Final analysis of the randomised PEAK trial: overall survival and tumour responses during first-line treatment with mFOLFOX6 plus either panitumumab or bevacizumab in patients with metastatic colorectal carcinoma

A meta-analysis of efficacy and safety data from head-to-head first-line trials of epidermal growth factor receptor inhibitors versus bevacizumab in adult patients with RAS wild-type metastatic colorectal cancer by sidedness

The first-line treatment choice of EGFRIs plus doublet chemotherapy vs. bevacizumab plus doublet chemotherapy remains a topic of interest for patients with left-sided RAS WT mCRC. We conducted a systematic literature review and meta-analysis of clinical trial data published between 2015 and 2024. We evaluated the relative efficacy and safety of first-line EGFRIs plus doublet chemotherapy (FOLFIRI or FOLFOX) vs. bevacizumab plus doublet chemotherapy for patients with RAS WT left-sided mCRC, as well as in all- and right-sided tumors. We identified eight trials with 2624 patients. Five trials reported outcomes by tumor sidedness. In the left-sided population, overall survival (OS) (Hazard Ratio (HR) = 0.80, 95% Confidence Interval (CI): 0.71-0.90) and objective response rate (ORR) (Odds ratio [OR]=1.61, 95% CI: 1.30-1.99) favored EGFRI plus chemotherapy, while no statistically significant differences were observed for progression-free survival (PFS) (HR=0.93, 95% CI: 0.84-1.04) or resection rate (RR). Similar results were found in the all-sided population. In the right-sided population, PFS favored bevacizumab plus chemotherapy (HR=1.45, 95% CI: 1.19-1.78), while no statistically significant differences were observed for OS (HR=1.17, 95% CI: 0.95-1.44), ORR (OR=0.99, 95% CI: 0.69-1.41), and RR. Early tumor shrinkage in the all-sided population favored EGFRI plus chemotherapy (OR=1.72; 95% CI: 1.36-2.17); limited data precluded evaluation by sidedness. Safety was available in 6 trials for all-sided tumors and 1 trial for left-sided tumors, each demonstrating typical class-specific adverse events. This most comprehensive meta-analysis indicates a benefit for first-line EGFRI plus chemotherapy over bevacizumab plus chemotherapy in patients with left-sided RAS WT mCRC.

Targeting the EGFR signalling pathway in metastatic colorectal cancer

Epidermal growth factor receptor (EGFR) and its activated downstream signalling pathways play a crucial role in colorectal cancer development and progression. After four decades of preclinical, translational, and clinical research, it has been shown that blocking the EGFR signalling pathway at different molecular levels represents a fundamental therapeutic strategy for patients with metastatic colorectal cancer. Nevertheless, the efficacy of molecularly targeted therapies is inescapably limited by the insurgence of mechanisms of acquired cancer cell resistance. Thus, in the era of precision medicine, a deeper understanding of the complex molecular landscape of metastatic colorectal cancer is required to deliver the best treatment choices to all patients. Major efforts are currently ongoing to improve patient selection, improve the efficacy of available treatments targeting the EGFR pathway, and develop novel combination strategies to overcome therapy resistance within the continuum of care of metastatic colorectal cancer.

Molecular insights into clinical trials for immune checkpoint inhibitors in colorectal cancer: Unravelling challenges and future directions

Colorectal cancer (CRC) is a complex disease with diverse etiologies and clinical outcomes. Despite considerable progress in development of CRC therapeutics, challenges remain regarding the diagnosis and management of advanced stage metastatic CRC (mCRC). In particular, the five-year survival rate is very low since mCRC is currently rarely curable. Over the past decade, cancer treatment has significantly improved with the introduction of cancer immunotherapies, specifically immune checkpoint inhibitors. Therapies aimed at blocking immune checkpoints such as PD-1, PD-L1, and CTLA-4 target inhibitory pathways of the immune system, and thereby enhance anti-tumor immunity. These therapies thus have shown promising results in many clinical trials alone or in combination. The efficacy and safety of immunotherapy, either alone or in combination with CRC, have been investigated in several clinical trials. Clinical trials, including KEYNOTE-164 and CheckMate 142, have led to Food and Drug Administration approval of the PD-1 inhibitors pembrolizumab and nivolumab, respectively, for the treatment of patients with unresectable or metastatic microsatellite instability-high or deficient mismatch repair CRC. Unfortunately, these drugs benefit only a small percentage of patients, with the benefits of immunotherapy remaining elusive for the vast majority of CRC patients. To this end, primary and secondary resistance to immunotherapy remains a significant issue, and further research is necessary to optimize the use of immunotherapy in CRC and identify biomarkers to predict the response. This review provides a comprehensive overview of the clinical trials involving immune checkpoint inhibitors in CRC. The underlying rationale, challenges faced, and potential future steps to improve the prognosis and enhance the likelihood of successful trials in this field are discussed.

Switching from FOLFIRI plus cetuximab to FOLFIRI plus bevacizumab based on early tumor shrinkage in RAS wild-type metastatic colorectal cancer: A phase II trial (HYBRID)

BACKGROUND

Long-term anti-EGFR antibody treatment increases the risk of severe dermatologic toxicities. This single-arm, phase II trial aimed to investigate the strategy of switching from cetuximab to bevacizumab in combination with FOLFIRI based on early tumor shrinkage (ETS) in patients with RAS wild-type metastatic colorectal cancer (mCRC).

METHODS

Radiologic assessment was performed to evaluate ETS, defined as ≥20% reduction in the sum of the largest diameters of target lesions 8 weeks after the introduction of FOLFIRI plus cetuximab. ETS-negative patients switched to FOLFIRI plus bevacizumab, whereas ETS-positive patients continued FOLFIRI plus cetuximab for eight more weeks, with a switch to FOLFIRI plus bevacizumab thereafter. The primary endpoint was progression-free survival.

RESULTS

This trial was prematurely terminated due to poor accrual after a total enrollment of 30 patients. In 29 eligible patients, 7 were ETS-negative and 22 were ETS-positive. Two ETS-negative patients and 17 ETS-positive patients switched to FOLFIRI plus bevacizumab 8 weeks and 16 weeks after initial FOLFIRI plus cetuximab, respectively. Median progression-free and overall survival durations were 13.4 and 34.7 months, respectively. Six (20%) patients experienced grade ≥3 paronychia, which improved to grade ≤2 by 18 weeks. Grade ≥3 acneiform rash, dry skin, and pruritus were not observed in any patients.

CONCLUSIONS

Our novel treatment strategy delivered acceptable survival outcomes and reduced severe dermatologic toxicities.

Prognostic and predictive biomarkers for anti-EGFR monoclonal antibody therapy in RAS wild-type metastatic colorectal cancer: a systematic review and meta-analysis

BACKGROUND

RAS mutations affect prognosis in patients with metastatic colorectal cancer (mCRC) and have been identified as strong negative predictive markers for anti-epidermal growth factor receptor monoclonal antibody (anti-EGFR mAb) therapy, but many tumors containing wild-type RAS genes still do not respond to these therapies. Some additional biomarkers may have prognostic or predictive roles, but conclusions remain controversial.

METHODS

We performed a meta-analysis and systematic review of randomized controlled trials comparing anti-EGFR mAb therapy with alternative therapy that investigated the prognostic and predictive impact of additional biomarkers in RAS wild-type (wt) mCRC patients. Hazard ratios (HRs) and 95% confidence intervals (CIs) for progression-free survival (PFS) and overall survival (OS) and odds ratios (ORs) for objective response rate (ORR) were calculated. The prognostic value of biomarkers was investigated by separately pooling HR and OR for different treatment groups in an individual study. The predictive value was assessed by pooling study interactions between treatment effects and biomarker subgroups.

RESULTS

Thirty publications reporting on eighteen trials were selected, including a total of 13,507 patients. In prognostic analysis, BRAF mutations were associated with poorer PFS [HRs = 3.76 (2.47-5.73) and 2.69 (1.82-3.98)] and OS [HRs = 2.66 (1.95-3.65) and 2.45 (1.55-3.88)] in both the experimental and control arms; low miR-31-3p expression appeared to have longer PFS and OS. In terms of predictive effect, a lack of response to anti-EGFR therapy was observed in patients with BRAF mutant tumors (Pinteraction < 0.01 for PFS). Patients with tumors with any mutation in the KRAS/NRAS/BRAF/PIK3CA gene also showed similar results compared with all wild-type tumors (Pinteraction for PFS, OS, and ORR were < 0.01, < 0.01 and 0.01, respectively). While low miR-31-3p expression could predict PFS (Pinteraction = 0.01) and OS (Pinteraction = 0.04) benefit. The prognostic and predictive value regarding PIK3CA mutations, PTEN mutations or deletions, EGFR, EREG/AREG, HER2, HER3, and HER4 expression remains uncertain.

CONCLUSIONS

In RAS wt mCRC patients receiving EGFR-targeted therapy, BRAF mutation is a powerful prognostic and therapy-predictive biomarker, with no effect found for PIK3CA mutation, PTEN mutation or deletion, but the combined biomarker KRAS/NRAS/BRAF/PIK3CA mutations predict resistance to anti-EGFR therapy. Low miR-31-3p expression may have positive prognostic and therapy predictive effects. Evidence on the prognostic and predictive roles of EGFR and its ligands, and HER2/3/4 is insufficient.

Chemotherapy and Targeted Therapy Strategies in Patients with Unresectable or Borderline Resectable Metastatic Colorectal Cancer: Evidence for a Lack of Focus on Resection Rates

BACKGROUND AND AIMS

Chemotherapy (CTx) with targeted therapy (TT) have increased the overall response rate (ORR) and improved survival in unresectable or borderline resectable metastatic colorectal cancer (mCRC). However, the resection rate is an endpoint with often suboptimal expert involvement. The aim was to investigate whether the improvements in ORR have translated to improved resection rates (RR).

STUDY DESIGN

A systematic literature search was performed using the PICO process.

STATISTICAL ANALYSIS

Odds ratios, and 95% confidence intervals (OR, 95% CI) were analyzed for ORR and RR using dichotomous values with the Mantel-Haenszel method. Progression-free survival (PFS) and overall survival (OS) were analyzed using the inverse-variance method and displayed as hazard ratios and 95% confidence intervals (HR, 95% CI).

RESULTS

The literature search returned 469 records. Sixteen articles with 5724 patients were selected for analysis. The qualitative analysis revealed low and moderate risk of bias endpoints. Higher ORR was observed with CTx + TT versus CTx only (OR: 0.62 [95% CI 0.45; 0.82], p = 0.002) and with triplet CTx + TT versus doublet CTx + TT (OR: 0.61 [95% CI 0.46; 0.81], p < 0.001). PFS and OS were improved by use of TT (HR: 0.68-0.84; p < 0.001 to 0.04). The overall RR was low (< 15%) and did not improve in the same way as the other endpoints.

CONCLUSION

The ORR and survival rates in unresectable and borderline resectable mCRC were improved by modern CTx and TT that did not translate into higher RR, mostly due to the lack of expert involvement.

Ibero-American Consensus Review and Incorporation of New Biomarkers for Clinical Practice in Colorectal Cancer

Advances in genomic technologies have significantly improved the management of colorectal cancer (CRC). Several biomarkers have been identified in CRC that enable personalization in the use of biologic agents that have shown to enhance the clinical outcomes of patients. However, technologies used for their determination generate massive amounts of information that can be difficult for the clinician to interpret and use adequately. Through several discussion meetings, a group of oncology experts from Spain and several Latin American countries reviewed the latest literature to provide practical recommendations on the determination of biomarkers in CRC based on their clinical experience. The article also describes the importance of looking for additional prognostic biomarkers and the use of histopathology to establish an adequate molecular classification. Present and future of immunotherapy biomarkers in CRC patients are also discussed, together with several techniques for marker determination, including liquid biopsy, next-generation sequencing (NGS), polymerase chain reaction (PCR), and fecal immunohistochemical tests. Finally, the role of Molecular Tumor Boards in the diagnosis and treatment of CRC is described. All of this information will allow us to highlight the importance of biomarker determination in CRC.

Adverse events during first-line treatments for mCRC: The Toxicity over Time (ToxT) analysis of three randomised trials

BACKGROUND

In clinical trials, the assessment of safety is traditionally focused on the overall rate of high-grade and serious adverse events (AEs). A new approach to AEs evaluation, taking into account chronic low-grade AEs, single patient's perspective, and time-related information, such as ToxT analysis, should be considered especially for less intense but potentially long-lasting treatments, such as maintenance strategies in metastatic colorectal cancer (mCRC).

PATIENTS AND METHODS

We applied ToxT (Toxicity over Time) evaluation to a large cohort of mCRC patients enroled in randomised TRIBE, TRIBE2, and VALENTINO studies, in order to longitudinally describe AEs throughout the whole treatment duration and to compare AEs evolution over cycles between induction and maintenance strategies, providing numerical and graphical results overall and per single patient. After 4-6 months of combination therapy, 5-fluorouracil/leucovorin (5-FU/LV) + bevacizumab or panitumumab was recommended in all studies except for the 50% of patients in the VALENTINO trial who received panitumumab alone.

RESULTS

Out of 1400 patients included, 42% received FOLFOXIRI (5-FU/LV, oxaliplatin, and irinotecan)/bevacizumab, 18% FOLFIRI/bevacizumab, 24% FOLFOX/bevacizumab, 16% FOLFOX/panitumumab. Mean grade of general and haematological AEs was higher in the first cycles, then progressively decreasing after the end of induction (p < 0.001), and always remaining at the highest levels with FOLFOXIRI/bevacizumab (p < 0.001). Neurotoxicity became more frequent over the cycles with late high-grade episodes (p < 0.001), while the incidence but not the grade of hand-and-foot syndrome gradually increased (p = 0.91). Anti-VEGF-related AEs were more severe in the first cycles, then setting over at low levels (p = 0.03), while anti-EGFR-related AEs still affected patients during maintenance.

CONCLUSIONS

Most of chemotherapy-related AEs (except for HFS and neuropathy) reach the highest level in the first cycles, then decrease, probably due to their active clinical management. Transition to maintenance allows relief from most AEs, especially with bevacizumab-based regimens, while anti-EGFR-related AEs may persist.

Impact of Colorectal Cancer Sidedness and Location on Therapy and Clinical Outcomes: Role of Blood-Based Biopsy for Personalized Treatment

Colorectal cancer is one of the most common malignant diseases in the United States and worldwide, and it remains among the top three causes of cancer-related death. A new understanding of molecular characteristics has changed the profile of colorectal cancer and its treatment. Even controlling for known mutational differences, tumor side of origin has emerged as an independent prognostic factor, and one that impacts response to therapy. Left- and right-sided colon cancers differ in a number of key ways, including histology, mutational profile, carcinogenesis pathways, and microbiomes. Moreover, the frequency of certain molecular features gradually changes from the ascending colon to rectum. These, as well as features yet to be identified, are likely responsible for the ongoing role of tumor sidedness and colorectal subsites in treatment response and prognosis. Along with tumor molecular profiling, blood-based biopsy enables the identification of targetable mutations and predictive biomarkers of treatment response. With the application of known tumor characteristics including sidedness and subsites as well as the utilization of blood-based biopsy, along with the development of biomarkers and targeted therapies, the field of colorectal cancer continues to evolve towards the personalized management of a heterogeneous cancer.

First-line systemic treatment strategies in patients with initially unresectable colorectal cancer liver metastases (CAIRO5): an open-label, multicentre, randomised, controlled, phase 3 study from the Dutch Colorectal Cancer Group

BACKGROUND

Patients with initially unresectable colorectal cancer liver metastases might qualify for local treatment with curative intent after reducing the tumour size by induction systemic treatment. We aimed to compare the currently most active induction regimens.

METHODS

In this open-label, multicentre, randomised, phase 3 study (CAIRO5), patients aged 18 years or older with histologically confirmed colorectal cancer, known RAS/BRAFV600E mutation status, WHO performance status of 0-1, and initially unresectable colorectal cancer liver metastases were enrolled at 46 Dutch and one Belgian secondary and tertiary centres. Resectability or unresectability of colorectal cancer liver metastases was assessed centrally by an expert panel of liver surgeons and radiologists, at baseline and every 2 months thereafter by predefined criteria. Randomisation was done centrally with the minimisation technique via a masked web-based allocation procedure. Patients with right-sided primary tumour site or RAS or BRAFV600E mutated tumours were randomly assigned (1:1) to receive FOLFOX or FOLFIRI plus bevacizumab (group A) or FOLFOXIRI plus bevacizumab (group B). Patients with left-sided and RAS and BRAFV600E wild-type tumours were randomly assigned (1:1) to receive FOLFOX or FOLFIRI plus bevacizumab (group C) or FOLFOX or FOLFIRI plus panitumumab (group D), every 14 days for up to 12 cycles. Patients were stratified by resectability of colorectal cancer liver metastases, serum lactate dehydrogenase concentration, choice of irinotecan versus oxaliplatin, and BRAFV600E mutation status (for groups A and B). Bevacizumab was administered intravenously at 5 mg/kg. Panitumumab was administered intravenously at 6 mg/kg. FOLFIRI consisted of intravenous infusion of irinotecan at 180 mg/m2 with folinic acid at 400 mg/m2, followed by bolus fluorouracil at 400 mg/m2 intravenously, followed by continuous infusion of fluorouracil at 2400 mg/m2. FOLFOX consisted of oxaliplatin at 85 mg/m2 intravenously together with the same schedule of folinic acid and fluorouracil as in FOLFIRI. FOLFOXIRI consisted of irinotecan at 165 mg/m2 intravenously, followed by intravenous infusion of oxaliplatin at 85 mg/m2 with folinic acid at 400 mg/m2, followed by continuous infusion of fluorouracil at 3200 mg/m2. Patients and investigators were not masked to treatment allocation. The primary outcome was progression-free survival, analysed on a modified intention-to-treat basis, excluding patients who withdrew consent before starting study treatment or violated major entry criteria (no metastatic colorectal cancer, or previous liver surgery for colorectal cancer liver metastases). The study is registered with ClinicalTrials.gov, NCT02162563, and accrual is complete.

FINDINGS

Between Nov 13, 2014, and Jan 31, 2022, 530 patients (327 [62%] male and 203 [38%] female; median age 62 years [IQR 54-69]) were randomly assigned: 148 (28%) patients to group A, 146 (28%) patients to group B, 118 (22%) patients to group C, and 118 (22%) patients to group D. Groups C and D were prematurely closed for futility. 521 patients were included in the modified intention-to-treat population (147 in group A, 144 in group B, 114 in group C, and 116 in group D). The median follow-up at the time of this analysis was 51·1 months (95% CI 47·7-53·1) in groups A and B and 49·9 months (44·5-52·5) in in groups C and D. Median progression-free survival was 9·0 months (95% CI 7·7-10·5) in group A versus 10·6 months (9·9-12·1) in group B (stratified hazard ratio [HR] 0·76 [95% CI 0·60-0·98]; p=0·032), and 10·8 months (95% CI 9·9-12·6) in group C versus 10·4 months (9·8-13·0) in group D (stratified HR 1·11 [95% CI 0·84-1·48]; p=0·46). The most frequent grade 3-4 events in groups A and B were neutropenia (19 [13%] patients in group A vs 57 [40%] in group B; p<0·0001), hypertension (21 [14%] vs 20 [14%]; p=1·00), and diarrhoea (five [3%] vs 28 [19%]; p<0·0001), and in groups C and D were neutropenia (29 [25%] vs 24 [21%]; p=0·44), skin toxicity (one [1%] vs 29 [25%]; p<0·0001), hypertension (20 [18%] vs eight [7%]; p=0·016), and diarrhoea (five [4%] vs 18 [16%]; p=0·0072). Serious adverse events occurred in 46 (31%) patients in group A, 75 (52%) patients in group B, 41 (36%) patients in group C, and 49 (42%) patients in group D. Seven treatment-related deaths were reported in group B (two due to multiorgan failure, and one each due to sepsis, pneumonia, portal vein thrombosis, septic shock and liver failure, and sudden death), one in group C (multiorgan failure), and three in group D (cardiac arrest, pulmonary embolism, and abdominal sepsis).

INTERPRETATION

In patients with initially unresectable colorectal cancer liver metastases, FOLFOXIRI-bevacizumab was the preferred treatment in patients with a right-sided or RAS or BRAFV600E mutated primary tumour. In patients with a left-sided and RAS and BRAFV600E wild-type tumour, the addition of panitumumab to FOLFOX or FOLFIRI showed no clinical benefit over bevacizumab, but was associated with more toxicity.

FUNDING

Roche and Amgen.

Molecular and genetic targets within metastatic colorectal cancer and associated novel treatment advancements

Colorectal cancer results in the deaths of hundreds of thousands of patients worldwide each year, with incidence expected to rise over the next two decades. In the metastatic setting, cytotoxic therapy options remain limited, which is reflected in the meager improvement of patient survival rates. Therefore, focus has turned to the identification of the mutational composition inherent to colorectal cancers and development of therapeutic targeted agents. Herein, we review the most up to date systemic treatment strategies for metastatic colorectal cancer based on the actionable molecular alterations and genetic profiles of colorectal malignancies.

Pan-Asian adapted ESMO Clinical Practice Guidelines for the diagnosis, treatment and follow-up of patients with metastatic colorectal cancer

The European Society for Medical Oncology (ESMO) Clinical Practice Guidelines for the diagnosis, treatment and follow-up of patients with metastatic colorectal cancer (mCRC), published in late 2022, were adapted in December 2022, according to previously established standard methodology, to produce the Pan-Asian adapted (PAGA) ESMO consensus guidelines for the management of Asian patients with mCRC. The adapted guidelines presented in this manuscript represent the consensus opinions reached by a panel of Asian experts in the treatment of patients with mCRC representing the oncological societies of China (CSCO), Indonesia (ISHMO), India (ISMPO), Japan (JSMO), Korea (KSMO), Malaysia (MOS), the Philippines (PSMO), Singapore (SSO), Taiwan (TOS) and Thailand (TSCO), co-ordinated by ESMO and the Japanese Society of Medical Oncology (JSMO). The voting was based on scientific evidence and was independent of the current treatment practices, drug access restrictions and reimbursement decisions in the different Asian countries. The latter are discussed separately in the manuscript. The aim is to provide guidance for the optimisation and harmonisation of the management of patients with mCRC across the different countries of Asia, drawing on the evidence provided by both Western and Asian trials, whilst respecting the differences in screening practices, molecular profiling and age and stage at presentation, coupled with a disparity in the drug approvals and reimbursement strategies, between the different countries.

Targeted Therapies in Colorectal Cancer: Recent Advances in Biomarkers, Landmark Trials, and Future Perspectives

In 2022, approximately 600,000 cancer deaths were expected; more than 50,000 of those deaths would be from colorectal cancer (CRC). The CRC mortality rate in the US has decreased in recent decades, with a 51% drop between 1976 and 2014. This drop is attributed, in part, to the tremendous therapeutic improvements, especially after the 2000s, in addition to increased social awareness regarding risk factors and diagnostic improvement. Five-fluorouracil, irinotecan, capecitabine, and later oxaliplatin were the mainstays of mCRC treatment from the 1960s to 2002. Since then, more than a dozen drugs have been approved for the disease, betting on a new chapter in medicine, precision oncology, which uses patient and tumor characteristics to guide the therapeutic choice. Thus, this review will summarize the current literature on targeted therapies, highlighting the molecular biomarkers involved and their pathways.

[Metastatic colorectal cancer-Modern treatment strategies and sequences]

The treatment of metastatic colorectal cancer (mCRC) has been considerably expanded and relevantly improved in recent years with new strategies, such as resection of liver and/or lung metastases, induction and maintenance treatment, the establishment of targeted therapies and molecularly defined strategies in defined subgroups. This article presents evidence-based treatment options and algorithms, with a focus on systemic treatment.

Systemic treatment for metastatic colorectal cancer

Significant progress has been achieved in the treatment of metastatic colorectal cancer (mCRC) patients during the last 20 years. There are currently numerous treatments available for the first-line treatment of mCRC. Sophisticated molecular technologies have been developed to reveal novel prognostic and predictive biomarkers for CRC. The development of next-generation sequencing and whole-exome sequencing, which are strong new tools for the discovery of predictive molecular biomarkers to facilitate the delivery of customized treatment, has resulted in tremendous breakthroughs in DNA sequencing technology in recent years. The appropriate adjuvant treatments for mCRC patients are determined by the tumor stage, presence of high-risk pathologic characteristics, microsatellite instability status, patient age, and performance status. Chemotherapy, targeted therapy, and immunotherapy are the main systemic treatments for patients with mCRC. Despite the fact that these novel treatment choices have increased overall survival for mCRC, survival remains optimal for individuals with non-metastatic disease. The molecular technologies currently being used to support our ability to practice personalized medicine; the practical aspects of applying molecular biomarkers to regular clinical practice; and the evolution of chemotherapy, targeted therapy, and immunotherapy strategies for the treatment of mCRC in the front-line setting are all reviewed here.

Systemic treatment for metastatic colorectal cancer

Significant progress has been achieved in the treatment of metastatic colorectal cancer (mCRC) patients during the last 20 years. There are currently numerous treatments available for the first-line treatment of mCRC. Sophisticated molecular technologies have been developed to reveal novel prognostic and predictive biomarkers for CRC. The development of next-generation sequencing and whole-exome sequencing, which are strong new tools for the discovery of predictive molecular biomarkers to facilitate the delivery of customized treatment, has resulted in tremendous breakthroughs in DNA sequencing technology in recent years. The appropriate adjuvant treatments for mCRC patients are determined by the tumor stage, presence of high-risk pathologic characteristics, microsatellite instability status, patient age, and performance status. Chemotherapy, targeted therapy, and immunotherapy are the main systemic treatments for patients with mCRC. Despite the fact that these novel treatment choices have increased overall survival for mCRC, survival remains optimal for individuals with non-metastatic disease. The molecular technologies currently being used to support our ability to practice personalized medicine; the practical aspects of applying molecular biomarkers to regular clinical practice; and the evolution of chemotherapy, targeted therapy, and immunotherapy strategies for the treatment of mCRC in the front-line setting are all reviewed here.

Primary tumour side as a driver for treatment choice in RAS wild-type metastatic colorectal cancer patients: a systematic review and pooled analysis of randomised trials

BACKGROUND

Retrospective subgroup analyses of previous trials in the first-line therapy of RAS wt metastatic colorectal cancer (mCRC) suggested a predictive impact of primary tumour side on the efficacy of anti-epidermal growth factor receptor (EGFR) agents. Recently, new head-to-head trials of doublets/bevacizumab versus doublets/anti-EGFR, PARADIGM and CAIRO5 were presented.

PATIENTS AND METHODS

We searched for phase II and III trials comparing doublet chemotherapy plus an anti-EGFR or bevacizumab as the first-line treatment for RAS wt mCRC patients. Overall survival (OS), progression-free survival (PFS), overall response rate (ORR) and radical resection rate result in the overall study populations and, according to the primary side, were pooled together in a two-stage analysis with random effects and fixed effect models. The interaction between sidedness and treatment effect was then analysed.

RESULTS

We identified five trials (PEAK, CALGB/SWOG 80405, FIRE-3, PARADIGM and CAIRO5), including 2739 patients, 77% left- and 23% right-sided. Among patients with left-sided mCRC, the use of anti-EGFRs was associated with higher ORR (74% versus 62%, OR = 1.77 [95% confidence interval {CI} 1.39-2.26-0.88], p < 0.0001), longer OS (hazard ratio [HR] = 0.77 [95% CI 0.68-0.88], p < 0.0001) and not significantly longer PFS (HR = 0.92, p = 0.19). Among patients with right-sided mCRC, the use of bevacizumab was associated with longer PFS (HR = 1.36 [95% CI 1.12-1.65], p = 0.002) and not significantly longer OS (HR = 1.17, p = 0.14). A subgroup analysis confirmed a significant interaction effect between the primary tumour side and treatment arm in terms of ORR (p = 0.02), PFS (p = 0.0004) and OS (p = 0.001). No differences in the radical resection rate were found according to treatment and sidedness.

CONCLUSIONS

Our updated metanalysis corroborates the role of the primary tumour location in the choice of the upfront therapy for RAS wt mCRC patients, leading to strongly recommend anti-EGFRs in left-sided tumours and to prefer bevacizumab in the right-sided.

Targeting BRAF V600E in metastatic colorectal cancer: where are we today?

Colorectal cancer (CRC) is the second most frequent cause of direct cancer death worldwide. The study of the molecular state of oncogenes has predictive and prognostic value in metastatic CRC (mCRC). The B-raf proto-oncogene (BRAF) gene mutation represents the 8%-12% of all mutations in mCRC. The BRAF V600E mutation, considered the most common alteration of BRAF, corresponds to a constitutive kinase with a high activating capacity of the RAS/RAF/MEK/ERK pathway after a cascade of successive phosphorylations in the transcription of genes. BRAF V600E mutation is more prevalent in women, elderly, right-sided colon cancer and Caucasian population. Unfortunately, it is considered a poor predictive and prognosis biomarker. Patients with mCRC BRAF V600E mutated (BRAFm) are generally associated with poor response to chemotherapy and short progression-free survival and overall survival. Recently, randomised clinical trials have studied the combination of different chemotherapy regimens with angiogenic inhibitors in mCRC BRAFm. In addition, new anti-BRAF and immunotherapy agents have also been studied in this population, with positive results. The objective of this review is to acknowledge the biology and molecular pathway of BRAF, critically analyse the clinical trials and the therapy options published until today and evaluate the options of treatment according to the patient's clinical presentation.

Phase IIIb study of the bevacizumab biosimilar candidate BI 695502 plus mFOLFOX6 in metastatic colorectal cancer

Aim: This study assessed the safety, efficacy, pharmacokinetics and immunogenicity of the bevacizumab biosimilar candidate BI 695502 plus mFOLFOX6 in patients with metastatic colorectal cancer (mCRC). Materials & methods: Patients with untreated mCRC received BI 695502 and chemotherapy (oxaliplatin, leucovorin and 5-fluorouracil). Primary end point: proportion of patients with prespecified adverse events (AEs). Results: Of 123 patients enrolled and treated, 58.5% experienced prespecified AEs. Median progression-free survival was 10.5 months, median overall survival was 19.4 months, and objective response rate was 61.0%. There were no antidrug antibody or neutralizing antidrug antibody-positive samples post-baseline. Trough BI 695502 plasma concentrations increased until cycle 9 and stabilized thereafter. Conclusion: BI 695502 has an acceptable safety and efficacy profile in the treatment of mCRC.

Trial Registration Number: NCT02776683 ( ClinicalTrials.gov ), 2015-003718-25 (EudraCT, European Clinical Trials Database https://www.clinicaltrialsregister.eu/ctr-search/search?query=2015-003718-25 )

Study name: Study 1302.3

Conversion Strategy in Left-Sided RAS/BRAF Wild-Type Metastatic Colorectal Cancer Patients with Unresectable Liver-Limited Disease: A Multicenter Cohort Study

Colorectal cancer (CRC) patients frequently develop liver metastases. Different treatment strategies are available according to the timing of appearance, the burden of metastatic disease, and the performance status of the patient. Systemic treatment (ST) represents the cornerstone of metastatic disease management. However, in select cases, combined ST and surgical resection can lead to remarkable survival outcomes. In the present multicentric cohort study, we explored the efficacy of a conversion strategy in a selected population of left-sided RAS/BRAF wild-type CRC patients with liver-limited metastatic disease. Methods: The primary endpoint was to compare survival outcomes of patients undergoing ST not leading to surgery, liver resection after conversion ST, and hepatic resection with perioperative ST. Furthermore, we explored survival outcomes depending on whether the case was discussed within a multidisciplinary team. Results: Between 2012 and 2020, data from 690 patients respecting the inclusion criteria were collected. Among these, 272 patients were deemed eligible for the analysis. The conversion rate was 24.1% of cases. Fifty-six (20.6%) patients undergoing surgical resection after induction treatment (i.e., ultimately resectable) had a significant survival advantage compared to those receiving systemic treatment not leading to surgery (176 pts, 64.7%) (5-year OS 60.8% and 11.7%, respectively, Log Rank test p < 0.001; HR = 0.273; 95% CI: 0.16−0.46; p < 0.001; 5-year PFS 22.2% and 6.3%, respectively, Log Rank test p < 0.001; HR = 0.447; 95% CI: 0.32−0.63; p < 0.001). There was no difference in survival between ultimately resectable patients and those who had liver resection with perioperative systemic treatment (potentially resectable—40 pts) (5-year OS 71.1%, Log Rank test p = 0.311. HR = 0.671; 95% CI: 0.31−1.46; p = 0.314; 5-year PFS 25.7%, Log Rank test p = 0.305. HR = 0.782; 95% CI: 0.49−1.25; p = 0.306). Conclusions: In our selected population of left-sided RAS/BRAF wild-type colorectal cancer patients with liver-limited disease, a conversion strategy was confirmed to provide a survival benefit. Patients not deemed surgical candidates at the time of diagnosis and patients judged resectable with perioperative systemic treatment have similar survival outcomes.

The optimal first-line treatment for patients with left-sided RAS wild-type metastatic colorectal cancer: Double-drug regimen or triple-drug regimen therapy

There are many treatments for metastatic colorectal cancer (mCRC). Among them, uncertainty remains especially concerning the clinical benefit of different regimens for left-sided RAS wild-type (WT) mCRC in the triple-drug therapy era. No studies have been conducted to answer this critical clinical issue. We performed a comprehensive analysis of published data and real-world data. First, we conducted analyses of the published trials to show the landscape of efficacy and safety in the treatments of left-sided RAS WT mCRC. Then, we initiated a multicenter real-world study as the validation dataset. This study included six published randomized controlled trials (RCTs) and a total of 1925 patients. The double-drug regimen plus cetuximab/panitumumab (D + C/P) achieved the longest overall survival (OS) in patients with left-sided mCRC (HR = 0.74, 95%CI: 0.57–0.98), while triple-drug regimen with bevacizumab (T + B, HR = 1.1, 95%CI: 0.63–2.0), compared with double-drug with bevacizumab (D + B). The D + C/P had the highest overall response rate (ORR) in patients with left-sided mCRC (OR = 1.8, 95%CI: 0.89–3.8), while T + B (OR = 1.8, 95%CI: 0.70–4.8), compared with D + B. The multicenter real-world cohort showed the double-drug regimen plus cetuximab had longer progression-free survival (PFS) in left-sided mCRC patients than the triple-drug regimen with bevacizumab. The safety analysis showed the incidence of the adverse events (grade≥3) in the triple-drug therapy plus bevacizumab was higher than that in the double-drug therapy plus cetuximab/panitumumab. This work demonstrates the ranking of three regimens for therapeutic efficacy and safety in patients with left-sided RAS WT mCRC. The double-drug regimen plus cetuximab/panitumumab appears more effective and safer than double-drug and triple-drug based regimens with bevacizumab. Further trials and cohort analyses on this topic would increase confidence in these results.

Epidermal Growth Factor Receptor Inhibitor Treatment Timing does not Impact Survival in Stage 4 Colon Cancer Treatment: A Retrospective Study

Introduction

Colon cancer impacts the lives of Kansans and those across the United States. Epidermal growth factor receptor (EGFR) inhibitors, such as panitumumab and cetuximab, have gained popularity as first-line treatment for stage 4 colon cancer despite their toxicities and have been used by clinicians in later lines of therapy. EGFR inhibitors have been proven to be an efficacious first-line treatment for stage 4 colon cancer, but no study has investigated outcomes comparing EGFR inhibitors as first-line treatment to its use as second- or third-line treatment. This study investigated EGFR inhibitor therapy estimated overall survival when used as first-, second-, and third-line treatment for stage 4 colon cancer.

Methods

A retrospective review was done for patients with stage 4 colon cancer who underwent EGFR inhibitor treatment at a large academic center from November 2007 to August 2021. The patients were stratified into five groups by the line in which they received the EGFR inhibitor treatment. A log-rank test was used to analyze the groups, and the median survival for each group was determined.

Results

A total of 68 patients were reviewed; 18 received first-line, 23 received second-line, 18 received third-line, 6 received fourth-line, and 3 received sixth-line treatment with an EGFR inhibitor. Fourth- and sixth-line therapies were excluded due to small patient size. There was no significant difference in estimated survival time between any of the lines. Median survival of the therapies was found.

Conclusions

There was no statistical difference in survival between the first-, second-, or third-line groups, which may provide justification for its use as a second- or third-line therapy.

Efficacy and safety of triplet chemotherapy plus anti-EGFR agents in metastatic colorectal cancer: a systematic review and meta-analysis

Background

To date, the optimal treatment for potentially resectable metastatic colorectal cancer (mCRC) patients has yet to be determined. Encouraging results have been reported in studies exploring the efficacy of triplet chemotherapy plus anti-epidermal growth factor receptor (anti-EGFR) target agents. Thus, we conducted a meta-analysis to evaluate the efficacy and safety of triplet chemotherapy plus anti-EGFR target agents.

Methods

We systematically searched the PubMed, Embase, and Web of Science databases from December 2004 to October 2021 for studies examining the efficacy of triplet chemotherapy plus anti-EGFR target agents in mCRC patients. The primary outcomes were the objective response rate (ORR) and R0 resection rate (R0RR), and the secondary outcomes were median progression-free survival (mPFS), median overall survival (mOS), and toxicity. Data were analyzed with R software 4.1.2.

Results

Fourteen studies comprising 762 patients with mCRC were included in this meta-analysis. Analysis with a random effects model revealed that after treatment with triplet chemotherapy plus anti-EGFR target agents, the pooled ORR was 82% (95% CI= 76–88%, I2= 76%), and the pooled R0RR of colorectal liver metastasis (CLM) was 59% (95% CI= 49–68%, I2= 60%). The mPFS ranged from 9.5 to 17.8 months, and the mOS ranged from 24.7 to 62.5 months. A total of 648 grade 3 or 4 adverse events were reported; the most commonly reported events were diarrhea (174/648), neutropenia (157/648), and skin toxicity (95/648), which had pooled prevalence rates of 29% (95% CI= 20–39%, I2= 84%), 28% (95% CI= 20–37%, I2= 77%), and 17% (95% CI= 11–24%, I2= 66%), respectively.

Conclusions

Triplet chemotherapy plus anti-EGFR agents therapy seems to be capable of increasing the ORR of mCRC patients and the R0RR of CLM patients. The toxicity of this treatment is manageable. High-quality randomized controlled trial (RCT) studies are required for further validation.

The effectiveness and safety of bevacizumab versus cetuximab in the treatment of colorectal cancer: a systematic review and meta-analysis

BACKGROUND

Despite available meta-analyses, comparative efficacy and safety between bevacizumab and cetuximab-containing therapies in treating advanced colorectal cancer (CRC) still need to be elucidated.

AIM

This meta-analysis aimed to investigate the efficacy and grade 3-5 treatment-related adverse events (TARE3-5) of bevacizumab versus cetuximab in treating advanced CRC.

METHOD

A random sample of 400 patients aged 65 years or older from a clinical trial in four Swedish hospitals was selected. All patients' emergency department visits within 12 months after discharge were assessed with AT-HARM10. The main outcome measures were the percentage of successfully assessed visits for applicability and the interrater reliability (Cohen's kappa).

RESULTS

Five RCTs and four observational cohort studies (2970 patients) were included. The bevacizumab-containing group was associated with a significantly lower ORR (risk ratio RR 0.91, 95% confidence interval CI 0.85-0.97, P = 0.006) than the cetuximab group. Bevacizumab was associated with significant superior DCR (RR 1.05, 95% CI 1.01 to 1.10, P = 0.02) and prolonged OS (hazard ratio HR 0.81, 95% CI 0.74-0.90, P < 0.0001) than cetuximab. No significant differences were observed for PFS (HR 0.97, 95% CI 0.92-1.03, P = 0.33) between the groups. Bevacizumab showed a lower rate of skin disorders (RR 0.10, 95% CI 0.02-0.43, P = 0.002) than cetuximab. There were no significant differences between the groups in the overall rate of TRAE3-5 (RR 0.92, 95% CI 0.84-1.01, P = 0.08). Subgroup analysis found a lower TARE3-5 rate in the bevacizumab group in RCTs (RR 0.91, 95% CI 0.83-1.00, P = 0.04).

CONCLUSION

Bevacizumab could increase DCR, prolong OS, and lower the skin disorder rate to treat patients with advanced CRC.

Primary tumor location as a predictor of survival in patients with RAS wild-type colorectal cancer who receive molecularly targeted drugs as first-line therapy: a multicenter real-world observational study by the Japanese Society for Cancer of the Colon and Rectum

BACKGROUND

Primary tumor location is considered a predictor of overall survival (OS) in RAS wild-type (WT) metastatic colorectal cancer (mCRC) treated with bevacizumab (BEV) or an anti-epidermal growth factor antibody (cetuximab or panitumumab [CET/PAN]) as first-line molecularly targeted therapy. BEV is recommended for right-sided mCRC and CET/PAN for left-sided mCRC based on post-hoc analyses of clinical trial data, but real-world evidence is lacking.

METHODS

We retrospectively collected data of patients who started BEV or CET/PAN plus 5-fluorouracil-based doublet chemotherapy between January 2013 and December 2016 as first-line treatment for RAS WT mCRC at any of 24 Japanese institutions. OS was compared between the BEV and CET/PAN groups according to primary tumor location by Cox multivariate regression analysis in the full cohort and in a propensity score-matched cohort.

RESULTS

In total, 935 patients were enrolled. Median OS was 24.6 months with BEV and 20.9 months with CET/PAN in right-sided mCRC (n = 213; adjusted hazard ratio [HR] 0.73, 95% confidence interval [CI] 0.50-1.06) and 35.7 months and 30.0 months, respectively, in left-sided mCRC (n = 722; adjusted HR 0.92, 95% CI 0.74-1.13). In the propensity score-matched cohort, OS was significantly better in the BEV group than in the CET/PAN group in right-sided mCRC (HR 0.52, 95% CI 0.28-0.96) but was not significantly different in left-sided mCRC (HR 0.78, 95% CI 0.53-1.07).

CONCLUSION

Real-world data showed that OS was better with BEV than with CET/PAN in right-sided mCRC. However, there was no significant difference in OS in left-sided mCRC.

Tumor Biomarker Testing for Metastatic Colorectal Cancer: a Canadian Consensus Practice Guideline

The systemic therapy management of metastatic colorectal cancer (mCRC) has evolved from primarily cytotoxic chemotherapies to now include targeted agents given alone or in combination with chemotherapy, and immune checkpoint inhibitors. A better understanding of the pathogenesis and molecular drivers of colorectal cancer not only aided the development of novel targeted therapies but led to the discovery of tumor mutations which act as predictive biomarkers for therapeutic response. Mutational status of the KRAS gene became the first genomic biomarker to be established as part of standard of care molecular testing, where KRAS mutations within exons 2, 3, and 4 predict a lack of response to anti- epidermal growth factor receptor therapies. Since then, several other biomarkers have become relevant to inform mCRC treatment; however, there are no published Canadian guidelines which reflect the current standards for biomarker testing. This guideline was developed by a pan-Canadian advisory group to provide contemporary, evidence-based recommendations on the minimum acceptable standards for biomarker testing in mCRC, and to describe additional biomarkers for consideration.

Upfront Modified Fluorouracil, Leucovorin, Oxaliplatin, and Irinotecan Plus Panitumumab Versus Fluorouracil, Leucovorin, and Oxaliplatin Plus Panitumumab for Patients With RAS/BRAF Wild-Type Metastatic Colorectal Cancer: The Phase III TRIPLETE Study by GONO

To verify whether the intensification of the upfront chemotherapy backbone with a modified schedule of modified fluorouracil, leucovorin, oxaliplatin, and irinotecan (mFOLFOXIRI) increases the activity of fluorouracil, leucovorin, and oxaliplatin when both regimens are combined with panitumumab as initial treatment for RAS and BRAF wild-type (wt) metastatic colorectal cancer (mCRC).

First-line chemotherapy with raltitrexed in metastatic colorectal cancer: an Association des Gastro-entérologues Oncologues (AGEO) multicentre study

BACKGROUND

In case of contraindication or intolerance to fluoropyrimidines, raltitrexed is a validated alternative in metastatic colorectal cancer (mCRC), associated or not with oxaliplatin. Little is known about the outcomes of raltitrexed combined with irinotecan or targeted therapies.

METHODS

This retrospective multicentre study enroled mCRC patients treated with first-line raltitrexed-based chemotherapy. Treatment-related toxicities were recorded. Progression-free survival (PFS) and overall survival (OS) were calculated from treatment start.

RESULTS

75 patients were treated with raltitrexed alone, TOMOX, or TOMIRI with or without bevacizumab. Grade 3-4 adverse events were seen in 31% of patients, without significant difference between the different treatment schedules. amongst the 36 patients with a history of fluoropyrimidine-induced cardiac toxicity, none developed cardiovascular events on raltitrexed. Median PFS and OS were 10.6 (95% CI 8.2 - 13.1) and 27.4 months (95% CI 24.1-38.1), respectively. Considering the chemotherapy regimen, TOMOX was significantly associated with better PFS and OS compared to TOMIRI and raltitrexed alone.

CONCLUSIONS

In patients with mCRC not eligible for fluoropyrimidines, first-line raltitrexed-based chemotherapy had an acceptable safety profile. PFS and OS were consistent with usual survival data in mCRC, and significantly better in patients treated with TOMOX, independently of associated targeted therapies.

Systematic literature review and network meta-analysis of pembrolizumab versus other interventions for previously untreated, unresectable or metastatic, microsatellite instability-high or mismatch repair-deficient colorectal cancer

Aim: To compare pembrolizumab with competing interventions for previously untreated, unresectable or metastatic microsatellite instability-high or mismatch repair-deficient colorectal cancer. Method: Trials were identified via a systematic literature review and synthesized using a Bayesian network meta-analysis with time-varying hazard ratios (HRs). Results: Using intention-to-treat data, HRs for overall survival were generally in favor of pembrolizumab but not statistically significant; however, statistical significance was reached versus all comparators by month 16 when accounting for crossover. Estimated HRs for progression-free survival significantly favored pembrolizumab versus all comparators by month 12. Pembrolizumab was also superior to all comparators in terms of grade ≥3 adverse events. Conclusion: These analyses suggest that pembrolizumab is a highly efficacious and safe treatment in this population.

Effect of Primary Tumor Location on Second- or Later-Line Treatment With Anti-Epidermal Growth Factor Receptor Antibodies in Patients With Metastatic Colorectal Cancer: A Retrospective Multi-Center Study

BACKGROUND

Current guidelines recommend anti-epidermal growth factor receptor monoclonal antibodies (anti-EGFR Ab) as first-line treatment only in patients with left-sided RAS wild type (RASwt) metastatic colorectal cancer (mCRC). However, there are no guideline recommendations specific to tumor sidedness in subsequent-line treatment. This study aimed to investigate the effect of primary tumor location on second- or later-line treatment outcomes in patients with KRASwt mCRC.

METHODS

Medical records of patients diagnosed with mCRC at 3 academic centers in Thailand (Siriraj, Chulalongkorn, and Ramathibodi hospital) between 2008 and 2019 were retrospectively reviewed. Patients with KRASwt mCRC who received anti-EGFR Ab in second- or later-line treatment were included. The impact of tumor sidedness on progression-free survival (PFS) was determined using Kaplan-Meier method, and those results were compared using log-rank test.

RESULTS

Among the 2,102 patients who had KRAS analysis data, 1,130 (54%) patients had KRASwt. Of those, 413 patients received anti-EGFR Ab in second- or later-line treatment. One hundred and sixty-two of 413 (39%) patients had extended RAS analysis. Seventy (17%) patients had right-sided tumors. Two hundred and thirty-eight (58%) patients received anti-EGFR Ab in the third line, and 132 (32%) patients and 43 (10%) patients were treated in the second and more than third line, respectively. Single-agent irinotecan was the most commonly used backbone chemotherapy (303/413, 73%). Patients with right-sided tumors had non-significantly inferior PFS compared to patients with left-sided tumors (median PFS: 5.7 months (mo), 95% confidence interval [CI]: 3.9-7.5 vs. 7.5 mo, 95% CI 6.5-8.5; p=0.17). Subgroup analysis showed no difference in PFS when stratified by treatment lines. Patient with right-sided tumors had significantly inferior OS compared to patients with left-sided tumors (median OS: 23.3 mo vs. 29.9 mo; p=0.005).

CONCLUSIONS

To date, this is the largest real world data of the effect of primary tumor location on anti-EGFR Ab which demonstrated that tumor sidedness has no significant impact on treatment outcomes in KRASwt mCRC patients receiving second- or later-line therapy. Our findings do not support the utility of tumor sidedness for treatment selection in these settings. We confirmed that patients with right-sided tumors had significantly worse survival.

Evaluation of histopathological heterogeneity of colorectal cancer liver metastasis sites after preoperative chemotherapy

Patients with liver metastases from colorectal cancer (CRLMs) frequently receive chemotherapy prior to liver resection. Histopathological assessment of the resected specimen can evaluate the response to chemotherapy. The present study analyzed the association between histopathological changes in the primary site and liver metastases. The present study comprised 45 patients with resectable CRLMs at the Surgical Oncology Department of Gifu University School of Medicine (Gifu, Japan) between January 2006 and August 2015. The study included 24 men and 21 women. The primary colonic tumor was located in the right side in 13 (28.9%) patients and the left side in 32 (71.9%) patients. The present study evaluated patients with metastatic colorectal cancer (31/45) after excluding those in whom histopathological heterogeneity between the primary and liver metastasis changed to grade 3 after chemotherapy. The group that underwent hepatectomy after chemotherapy (n=25) was compared with the group that underwent hepatectomy alone (n=6). In 16 (53.3%) out of 25 patients, histopathological heterogeneity of the liver metastasis was lost (P=0.04). In conclusion, chemotherapy appeared to change histopathological heterogeneity. The present study suggested that the histopathological change of intratumoral heterogeneity is reflected by the response to chemotherapy.

Personalizing first-line treatment in advanced colorectal cancer: Present status and future perspectives

BACKGROUND

Colorectal cancer is one of the most frequent neoplasms worldwide, and the majority of patients are diagnosed in advanced stages. Metastatic colorectal cancer (mCRC) harbors several mutations with different prognostic and predictive values; KRAS, NRAS, and BRAF mutations are the best known. Indeed, RAS and BRAF molecular status are associated with a different response to monoclonal antibodies (Anti-epidermal growth factor receptor and anti-vascular endothelial growth factor receptor agents), which are usually added to chemotherapy in first-line, and thus allow to select the optimal therapy for patients with mCRC. Furthermore, sidedness is an important predictive and prognostic factor in mCRC, which is explained by the different molecular profile of left and right-sided tumors. Recently, microsatellite instability-high has emerged as a predictive factor of response and survival from immune checkpoint inhibitors in mCRC. Finally, several other alterations have been described in lower frequencies, such as human epidermal growth factor receptor-2 overexpression/amplification, PIK3CA pathway alterations, phosphatase and tension homolog loss, and hepatocyte growth factor/mesenchymal-epithelial transition factor pathway dysregulation, with several targeted therapies already demonstrating activity or being tested in currently ongoing clinical trials.

AIM

To review the importance of studying the predictive and prognostic roles of the molecular profile of mCRC, the changes occurred in recent years and how they would potentially change in the near future, to guide physicians in treatment decisions.

RELEVANCE FOR PATIENTS

Today, several different therapeutic options can be offered to patients in the first-line setting of mCRC. Therapies at present approved or under investigation in clinical trials will be thoroughly reviewed, with special emphasis on the molecular rationale behind them. Understanding the molecular status, resistance mechanisms and potential new druggable targets may allow physicians to choose the best therapeutic option in the first-line mCRC.

[Multimodal, interdisciplinary therapeutic concepts for liver metastasized colorectal cancer]

About half of all patients with colorectal carcinoma (CRC) develop metastases mainly in the liver during the course of their disease. Metastatic disease is associated with a low 5-year overall survival rate of only 5-7 %, particularly when there is no possibility of local treatment. However, if there is an opportunity to resect the metastases, especially isolated liver metastases, the chance of long-term survival is approximately 15-27 % after both primary resection or secondary resection after neoadjuvant pretreatment. Overall, long-term survival of patients with metastatic CRC has improved significantly in recent years due to a combination of modern systemic therapies, advanced liver surgery and local ablative procedures.Of note, for the vast majority of patients, metastatic resection does not mean cure, but a significant prolongation of overall survival with a good quality of life. Chemotherapy-free intervals after metastasis resection maintain quality of life and can help to reduce toxicity.In this review, we would like to present the "toolbox" for the multidisciplinary treatment of metastatic CRC and give recommendations how the individual modalities should be optimally used, considering tumor-specific characteristics and patient preferences.

Liver transplantation for non-resectable colorectal liver metastases: the International Hepato-Pancreato-Biliary Association consensus guidelines

Colorectal cancer is a prevalent disease worldwide, with more than 50% of patients developing metastases to the liver. Despite advances in improving resectability, most patients present with non-resectable colorectal liver metastases requiring palliative systemic therapy and locoregional disease control strategies. There is a growing interest in the use of liver transplantation to treat non-resectable colorectal liver metastases in well selected patients, leading to a surge in the number of studies and prospective trials worldwide, thereby fuelling the emerging field of transplant oncology. The interdisciplinary nature of this field requires domain-specific evidence and expertise to be drawn from multiple clinical specialities and the basic sciences. Importantly, the wider societal implication of liver transplantation for non-resectable colorectal liver metastases, such as the effect on the allocation of resources and national transplant waitlists, should be considered. To address the urgent need for a consensus approach, the International Hepato-Pancreato-Biliary Association commissioned the Liver Transplantation for Colorectal liver Metastases 2021 working group, consisting of international leaders in the areas of hepatobiliary surgery, colorectal oncology, liver transplantation, hepatology, and bioethics. The aim of this study was to standardise nomenclature and define management principles in five key domains: patient selection, evaluation of biological behaviour, graft selection, recipient considerations, and outcomes. An extensive literature review was done within the five domains identified. Between November, 2020, and January, 2021, a three-step modified Delphi consensus process was undertaken by the workgroup, who were further subgrouped into the Scientific Committee, Expert Panel, and Transplant Centre Representatives. A final consensus of 44 statements, standardised nomenclature, and a practical management algorithm is presented. Specific criteria for clinico-patho-radiological assessments with molecular profiling is crucial in this setting. After this, the careful evaluation of biological behaviour with bridging therapy to transplantation with an appropriate assessment of the response is required. The sequencing of treatment in synchronous metastatic disease requires special consideration and is highlighted here. Some ethical dilemmas within organ allocation for malignant indications are discussed and the role for extended criteria grafts, living donor transplantation, and machine perfusion technologies for non-resectable colorectal liver metastases are reviewed. Appropriate immunosuppressive regimens and strategies for the follow-up and treatment of recurrent disease are proposed. This consensus guideline provides a framework by which liver transplantation for non-resectable colorectal liver metastases might be safely instituted and is a meaningful step towards future evidenced-based practice for better patient selection and organ allocation to improve the survival for patients with this disease.

Randomized phase II study of SOX+B-mab versus SOX+C-mab in patients with previously untreated recurrent advanced colorectal cancer with wild-type KRAS (MCSGO-1107 study)

Background

Although chemotherapy for metastatic colorectal cancer (mCRC) has improved, the standard chemotherapy regimens for patients with RAS wild-type mCRC remain debated. This study aimed to compare S-1 and oxaliplatin (SOX) + bevacizumab (B-mab) with SOX + cetuximab (C-mab) in patients with previously untreated recurrent advanced CRC with wild-type KRAS.

Methods

This randomized phase II, open-label, multicenter study compared the efficacy and safety of SOX+B-mab with SOX+C-mab in patients with previously untreated advanced CRC with wild-type KRAS. Between February 2012 and October 2016, 45 patients were enrolled.

Results

Overall response rates were 59.1 and 43.5% (p = 0.29) and disease control rates were 90.9 and 91.3% (p = 0.96) in the SOX+B-mab and SOX+C-mab groups, respectively. Median overall survival (OS) was 25.3 and 15.5 months (HR = 0.607, p = 0.167) and median progression-free survival (PFS) were 11.7 and 5.5 months (HR = 0.558, p = 0.077) in the SOX+B-mab and SOX+C-mab groups, respectively. The OS and PFS of patients with early tumor shrinkage (ETS) were not significantly different in the SOX+B-mab group. However, they were significantly better when ETS was ≥20 in the SOX+C-mab group (p = 0.032 and p = 0.003, respectively).

Conclusions

The efficacy and safety of SOX+B-mab and SOX+C-mab for wild-type KRAS recurrent advanced CRC as first-line chemotherapy were almost the same. Consideration of the treatment strategy based on ETS may improve patient prognosis, especially in patients receiving the SOX+C-mab regimen.

Trial registration

UMIN Clinical Trials Registry (UMIN000006706).

Date of registration: NOV/11/2011.

URL of trial registry record:

https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000007920

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08690-y.

MONARCC: a randomised phase II study of panitumumab monotherapy and panitumumab plus 5-fluorouracil as first-line therapy for RAS and BRAF wildtype metastatic colorectal cancer: a study by the Australasian Gastrointestinal Trials Group (AGITG)

Background

Doublet chemotherapy in combination with a biologic agent has been a standard of care in patients with metastatic colorectal cancer for over a decade. The evidence for a “lighter” treatment approach is limited to mono-chemotherapy plus bevacizumab in the RAS unselected population. Anti-EGFR antibodies have activity as monotherapy or in combination with chemotherapy in RAS wildtype metastatic colorectal cancer; however their role in first-line treatment in combination with 5-fluorouracil monotherapy or when given alone has not been well studied. MONARCC aims to investigate this approach in an elderly population.

Methods/design

MONARCC is a prospective, open-label, multicentre, non-comparative randomised phase II trial. Eligible patients aged ≥70 with unresectable metastatic, untreated, RAS/BRAF wildtype metastatic colorectal cancer will be randomised 1:1 to receive panitumumab alone or panitumumab plus infusional 5-fluorouracil. RAS and BRAF analyses will be performed in local laboratories. Comprehensive Health Assessment and Limited Health Assessments will be performed at baseline and at 16 weeks, respectively, to assess frailty. The Patient Symptom Questionnaire and Overall Treatment Utility are to be undertaken at different timepoints to assess the impact of treatment-related toxicities and quality of life. Treatment will be delivered every 2 weeks until disease progression, unacceptable toxicity (as determined by treating clinician or patient), delay of treatment of more than 6 weeks, or withdrawal of consent. The primary end point is 6-month progression-free survival in both arms. Secondary end points include overall survival, time to treatment failure, objective tumour response rate as defined by RECIST v1.1 and safety (adverse events). Tertiary and correlative endpoints include the feasibility and utility of a comprehensive geriatric assessment, quality of life and biological substudies.

Discussion

MONARCC investigates the activity and tolerability of first-line panitumumab-based treatments with a view to expand on current treatment options while maximising progression-free and overall survival and quality of life in molecularly selected elderly patients with metastatic colorectal cancer.

Trial registration

Australia New Zealand Clinical Trials Registry: ACTRN12618000233224, prospectively registered 14 February 2018.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08644-4.

Precision oncology in metastatic colorectal cancer - from biology to medicine

Remarkable progress has been made in the development of biomarker-driven targeted therapies for patients with multiple cancer types, including melanoma, breast and lung tumours, although precision oncology for patients with colorectal cancer (CRC) continues to lag behind. Nonetheless, the availability of patient-derived CRC models coupled with in vitro and in vivo pharmacological and functional analyses over the past decade has finally led to advances in the field. Gene-specific alterations are not the only determinants that can successfully direct the use of targeted therapy. Indeed, successful inhibition of BRAF or KRAS in metastatic CRCs driven by activating mutations in these genes requires combinations of drugs that inhibit the mutant protein while at the same time restraining adaptive resistance via CRC-specific EGFR-mediated feedback loops. The emerging paradigm is, therefore, that the intrinsic biology of CRC cells must be considered alongside the molecular profiles of individual tumours in order to successfully personalize treatment. In this Review, we outline how preclinical studies based on patient-derived models have informed the design of practice-changing clinical trials. The integration of these experiences into a common framework will reshape the future design of biology-informed clinical trials in this field.

Current therapy of advanced colorectal cancer according to RAS/RAF mutational status

Colorectal cancer is a clinically and molecularly heterogeneous disease. Currently, extended RAS and BRAF mutation testing is obligatory in routine clinical practice before starting any treatment in the metastatic setting. Treatment decision making also includes assessment of the clinical condition of the patient, definition of the treatment goal, and consideration of the primary tumor site. Biological treatment is part of the first-line drug combination unless contraindicated. Mutational status is significantly associated with the outcome of patients and is strongly predictive for anti-EGFR-targeted therapy. The prognosis of RAS mutant CRC is clearly inferior to wild-type cases. RAS remains an elusive target, and specific treatment options are not yet available. Recently, promising results of a direct KRAS G12C inhibitor have been reported; however, further confirmation is needed. The biomarker landscape in mCRC is evolving; new promising markers are awaited with the chance of more precise targeted treatment.

Assessing prognostic value of early tumor shrinkage and depth of response in first-line therapy for patients with advanced unresectable pancreatic cancer

Background

The prognostic potential of early tumor shrinkage (ETS) and depth of response (DpR) in pancreatic cancer (PC) is unclear. Here, we recruited 90 patients with recurrent and metastatic PC (RMPC) who had received chemotherapy as first-line therapy to assess the prognostic potential of these markers.

Methods

ETS is characterized as a ≥ 20% depletion in the sum-of-the-longest-diameters (SLD) of measurable tumor lesions at 6–12 weeks than the baseline. DpR is the maximum shrinkage (%) from the baseline to nadir. We evaluated corrections in ETS and DpR with survival.

Results

Of the 63 patients in which ETS assessment was possible, 21 (33.3%) achieved ETS. We found a significant association between the incidence of ETS and an improved rate of progression-free survival (PFS; 6.5 vs. 2.2 months; p < 0.001) and overall survival (OS; 12.1 vs. 6.0 months; p = 0.014). The median value of DpR was − 23.66%. DpR was also related to improved PFS (9.3 vs. 3.1 months; p < 0.001) and OS (18.2 vs. 7.3 months; p < 0.001). Patients who had distant metastasis, not local recurrence, with ETS showed markedly better outcomes. In a multivariate model, both ETS and DpR were independent predictors of OS in the whole population.

Conclusions

ETS and DpR may predict favorable outcomes for RMPC patients who had received chemotherapy as first-line therapy, independent of the agents used. Further studies on the exploratory analyses of the optimum ETS cut-off value in recurrent PC patients to predict favorable clinical outcomes are required.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-01870-x.

The Budget Impact of Monoclonal Antibodies Used to Treat Metastatic Colorectal Cancer in Minas Gerais, Brazil

INTRODUCTION

Biological medicines have increased the cost of cancer treatments, which also raises concerns about sustainability. In Brazil, three monoclonal antibodies (mAbs)-bevacizumab, cetuximab, and panitumumab-are indicated for the treatment of metastatic colorectal cancer (mCRC) but not currently funded by the Unified Health System (SUS). However, successful litigation has led to funding in some cases.

OBJECTIVE

Our objective was to evaluate the budgetary impact of including the mAbs bevacizumab, cetuximab, and panitumumab in standard chemotherapy for the treatment of mCRC within the SUS of Minas Gerais (MG), Brazil.

METHOD

A budget impact analysis of incorporating mAbs as first-line treatment of mCRC in MG was explored. The perspective taken was that of the Brazilian SUS, and a 5-year time horizon was applied. Data were collected from lawsuits undertaken between January 2009 and December 2016, and the model was populated with data from national databases and published sources. Costs are expressed in $US.

RESULTS

In total, 351 lawsuits resulted in funding for first-line treatment with mAbs for mCRC. The three alternative scenarios analyzed resulted in cost increases of 348-395% compared with the reference scenario. The use of panitumumab had a budgetary impact of $US103,360,980 compared with the reference scenario over a 5-year time horizon, and bevacizumab and cetuximab had budgetary impacts of $US111,334,890 and 113,772,870, respectively. The use of the anti-epidermal growth factor receptor (EGFR) mAbs (cetuximab and panitumumab) is restricted to the approximately 41% of patients with KRAS mutations, so the best cost alternative for incorporation would be the combination of panitumumab and bevacizumab, with a cost of approximately $US106 million.

CONCLUSION

These results highlight the appreciable costs for incorporating bevacizumab, cetuximab, and panitumumab into the SUS. Appreciable discounts are likely to be necessary before incorporation of these mAbs is approved.

MYC Up-regulation Is a Useful Biomarker for Preoperative Neoadjuvant Chemotherapy Combined With Anti-EGFR in Liver Metastasis from Colorectal Cancer

BACKGROUND/AIM

At present, there are no biomarkers to predict the effects of molecular targeted drugs in patients with CRC with liver metastasis. Thus, we performed this study to explore potential biomarkers for these patients.

MATERIALS AND METHODS

We obtained cancer tissue specimens from liver metastasis-bearing CRC patients who received the following preoperative neoadjuvant chemotherapies with molecular targeted drugs: i) no therapy (n=3), ii) 5-FU+oxaliplatin+anti-EGFR (n=3), iii) and 5-FU+oxaliplatin+anti-VEGF (n=3).

RESULTS

We investigated the RNA expression of 84 genes related to cancer drug resistance using an RT-PCR array. The MYC gene was the only gene that was significantly up-regulated in CRC tissue specimens from anti-EGFR group in comparison to the anti-VEGF group.

CONCLUSION

MYC up-regulation in the primary CRC tissues may be a potentially useful biomarker for selecting anti-EGFR combination therapy in neoadjuvant chemotherapy for CRC with liver metastasis.

Cetuximab plus irinotecan administered biweekly with reduced infusion time to heavily pretreated patients with metastatic colorectal cancer and related RAS and BRAF mutation status

Metastatic colorectal cancer (mCRC) is treated with cetuximab 250 mg/m2 administered weekly over 1 hour or biweekly (q2w) over 3.5 hours when combined with irinotecan. This prospective study investigated cetuximab 500 mg/m2 plus irinotecan 180 mg/m2 administered q2w over 1.5 hours independent of RAS or BRAF mutation status in mCRC patients in a third-line setting. The intention-to-treat population included 181 patients. No patients had complete response, 18% had partial responses (PR) and 48% stable disease (SD). For cetuximab, a relative dose intensity of ≥90% was reached in 78% and for irinotecan in 67% of the patients. Grade 3 to 4 toxicities were pain (17%), fatigue (9%), neutropenia (8%), diarrhea (8%), rash (8%), infection (7%) and hypersensitivity (3%). No deaths occurred. Next-generation sequencing in 96.7% of the patients revealed that 50.3% had RAS and BRAFV600E wild type (WT), with a mutation type (MT) in 45.1% of the RAS and 4.4% of the BRAFV600E genes. In patients with RAS-WT and RAS-MT tumors, a PR was obtained in 32% and 4% (P = .000003) and an SD in 43% and 53%, respectively, with a superior PFS (6.2 vs 3.7 months; hazard ratio [HR] 2.12, P = .00001) and OS (12.9 vs 8.8 months; HR 1.71, P = .0008). Treatment efficacy was poor in 7.4% of patients with an RAS mutation outside KRAS exon 2 and in 38% of patients with KRAS exon 2 mutations. Administration of cetuximab and irinotecan q2w, shortening treatment time from 3.5 to 1.5 hours, is recommended as standard therapy.

Limited Liver or Lung Colorectal Cancer Metastases. Systemic Treatment, Surgery, Ablation or SBRT

The prognosis for oligometastatic colorectal cancer has improved in recent years, mostly because of recent advances in new techniques and approaches to the treatment of oligometastases, including new surgical procedures, better systemic treatments, percutaneous ablation, and stereotactic body radiation therapy (SBRT). There are several factors to consider when deciding on the better approach for each patient: tumor factors (metachronous or synchronous metastases, RAS mutation, BRAF mutation, disease-free interval, size and number of metastases), patient factors (age, frailty, comorbidities, patient preferences), and physicians' factors (local expertise). These advances have presented major challenges and opportunities for oncologic multidisciplinary teams to treat patients with limited liver and lung metastases from colorectal cancer with a curative intention. In this review, we describe the different treatment options in patients with limited liver and lung metastases from colorectal cancer, and the possible combination of three approaches: systemic treatment, surgery, and local ablative treatments.

Are All Anti-Angiogenic Drugs the Same in the Treatment of Second-Line Metastatic Colorectal Cancer? Expert Opinion on Clinical Practice

Targeting tumor-driven angiogenesis is an effective strategy in the management of metastatic colorectal cancer (mCRC); however, the choice of second-line therapy is complicated by the availability of several drugs, the occurrence of resistance and the lack of validated prognostic and predictive biomarkers. This review examines the use of angiogenesis-targeted therapies for the second-line management of mCRC patients. Mechanisms of resistance and anti-placental growth factor agents are discussed, and the role of aflibercept, a recombinant fusion protein consisting of portions of human vascular endothelial growth factor receptor (VEGFR)-1 and VEGFR-2, is highlighted. The novel mechanism of action of aflibercept makes it a useful second-line agent in mCRC patients progressing after oxaliplatin-based chemotherapy, as well as in those with resistance after bevacizumab.

Colon Cancer, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology

This selection from the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Colon Cancer focuses on systemic therapy options for the treatment of metastatic colorectal cancer (mCRC), because important updates have recently been made to this section. These updates include recommendations for first-line use of checkpoint inhibitors for mCRC, that is deficient mismatch repair/microsatellite instability-high, recommendations related to the use of biosimilars, and expanded recommendations for biomarker testing. The systemic therapy recommendations now include targeted therapy options for patients with mCRC that is HER2-amplified, or BRAF V600E mutation-positive. Treatment and management of nonmetastatic or resectable/ablatable metastatic disease are discussed in the complete version of the NCCN Guidelines for Colon Cancer available at NCCN.org. Additional topics covered in the complete version include risk assessment, staging, pathology, posttreatment surveillance, and survivorship.

Effect of Primary Tumor Location on Postmetastasectomy Survival in Patients with Colorectal Cancer Liver Metastasis

BACKGROUND

The effects of primary tumor location on colorectal liver metastasis (CRLM) and post-hepatic-metastasectomy overall survival (OS) are controversial. This study evaluated the difference in post-hepatic-metastasectomy OS among right-sided colon, left-sided colon, and rectal cancer groups.

METHODS

In total, 381 patients who underwent curative-intent CRLM resection were enrolled. Patients were grouped based on the primary tumor location (right-sided, left-sided, and rectum). The Kaplan-Meier analysis and log-rank test were performed for survival analysis. The univariate and multivariate analyses of clinical and pathological factors were performed using the Cox proportional hazards model.

RESULTS

Significant OS difference was noted among the three groups (log-rank, p = 0.014). The multivariate analysis revealed a 32% lower death risk in left-sided colon cancer compared with right-sided colon cancer (hazard ratio [HR] 0.68, p = 0.042), whereas no OS difference was noted between the rectal cancer and right-sided colon cancer groups. The left- versus right-sided OS advantage was noted only in the KRAS wild-type subgroup (HR 0.46, p = 0.002), and a rectal versus right-sided OS disadvantage was noted in the KRAS mutant subgroup (HR 1.78, p = 0.03).

CONCLUSIONS

The CRLM post-hepatic-metastasectomy OS was superior in left-sided colon cancer than in right-sided colon cancer and was similar in rectal and right-sided colon cancer. The OS difference in different primary tumor locations is dependent on KRAS mutation status, with a decreased left- versus right-sided death risk noted only in KRAS wild-type colon cancer and an increased rectal versus right-sided death risk noted only in KRAS mutant colon cancer.

An evaluation of RAS testing among metastatic colorectal cancer patients in the USA

Background: Data on RAS testing practices prior to metastatic colorectal cancer (mCRC) treatment initiation are lacking in the USA. Materials & methods: Flatiron data were utilized for patients diagnosed with mCRC between 2011 and 2017. Flatiron is a longitudinal, demographically and geographically diverse database representing data from over 1.5 million active US patients treated at 255 community and hospital-affiliated oncology clinics. Results: Among 17,387 mCRC patients 69% were RAS tested and 31% were never tested. Timing of RAS testing was as follows: 23% were tested at the time of their initial CRC diagnosis, 60% following mCRC diagnosis but prior to first line of treatment, 3% prior to third line, the remaining 14% were tested following third line. Conclusion: A third (31%) of patients failed to receive RAS testing, therefore all treatment options were unavailable to them. These data highlight how universal testing has not been achieved.

Diagnosis and Treatment of Metastatic Colorectal Cancer: A Review

IMPORTANCE

Colorectal cancer (CRC) is the third most common cause of cancer mortality worldwide with more than 1.85 million cases and 850 000 deaths annually. Of new colorectal cancer diagnoses, 20% of patients have metastatic disease at presentation and another 25% who present with localized disease will later develop metastases.

OBSERVATIONS

Colorectal cancer is the third most common cause of cancer mortality for men and women in the United States, with 53 200 deaths projected in 2020. Among people diagnosed with metastatic colorectal cancer, approximately 70% to 75% of patients survive beyond 1 year, 30% to 35% beyond 3 years, and fewer than 20% beyond 5 years from diagnosis. The primary treatment for unresectable metastatic CRC is systemic therapy (cytotoxic chemotherapy, biologic therapy such as antibodies to cellular growth factors, immunotherapy, and their combinations.) Clinical trials completed in the past 5 years have demonstrated that tailoring treatment to the molecular and pathologic features of the tumor improves overall survival. Genomic profiling to detect somatic variants is important because it identifies the treatments that may be effective. For the 50% of patients with metastatic CRC with KRAS/NRAS/BRAF wild-type tumors, cetuximab and panitumumab (monoclonal antibodies to the epithelial growth factor receptor [EGFR]), in combination with chemotherapy, can extend median survival by 2 to 4 months compared with chemotherapy alone. However, for the 35% to 40% of patients with KRAS or NRAS sequence variations (formerly termed mutations), effective targeted therapies are not yet available. For the 5% to 10% with BRAF V600E sequence variations, targeted combination therapy with BRAF and EGFR inhibitors extended overall survival to 9.3 months, compared to 5.9 months for those receiving standard chemotherapy. For the 5% with microsatellite instability (the presence of numerous insertions or deletions at repetitive DNA units) or mismatch repair deficiency, immunotherapy may be used in the first or subsequent line and has improved treatment outcomes with a median overall survival of 31.4 months in previously treated patients.

CONCLUSIONS AND RELEVANCE

Advances in molecular profiling of metastatic CRC facilitate the ability to direct treatments to the biologic features of the tumor for specific patient subsets. Although cures remain uncommon, more patients can anticipate extended survival. Genomic profiling allows treatment selection so that more patients derive benefit and fewer are exposed to toxicity from ineffective therapies.

Molecular Genetics and the Role of Molecularly Targeted Agents in Metastatic Colorectal Carcinoma

BACKGROUND

Colorectal cancer (CRC) is one of the leading causes of mortality and morbidity in the world. It is the third most common malignancy and fourth leading cancer-related deaths worldwide. In the USA, CRC is the third most commonly diagnosed cancer in both men and women. It is caused by genetic components and potential environmental factors such as consumption of processed meat, red meat, animal fats, low fiber intake, and obesity. Despite the utilization of effective screening modalities and guidelines in the USA, a significant number of patients are diagnosed with advanced, metastatic disease at the time of presentation to the physician. Recent advances in the understanding of molecular medicine with subsequent development and incorporation of newer therapeutic agents into current chemotherapeutic regimens have improved outcomes; however, the management of metastatic CRC remains challenging, particularly for the treating oncologists.

METHODS

We conducted a literature search on CRC mainly related to molecular genetics, targeted biologic agents, and published clinical trials. We also searched and reviewed ongoing clinical trials from Clinicaltrials.gov.

RESULTS AND CONCLUSIONS

Alterations in several oncogenes are associated with CRC, among those RAS, BRAF, and HER2 are of current clinical importance. Chemotherapy drugs, along with vascular endothelial growth factor or epidermal growth factor receptor monoclonal antibodies, are proven to be efficient with manageable toxicity profiles in metastatic CRC. Additional researches on Her-2-directed therapy, BRAF-targeted agents, immunotherapeutic, and newer molecularly targeted agents are needed for further improvement in outcome.