For patients with previously untreated mCRC receiving FOLFOX chemotherapy,an elevated pre-chemotherapy LMR is an independent favorable prognostic factor for PFS and OS,and changes in the LMR before and after chemotherapy seem to predict the benefit of chemotherapy.

Cetuximab plus FOLFOX6 or FOLFIRI in metastatic colorectal cancer: CECOG trial

AIM: To investigate efficacy and safety of cetuximab combined with two chemotherapy regimens in patients with unresectable metastatic colorectal cancer (mCRC). METHODS: Randomized patients received cetuximab with 5-fluorouracil (5-FU), folinic acid (FA) and oxaliplatin (FOLFOX) 6 (arm A, n = 74) or 5-FU, FA and irinotecan (FOLFIRI) (arm B, n = 77). KRAS mutation status was determined retrospectively in a subset of tumors (n = 117). RESULTS: No significant difference was found between treatment arms A and B in the progression-free survival (PFS) rate at 9 mo, 45% vs 34%; median PFS, 8.6 mo vs 8.3 mo [hazard ratio (HR) = 1.06]; overall response rate (ORR) 43% vs 45% [odds ratio (OR) = 0.93] and median overall survival (OS), 17.4 mo vs 18.9 mo (HR = 0.98). Patients with KRAS wild-type tumors demonstrated improved PFS (HR = 0.55, P = 0.0051), OS, (HR = 0.62, P = 0.0296) and ORR (53% vs 36%) and in arm A, improved PFS (HR = 0.49, P = 0.0196), OS (HR = 0.48, P = 0.0201) and ORR (56%vs 30%), compared with patients with KRAS mutated tumors. In arm B no significant differences were found in efficacy by KRAS mutation status. Treatment in arms A and B was generally well tolerated. CONCLUSION: This study confirms that combinations of cetuximab with FOLFOX6 or FOLFIRI are effective and significantly improve clinical outcome in KRAS wild-type compared with KRAS mutated mCRC.

Role of targeted therapy in metastatic colorectal cancer

Colorectal cancer(CRC) is a significant cause of cancer-related morbidity and mortality all over the world.Improvements of cytotoxic and biologic agents have prolonged the survival in metastatic CRC(mC RC),with a median overall survival of approximately 2 years and more in the past two decades.The biologic agents that have proven clinical benefits in m CRC mainly target vascular endothelial growth factor(VEGF) and epidermal growth factor receptor(EGFR).In particular,bevacizumab targeting VEGF and cetuximab and panitumumab targeting EGFR have demonstrated sig-nificant survival benefits in combination with cytotoxic chemotherapy in the first-line,second-line,or salvage setting.Aflibercept,ramucirumab,and regorafenib are also used in second-line or salvage therapy.Recent retrospective analyses have shown that KRAS or NRAS mutations were negative predictive markers for anti-EGFR therapy.Based on the evidence from large rand-omized clinical trials,personalized therapy is necessary for patients with m CRC according to their tumor biology and characteristics.The aim of this paper was to summarize the results of the major randomized clinical trials and highlight the benefits of the molecular targeted agents in patients with mC RC.

Mechanisms of resistance to anti-epidermal growth factor receptor inhibitors in metastatic colorectal cancer

The prognosis of patients with metastatic colorectal cancer (mCRC) remain poor despite the impressive improvement of treatments observed over the last 20 years that led to an increase in median overall survival from 6 mo, with the only best supportive care, to approximately 30 mo with the introduction of active chemotherapy drugs and targeted agents. The monoclonal antibodies (moAbs) cetuximab and panitumumab, directed against the epidermal growth factor receptor (EGFR), undoubtedly represent a major step forward in the treatment of mCRC, given the relevant efficacy in terms of progression-free survival, overall survival, response rate, and quality of life observed in several phase III clinical trials among different lines of treatment. However, the anti-EGFR moAbs were shown only to be effective in a subset of patients. For instance, KRAS and NRAS mutations have been identified as biomarkers of resistance to these drugs, improving the selection of patients who might derive a benefit from these treatments. Nevertheless, several other alterations might affect the response to these drugs, and unfortunately, even the responders eventually become resistant by developing secondary (or acquired) resistance in approximately 13-18 mo. Several studies highlighted that the landscape of responsible alterations of both primary and acquired resistance to anti-EGFR drugs biochemically converge into MEK-ERK and PIK3CA-AKT pathways. In this review, we describe the currently known mechanisms of primary and acquired resistance to anti-EGFR moAbs together with the various strategies evaluated to prevent, overcame or revert them.

Role of cetuximab in first-line treatment of metastatic colorectal cancer

The treatment of metastatic colorectal cancer(mCRC)has evolved considerably in the last decade,currently allowing most mCRC patients to live more than two years.Monoclonal antibodies targeting the epidermal growth factor receptor(EGFR)and vascular endothelial growth factor play an important role in the current treatment of these patients.However,only antibodies directed against EGFR have a predictive marker of response,which is the mutation status of v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog(KRAS).Cetuximab has been shown to be effective in patients with KRAS wild-type mCRC.The CRYSTAL study showed that adding cetuximab to FOLFIRI(regimen of irinotecan,infusional fluorouracil and leucovorin)significantly improved results in the first-line treatment of KRAS wildtype mCRC.However,results that evaluate the efficacy of cetuximab in combination with oxaliplatin-based chemotherapy in this setting are contradictory.On the other hand,recent advances in the management of colorectal liver metastases have improved survival in these patients.Adding cetuximab to standard chemotherapy increases the response rate in patients with wild-type KRAS and can thus increase the resectability rate of liver metastases in this group of patients.In this paper we review the different studies assessing the efficacy of cetuximab in the first-line treatment of mCRC.

KRAS mutation testing in metastatic colorectal cancer

The KRAS oncogene is mutated in approximately 35%-45% of colorectal cancers, and KRAS mutational status testing has been highlighted in recent years. The most frequent mutations in this gene, point substitutions in codons 12 and 13, were validated as negative predictors of response to anti-epidermal growth factor receptor antibodies. Therefore, determining the KRAS mutational status of tumor samples has become an essential tool for managing patients with colorectal cancers. Currently, a variety of detection methods have been established to analyze the mutation status in the key regions of the KRAS gene; however, several challenges remain related to standardized and uniform testing, including the selection of tumor samples, tumor sample processing and optimal testing methods. Moreover, new testing strategies, in combination with the mutation analysis of BRAF , PIK3CA and loss of PTEN proposed by many researchers and pathologists, should be promoted. In addition, we recommend that microsatellite instability, a prognostic factor, be added to the abovementioned concomitant analysis. This review provides an overview of KRAS biology and the recent advances in KRAS mutation testing. This review also addresses other aspects of status testing for determining the appropriate treatment and offers insight into the potential drawbacks of mutational testing.

Significance of postoperative follow-up of patients with metastatic colorectal cancer using circulating tumor DNA

BACKGROUND One of the most notable applications for circulating tumor DNA(ctDNA)detection in peripheral blood of patients with metastatic colorectal cancer(mCRC)is a long-term postoperative follow-up.Sometimes referred to as a“liquid(re)biopsy”it is a minimally invasive procedure and can be performed repeatedly at relatively short intervals(months or even weeks).The presence of the disease and the actual extent of the tumor burden(tumor mass)within the patient’s body can be monitored.This is of particular importance,especially when evaluating radicality of surgical treatment as well as for early detection of disease progression or recurrence.AIM To confirm the radicality of surgery using ctDNA and compare available methods for detection of recurrence in metastatic colorectal cancer.METHODSA total of 47 patients with detected ctDNA and indications for resection of mCRC were enrolled in the multicenter study involving three surgical centers.Standard postoperative follow-ups using imaging techniques and the determination of tumor markers were supplemented by ctDNA sampling.In addition to the baseline ctDNA testing prior to surgery,a postoperative observation was conducted by evaluating ctDNA presence up to a week after surgery and subsequently at approximately three-month intervals.The presence of ctDNA was correlated with radicality of surgical treatment and the actual clinical status of the patient.RESULTS Among the monitored patients,the R0(curative)resection correlated with postoperative ctDNA negativity in 26 out of 28 cases of surgical procedures(26/28,93%).In the remaining cases of R0 surgeries that displayed ctDNA,both patients were diagnosed with a recurrence of the disease after 6 months.In 7 patients who underwent an R1 resection,4 ctDNA positivities(4/7,57%)were detected after surgery and associated with the confirmation of early disease recurrence(after 3 to 7 months).All 15 patients(15/15,100%)undergoing R2 resection remained constantly ctDNA positive during the entire follow-up period.In 22 cases of recurrence,ctDNA positivity was detected 22 times(22/22,100%)compared to 16 positives(16/22,73%)by imaging methods and 15 cases(15/22,68%)of elevated tumor markers.CONCLUSION ctDNA detection in patients with mCRC is a viable tool for early detection of disease recurrence as well as for confirmation of the radicality of surgical treatment.