Comparative molecular analyses of left-sided colon, right-sided colon, and rectal cancers

First-Line Therapy in Metastatic, RAS Wild-Type, Left-Sided Colorectal Cancer: Should Everyone Receive Anti-EGFR Therapy?

PURPOSE OF REVIEW

This narrative review explores the efficacy and applicability of anti-EGFR therapy as the first-line treatment for patients with RAS wild-type (WT) left-sided metastatic colorectal cancer (mCRC). It critically examines current guidelines, along with recent evidence in the literature, to assess whether it should be universally applied.

RECENT FINDINGS

Recent evidences highlight the variability of the response to anti-EGFR therapies due to molecular diversity and several clinical factors, such as RAS mutational status and primary tumor location. Anti-EGFR plus chemotherapy is the standard first-line treatment for most patients with MSS, RAS-WT, left-sided mCRC. Whether this combination is the best treatment for these patients remains an open question. This review delves into the role of EGFR inhibition in mCRC, focusing on clinical factors and the knowledge of biology, molecular targets, and biomarkers. It underscores the crucial role of a personalized approach, empowering healthcare providers and equipping them with the confidence to make informed decisions.

Trastuzumab deruxtecan in patients with HER2-positive advanced colorectal cancer (DESTINY-CRC02): primary results from a multicentre, randomised, phase 2 trial

BACKGROUND

Trastuzumab deruxtecan has shown encouraging activity in patients with treatment-refractory HER2-positive, RAS wild-type and BRAF wild-type metastatic colorectal cancer. Dose optimisation and further antitumour assessments in patients with RAS mutations and those with previous anti-HER2 therapy are warranted. We aimed to evaluate two doses of trastuzumab deruxtecan (5·4 mg/kg and 6·4 mg/kg) to establish the recommended dose in patients with pretreated HER2-positive, RAS wild-type or mutant metastatic colorectal cancer.

METHODS

DESTINY-CRC02 was a multicentre, randomised, two-stage, two-arm, phase 2 study done in 53 research hospitals and medical centres in Australia, Belgium, France, Italy, Japan, South Korea, Spain, Taiwan, the UK, and the USA. Eligible patients were aged 18 years and older or 20 years and older (depending on region) with pretreated pathologically documented, unresectable, recurrent, or metastatic HER2-positive, and RAS wild-type or mutant colorectal cancer. Patients were required to have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 and have received previous chemotherapy, and anti-EGFR, anti-VEGF, or anti-PD-L1 therapy, if clinically indicated. In stage 1, patients were randomly assigned (1:1), via a secure interactive response technology system, to receive 5·4 mg/kg or 6·4 mg/kg trastuzumab deruxtecan administered intravenously every 21 days. Stratification factors were ECOG performance status, HER2 status, and RAS status. In stage 2, patients were assigned into the 5·4 mg/kg treatment group only. The primary endpoint was confirmed objective response rate by blinded independent central review, assessed in all patients for whom treatment was assigned (full analysis set). Safety was assessed in all patients who received at least one dose of study drug. This trial is registered with ClinicalTrials.gov, NCT04744831, and is ongoing (not recruiting).

FINDINGS

Between March 5, 2021, and March 29, 2022, 135 patients were centrally screened, 122 of whom were enrolled. In stage 1, 40 patients each were randomly assigned to receive trastuzumab deruxtecan 5·4 mg/kg and 6·4 mg/kg. In stage 2, an additional 42 patients were enrolled in the 5·4 mg/kg group. 64 (52%) participants were male and 58 (48%) were female. The median duration of follow-up was 8·9 months (IQR 6·7-10·5) in the 5·4 mg/kg group and 10·3 months (5·9-12·7) in the 6·4 mg/kg group. The confirmed objective response rate by blinded independent central review was 37·8% (31/82 [95% CI 27·3-49·2]) in the 5·4 mg/kg group and 27·5% (11/40 [14·6-43·9]) in the 6·4 mg/kg group. 34 (41%) of 83 patients in the 5·4 mg/kg group and 19 (49%) of 39 in the 6·4 mg/kg group had grade 3 or worse drug-related treatment-emergent adverse events. The most common grade 3 or worse drug-related treatment-emergent adverse events were neutrophil count decreased (13 [16%] of 83 patients), anaemia (six [7%]), nausea (six [7%]), and white blood cell count decreased (five [6%]) in the 5·4 mg/kg group; and were neutrophil count decreased (10 [26%] of 39 patients), anaemia (eight [21%]), platelet count decreased (four [10%]), and white blood cell count decreased (four [10%]) in the 6·4 mg/kg group. Drug-related serious adverse events occurred in 11 (13%) of 83 patients in the 5·4 mg/kg group and six (15%) of 39 patients in the 6·4 mg/kg group; the most common in the 5·4 mg/kg group was nausea (three [4%] patients) and the most common in the 6·4 mg/kg group were fatigue (two [5%] patients), neutropenia (two [5%]), and thrombocytopenia (two [5%]). A drug-related treatment-emergent adverse event related to death occurred in one (1%) patient in the 5·4 mg/kg group (due to hepatic failure). Adjudicated drug-related interstitial lung disease or pneumonitis events were observed in seven (8%) patients in the 5·4 mg/kg group (all grade 1 or 2) and in five (13%) patients in the 6·4 mg/kg group (four grade 1 or 2; one grade 5).

INTERPRETATION

The promising antitumour activity and favourable safety profile support trastuzumab deruxtecan 5·4 mg/kg as the optimal single-agent dose for patients with pretreated HER2-positive metastatic colorectal cancer, including those with RAS mutations, previous anti-HER2 therapy, or both.

FUNDING

Daiichi Sankyo and AstraZeneca.

Right vs. Left colorectal cancer - Where do we draw the line?

PURPOSE

No consensus on the definition of right and left colorectal cancer (CRC) exists, nor studies offering histological or molecular basis for such categorisation. This study investigated the regional variations in the histological and molecular characteristics of CRCs, with the objective of determining an optimal division point between right and left CRCs.

MATERIALS AND METHODS

An observational study of consecutive patients who underwent CRC resection (1995-2022) at Concord Hospital, Sydney was performed. Clinicopathological data were extracted from a prospective database and seven permutations of right-left divisions considered. Logistic regression tested association between the right-left divisions and pathological characteristics. Receiver operating characteristic and area under the curve (AUC) analyses determined the discriminative ability of each division to predict 18 pathology characteristics.

RESULTS

3753 patients underwent a CRC resection (2120 male; mean 69.5yrs [SD12.6]). There was regional variation in tumours with respect to tumour infiltrating lymphocytes (TILs), mismatch repair deficiency (dMMR), and mutant BRAF (mBRAF). Left-sided tumours were less likely to demonstrate TILs (P < 0.001), be dMMR (P < 0.001), and express mBRAF (P < 0.001). Division at the descending-sigmoid junction yielded highest discriminative abilities: TILs - AUC 0.66, dMMR - AUC 0.76, and mBRAF - AUC 0.73.

CONCLUSION

This is the first study to provide a pathological basis on which right- and left-sided cancers may be defined, and found the optimal division point between the right and left colorectum to be at the descending-sigmoid junction. Further research is needed to determine whether this can facilitate individualised patient management.

Early-Onset colorectal Cancer: From the laboratory to the clinic

Colorectal cancer that occurs before age of 50 is defined as Early-Onset Colorectal Cancer (EOCRC). Its incidence has worryingly increased since the late 90 s and is expected to keep rising in the next future, despite Late-Onset CRC (LOCRC) is decreasing worldwide. Because of this, there is an urgent need to better understand this subset of patients in order to give them the best treatment possible. However, most of the literature is retrospective and often discordant. In this review, we aim to provide a general overview of the issue, endeavoring to highlight the current available knowledge. We decided to move from the beginning, investigating risk factors and inheritance, passing through diagnosis and clinical aspects, and to conclude with the translational part, focusing on the biology of the tumor. However, lot of questions remain open, including screening age and prognosis. Indeed, young patients tend to be treated more aggressively, even if a survival benefit has not been proven yet. Every clinician should be aware of the best practice for young people, and more translational studies are awaited in order to clarify is EOCRC represents a distinct biological entity.

An Evolving Landscape: New Therapies for Metastatic Colorectal Cancer

Substantial progress is being made in the development of novel therapies directed against colorectal cancer. The discovery of various molecular markers and advances in tumor profiling have facilitated the development of new targeted agents and immunotherapy. Not only have these drugs improved progression-free survival and even overall survival in some cases, but their related outcomes have also raised questions as to how to best combine or sequence therapies for even greater efficacy. Furthermore, we are beginning to understand how these combination therapies may yield for greater therapeutic response for patients with microsatellite stable colorectal cancer for which there is much need for improvement. In this article, we review recent trial data and explore the outcomes of various targeted therapies and immunotherapies for patient with advanced colorectal cancer.

Resistance to Anti-HER2 Therapies in Gastrointestinal Malignancies

Human epidermal growth factor 2 (HER2) is a tyrosine kinase receptor that interacts with multiple signaling pathways related to cellular growth and proliferation. Overexpression or amplification of HER2 is linked to various malignancies, and there have been decades of research dedicated to targeting HER2. Despite the landmark ToGA trial, progress in HER2-positive gastrointestinal malignancies has been hampered by drug resistance. This review examines current HER2 expression patterns and therapies for gastroesophageal, colorectal, biliary tract, and small bowel cancers, while dissecting potential resistance mechanisms that limit treatment effectiveness.

HER2 Gene Expression Levels Are Predictive and Prognostic in Patients With Metastatic Colorectal Cancer Enrolled in CALGB/SWOG 80405

PURPOSE

The phase III Cancer and Leukemia Group B (CALGB)/SWOG 80405 trial found no difference in overall survival (OS) in patients with metastatic colorectal cancer receiving first-line chemotherapy in combination with either bevacizumab or cetuximab. We investigated the potential prognostic and predictive value of HER2 amplification and gene expression using next-generation sequencing (NGS) and NanoString data.

PATIENTS AND METHODS

Primary tumor DNA from 559 patients was profiled for HER2 amplification by NGS (FoundationOne CDx). Tumor tissue from 925 patients was tested for NanoString gene expression using an 800-gene panel. OS and progression-free survival (PFS) were the time-to-event end points.

RESULTS

High HER2 expression (dichotomized at median) was associated with longer PFS (11.6 v 10 months, P = .012) and OS (32 v 25.3 months, P = .033), independent of treatment. An OS benefit for cetuximab versus bevacizumab was observed in the high HER2 expression group (P = .02), whereas a worse PFS for cetuximab was seen in the low-expression group (P = .019). When modeled as a continuous variable, increased HER2 expression was associated with longer OS (hazard ratio [HR], 0.83 [95% CI, 0.75 to 0.93]; adjusted P = .0007) and PFS (HR, 0.82 [95% CI, 0.74 to 0.91]; adjusted P = .0002), reaching a plateau effect after the median. In patients with HER2 expression lower than median, treatment with cetuximab was associated with worse PFS (HR, 1.38 [95% CI, 1.12 to 1.71]; adjusted P = .0027) and OS (HR, 1.28 [95% CI, 1.02 to 1.59]; adjusted P = .03) compared with that with bevacizumab. A significant interaction between HER2 expression and the treatment arm was observed for OS (Pintx = .017), PFS (Pintx = .048), and objective response rate (Pintx = .001).

CONCLUSION

HER2 gene expression was prognostic and predictive in CALGB/SWOG 80405. HER2 tumor expression may inform treatment selection for patients with low HER2 favoring bevacizumab- versus cetuximab-based therapies.

HER2-neu Expression and Survival in Colorectal Cancer in the South of Egypt; Immunohistochemistry and Genetic Study

BACKGROUND

Colorectal cancer (CRC) is a major public health problem and one of leading cancer related death all over the world. One of the prognostic parameters that play a role in different types of cancer is HER2. However, the role of HER2 in CRC and its relation with clinicopathological features and survival is conflicting. We hypothesize that HER2 has different patterns of expression in CRC which may affect the prognosis of patients.

MATERIAL & METHODS

We studied sixty specimens of colorectal carcinoma for HER2 immunohistochemistry and gene amplification and correlate it with clinicopathological features and patients` survival.

RESULTS

Our data showed that negative HER2 expression was statistically associated with female gender (P = 0.010) and low & intermediate tumor budding (P = 0.030). There was a statistically significant relation between HER2 IHC and HER2 FISH amplification (P=0.000). Although neither HER2 immunoexpression and FISH amplification showed significant relation with overall survival nor disease free survival, HER2 amplified CRCs tended to have a worse survival compared with negative CRCs (40 months versus 50 months). The presence of male gender, lymphovascular invasion, nodal metastasis and distant metastasis (P = 0.013, 0.006, 0.006 and 0.000 respectively) were significantly statistically associated with poor overall survival. The presence of tumor grade III and high tumor budding (P = 0.035 and 0.007 respectively) were significantly statistically associated with shorter disease free survival.

CONCLUSIONS

Our results showed that HER2 IHC 3+ staining is highly predictive of HER2 gene amplification in colorectal carcinomas. There is a tendency towards poorer prognosis in amplified HER2 CRC cases.

RAS/RAF mutations and microsatellite instability status in primary colorectal cancers according to HER2 amplification

HER2 amplification-associated molecular alterations and clinicopathologic features in colorectal cancers (CRCs) have not been well established. In this study, we assessed the prevalence of HER2 amplification and microsatellite instability (MSI) status of 992 patients with primary CRC. In addition, molecular alterations of HER2 amplified and unamplified CRCs were examined and compared by next-generation sequencing. HER2 amplifications were found in 41 (4.1%) of 992 primary CRCs. HER2 amplification was identified in 1.0% of the right colonic tumors, 5.1% of the left colonic tumors, and 4.8% of the rectal tumors. Approximately 95% of HER2 amplification was observed in the left colon and rectum. Seven (87.5%) of eight metastatic tumors showed HER2 amplification. Most clinicopathologic features were unrelated to HER2 amplification except tumor size and MSI status. All 41 HER2 amplified CRCs were microsatellite stable. In a molecular analysis of frequently identified somatic mutations in CRCs, HER2 amplified CRCs showed a lower rate of KRAS mutations (24.4%) but a higher rate of TP53 mutations (83%) than unamplified CRCs. No BRAF and NRAS mutations were identified in HER2 amplified CRCs. Our study suggests that HER2 amplified CRCs are mutually exclusive of MSI and harbor less frequent KRAS/NRAS/BRAF mutations but frequent T53 mutations.

HER2-Positive Metastatic Colorectal Cancer

OPINION STATEMENT

Targeted treatment strategies are available for human epidermal growth factor receptor 2 (HER2)-positive (amplified and/or overexpressed) metastatic colorectal cancer (mCRC), and HER2 testing is indicated in patients with mCRC. At present, standard of care first-line treatment for those with HER2-positive mCRC remains chemotherapy in combination with epidermal growth factor receptor (EGFR) inhibitors or bevacizumab, depending on RAS/BRAF mutational status and tumor sidedness. HER2-targeted agents should be considered for those with RAS/BRAF wild-type disease in subsequent-line treatment and in first-line treatment for patients not appropriate for intensive therapy. While the choice of anti-HER2 therapy is empiric given lack of head-to-head comparisons, the combination of trastuzumab plus tucatinib has received FDA accelerated approval for use in this setting and is generally the authors' preference. Trastuzumab plus lapatinib, trastuzumab plus pertuzumab, and trastuzumab deruxtecan (T-DXd) also have evidence of efficacy in this setting. As T-DXd has demonstrated activity following treatment with other HER2-targeted regimens and carries an increased risk of high-grade toxicities, the authors favor reserving it for use after progression on prior anti-HER2 therapy. HER2-targeted therapies that inhibit signal transduction appear to have limited activity in those with RAS mutations, including trastuzumab-containing regimens. However, the antibody drug conjugate T-DXd has some data showing efficacy in this setting, and the authors would consider T-DXd in subsequent-line therapy for HER2-positive, RAS-mutated mCRC. Several areas of uncertainty remain regarding how to best utilize HER2-targeted therapies in mCRC. These include the optimal sequence of anti-HER2 therapies with chemotherapy and anti-EGFR therapies, the optimal combination partners for anti-HER2 therapies, and the incorporation of predictive biomarkers to guide use of anti-HER2 therapies. Results of ongoing studies may thus alter the treatment paradigm above in the coming years.

Distinct Driver Pathway Enrichments and a High Prevalence of TSC2 Mutations in Right Colon Cancer in Chile: A Preliminary Comparative Analysis

Colorectal cancer (CRC) is the second leading cause of cancer deaths globally. While ethnic differences in driver gene mutations have been documented, the South American population remains understudied at the genomic level, despite facing a rising burden of CRC. We analyzed tumors of 40 Chilean CRC patients (Chp) using next-generation sequencing and compared them to data from mainly Caucasian cohorts (TCGA and MSK-IMPACT). We identified 388 mutations in 96 out of 135 genes, with TP53 (45%), KRAS (30%), PIK3CA (22.5%), ATM (20%), and POLE (20%) being the most frequently mutated. TSC2 mutations were associated with right colon cancer (44.44% in RCRC vs. 6.45% in LCRC, p-value = 0.016), and overall frequency was higher compared to TCGA (p-value = 1.847 × 10-5) and MSK-IMPACT cohorts (p-value = 3.062 × 10-2). Limited sample size restricts definitive conclusions, but our data suggest potential differences in driver mutations for Chilean patients, being that the RTK-RAS oncogenic pathway is less affected and the PI3K pathway is more altered in Chp compared to TCGA (45% vs. 25.56%, respectively). The prevalence of actionable pathways and driver mutations can guide therapeutic choices, but can also impact treatment effectiveness. Thus, these findings warrant further investigation in larger Chilean cohorts to confirm these initial observations. Understanding population-specific driver mutations can guide the development of precision medicine programs for CRC patients.

RAS/RAF Comutation and ERBB2 Copy Number Modulates HER2 Heterogeneity and Responsiveness to HER2-directed Therapy in Colorectal Cancer

PURPOSE

ERBB2-amplified colorectal cancer is a distinct molecular subtype with expanding treatments. Implications of concurrent oncogenic RAS/RAF alterations are not known.

EXPERIMENTAL DESIGN

Dana-Farber and Foundation Medicine Inc. Colorectal cancer cohorts with genomic profiling were used to identify ERBB2-amplified cases [Dana-Farber, n = 47/2,729 (1.7%); FMI, n = 1857/49,839 (3.7%)]. Outcomes of patients receiving HER2-directed therapies are reported (Dana-Farber, n = 9; Flatiron Health-Foundation Medicine clinicogenomic database, FH-FMI CGDB, n = 38). Multisite HER2 IHC and genomic profiling were performed to understand HER2 intratumoral and interlesional heterogeneity. The impact of concurrent RAS comutations on the effectiveness of HER2-directed therapies were studied in isogenic colorectal cancer cell lines and xenografts.

RESULTS

ERBB2 amplifications are enriched in left-sided colorectal cancer. Twenty percent of ERBB2-amplified colorectal cancers have co-occurring oncogenic RAS/RAF alterations. While RAS/RAF WT colorectal cancers typically have clonal ERBB2 amplification, colorectal cancers with co-occurring RAS/RAF alterations have lower level ERRB2 amplification, higher intratumoral heterogeneity, and interlesional ERBB2 discordance. These distinct genomic patterns lead to differential responsiveness and patterns of resistance to HER2-directed therapy. ERBB2-amplified colorectal cancer with RAS/RAF alterations are resistant to trastuzumab-based combinations, such as trastuzumab/tucatinib, but retain sensitivity to trastuzumab deruxtecan in in vitro and murine models. Trastuzumab deruxtecan shows clinical efficacy in cases with high-level ERBB2-amplified RAS/RAF coaltered colorectal cancer.

CONCLUSIONS

Co-occurring RAS/RAF alterations define a unique subtype of ERBB2-amplified colorectal cancer that has increased intratumoral heterogeneity, interlesional discordance, and resistance to trastuzumab-based combinations. Further examination of trastuzumab deruxtecan in this previously understudied cohort of ERBB2-amplified colorectal cancer is warranted.

Negative Hyperselection of Resistance Mutations for Panitumumab Maintenance in RAS Wild-Type Metastatic Colorectal Cancer (PanaMa Phase II Trial, AIO KRK 0212)

PURPOSE

We evaluated additional mutations in RAS wild-type (WT) metastatic colorectal cancer (mCRC) as prognostic and predictive biomarkers for the efficacy of added panitumumab to a 5-fluorouracil plus folinic acid (FU/FA) maintenance as pre-specified analysis of the randomized PanaMa trial.

PATIENTS AND METHODS

Mutations (MUT) were identified using targeted next-generation sequencing (NGS; Illumina Cancer Hotspot Panel v2) and IHC. RAS/BRAF V600E/PIK3CA/AKT1/ALK1/ERBB2/PTEN MUT and HER2/neu overexpressions were negatively hyperselected and correlated with median progression-free survival (PFS) and overall survival (OS) since start of maintenance treatment, and objective response rates (ORR). Univariate/multivariate Cox regression estimated hazard ratios (HR) and 95% confidence intervals (CI).

RESULTS

202 of 248 patients (81.5%) of the full analysis set (FAS) had available NGS data: hyperselection WT, 162 (80.2%); MUT, 40 (19.8%). From start of maintenance therapy, hyperselection WT tumors were associated with longer median PFS as compared with hyperselection MUT mCRC (7.5 vs. 5.4 months; HR, 0.75; 95% CI, 0.52-1.07; P = 0.11), OS (28.7 vs. 22.2 months; HR, 0.53; 95% CI, 0.36-0.77; P = 0.001), and higher ORR (35.8% vs. 25.0%, P = 0.26). The addition of panitumumab to maintenance was associated with significant benefit in hyperselection WT tumors for PFS (9.2 vs. 6.0 months; HR, 0.66; 95% CI, 0.47-0.93; P = 0.02) and numerically also for OS (36.9 vs. 24.9 months; HR, 0.91; 95% CI, 0.61-1.36; P = 0.50), but not in hyperselection MUT tumors. Hyperselection status interacted with maintenance treatment arms in terms of PFS (P = 0.06) and OS (P = 0.009).

CONCLUSIONS

Extended molecular profiling beyond RAS may have the potential to improve the patient selection for anti-EGFR containing maintenance regimens.

A Randomized Phase III Trial of Complete Mesocolic Excision Compared with Conventional Surgery for Right Colon Cancer: Interim Analysis of a Nationwide Multicenter Study of the Italian Society of Surgical Oncology Colorectal Cancer Network (CoME-in trial)

BACKGROUND

Although complete mesocolic excision (CME) is supposed to be associated with a higher lymph node (LN) yield, decreased local recurrence, and survival improvement, its implementation currently is debated because the evidence level of these data is rather low and still not supported by randomized controlled trials.

METHOD

This is a multicenter, randomized, superiority trial (NCT04871399). The 3-year disease-free survival (DFS) was the primary end point of the study. The secondary end points were safety (duration of operation, perioperative complications, hospital length of stay), oncologic outcomes (number of LNs retrieved, 3- and 5-year overall survival, 5-year DFS), and surgery quality (specimen length, area and integrity rate of mesentery, length of ileocolic and middle-colic vessels). The trial design required the LN yield to be higher in the CME group at interim analysis.

RESULTS

Interim data analysis is presented in this report. The study enrolled 258 patients in nine referral centers. The number of LNs retrieved was significantly higher after CME (25 vs. 20; p = 0.012). No differences were observed with respect to intra- or post-operative complications, postoperative mortality, or duration of surgery. The hospital stay was even shorter after CME (p = 0.039). Quality of surgery indicators were higher in the CME arm of the study. Survival data still were not available.

CONCLUSIONS

Interim data show that CME for right colon cancer in referral centers is safe and feasible and does not increase perioperative complications. The study documented with evidence that quality of surgery and LN yield are higher after CME, and this is essential for continuation of patient recruitment and implementation of an optimal comparison. Trial registration The trial was registered at ClinicalTrials.gov with the code NCT04871399 and with the acronym CoME-In trial.

Racial disparities in colorectal cancer clinicopathological and molecular tumor characteristics: a systematic review

PURPOSE

African Americans have the highest colorectal cancer (CRC) mortality of all racial groups in the USA, which may relate to differences in healthcare access or advanced stage at diagnosis. Recent evidence indicates that differences in tumor characteristics may also underlie disparities in mortality. To highlight recent findings and areas for investigation, we completed the first systematic review of racial disparities in CRC tumor prognostic markers, including clinicopathological markers, microsatellite instability (MSI), oncogene mutations, and novel markers, including cancer stem cells and immune markers.

METHODS

Relevant studies were identified via PubMed, limited to original research published within the last 10 years. Ninety-six articles were identified that compared the prevalence of mortality-related CRC tumor characteristics in African Americans (or other African ancestry populations) to White cases.

RESULTS

Tumors from African ancestry cases are approximately 10% more likely to contain mutations in KRAS, which confer elevated mortality and resistance to epidermal growth factor receptor inhibition. Conversely, African Americans have approximately 50% lower odds for BRAF-mutant tumors, which occur less frequently but have similar effects on mortality and therapeutic resistance. There is less consistent evidence supporting disparities in mutations for other oncogenes, including PIK3CA, TP53, APC, NRAS, HER2, and PTEN, although higher rates of PIK3CA mutations and lower prevalence of MSI status for African ancestry cases are supported by recent evidence. Although emerging evidence suggests that immune markers reflecting anti-tumor immunity in the tumor microenvironment may be lower for African American cases, there is insufficient evidence to evaluate disparities in other novel markers, cancer stem cells, microRNAs, and the consensus molecular subtypes.

CONCLUSION

Higher rates of KRAS-mutant tumors in in African Americans may contribute to disparities in CRC mortality. Additional work is required to understand whether emerging markers, including immune cells, underlie the elevated CRC mortality observed for African Americans.

Treatment options for HER2-expressing colorectal cancer: updates and recent approvals

Colorectal cancer is a leading cause of cancer-related mortality worldwide. Approximately 3-5% of colorectal tumors harbor human epidermal growth factor receptor (HER2) amplification which is associated with a higher incidence of intracranial metastasis and overall worse outcomes. In the setting of refractory metastatic RAS wild-type tumors, evidence supports the use of various HER2-blocking agents, including monoclonal antibodies, tyrosine kinase inhibitors, and novel antibody-drug conjugates. With a number of relatively active agents clinically available and even more in development, it is crucial for clinicians to familiarize themselves with the mechanisms of action, efficacy data, and safety profiles of these treatments. In this review, we aim to summarize key findings from past and ongoing trials with anti-HER2 agents in metastatic colorectal cancer.

Location Has Prognostic Impact on the Outcome of Colorectal Mucinous Adenocarcinomas

Mucinous (colloid) adenocarcinomas (MAs) are a rare histological subtype of tumors defined by extracellular mucin comprising more than 50% of the tumor. These tumors are on a continuum of mucin-producing malignancies with signet ring cell adenocarcinomas (SRCCs), which instead produce intracellular mucin. Mucin-containing cancers occur primarily in the stomach and colon, where for SRCCs, outcomes are relatively worse in the proximal stomach and the rectum. It is not known if MAs have similar outcomes. In this study, we use the Surveillance, Epidemiology, and End Results (SEER) database to examine the effects of tumor localization, age, sex, and stage on colorectal and gastric cancer outcomes for MAs. For right colon cancers, MAs are more common, particularly in females, and have slightly better or equivalent outcomes across all stages and ages compared to conventional adenocarcinomas, but outcomes are progressively worse compared to conventional adenocarcinomas for left colon and rectal cancers. Unlike SRCCs, MAs have similar outcomes to conventional adenocarcinomas in all stomach locations. Overall, these results suggest that MAs have an intrinsically different tumor biology in the left colon and rectum that promotes pathogenesis. Decoding this phenomenon could lead to more effectively tailored patient treatment regimens.

Exploring extracellular matrix and prostaglandin pathway alterations across varying resection margin distances of right-sided colonic adenocarcinoma

BACKGROUND

Surgical resection followed by indicated adjuvant therapy offers potential curative treatment in colonic adenocarcinoma. Beyond the well-established seed and soil theory of colon cancer progression, the 'normal-appearing' tissues near the tumor are not genuinely normal and remain as remnants in patients following surgery. Our objective was to elucidate the alteration of gene expression and pathways across various distances of resection margins in right-sided colonic adenocarcinoma.

METHODS

Twenty-seven fresh samples of primary cancer and 56 matched non-tumor tissues adjacent to the tumor (NAT) were collected from patients with resectable right-sided colon cancer. NAT were systematically obtained at varying distances (1, 5, and 10 cm) on both proximal and distal sides. Comprehensive gene expression analysis was performed using 770-gene PanCancer Progression Panel, delineating distinctive pathways and functional predictions for each region.

RESULTS

Distinctive gene signatures and pathways exhibited by normal-appearing tissues were discovered at varying distances from cancer. Notably, SFRP2, PTGDS, COL1A1, IL1B, THBS2, PTGIS, COL1A2, NPR1, and BGN were upregulated, while ENPEP, MMP1, and NRCAM were downregulated significantly in 1-cm tissue compared to farther distances. Substantial alterations in the extracellular matrix (ECM) and prostaglandin/thromboxane synthesis were significantly evident at the 1-cm distance. Functional analysis indicated enhanced cell viability and survival, alongside reduced cellular death and apoptosis.

CONCLUSIONS

Different distances exerted a significant impact on gene alteration within the normal-looking mucosa surrounding primary cancer, influenced by various mechanisms. These findings may highlight potential therapeutic targets related to the ECM and prostaglandin/thromboxane pathways for treatment strategies.

Implications of Rectal Cancer Radiotherapy on the Immune Microenvironment: Allies and Foes to Therapy Resistance and Patients' Outcome

Aside from surgical resection, locally advanced rectal cancer is regularly treated with neoadjuvant chemoradiotherapy. Since the concept of cancer treatment has shifted from only focusing on tumor cells as drivers of disease progression towards a broader understanding including the dynamic tumor microenvironment (TME), the impact of radiotherapy on the TME and specifically the tumor immune microenvironment (TIME) is increasingly recognized. Both promoting as well as suppressing effects on anti-tumor immunity have been reported in response to rectal cancer (chemo-)radiotherapy and various targets for combination therapies are under investigation. A literature review was conducted searching the PubMed database for evidence regarding the pleiotropic effects of (chemo-)radiotherapy on the rectal cancer TIME, including alterations in cytokine levels, immune cell populations and activity as well as changes in immune checkpoint proteins. Radiotherapy can induce immune-stimulating and -suppressive alterations, potentially mediating radioresistance. The response is influenced by treatment modalities, including the dosage administered and the highly individual intrinsic pre-treatment immune status. Directly addressing the main immune cells of the TME, this review aims to highlight therapeutical implications since efficient rectal cancer treatment relies on personalized strategies combining conventional therapies with immune-modulating approaches, such as immune checkpoint inhibitors.

Optimizing the first-line treatment for metastatic colorectal cancer

Colorectal cancer represents an important oncological challenge both for its incidence, which makes it an important health problem, and for its biological complexity, which has made clinical results very difficult in terms of outcome for this category of patients. To date these diseases should not be treated as a single entity but it is necessary to distinguish colorectal cancers based on characteristics that nowadays are essential to have greater therapeutic benefits. These include the sideness of the disease, the state of microsatellites, the presence of prognostic and predictive mutations of response to treatments currently available in clinical practice, which are associated with new therapeutic targets. The greatest challenge in the future will be to circumvent the resistance mechanisms that make this disease very difficult to treat with good long-term results by studying effective combination treatments with a good toxicity profile. Once such combinations or targeted treatments are consolidated, it will be desirable to shift the best therapies to the first line treatment to make them immediately accessible to the patient. It will also be essential to refine the selection of patients who can benefit from these treatments.

Phase II study of capecitabine-based concomitant chemoradiation followed by durvalumab as a neoadjuvant strategy in locally advanced rectal cancer: the PANDORA trial

BACKGROUND

This study investigated the efficacy of chemoradiotherapy (CRT) followed by durvalumab as neoadjuvant therapy of locally advanced rectal cancer.

PATIENTS AND METHODS

The PANDORA trial is a prospective, phase II, open-label, single-arm, multicenter study aimed at evaluating the efficacy and safety of preoperative treatment with durvalumab (1500 mg every 4 weeks for three administrations) following long-course radiotherapy (RT) plus concomitant capecitabine (5040 cGy RT in 25-28 fractions over 5 weeks and capecitabine administered at 825 mg/m2 twice daily). The primary endpoint was the pathological complete response (pCR) rate; secondary endpoints were the proportion of clinical complete remissions and safety. The sample size was estimated assuming a null pCR proportion of 0.15 and an alternative pCR proportion of 0.30 (α = 0.05, power = 0.80). The proposed treatment could be considered promising if ≥13 pCRs were observed in 55 patients (EudraCT: 2018-004758-39; NCT04083365).

RESULTS

Between November 2019 and August 2021, 60 patients were accrued, of which 55 were assessable for the study's objectives. Two patients experienced disease progression during treatment. Nineteen out of 55 eligible patients achieved a pCR (34.5%, 95% confidence interval 22.2% to 48.6%). Regarding toxicity related to durvalumab, grade 3 adverse events (AEs) occurred in four patients (7.3%) (diarrhea, skin toxicity, transaminase increase, lipase increase, and pancolitis). Grade 4 toxicity was not observed. In 20 patients (36.4%), grade 1-2 AEs related to durvalumab were observed. The most common were endocrine toxicity (hyper/hypothyroidism), dermatologic toxicity (skin rash), and gastrointestinal toxicity (transaminase increase, nausea, diarrhea, constipation).

CONCLUSION

This study met its primary endpoint showing that CRT followed by durvalumab could increase pCR with a safe toxicity profile. This combination is a promising, feasible strategy worthy of further investigation.

Dichotomous colorectal cancer behaviour

Colorectal cancer (CRC) is the third most common malignant tumor and one of the deadliest cancers. At molecular level, CRC is a heterogeneous disease that could be divided in four Consensus Molecular Subtypes. Given the differences in the disease due to its anatomical location (proximal and distal colon), another classification should be considered. Here, we review the current knowledge on CRC dichotomic´s behaviour based on two different entities; right and left-sided tumors, their impact on clinical trial data, microbiota spatial composition and the interaction with the nervous system. We discuss recent advances in understanding how the spatial tumor heterogeneity influences the tumor growth, progression, and responses to current therapies.

Impact of gender and mutational differences in hormone receptor expressing non-small cell lung cancer

Background

The incidence of lung cancer in the US has been decreasing but a bigger decline has been observed in men despite similar declines in tobacco use between men and women. Multiple theories have been proposed, including exposure to exogenous estrogens. Our study seeks to understand the relationship between hormone receptors (HR), gender, and the genomic landscape of non-small lung cancer (NSCLC).

Methods

3,256 NSCLC tumor samples submitted for molecular profiling between 2013-2018 were retrospectively identified and assessed for HR expression. Hormone receptor (HR+) was defined as ≥ 1% nuclear staining of estrogen receptor-alpha (ER-a) or progesterone receptor (PR) by immunohistochemistry. DNA sequencing by NGS included cases sequenced by the Illumina MiSeq hot spot 47 gene panel (n=2753) and Illumina NextSeq 592 gene panel (n=503). An adjusted p-value (q-value) <0.05 was determined significant.

Results

HR+ was identified in 18.3% of NSCLC. HR+ occurred more commonly in women compared to men (19.6% vs 11.4%, p <0.0001, q <0.0001). EGFR mutations occurred more commonly in HR+ NSCLC than HR- NSCLC (20.2% vs. 14.6%, p = 0.002, q=0.007). Overall, men with EGFR mutations were affected by HR status with a higher prevalence in HR+ NSCLC while such differences were not seen in women. However, in women ages ≤45, there was a trend towards greater prevalence HR+ NSCLC (25.25% vs. 11.32%, q= 0.0942) and 10/25 (40.0%) of HR+ cases in young women were found to be EGFR mutated. KRAS mutations and ALK+ IHC expression occurred more in HR+ NSCLC whereas TP53 mutations occurred more in HR- NSCLC.

Conclusions

Women were more likely to have HR+ NSCLC than men and EGFR and KRAS mutations occurred more commonly in HR+ NSCLC. Additional studies with more strict inclusion criteria for HR+ are warranted to see if there is benefit to targeting HR in these subgroups.

KRAS mutations and their associations with clinicopathological features and survival in Vietnamese non‑polyp colon cancer patients

The aim of the present study was to determine Kirsten Ras sarcoma virus (KRAS) mutations and the associations of KRAS mutations with clinicopathological features and treatment outcomes in Vietnamese non-polyp colon cancer (NPCC) patients. The data in the present study covered 194 patients with non-polyp colon cancers at stages II or III, according to the 8th edition of the American Joint Committee on Cancer staging system, in northern Vietnam from January 2016 to August 2020. All patients underwent radical surgery and adjuvant therapy with FOLFOX4 or XELOX. Subsequently, the recruited patients were followed-up with scheduled hospital exams for diagnosing recurrence. Genomic DNA samples were prepared from dissected tumors and specific sequences of the KRAS gene were amplified by polymerase chain reactions (PCR). The mutations at codons 12, 13, 59, 60, 61, 117 and 146 of the gene were determined. Possible associations of the KRAS mutations with clinicopathological properties and the survival of patients were analysed. The KRAS mutation rate was 47.9% in Vietnamese patients with NPCC, of those, mutations in exon 2 accounted for 91.4% of all detected mutations. The mutated-KRAS patients exhibited a significantly higher rate of anemia. Moreover, the KRAS mutation rate was higher in females (57.1%) than in males (39.8%). The KRAS mutation rate was also higher in patients with right colon cancers. Furthermore, KRAS mutations were an independent prognosis for poor disease-free survival (DFS) and overall survival (OS) in stage II patients. Among left-sided colon patients, mutated KRAS was a significant predictive factor for poor DFS but not for OS. The present study revealed a very high mutation rate of KRAS in Vietnamese patients with NPCC. The data of the present study indicated that the mutation status was associated with female patients and right-sided tumors. The KRAS mutations were a negative factor for the survival of patients with stage II NPCC and patients with left-sided colon cancer.

Colorectal adenocarcinoma in Uganda: are right-sided and left-sided colon cancers two distinct disease entities?

INTRODUCTION

In Western countries, right-sided colon cancers (RSCC) present at an older age and advanced stage. Researchers believe that there is a difference between left-sided colon cancer (LSCC) and RSCC. In Uganda, however, it is unknown whether differences exist in the pathological profile between RSCC and LSCC. The aim of this study was to determine the differences in clinicopathological characteristics between RSCC and LSCC in Ugandan patients.

METHODOLOGY

A cross-sectional study was conducted in which colorectal adenocarcinoma formalin-fixed paraffin-embedded tissue (FFPE) blocks were obtained from 2008 to 2021. Colorectal specimens were obtained from prospectively recruited patients. In the retrospective study arm, FFPE blocks and data were obtained from the archives of pathology laboratory repositories. Parameters studied included age, sex, location of the tumour, grade, stage, lymphovascular (LVI) status, and histopathological subtype between LSCC and RSCC.

RESULTS

Patients with RSCC were not older than those with LSCC (mean age, 56.3 years vs 53.5 years; p = 0.170). There was no difference in the stage between RSCC and LSCC. Poorly differentiated tumours were more commonly found in RSCC than in LSCC (18.7% vs 10.1%; p = 0.038). Moderately and poorly differentiated colonic tumours were more common with RSCC (89.3%) than with LSCC (75.1%) (p = 0.007). Younger patients had more poorly differentiated tumours than older patients (19.6% versus 8.6%; p = 0.002). LVI was more common with RSCC than with LSCC (96.8% vs 85.3%; p = 0.014). Mucinous adenocarcinoma (MAC) was more common with RSCC (15.8%) compared with LSCC (8.5%) (p = 0.056) although statistical significance was borderline.

CONCLUSIONS

Clinicopathological features of RSCCs tend to be different from those of LSCCs. RSCCs tend to be associated with MAC, a higher grade and LVI status compared to LSCC. LSCC and RSCC present predominantly with an advanced stage; therefore, national screening programmes for the early detection of CRC are necessary to reduce mortality in our Ugandan population.

Immune escape and resistance to immunotherapy in mismatch repair deficient tumors

Up to 30% of colorectal, endometrial and gastric cancers have a deficiency in mismatch repair (MMR) protein expression due to either germline or epigenetic inactivation. Patients with Lynch Syndrome who inherit an inactive MMR allele have an up to 80% risk for developing a mismatch repair deficient (MMRd) cancer. Due to an inability to repair DNA, MMRd tumors present with genomic instability in microsatellite regions (MS). Tumors with high MS instability (MSI-H) are characterized by an increased frequency of insertion/deletions (indels) that can encode novel neoantigens if they occur in coding regions. The high tumor antigen burden for MMRd cancers is accompanied by an inflamed tumor microenvironment (TME) that contributes to the clinical effectiveness of anti-PD-1 therapy in this patient population. However, between 40 and 70% of MMRd cancer patients do not respond to treatment with PD-1 blockade, suggesting that tumor-intrinsic and -extrinsic resistance mechanisms may affect the success of checkpoint blockade. Immune evasion mechanisms that occur during early tumorigenesis and persist through cancer development may provide a window into resistance pathways that limit the effectiveness of anti-PD-1 therapy. Here, we review the mechanisms of immune escape in MMRd tumors during development and checkpoint blockade treatment, including T cell dysregulation and myeloid cell-mediated immunosuppression in the TME. Finally, we discuss the development of new therapeutic approaches to tackle resistance in MMRd tumors, including cancer vaccines, therapies targeting immunosuppressive myeloid programs, and immune checkpoint combination strategies.

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.

Early Onset Metastatic Colorectal Cancer: Current Insights and Clinical Management of a Rising Condition

Despite a recent overall decrease in colorectal cancer (CRC) incidence and mortality, there has been a significant rise in CRC diagnoses in young adults. Early onset colorectal cancer (EOCRC) is defined as CRC diagnosed before the age of 50. Possible predisposing conditions include not only genetic syndromes but also other risk factors, such as microbiome alteration, antibiotic exposure, obesity, diabetes mellitus, and inflammatory bowel disease. EOCRC tends to be diagnosed later than in the older counterpart because of a lack of awareness and the fact that screening for CRC usually starts at the age of 50. Furthermore, CRC in young adults seems to be related to unique molecular features and more aggressive clinical behavior. This paper aims to provide an in-depth review of this poorly understood subject, with a comprehensive review of the state of the art and considerations for future perspectives.

Impact of Primary Tumor Location and Genomic Alterations on Survival Following Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemoperfusion for Colorectal Peritoneal Metastases

BACKGROUND

Colorectal cancer leads to peritoneal metastases (CRPM) in 10% of cases. Cytoreductive surgery with hyperthermic intraperitoneal chemoperfusion (CRS-HIPEC) improves survival. Primary tumor location and abnormalities in RAS, BRAF, and mismatch repair/microsatellite stability (MMR/MSI) may affect post-CRS-HIPEC survival, but studies have not been consistent. We estimated the effects of primary tumor site and genomic alterations on post-CRS-HIPEC survival.

METHODS

This retrospective cohort study included CRS-HIPEC cases for CRPM at a high-volume center from 2001 to 2020. Next-generation sequencing and microsatellite testing defined the RAS, BRAF, and MMR/MSI genotypes. Adjusted effects of tumor sidedness and genomics on survival were evaluated using a multivariable Cox proportional hazards model. We analyzed these variables' effects on progression-free survival and the effects of immune checkpoint-inhibitors.

RESULTS

A total of 250 patients underwent CRS-HIPEC with testing for RAS, BRAF, and MMR/MSI; 50.8% of patients were RAS-mutated, 12.4% were BRAF-mutated, and 6.8% were deficient-MMR/MSI-high (dMMR/MSI-H). Genomic alterations predominated in right-sided cancers. After adjustment for comorbidities and oncological and perioperative variables, rectal origin [hazard ratio (HR) 1.9, p = 0.01], RAS mutation (HR 1.6, p = 0.01), and BRAF mutation (HR 1.7, p = 0.05) were associated with worse survival. RAS mutation was also associated with shorter progression-free survival (HR 1.6, p = 0.01 at 6 months post-operatively), and dMMR/MSI-H status was associated with superior survival (HR 0.3, p = 0.01 at 2 years). dMMR/MSI-H patients receiving immune checkpoint-inhibitors trended toward superior survival.

CONCLUSIONS

Rectal origin, RAS mutations, and BRAF mutations are each associated with poorer survival after CRS-HIPEC for CRPM. Patients with CRPM and dMMR/MSI-H status have superior survival. Further research should evaluate benefits of immune checkpoint-inhibitors in this subgroup.

Activated tissue resident memory T-cells (CD8+CD103+CD39+) uniquely predict survival in left sided "immune-hot" colorectal cancers

Introduction

Characterization of the tumour immune infiltrate (notably CD8+ T-cells) has strong predictive survival value for cancer patients. Quantification of CD8 T-cells alone cannot determine antigenic experience, as not all infiltrating T-cells recognize tumour antigens. Activated tumour-specific tissue resident memory CD8 T-cells (T_RM) can be defined by the co-express of CD103, CD39 and CD8. We investigated the hypothesis that the abundance and localization of T_RM provides a higher-resolution route to patient stratification.

Methods

A comprehensive series of 1000 colorectal cancer (CRC) were arrayed on a tissue microarray, with representative cores from three tumour locations and the adjacent normal mucosa. Using multiplex immunohistochemistry we quantified and determined the localization of T_RM.

Results

Across all patients, activated T_RM were an independent predictor of survival, and superior to CD8 alone. Patients with the best survival had immune-hot tumours heavily infiltrated throughout with activated T_RM. Interestingly, differences between right- and left-sided tumours were apparent. In left-sided CRC, only the presence of activated T_RM (and not CD8 alone) was prognostically significant. Patients with low numbers of activated T_RM cells had a poor prognosis even with high CD8 T-cell infiltration. In contrast, in right-sided CRC, high CD8 T-cell infiltration with low numbers of activated T_RM was a good prognosis.

Conclusion

The presence of high intra-tumoural CD8 T-cells alone is not a predictor of survival in left-sided CRC and potentially risks under treatment of patients. Measuring both high tumour-associated T_RM and total CD8 T-cells in left-sided disease has the potential to minimize current under-treatment of patients. The challenge will be to design immunotherapies, for left-sided CRC patients with high CD8 T-cells and low activate T_RM,that result in effective immune responses and thereby improve patient survival.

A Phase II Trial of Trifluridine/Tipiracil in Combination with Cetuximab Rechallenge in Patients with RAS Wild-Type mCRC Refractory to Prior Anti-EGFR Antibodies: WJOG8916G Trial

BACKGROUND

Trifluridine/tipiracil (FTD/TPI) improved the overall survival in patients with metastatic colorectal cancer (mCRC) who had previously received standard chemotherapies; however, the clinical outcomes remain poor.

OBJECTIVE

A multicenter phase II study aimed to assess the efficacy and safety of FTD/TPI plus cetuximab rechallenge.

PATIENTS AND METHODS

Patients with histologically confirmed RAS wild-type mCRC refractory to prior anti-epidermal growth factor receptor (anti-EGFR) antibody were enrolled and treated with FTD/TPI (35 mg/m² twice daily on days 1-5 and 8-12) plus cetuximab (initially 400 mg/m², followed by weekly 250 mg/m²) every 4 weeks. The primary endpoint was disease control rate (DCR), expecting a target DCR of 65% and null hypothesis of 45% with 90% power and 10% one-sided alpha error. Gene alterations of RAS, BRAF, EGFR, PIK3CA, ERBB2, and MET in pre-treatment circulating tumor DNA were evaluated using the Guardant360 assay.

RESULTS

A total of 56 patients (median age 60 years; left-sided tumors 91%; objective partial or complete response during the prior anti-EGFR therapy 61%) were enrolled. The DCR was 54% (80% confidence interval [CI] 44-63; P = 0.12), with a partial response rate of 3.6%. Median progression-free survival (PFS) was 2.4 months (95% CI 2.1-3.7). In the circulating tumor DNA analysis, patients without any alterations of the six genes (n = 20) demonstrated higher DCR (75% vs. 39%; P = 0.02) and longer PFS (median 4.7 vs. 2.1 months; P < 0.01) than those with any gene alterations (n = 33). The most common grade 3/4 hematologic adverse event was neutropenia (55%). No treatment-related deaths occurred.

CONCLUSIONS

FTD/TPI plus cetuximab rechallenge did not demonstrate clinically meaningful efficacy in all mCRC patients, but might be beneficial for the molecularly selected population.

Peritoneal metastases from primary appendiceal and colorectal carcinomas demonstrate distinct molecular identities on comprehensive tumor analysis

BACKGROUND AND OBJECTIVES

Published data comparing peritoneal metastases from appendiceal cancers (pAC) and colorectal cancers (pCRC) remain sparse. We compared pAC and pCRC using comprehensive tumor profiling (CTP).

METHODS

CTP was performed, including next-generation sequencing and analysis of copy number variation (CNV), microsatellite instability (MSI) and tumor mutational burden (TMB).

RESULTS

One hundred thirty-six pAC and 348 pCRC samples underwent CTP. The cohorts' age and gender were similar. pCRC demonstrated increased pathogenic variants (PATHs) in APC (48% vs. 3%, p < 0.01), ARID1A (12% vs. 2%, p < 0.01), BRAF (12% vs. 2%, p < 0.01), FBXW7 (7% vs. 2%, p < 0.01), KRAS (52% vs. 41%, p < 0.05), PIK3CA (15% vs. 2%, p < 0.01), and TP53 (53% vs. 23%, p < 0.01), and decreased PATHs in GNAS (8% vs. 31%, p < 0.01). There was no difference in CNV, fusion rate, or MSI. Median TMB was higher in pCRC (5.8 vs. 5.0 mutations per megabase, p = 0.0007). Rates of TMB-high tumors were similar (pAC 2.1% vs. pCRC 9.0%, p = 0.1957). pCRC had significantly more TMB-high tumors at lower thresholds.

CONCLUSIONS

Despite a reduced overall TMB, pAC demonstrated mutations distinct from those seen in pCRC. These may serve as discrete biomarkers for future study.

Influence of location-dependent sex difference on PD-L1, MMR/MSI, and EGFR in colorectal carcinogenesis

BACKGROUND

The incidence and mortality rates of colorectal cancer (CRC) has been reported to be strongly associated to sex/gender difference. CRC shows sexual dimorphism, and sex hormones have been shown to affect the tumor immune microenvironment. This study aimed to investigate location-dependent sex differences in tumorigenic molecular characteristics in patients with colorectal tumors, including adenoma and CRC.

METHODS

A total of 231 participants, including 138 patients with CRC, 55 patients with colorectal adenoma, and 38 healthy controls, were recruited between 2015 and 2021 at Seoul National University Bundang Hospital. All patients underwent colonoscopy and acquired tumor lesion samples were further analyzed for programmed death-ligand 1 (PD-L1), epidermal growth factor receptor (EGFR) expression, deficient mismatch repair (dMMR), and microsatellite instability (MSI) status. This study was registered with ClinicalTrial.gov, number NCT05638542.

RESULTS

The average of combined positive score (CPS) was higher in serrated lesions and polyps (lesions/polyps) compared to conventional adenomas (5.73 and 1.41, respectively, P < 0.001). No significant correlation was found between sex and PD-L1 expression within the groups, regardless of histopathological diagnosis. In multivariate analysis where each sex was further stratified by tumor location due to their interaction in CRC, PD-L1 expression was inversely correlated with males having proximal CRC with a CPS cutoff of 1 (Odds ratio (OR) 0.28, P = 0.034). Females with proximal CRC showed a significant association with dMMR/MSI-high (OR 14.93, P = 0.032) and high EGFR expression (OR 4.17, P = 0.017).

CONCLUSION

Sex and tumor location influenced molecular features such as PD-L1, MMR/MSI status and EGFR expression in CRC, suggesting a possible underlying mechanism of sex-specific colorectal carcinogenesis.

Prognostic Role for Primary Tumor Location in Patients With Colorectal Liver Metastases: A Comparison of Right-Sided Colon, Left-Sided Colon, and Rectum

BACKGROUND

Although right-sided colon cancer is increasingly recognized as having a worse prognosis than left-sided colorectal cancer for colorectal liver metastases, little is known about the differences between the left-sided colon and rectum.

OBJECTIVE

This study evaluated the prognostic value of primary tumor location in patients with colorectal liver metastases by examining the left-sided colon and rectum separately.

DESIGN

This was a retrospective study from 2003 to 2017.

SETTINGS

The study was conducted in a National Cancer Center Hospital.

PATIENTS

The study cohort included 489 patients with colorectal liver metastases from right-sided colon cancer ( n = 119, 24%), left-sided colon cancer ( n = 251, 51%), or rectal cancer ( n = 119, 24%) who underwent hepatic resection.

MAIN OUTCOME MEASURES

Primary outcomes were relapse-free survival and overall survival.

RESULTS

Five-year relapse-free survival rates for patients with right-sided colon cancer, left-sided colon cancer, and rectal cancer were 28.6%, 34.1%, and 26.4%, and 5-year overall survival rates were 53.9%, 70.3%, and 60.8%. Multivariable analysis revealed significant differences in relapse-free survival and overall survival between left-sided colon cancer and rectal cancer (relapse-free survival: HR = 1.37, p = 0.03; overall survival: HR = 1.49, p = 0.03) and between left-sided colon cancer and right-sided colon cancer (relapse-free survival: HR = 1.39, p = 0.02; overall survival: HR = 1.60, p = 0.01), but not between right-sided colon cancer and rectal cancer. In patients with recurrence ( n = 325), left-sided colon cancer had the lowest multiple-site recurrence rate and the highest surgical resection rate for recurrence (left-sided colon cancer, 20%/46%; right-sided colon cancer, 32%/30%; rectal cancer, 26%/39%).

LIMITATIONS

This study was retrospective in design.

CONCLUSIONS

Rectal cancer was associated with worse relapse-free survival and overall survival compared with left-sided colon cancer in patients with colorectal liver metastases who underwent hepatic resection. Our findings suggest that the left-sided colon and rectum should be considered distinct entities in colorectal liver metastases. See Video Abstract at http://links.lww.com/DCR/B882 .

PAPEL PRONSTICO DE LA UBICACIN DEL TUMOR PRIMARIO EN PACIENTES CON METSTASIS HEPTICAS COLORRECTALES UNA COMPARACIN ENTRE COLON DERECHO, COLON IZQUIERDO Y RECTO

ANTECEDENTES:Aunque se reconoce cada vez más que el cáncer de colon del lado derecho tiene un peor pronóstico que el cáncer colorrectal del lado izquierdo para las metástasis hepáticas colorrectales, se sabe poco acerca de las diferencias entre el recto y el colon del lado izquierdo.OBJETIVO:Este estudio evaluó el valor pronóstico de la ubicación del tumor primario en pacientes con metástasis hepáticas colorrectales examinando el recto y el colon del lado izquierdo por separado.DISEÑO:Este fue un estudio retrospectivo de 2003 a 2017.ENTORNO CLÍNICO:El estudio se llevó a cabo en un Hospital del Centro Nacional de Cáncer.PACIENTES:La cohorte del estudio incluyó a 489 pacientes con metástasis hepáticas colorrectales de cáncer de colon del lado derecho (n = 119, 24%), cáncer de colon del lado izquierdo (n = 251, 51%) o cáncer de recto (n = 119, 24%). %) que fueron sometidos a resección hepática.PRINCIPALES MEDIDAS DE VALORACIÓN:Los resultados primarios fueron la supervivencia sin recaídas y la supervivencia general.RESULTADOS:Las tasas de supervivencia sin recaída a cinco años para los pacientes con cáncer de colon derecho, cáncer de colon izquierdo y cáncer de recto fueron del 28,6%, 34,1%, y 26,4%, respectivamente, y las tasas de supervivencia general a los 5 años fueron del 53,9%, 70,3%, y 60,8%, respectivamente. El análisis multivariable reveló diferencias significativas en la supervivencia sin recaída y la supervivencia general entre el cáncer de colon izquierdo y el cáncer de recto (supervivencia sin recaída: HR = 1,37, p = 0,03; supervivencia general: HR = 1,49, p = 0,03) y entre el cáncer de colon izquierdo y el cáncer de colon del lado derecho (supervivencia libre de recaídas: HR = 1,39, p = 0,02; supervivencia global: HR = 1,60, p = 0,01), pero no entre el cáncer de colon del lado derecho y el cáncer de recto. En pacientes con recurrencia (n = 325), el cáncer de colon izquierdo tuvo la tasa de recurrencia en sitios múltiples más baja y la tasa de resección quirúrgica más alta por recurrencia (cáncer de colon izquierdo, 20%/46%; cáncer de colon derecho, 32%/30%; cáncer de recto, 26%/39%).LIMITACIONES:Este estudio fue de diseño retrospectivo.CONCLUSIONES:El cáncer de recto se asoció con una peor supervivencia sin recaída y una supervivencia general peor en comparación con el cáncer de colon izquierdo en pacientes con metástasis hepáticas colorrectales que se sometieron a resección hepática. Nuestros hallazgos sugieren que el colon y el recto del lado izquierdo deben considerarse entidades distintas en las metástasis hepáticas colorrectales. Consulte Video Resumen en http://links.lww.com/DCR/B882 . (Tradducción-Dr. Ingrid Melo ).

The Prognostic Impact of Microsatellite Instability on the Outcome of Appendiceal Adenocarcinoma: a National Cancer Database Analysis

BACKGROUND

Microsatellite instability (MSI) is recognized as a favorable outcome predictor in colorectal cancer. However, its impact on overall survival (OS) of appendiceal carcinoma has not been thoroughly studied. This study aimed to assess the impact of MSI on OS of patients with appendiceal adenocarcinoma, stratified by disease stage, tumor histology, and patients' demographics.

METHODS

This was a retrospective cohort analysis of the colon cancer National Cancer Database (NCDB) between 2005 and 2019. Patients with appendiceal adenocarcinoma with known MSI status were included and subdivided according to MSI status into positive and negative. Primary outcome was OS stratified by MSI status.

RESULTS

The study included 1681 (50.1% male) patients with a mean age of 58.9 ± 14.2 years; 211 (12.5%) had MSI-positive tumors (69 MSI low, 53 MSI high, and 89 not specified). Mean 5-year OS of patients with MSI-positive and MSI-negative carcinomas was similar (81.9 versus 78.6 months, p = 0.747). Patients with stage IV MSI-positive carcinomas had significantly longer OS than patients with MSI-negative carcinomas of the same stage (41.3 vs 26.5 months, p = 0.02). Differences in OS for patients with stages I-III were not statistically significant. Compared to MSI-negative/low carcinomas, MSI-high tumors had more advanced pathologic TNM stage (stage III: 23.9% vs 17.8%-stage IV: 41.3% vs 35.4%, p = 0.003), received more chemotherapy (56% vs 41%, p = 0.04), yet had similar OS (81.9 vs 78.9 months, p = 0.357).

CONCLUSIONS

MSI status of appendiceal adenocarcinomas did not significantly impact survival, except for stage IV disease in which a survival benefit of MSI was noted.

Potential for cure and predictors of long-term survival after radiofrequency ablation for colorectal liver metastases: A 20-years single-center experience

BACKGROUND

Additional radiofrequency ablation (RFA) of liver-limited colorectal liver metastases (CRLM) improves overall (OS) and recurrence-free survival (RFS) over systemic therapy alone. We aimed to assess the potential and predictive factors of long-term survival and cure to optimize patient selection for RFA application.

METHODS

Retrospective review of a prospectively maintained single-center database of consecutive patients undergoing RFA for liver-limited CRLM after systemic therapy between 2002 and 2020. Clinicopathologic characteristics and KRAS/BRAF-genotype data (tested routinely since 2010) were correlated to RFS and OS. Cure was defined as ≥10-years RFS (long-term survival as ≥5-years OS) following RFA.

RESULTS

For the entire cohort of 158 patients (median follow-up 13.6 years), co-occurrence of three factors, RECIST-defined response, number of ≤3 CRLM, and ≤3 cm maximum size determined a survival plateau that distinguished cured from non-cured patients (10-years RFS: 15.5% vs 0%, p < 0.0001). Among 59 patients (37.3%) being tested, 4(6.8%) were BRAF-mt, 15(25.4%) KRAS-mt, and 40(67.8%) KRAS/BRAF-wt. OS (median follow-up 8.3 years) was estimated to be higher with KRAS/BRAF-wt compared to a mutant KRAS or BRAF status (5-years OS: 22.8% vs 3.4%, p = 0.0018).

CONCLUSION

This study indicates about 15% chance of cure following RFA of low-volume liver-limited CRLM after downsizing by systemic therapy and a negative effect of KRAS or BRAF mutation on long-term survival after CRLM ablation. These findings may improve clinical decision-making in patients potentially candidate to RFA of CRLM and encourage further investigations on molecular factors determining an oligometastatic state of CRLM curable with focal ablative therapy.

TIMP1 promotes cell proliferation and invasion capability of right-sided colon cancers via the FAK/Akt signaling pathway

Although right-sided colorectal cancer (CRC) shows a worse prognosis than left-sided CRC, the underlying mechanism remains unclear. We established patient-derived organoids (PDOs) from left- and right-sided CRCs and directly compared cell proliferation and invasion capability between them. We then analyzed the expression of numerous genes in signal transduction pathways to clarify the mechanism of the differential prognosis. Cell proliferation activity and invasion capability in right-sided cancer PDOs were significantly higher than in left-sided cancer PDOs and normal PDOs, as revealed by Cell Titer Glo and transwell assays, respectively. We then used quantitative RT-PCR to compare 184 genes in 30 pathways among right-sided and left-sided cancer and normal PDOs and found that the TIMP1 mRNA level was highest in right-sided PDOs. TIMP1 protein levels were upregulated in right-sided PDOs compared with normal PDOs but was downregulated in left-sided PDOs. TIMP1 knockdown with shRNA significantly decreased cell proliferation activity and invasion capability in right-sided PDOs but not in left-sided PDOs. Moreover, TIMP1 knockdown significantly decreased pFAK and pAkt expression levels in right-sided PDOs but not in left-sided PDOs. A database analysis of The Cancer Genome Atlas revealed that TIMP1 expression in right-sided CRCs was significantly higher than in left-sided CRCs. Kaplan-Meier survival analysis showed significantly shorter overall survival in high-TIMP1 patients versus low-TIMP1 patients with right-sided CRCs but not left-sided CRCs. Our data suggest that TIMP1 is overexpressed in right-sided CRCs and promotes cell proliferation and invasion capability through the TIMP1/FAK/Akt pathway, leading to a poor prognosis. The TIMP1/FAK/Akt pathway can be a target for therapeutic agents in right-sided CRCs.

Extensive genomic analysis in patients with KRAS-mutated solid tumors shows high frequencies of concurrent alterations and potential targets but has limited clinical impact

BACKGROUND

This study aimed to investigate the distribution and frequency of concurrent alterations in different cancers across KRAS subtypes and in different KRAS subtypes across cancers, and to identify potentially actionable targets and patients who received targeted treatment matched to their genomic profile (GP).

MATERIALS AND METHODS

In this descriptive and single-center study, we included 188 patients with solid tumors harboring KRAS mutations in codon 12, 13, 61, 117, or 146, referred to the Phase 1 Unit, Rigshospitalet, Copenhagen, Denmark from mid-2016 to 2020. Genomic co-alterations were detected with whole-exome sequencing, RNA sequencing, SNP array, and mRNA expression array on fresh biopsies. The study is part of the Copenhagen Prospective Personalized Oncology study (NCT02290522).

RESULTS

The majority of patients had colorectal cancer (60.1%), non-small cell lung cancer (11.2%), or pancreatic cancer (10.6%). Most tumors were KRAS-mutated in codon 12 or 13 (93.7%) including G12D (27.1%), G12V (26.6%), G12C (11.7%), and G13D (11.2%). A total of 175 different co-alterations were found, most frequently pathogenic APC and TP53 mutations (55.9% and 46.4%, respectively) and high expression of CEACAM5 (73.4%). Different cancers and KRAS subtypes showed different patterns of co-alterations, and 157 tumors (83.5%) had potentially actionable targets with varying evidence of targetability (assessed using ESMO Scale for Clinical Actionability of molecular Targets). Of the 188 patients included in the study, 15 (7.4%) received treatment matched to their GP (e.g., immunotherapy and synthetic lethality drugs), of whom one had objective partial response according to Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1.

CONCLUSION

Performing extensive genomic analysis in patients with known KRAS-mutated solid tumors may contribute with information to the genomic landscape of cancers and identify targets for immunotherapy or synthetic lethality drugs, but currently appears to have overall limited clinical impact, as few patients received targeted therapy matched to their GP.

Emerging Role of ERBB2 in Targeted Therapy for Metastatic Colorectal Cancer: Signaling Pathways to Therapeutic Strategies

Despite recent improvements in the comprehensive therapy of malignancy, metastatic colorectal cancer (mCRC) continues to have a poor prognosis. Notably, 5% of mCRC cases harbor Erb-B2 receptor tyrosine kinase 2 (ERBB2) alterations. ERBB2, commonly referred to as human epidermal growth factor receptor 2, is a member of the human epidermal growth factor receptor family of protein tyrosine kinases. In addition to being a recognized therapeutic target in the treatment of gastric and breast malignancies, it is considered crucial in the management of CRC. In this review, we describe the molecular biology of ERBB2 from the perspective of biomarkers for mCRC-targeted therapy, including receptor structures, signaling pathways, gene alterations, and their detection methods. We also discuss the relationship between ERBB2 aberrations and the underlying mechanisms of resistance to anti-EGFR therapy and immunotherapy tolerance in these patients with a focus on novel targeted therapeutics and ongoing clinical trials. This may aid the development of a new standard of care in patients with ERBB2-positive mCRC.

Biomarkers in Metastatic Colorectal Cancer: Status Quo and Future Perspective

Colorectal cancer (CRC) is the third most frequent cancer worldwide, and its incidence is steadily increasing. During the last two decades, a tremendous improvement in outcome has been achieved, mainly due to the introduction of novel drugs, targeted treatment, immune checkpoint inhibitors (CPIs) and biomarker-driven patient selection. Moreover, progress in molecular diagnostics but also improvement in surgical techniques and local ablative treatments significantly contributed to this success. However, novel therapeutic approaches are needed to further improve outcome in patients diagnosed with metastatic CRC. Besides the established biomarkers for mCRC, such as microsatellite instability (MSI) or mismatch repair deficiency (dMMR), RAS/BRAF, sidedness and HER2 amplification, new biomarkers have to be identified to better select patients who derive the most benefit from a specific treatment. In this review, we provide an overview about therapeutic relevant and established biomarkers but also shed light on potential promising markers that may help us to better tailor therapy to the individual mCRC patient in the near future.

The clinical value of C-reactive protein and its association with tumour location in patients undergoing curative surgery for colorectal cancer - a ScotScan collaborative study

INTRODUCTION

The presence of preoperative systemic inflammatory response (SIR) is an established negative prognostic factor for patients diagnosed with colorectal cancer (CRC). C-reactive protein (CRP) is known to be implicated in detrimental immune responses. The biological differences between right-sided and left-sided CRC are gaining increasing attention. Our aim was to analyse the prognostic value of CRP and explore the association between tumour location and SIR.

MATERIAL AND METHODS

A total of 2059 patients treated for stage I-III CRC, identified from the prospectively sampled ScotScan Collaborative dataset, were included. The clinical and prognostic value of five CRP levels (<10/11-30/31-60/61-100/>100 mg/l) were examined. Additionally, the relationship between SIR and tumour location was explored.

RESULTS

Increasing levels of CRP were associated with impaired overall and cancer-specific outcome. Presence of SIR was independently associated with right-sided tumour location (p<0.001). However, the impact of SIR on cancer-specific survival (CSS) was greater for left-sided tumour location, even when adjusted for other clinicopathological factors.

CONCLUSIONS

This study confirms CRP as a routinely available, valid, and clinically relevant strong prognostic marker of SIR in CRC patients. Right-sided tumours were more often associated with SIR, but the prognostic impact was stronger in left-sided tumours.

Colon Cancer Pharmacogenetics: A Narrative Review

Currently, metastatic colon cancer is treated with monotherapeutic regimens such as folinic acid, fluorouracil, and oxaliplatin (FOLFOX), capecitabine and oxaliplatin (CapeOX), and leucovorin, fluorouracil, and irinotecan hydrochloride (FOLFIRI). Other treatments include biological therapies and immunotherapy with drugs such as bevacizumab, panitumumab, cetuximab, and pembrolizumab. After the research, it was found that some mutations make those treatments not as effective in all patients. In this bibliographic review, we investigated the pharmacogenetic explanations for how mutations in the genes coding for rat sarcoma virus (RAS) and rapidly accelerated fibrosarcoma (RAF) reduce the effectiveness of these treatments and allow the continued proliferation of tumors. Furthermore, we note that patients with mutations in the dihydropyrimidine dehydrogenase (DPDY) gene usually require lower doses of therapies such as 5-fluorouracyl (5-FU) and capecitabine to avoid severe adverse effects. Some other mutations in the thymidylate synthase gene (TSYM), methylenetetrahydrofolate reductase gene (MTHFR), and ATP binding cassette transporter B (ABCB1 and ABCB2) affect efficacy and security of the treatments. It is important to address the clinical implication of the oncologist in the study of gene mutations than can influence in the antitumoral response and safety of colon cancer treatments.

Diabetes mellitus in relation to colorectal tumor molecular subtypes: A pooled analysis of more than 9000 cases

Diabetes is an established risk factor for colorectal cancer. However, colorectal cancer is a heterogeneous disease and it is not well understood whether diabetes is more strongly associated with some tumor molecular subtypes than others. A better understanding of the association between diabetes and colorectal cancer according to molecular subtypes could provide important insights into the biology of this association. We used data on lifestyle and clinical characteristics from the Colorectal Cancer Family Registry (CCFR) and the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO), including 9756 colorectal cancer cases (with tumor marker data) and 9985 controls, to evaluate associations between reported diabetes and risk of colorectal cancer according to molecular subtypes. Tumor markers included BRAF and KRAS mutations, microsatellite instability and CpG island methylator phenotype. In the multinomial logistic regression model, comparing colorectal cancer cases to cancer-free controls, diabetes was positively associated with colorectal cancer regardless of subtype. The highest OR estimate was found for BRAF-mutated colorectal cancer, n = 1086 (ORfully adj : 1.67, 95% confidence intervals [CI]: 1.36-2.05), with an attenuated association observed between diabetes and colorectal cancer without BRAF-mutations, n = 7959 (ORfully adj : 1.33, 95% CI: 1.19-1.48). In the case only analysis, BRAF-mutation was differentially associated with diabetes (Pdifference  = .03). For the other markers, associations with diabetes were similar across tumor subtypes. In conclusion, our study confirms the established association between diabetes and colorectal cancer risk, and suggests that it particularly increases the risk of BRAF-mutated tumors.

Precision Medicine in Metastatic Colorectal Cancer: Targeting ERBB2 (HER-2) Oncogene

Colorectal cancer (CRC) is the third most common cancer in terms of incidence rate in adults and the second most common cause of cancer-related death in Europe. The treatment of metastatic CRC (mCRC) is based on the use of chemotherapy, anti-vascular endothelial growth factor (VEGF), and anti-epidermal growth factor receptor (EGFR) for RAS wild-type tumors. Precision medicine tries to identify molecular alterations that could be treated with targeted therapies. ERBB2 amplification (also known as HER-2) has been identified in 2-3% of patients with mCRC, but there are currently no approved ERBB2-targeted therapies for mCRC. The purpose of this review is to describe the molecular structure of ERBB2, clinical features of these patients, diagnosis of ERBB2 alterations, and the most relevant clinical trials with ERBB2-targeted therapies in mCRC.

Interaction between microbiota and immunity and its implication in colorectal cancer

Colorectal cancer (CRC) is one of the leading causes of cancer-related death in the world. Besides genetic causes, colonic inflammation is one of the major risk factors for CRC development, which is synergistically regulated by multiple components, including innate and adaptive immune cells, cytokine signaling, and microbiota. The complex interaction between CRC and the gut microbiome has emerged as an important area of current CRC research. Metagenomic profiling has identified a number of prominent CRC-associated bacteria that are enriched in CRC patients, linking the microbiota composition to colitis and cancer development. Some microbiota species have been reported to promote colitis and CRC development in preclinical models, while a few others are identified as immune modulators to induce potent protective immunity against colitis and CRC. Mechanistically, microbiota regulates the activation of different immune cell populations, inflammation, and CRC via crosstalk between innate and adaptive immune signaling pathways, including nuclear factor kappa B (NF-κB), type I interferon, and inflammasome. In this review, we provide an overview of the potential interactions between gut microbiota and host immunity and how their crosstalk could synergistically regulate inflammation and CRC, thus highlighting the potential roles and mechanisms of gut microbiota in the development of microbiota-based therapies to prevent or alleviate colitis and CRC.

Comprehensive assessment of actionable genomic alterations in primary colorectal carcinoma using targeted next-generation sequencing

Background

The clinical utility of comprehensive genomic profiling (CGP) for guiding treatment has gradually become the standard-of-care procedure for colorectal carcinoma (CRC). Here, we comprehensively assess emerging targeted therapy biomarkers using CGP in primary CRC.

Methods

A total of 575 primary CRCs were sequenced by ACTOnco® assay for genomic alterations, tumour mutational burden (TMB), and microsatellite instability (MSI).

Results

Eighteen percent of patients were detected as MSI-High (MSI-H), and the remaining cases were classified as microsatellite stable (MSS). Driver mutation prevalence in MSS CRCs were APC (74%), TP53 (67%), KRAS (47%), PIK3CA (21%) and BRAF (13%). The median TMBs for MSI-H and MSS patients were 37.8 mutations per mega base (mut/Mb) and 3.9 mut/Mb, respectively. Forty-seven percent of MSI-H CRC harboured at least one loss-of-function mutations in genes that may hamper immune checkpoint blockade. Among MSS RAS/RAF wild-type CRCs, 59% had at least one actionable mutation that may compromise the efficacy of anti-EGFR therapy. For late-stage CRC, 51% of patients are eligible for standard care actionability and the remaining 49% could be enrolled in clinical trials with investigational drugs.

Conclusions

This study highlights the essential role of CGP for identifying rational targeted therapy options in CRC.

Human Epidermal Growth Factor Receptor 2-Targeting Approaches for Colorectal Cancer: Clinical Implications of Novel Treatments and Future Therapeutic Avenues

The treatment paradigm for colorectal cancer (CRC) has changed significantly over the past decade with targeted therapeutics. Human epidermal growth factor receptor 2 (HER2) amplification is seen among 3%-4% of patients with metastatic CRC (mCRC). The biological discovery of HER2 amplification in cancer cells has led to practice-changing drug development for several solid tumors, including breast, gastric, and esophageal cancers. HER2 amplification is now highly actionable in CRC with distinct therapeutic combinations, including the combination of monoclonal antibodies and HER2 receptor-specific tyrosine kinase inhibitors, as well as antibody-drug conjugates, that delivers targeted cytotoxic agents. However, it is essential to define the therapeutic role and sequence of these different combinations, some of which are already part of standard clinical practice. In this review article, we discuss recent clinical studies demonstrating the clinical benefits of each distinct therapeutic approach and their impacts on the current management of HER2-amplified mCRC. We also review ongoing clinical trials targeting the HER2 pathway in mCRC and elaborate on novel therapeutic opportunities in this space that may further define the changing paradigm of HER2-targeted therapy for CRC.

Comparison of Prognosis and Lymph Node Metastasis in T1-Stage Colonic and Rectal Carcinoma: A Retrospective Study

Background

Limited evidence and contradictory results have been reported regarding the impact of tumor site on lymph node metastasis (LNM) and prognosis in T1 stage adenocarcinoma (AC). We aimed to compare two anatomic locations in terms of LNM and prognosis using a comprehensive statistical analysis of a large population.

Methods

The Surveillance, Epidemiology, and End Results (SEER) database and our center (First Affiliated Hospital of Nanchang University) were used to extract patient information. Univariate and multivariate logistic or Cox regression and propensity score matching were used to explore the association between LNM/survival and tumor site.

Results

Information for 12,404 patients, including 9655 colonic AC and 2749 rectal AC patients, was extracted from the SEER database. The 516 AC patients included 184 colonic and 332 rectal AC patients from our center. Multivariate logistic regression analysis revealed a correlation between LNM and tumor site (colon vs rectum, odds ratio [OR] =1.52, 95% CI, 1.349–1.714, P<0.001). Additionally, we found that younger age, T1b stage, poor differentiation, and lymphatic invasion were risk factors for LNM. After adjusting for confounding factors by PSM, we found that the location of the rectum remained a higher risk factor for LNM. However, we found that patients diagnosed with rectal AC had a prognosis similar to that of patients diagnosed with colonic AC, which was demonstrated by the analysis of SEER data and data from our center.

Conclusion

T1-stage rectal AC may have a higher risk of LNM than colonic AC, while rectal AC has a prognosis similar to that of colonic AC.