Left-sided Primary Tumors Research Articles

KRASG12D-Mutated Metastatic Colorectal Cancer: Clinical, Molecular, Immunologic, and Prognostic Features of a New Emerging Targeted Alteration

PURPOSE KRASG12D mutation (mut) occurs in about 10%-12% of metastatic colorectal cancer (mCRC). Recently, novel KRASG12D inhibitors have been developed and are currently under investigation in phase I/II clinical trials in solid tumors including mCRC. We aimed at performing a comprehensive characterization of clinical, molecular, immunologic, and prognostic features of KRASG12D-mutated mCRC to inform the design and the interpretation of future trials. METHODS We performed a pooled analysis of phase III TRIBE and TRIBE2 studies comparing 5-fluorouracil, leucovorin, oxaliplatin, and irinotecan (FOLFOXIRI)/bevacizumab (bev) to doublets (5-fluorouracil, leucovorin, and oxaliplatin or 5-fluorouracil, leucovorin, and irinotecan)/bev. RESULTS One hundred and thirty-six (16%) of 854 patients with available KRASG12D mutational status were KRASG12D mutated. KRASG12D-mutated patients had more frequently right-sided primary tumor and were less likely to present liver-only metastases with respect to other RAS mutated and all-wild-type (wt) patients. Compared with the BRAFV600E-mutated group, KRASG12D-mutated patients had more frequently left-sided primary tumor, resected primary tumor at the time of diagnosis, and Eastern Cooperative Oncology Group performance status 0. KRASG12D-mutated patients had better prognosis than BRAFV600E-mutated and worse prognosis than all wt patients. No prognostic difference was evident between KRASG12D mut and other RAS mut patients overall or according to other specific KRAS or NRAS hotspot mutations. No interaction effect was observed between KRASG12D mut and the benefit provided by FOLFOXIRI/bev compared with doublets/bev. PIK3CA mut were reported more frequently among KRASG12D-mutated tumors compared with both other RAS mut and all wt. CONCLUSION A detail estimation of KRASG12D mut mCRC patients' characteristics and expected outcomes may be useful when planning future studies in this subgroup. The high prevalence of PI3K/PTEN/Akt pathway activating alterations may affect the efficacy of targeted strategies.

Is early-onset colorectal cancer an evolving pandemic? Real-world data from a tertiary cancer center.

Early onset Colorectal Cancer (EOCRC), defined as those diagnosed under the age of 50, has been increasing rapidly since 1970. UK data on EOCRC are currently limited and better understanding of the condition is needed. A single-center retrospective study of patients with EOCRC treated over 9 years (2013-2021) at a large UK cancer center was performed. Clinicopathological features, risk factors, molecular drivers, treatment, and survival were analyzed. In total, 203 patients were included. A significant increase in cases was reported from 2018-2019 (n = 33) to 2020-2021 (n = 118). Sporadic EOCRC accounted for 70% of cases and left-sided tumors represented 70.9% (n = 144). Median duration of symptoms was 3 months, while 52.7% of the patients had de-novo metastatic disease. Progression-free survival after first-line chemotherapy was 6 months (95% CI, 4.85-7.15) and median overall survival (OS) was 38 months (95% CI, 32.86-43.14). In the advanced setting, left-sided primary tumors were associated with a median OS benefit of 14 months over right-sided primaries (28 vs 14 months, P = .009). Finally, primary tumor resection was associated with median OS benefit of 21 months compared with in situ tumors (38 vs 17 months, P < .001). The incidence of EOCRC is increasing, and survival outcomes remain modest. Raising public awareness and lowering the age for colorectal cancer screening are directions that could improve EOCRC clinical outcomes. There is also a need for large prospective studies to improve the understanding of the nature of EOCRC and the best therapeutic approaches.

Patterns of recurrence after curative intent hepatic resection for colorectal liver metastasis

BackgroundImproved surgical techniques and more intensive systemic therapy have increased the number of patients with oligometastatic colorectal cancer eligible for resection, but a significant percentage of these cases will ultimately recur. Furthermore, distinct recurrence patterns have been associated with different outcomes. MethodsData for 195 patients who underwent curative-intent colorectal liver metastasis (CRLM) resection between 2016 and 2022 at Johns Hopkins Hospital were retrospectively collected. Cox regression univariate and multivariate analyses identified features associated with survival outcomes. Association between risk factors and site of recurrences was conducted via logistic regression with initial recurrences grouped into intrahepatic-only, extrahepatic-only, and concurrent intra- and extrahepatic recurrence. ResultsThe 1- and 2-year recurrence-free survival (RFS) rates were 46% and 22%, respectively. The 1- and 2-year overall survival (OS) rates were 95% and 88%, respectively. The median OS was 71.7 months. Multivariate analysis identified age <60 years, N2 nodal status, R1 liver margin, and higher preoperative carcinoembryonic antigen as top prognostic factors for worse RFS. Additionally, patients with left-sided primary tumors had a higher risk of intrahepatic-only recurrence, whereas mutant KRAS was associated with a higher risk of extrahepatic recurrence with or without liver recurrence. ConclusionThese results from a recent cohort of patients treated with current standard-of-care therapies identify features associated with elevated risk and specific patterns of recurrence. These insights into CRLM recurrence patterns support a larger prospective study to identify subgroups of patients who may require additional therapies to prevent recurrence.

Impact of primary tumor sidedness and sex on prognosis and anti-epidermal growth factor receptor antibody efficacy in BRAF-mutant metastatic colorectal cancer: a pooled analysis of AIO studies FIRE-1, CIOX, FIRE-3, XELAVIRI, and VOLFI

Primary tumor (PT) sidedness is an established prognostic marker in metastatic colorectal cancer (mCRC) and has a predictive impact on the efficacy of anti-epidermal growth factor receptor (anti-EGFR) antibody [monoclonal antibody (mAb)] in patients with RAS wild-type mCRC. This investigation focuses on patients with BRAFV600E-mutated (BRAFmt) mCRC and examines the efficacy of anti-EGFR mAbs in relation to primary tumor sidedness (PTS). This pooled analysis was carried out using individual patient data from five randomized studies in the first-line setting of mCRC. The population of interest was limited to patients with BRAFmt mCRC and known PTS. For analysis, treatment was stratified into two groups: those treated with anti-EGFR mAbs and those without. Dichotomous variables, such as overall response rate and objective response rate (ORR), were compared using chi-square or Fisher's exact test. Time-to-event endpoints [progression-free survival (PFS) and overall survival (OS)] were analyzed using the Kaplan-Meier method, log-rank test, and Cox regression. An interaction test was carried out via Cox regression. A total of 102 patients with BRAFmt mCRC were identified. The type of targeted therapy (anti-EGFR-based versus non-anti-EGFR) did not significantly impact the outcome. However, in patients with left-sided primary tumors, anti-EGFR mAb-based treatment, compared with non-anti-EGFR, was associated with a higher ORR (58% versus 34%; P < 0.01), trended toward improved PFS [hazard ratio (HR) 0.62; 95% confidence interval (CI) 0.34-1.13; P= 0.12], and demonstrated prolonged OS (HR 0.38; 95% CI 0.20-0.72; P < 0.01). In patients with right-sided primary tumors, anti-EGFR-based therapy had no effect on ORR (33% versus 36%; P > 0.99), induced inferior PFS (HR 1.97; 95% CI 1.12-3.47; P= 0.02), and trended toward a worse OS (HR 1.76; 95% CI 0.99-3.13; P= 0.05). This analysis suggests that PTS has predictive value for the efficacy of anti-EGFR mAb in the first-line treatment of BRAFmt mCRC.

The molecular landscape of PIWIL1 expression in colorectal adenocarcinoma (CRC).

3546 Background: PIWIL1 is a cancer testis antigen overexpressed in solid tumors, particularly CRC, and is associated with advanced stage and poor prognosis. It is potentially a new therapeutic target as PIWIL1 is not expressed in adult somatic tissue. A novel T cell receptor/PIWIL1 bispecific antibody is in development, restricted to individuals with human leukocyte antigen (HLA) A-02. We sought to characterize the molecular landscape of PIWIL1 in CRC. Methods: 26,581 CRC tumors were tested by next-generation sequencing (NGS) on DNA (592-gene or whole exome [WES]) and RNA (whole transcriptome [WTS]) at Caris Life Sciences (Phoenix, AZ). dMMR/MSI-H was tested by immunohistochemistry (IHC) and NGS, HLA genotypes by WES and PD-L1 by IHC (SP142, 2+, 5%). Tumor mutational burden (TMB) high was defined as ≥ 10 mt/Mb. RNA expression was used to estimate the tumor microenvironment using QuantiSEQ and RNA signatures (interferon gamma [IFNγ]; T-cell inflamed [TIS]) predictive of immune checkpoint blockade (IO) response. The top (H) and bottom (L) quartiles of PIWIL1 expression were compared using Chi-square/Fisher-Exact, and significance was determined as p adjusted for multiple comparisons (Q&lt;0.05). Real-world overall survival (rwOS) was obtained from insurance claims and calculated from tissue collection to last contact. Results: Patients with PIWIL1-H were older (median age 65 v 61, Q&lt;0.01) and more likely to be female (50.8% v 41.3%, Q&lt;0.01), compared to PIWIL1-L. PIWIL1 median expression was higher in right- v left-sided primary tumors (2.0 v 1.3 transcripts per million [TPM], Q&lt;0.05). No significant difference in PIWIL1 expression was observed among HLA genotypes. dMMR/MSI-H, TMB-H and PD-L1+ were higher in PIWIL1-H v PIWIL1-L (13.9% v 6.5%, 17.6% v 10.4%, 6.4% v 3.4%, all Q&lt;0.05). IO-related gene expression ( LAG3, IDO1, CTLA4 and others) were positively associated with PIWIL1 expression (fold change [FC]: 1.4-2.7, Q&lt;0.05). High IFNγ and TIS were associated with PIWIL1-H (Q&lt;0.001). PIWIL1 expression showed a positive association with infiltration of neutrophils, monocytes, CD4+T, dendritic and NK cells (FC: 1.3-2.9, Q&lt;0.05) while Tregs and M1 macrophages had a negative association (0.8-0.9, Q&lt;0.05). In pMMR/MSS CRC, KRAS, BRAF and TP53 mutations and loss of heterozygosity were higher in PIWIL1-H v PIWIL1-L (81% v 69%, 53% v 41%, 16% v 3%, 14% v 10%, all Q&lt;0.05) but not for PIK3CAmutations (14% v 17%). For rwOS, PIWIL1-H had longer median OS than PIWIL1-L, 31.2 v 28.8 months (HR 0.95; 95% CI 0.90-0.99, p=0.043). There was no significant rwOS difference observed in IO-treated tumors. Conclusions: PIWIL1-H CRC is associated with higher rates of dMMR/MSI-H, TMB-H and PD-L1+ as well as IO-related gene expression and signatures that are predictive of response to IO. These data suggest the PIWIL1-H subpopulation could potentially derive substantial benefit from PIWIL1-targeted immunotherapy which should be evaluated in clinical trials.

Abstract 925: Continuing anti-EGFR treatment prolonged survival in mCRC patients receiving conversion liver resection

Abstract Introduction: Anti-EGFR monoclonal antibody plus doublet chemotherapy is the mainstay of first-line treatment of RAS/BRAF wild-type metastatic colorectal cancer (mCRC) patients. Some of these patients might undergo secondary resection. However, there is no standardized suggestion on whether colorectal cancer liver metastasis patients should keep target therapy after secondary resection. NCCN guidelines suggest chemotherapy only in patients receiving primary liver resection. Whether we could spare the use of target therapy after secondary resection is the main aim of our study. Methods: Using Taiwan's National Health Insurance Research Database, we established a cohort of KRAS wild-type mCRC patients treated with first-line anti-EGFR therapy plus doublet chemotherapy between 2013 and 2018. Secondary surgery was defined as either resection of liver metastases or radiofrequency ablation. Results: 5694 stage IV mCRC patients received anti-EGFR MAb plus doublet chemotherapy as a first-line treatment between 2013 and 2018. 174 patients were enrolled in the final analysis, with 153 continuing anti-EGFR MAb after secondary resection and 21 patients without anti-EGFR MAb. Compared with those who without anti-EGFR therapy after secondary resection, patients who continued anti-EGFR MAb exhibited significantly longer overall survival (OS; median, 43.8 vs. 31.9 months, p = 0.031) but not in time to treatment failure (TTF; median, 22.2 vs. 26.6 months, p = 0.841). The OS benefits of continuing anti-EGFR MAb remained regardless of left-sided or right-sided primary tumors (40.9 vs. 43.0 months, p = 0.980). The patient cohort from 2016 to 2018 showed more prolonged survival than from 2012 to 2015 (not reached vs. 40.450, p = 0.0305). TTF has no statistical difference when considering patient cohort or primary tumor location. In multivariate analyses, continuing first-line anti-EGFR MAb therapy after secondary resection remained an independent predictor of longer OS. Conclusion: For mCRC patients who received secondary resection after first-line anti-EGFR and doublet chemotherapy, continuing anti-EGFR MAb after resection was associated with significantly longer OS regardless of primary tumor sidedness. Citation Format: Yao-Yu Hsieh, Chin-Wen Tsai, T-CARE Group, Yi-Hsieh Liang. Continuing anti-EGFR treatment prolonged survival in mCRC patients receiving conversion liver resection [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 925.

Fluoropyrimidine type, patient age, tumour sidedness and mutation status as determinants of benefit in patients with metastatic colorectal cancer treated with EGFR monoclonal antibodies: individual patient data pooled analysis of randomised trials from the ARCAD database

BackgroundKRAS mutations in metastatic colorectal cancer (mCRC) are used as predictive biomarkers to select therapy with EGFR monoclonal antibodies (mAbs). Other factors may be significant determinants of benefit.MethodsIndividual patient data from randomised trials with a head-to-head comparison between EGFR mAb versus no EGFR mAb (chemotherapy alone or best supportive care) in mCRC, across all lines of therapy, were pooled. Overall survival (OS) and progression-free survival (PFS) were compared between groups. Treatment effects within the predefined KRAS biomarker subsets were estimated by adjusted hazard ratio (HRadj) and 95% confidence interval (CI). EGFR mAb efficacy was measured within the KRAS wild-type subgroup according to BRAF and NRAS mutation status. In both KRAS wild-type and mutant subgroups, additional factors that could impact EGFR mAb efficacy were explored including the type of chemotherapy, line of therapy, age, sex, tumour sidedness and site of metastasis.Results5675 patients from 8 studies were included, all with known mCRC KRAS mutation status. OS (HRadj 0.90, 95% CI 0.84–0.98, p = 0.01) and PFS benefit (HRadj 0.73, 95% CI 0.68–0.79, p < 0.001) from EGFR mAbs was observed in the KRAS wild-type group. PFS benefit was seen in patients treated with fluorouracil (HRadj 0.75, 95% CI 0.68–0.82) but not with capecitabine-containing regimens (HRadj 1.04, 95% CI 0.86–1.26) (pinteraction = 0.002). Sidedness also interacted with EGFR mAb efficacy, with survival benefit restricted to left-sided disease (pinteraction = 0.038). PFS benefits differed according to age, with benefits greater in those under 70 (pinteraction = 0.001). The survival benefit was not demonstrated in those patients with mutations found in the KRAS, NRAS or BRAF genes. The presence of liver metastases interacted with EGFR mAb efficacy in patients with KRAS mutant mCRC (pinteraction = 0.004).ConclusionThe benefit provided by EGFR mAbs in KRAS WT mCRC is associated with left-sided primary tumour location, younger patient age and absence of NRAS or BRAF mutations. Survival benefit is observed with fluorouracil but not capecitabine. Exploratory results support further research in KRAS mutant mCRC without liver metastases.

Baseline ctDNA gene alterations as a biomarker of survival after panitumumab and chemotherapy in metastatic colorectal cancer.

Certain genetic alterations and right-sided primary tumor location are associated with resistance to anti-epidermal growth factor (EGFR) treatment in metastatic colorectal cancer (mCRC). The phase 3 PARADIGM trial (n = 802) demonstrated longer overall survival with first-line anti-EGFR (panitumumab) versus antivascular endothelial growth factor (bevacizumab) plus modified FOLFOX6 in patients with RAS wild-type mCRC with left-sided primary tumors. This prespecified exploratory biomarker analysis of PARADIGM (n = 733) evaluated the association between circulating tumor DNA (ctDNA) gene alterations and efficacy outcomes, focusing on a broad panel of gene alterations associated with resistance to EGFR inhibition, including KRAS, NRAS, PTEN and extracellular domain EGFR mutations, HER2 and MET amplifications, and ALK, RET and NTRK1 fusions. Overall survival was prolonged with panitumumab plus modified FOLFOX6 versus bevacizumab plus modified FOLFOX6 in patients with ctDNA that lacked gene alterations in the panel (that is, negative hyperselected; median in the overall population: 40.7 versus 34.4 months; hazard ratio, 0.76; 95% confidence interval, 0.62-0.92) but was similar or inferior with panitumumab in patients with ctDNA that contained any gene alteration in the panel (19.2 versus 22.2 months; hazard ratio, 1.13; 95% confidence interval, 0.83-1.53), regardless of tumor sidedness. Negative hyperselection using ctDNA may guide optimal treatment selection in patients with mCRC. ClinicalTrials.gov registrations: NCT02394834 and NCT02394795 .

Real-world clinical efficacy of epidermal growth factor receptor inhibitors (EGFRi) in patients with early-onset (eo), metastatic colorectal cancer (mCRC).

36 Background: The incidence of eo CRC (age of onset: &lt;50 years) is rising globally, although specific reasons remain unknown. In a prior study using the ARCAD database, the addition of EGFRi to chemotherapy (chemo) significantly improved progression-free survival (PFS) in late-onset (lo) KRAS wild-type (wt) left-sided mCRC patients (pts); however, no such effect was observed in eo mCRC pts (Jin Z et al., 2022). Methods: This retrospective study used the nationwide Flatiron Health electronic health record-derived de-identified database of adult patients diagnosed with mCRC on/after January 1, 2013 with data cut-off on June 30, 2023. The cohort included pts with RAS/BRAF wt and left-sided primary tumors who were treated with first-line (1L) chemo+EGFRi, chemo+bevacizumab (bev), or chemo alone. Associations of disease onset and 1L therapy with real-world overall survival and time to next treatment (rwOS, rwTTNT) were assessed using Kaplan-Meier methods and hazard models adjusted for clinical confounders including year of metastatic diagnosis, group stage at initial diagnosis, site of disease, gender, race/ethnicity, and ECOG performance status. Results: Among 895 left-sided RAS/BRAF wt mCRC pts, 216 and 679 pts had eo and lo mCRC, respectively. In pts treated with chemo+EGFRi vs chemo alone, the adjusted hazard ratio (HR) (95% CI) of rwTTNT was 0.93 (0.56-1.53) and 0.77 (0.58-1.02) for eo and lo pts, respectively; the adjusted HR (95% CI) of rwOS was 0.96 (0.51-1.83) and 0.78 (0.57-1.07) in eo and lo pts, respectively. In pts treated with chemo+bev vs chemo alone, the adjusted HR (95% CI) of rwTTNT was 1.00 (0.62-1.60) and 0.75 (0.58-0.97) for eo and lo pts, respectively; the adjusted HR (95% CI) of rwOS was 0.97 (0.54-1.75) and 0.78 (0.58-1.03) in eo and lo pts, respectively. Conclusions: Adding EGFRi to chemotherapy suggested potential improvements in rwTTNT and rwOS in lo pts but not in eo pts, similar to findings from the prior ARCAD database study. Such differences in outcomes, similarly observed in pts treated with chemo+bev, underscore the need for tailored therapeutic strategies. Given the wide confidence intervals in this study, future research with larger patient cohorts or longer follow-up may yield more precise estimates of these differences. [Table: see text]

Surveillance of resected metastatic colorectal cancer utilizing circulating DNA.

214 Background: There is limited data to guide surveillance in patients with metastatic colorectal cancer (CRC) who have had curative resection using circulating tumor DNA (ctDNA) in addition to labs and imaging studies. Minimal residual disease (MRD) assays utilize circulating tumor DNA (ctDNA) for the purposes of monitoring for early recurrence and predicting therapeutic response. In this study, we aim to investigate the utility of ctDNA monitoring in the setting of resected metastatic CRC. Methods: Patients were identified through retrospective search at a tertiary care and several satellite settings to identify patients with metastatic CRC who had undergone curative resection and later had ctDNA monitoring (using Signatera assay). IRB approval was obtained for the study. We recorded demographic information (sex, race, age at diagnosis), disease characteristics (stage at diagnosis, site of primary cancer, site of metastasis), treatment regimens, clinical outcomes (recurrence, survival) and follow-up data. Our primary outcome was to evaluate the rate of recurrence in patients with metastatic CRC who had curative resection in two different population, ctDNA positive or ctDNA negative, post-surgery. Results: We identified 35 patients with a median age of 55 years (range 31 – 82) at the time of metastatic diagnosis. In this study cohort, 20 (57%) were female; 23 (66%) were white, and 10 (29%) were African American. 22 (63%) patients had left-sided primary tumors and the remaining (47%) had right-sided primary tumors. At the time of presentation, 23 (66%) patients had synchronous metastases and 12 (34%) developed metachronous metastases. ctDNA positivity was reported in 21 (60%) pts post-curative therapy. Median time from curative therapy to ctDNA positivity was 62 days. 22 (63%) pts experienced recurrence of disease post-curative resection. Median time to recurrence after ctDNA test was first positive was 6.6 months. Among 21 patients in ctDNA positive group, 19 (86%) developed recurrences and among 14 ctDNA negative patients, only 3 (21%) developed recurrences (p-value &lt;0.01). Recurrence free survival was significantly shorter in patients who were ctDNA positive post surgery (Median RFS: 7.17 months, 95% CI: 4.4-18.0 months) compared to those who were ctDNA negative (Median RFS: 30.8 months; 95% CI: 12.6-NR) (p-value=0.005). Conclusions: In patients with metastatic CRC who underwent curative resection ctDNA may have utility in predicting disease recurrence at both academic and community sites. Larger studies are needed for validation of ctDNA as an adjunct test for surveillance in broader population.

Nonoperative management of the primary tumor in patients with unresectable stage IV colon cancer treated with systemic chemotherapy: Higher complication rates for left-sided colon tumors

IntroductionTreatment of the primary tumor in asymptomatic patients with unresectable colorectal metastases remains controversial. MethodsData from patients with synchronous stage IV colon cancer and an untreated primary tumor who started treatment aimed at metastatic disease at a specialized cancer center between 2014 and 2018 were analyzed retrospectively. Main outcome was primary tumor-related complications comparing left-sided and right-sided colon cancer. A competing-risk regression model was used to identify predictors of complications. ResultsOf 523 patients with metastatic colon cancer at presentation, 221 started treatment aimed at metastatic disease; these patients constituted the study cohort. The primary tumor was left-sided in 109 patients (49%) and right-sided in 112 patients (51%). In total, 46 patients (21%) developed a complication that required invasive intervention. Complications occurred more frequently in patients with left-sided tumors than in patients with right-sided tumors (29% vs 13%, P = 0.003). Eighteen patients (8%) underwent non-surgical intervention. Six patients (33%) failed non-surgical management and underwent surgery. Of 34 patients (15%) who underwent surgical intervention, 20 underwent an emergency colectomy and 14 underwent diversion with a permanent stoma. Overall, 10% of patients ended up with a permanent stoma. In competing-risk analysis, only left-sided primary tumor (hazard ratio 2.62; 95% CI 1.40–4.89; P = 0.003) was significantly associated with primary tumor-related complications requiring invasive intervention. ConclusionsPatients with asymptomatic metastatic left-sided tumors have a higher risk for primary tumor-related complications than patients with right-sided tumors. Close monitoring and early surgical rescue should be considered for patients with left-sided colon cancer who are managed nonoperatively.

Postoperative morbidity after simultaneous versus staged resection of synchronous colorectal liver metastases: Impact of hepatic tumor burden

BackgroundWe sought to characterize the risk of postoperative complications relative to the surgical approach and overall synchronous colorectal liver metastases tumor burden score. MethodsPatients with synchronous colorectal liver metastases who underwent curative-intent resection between 2000 and 2020 were identified from an international multi-institutional database. Propensity score matching was employed to control for heterogeneity between the 2 groups. A virtual twins analysis was performed to identify potential subgroups of patients who might benefit more from staged versus simultaneous resection. ResultsAmong 976 patients who underwent liver resection for synchronous colorectal liver metastases, 589 patients (60.3%) had a staged approach, whereas 387 (39.7%) patients underwent simultaneous resection of the primary tumor and synchronous colorectal liver metastases. After propensity score matching, 295 patients who underwent each surgical approach were analyzed. Overall, the incidence of postoperative complications was 34.1% (n = 201). Among patients with high tumor burden scores, the surgical approach was associated with a higher incidence of postoperative complications; in contrast, among patients with low or medium tumor burden scores, the likelihood of complications did not differ based on the surgical approach. Virtual twins analysis demonstrated that preoperative tumor burden score was important to identify which subgroup of patients benefited most from staged versus simultaneous resection. Simultaneous resection was associated with better outcomes among patients with a tumor burden score <9 and a node-negative right-sided primary tumor; in contrast, staged resection was associated with better outcomes among patients with node-positive left-sided primary tumors and higher tumor burden score. ConclusionAmong patients with high tumor burden scores, simultaneous resection of the primary tumor and liver metastases was associated with an increased incidence of postoperative complications.

The Effects of Primary Tumor Location on Survival after Liver Resection for Colorectal Liver Metastasis in the Mediterranean Population.

(1) Background: There is an abundance of literature available on predictors of survival for patients with colorectal liver metastases (CRLM) but minimal information available on the relationship between the primary tumor location and CRLM survival. The studies that focus on the primary tumor location and CRLM survival exhibit a great deal of controversy and inconsistency with regard to their results (some studies show statistically significant connections between the primary tumor location and prognosis versus other studies that find no significant relationship between these two factors). Furthermore, the majority of these studies have been conducted in the West and have studied more diverse and heterogenous populations, which may be a contributing factor to the conflicting results. (2) Methods: We included patients who underwent liver resection for CRLM between December 2004 and January 2019 at two university-affiliated medical centers in Israel: Carmel Medical Center (Haifa) and Rabin Medical Center (Petach Tikvah). Primary tumors located from the cecum up to and including the splenic flexure were labeled as right-sided primary tumors, whereas tumors located from the splenic flexure down to the anal verge were labeled as left-sided primary tumors. (3) Results: We identified a total of 501 patients. Of these patients, 225 had right-sided primary tumors and 276 had left-sided primary tumors. Patients with right-sided tumors were significantly older at the time of liver surgery compared to those with left-sided tumors (66.1 + 12.7 vs. 62 + 13.1, p = 0.002). Patients with left-sided tumors had slightly better overall survival rates than those with right-sided tumors. However, the differences were not statistically significant (57 vs. 50 months, p = 0.37 after liver surgery). (4) Conclusions: The primary tumor location does not significantly affect patient survival after liver resection for colorectal liver metastasis in the Mediterranean population.

Treatment outcome comparisons of first-line targeted therapy in patients with KRAS wild-type metastatic colorectal cancer: A nationwide database study.

The first-line systemic therapy for metastatic colorectal cancer (mCRC) is a combination of one targeted therapy agent and a chemotherapy doublet. Whether bevacizumab or anti-epidermal growth factor receptor (anti-EGFR) monoclonal antibody (mAb) is the more effective addition to a chemotherapy doublet as the first-line treatment for inoperable KRAS wild-type mCRC remains controversial in prior clinical trials. Moreover, the association between the sidedness of primary tumors and the efficacy of anti-EGFR mAb needs to be addressed. We established a cohort of patients with KRAS wild-type mCRC who were treated with first-line targeted therapy plus doublet chemotherapy between 2013 and 2018 using Taiwan's National Health Insurance Research Database. Secondary surgery was defined as either resection of primary tumors, liver metastases, lung metastases, or radiofrequency ablation. A total of 6482 patients were included; bevacizumab and anti-EGFR mAb were the first-line targeted therapies in 3334 (51.4%) and 3148 (48.6%) patients, respectively. Compared with those who received bevacizumab, patients who received anti-EGFR mAb exhibited significantly longer overall survival (OS; median, 23.1 vs. 20.2 months, p = 0.012) and time to treatment failure (TTF; median, 11.3 vs. 10 months, p < 0.001). Among left-sided primary tumors, the OS and TTF benefits of anti-EGFR mAb remained. Among right-sided primary tumors, the OS and TTF were similar regardless of the type of targeted therapy. In multivariate analyses, first-line anti-EGFR mAb therapy remained an independent predictor of longer OS and TTF for left-sided primary tumors. Patients who received anti-EGFR mAb were more likely to receive secondary surgery (29.6% vs. 22.6%, p < 0.0001) than patients who received bevacizumab. For patients who received first-line doublet chemotherapy for KRAS wild-type mCRC, adding anti-EGFR mAb was associated with significantly longer OS and TTF, especially for left-sided primary tumors.

Modified FOLFOXIRI plus cetuximab and avelumab as initial therapy in RAS wild-type unresectable metastatic colorectal cancer: Results of the phase II AVETRIC trial by GONO.

3575 Background: The modified schedule of FOLFOXIRI (mFOLFOXIRI) in combination with an anti-EGFR agent showed a manageable safety profile and remarkable activity in RAS wild-type (wt) metastatic colorectal cancer (mCRC). The association of an active cytotoxic regimen with cetuximab (cet) may increase the exposure of tumour-associated neoantigens and induce immunogenic cell death and antibody-dependent cell-mediated cytotoxicity thus enabling the effect of immune checkpoint inhibitors. The AVETRIC study aimed at exploring the efficacy and safety of first-line mFOLFOXIRI plus cet and avelumab (ave) in RAS wt mCRC patients (pts). Methods: AVETRIC is a prospective, open label, multicenter, phase II, single arm trial in which initially unresectable and previously untreated RAS wt mCRC pts received mFOLFOXIRI (irinotecan 150 mg/sqm, oxaliplatin 85 mg/sqm, folinate 200 mg/sqm leucovorin [LV], and 5-fluorouracil [5FU] 2400 mg/sqm) plus cet (500 mg/sqm) and ave (800 mg) every 2 weeks up to 12 cycles followed by maintenance with 5FU/LV plus cet and ave until disease progression. A safety run-in phase including the first 6 enrolled pts was planned. Due to the occurrence of grade 3-4 diarrhoea in 2 (33%) pts, the protocol study was amended to reduce the irinotecan dose to 130 mg/sqm. Primary endpoint was Progression Free Survival (PFS). Fifty-eight pts were needed to detect an increase in median PFS (mPFS) from 10.0 to 19.4 months (mos), setting one-sided α and β errors at 0.05 and 0.10, respectively. The trial is registered at Clinicaltrial.gov, NCT04513951. Results: Between Jun 2020 and Dec 2021, 62 pts were enrolled in 16 Italian centres. Main pts' characteristics were: median age 56 yrs, ECOG PS 0 87%, synchronous metastases 94%, liver-only disease 42%, left-sided primary tumour 89%; all pts had BRAF wt and proficient MMR (pMMR) tumours. The primary endpoint was met. At a median follow-up of 16.0 months, 39 (63%) events were recorded and mPFS was 14.1 months (90% CI 12.0-16.7, Brookmeyer-Crowley test p &lt; 0.001). Response rate and disease control rate were 82% and 98%, respectively, and R0 resection rate was 21% (27% in liver-only subgroup). Early tumour shrinkage was achieved in 74% pts and median deepness of response was 56%. In pts treated after study amendment (n = 56), main grade 3-4 adverse events were neutropenia (27%), diarrhoea (27%), skin rash (14%), asthenia (14%), nausea (11%), stomatitis (7%), febrile neutropenia (2%). Grade 3-4 immune-related adverse events occurred in 6% of pts. Overall survival results are still immature. Conclusions: AVETRIC study met its primary endpoint, showing that combining mFOLFOXIRI plus cet and ave achieves promising results in terms of PFS as well as response rate, in pts with pMMR RAS and BRAF wt mCRC. Translational analyses to evaluate the impact of immune-related biomarkers are ongoing. Clinical trial information: NCT04513951 .

Abstract 1177: Genomic characteristics and clinical outcomes of early onset colorectal cancer (EOCRC): Findings from AACR Project GENIE Biopharma Collaborative registry

Abstract Background: By 2030, the incidence of EOCRC is predicted to increase by more than 140%. A better understanding of the molecular features of EOCRC is needed. Methods: The AACR GENIE Biopharma Collaborative CRC 1.2-consortium dataset consists of clinical and genomic data from a cohort of CRC patients (pts) with next generation tumor sequencing (55-500 genes) from 2015 to 2017 at three academic centers. Imaging reports and medical oncology notes were retrospectively curated. EOCRC was defined as age at diagnosis &amp;lt; 50 years; while later onset CRC (LOCRC) as ≥ 50 years. Association with clinical variables was analyzed using Chi-Square or Fisher’s exact test. Associations with genomic alterations were analyzed using the Benjamini-Hochberg procedure for multiple testing; the associations were evaluated among the overall study population and by stage. Kaplan-Meier method was used to estimate the median overall survival (OS) and was adjusted to left truncation bias introduced by the inclusion criteria for this project. Results: A total of 1507 pts with CRC, 519 (34%) with EOCRC, were analyzed. EOCRC pts were more likely to be diagnosed with Stage IV than LOCRC (51% vs 44%, p&amp;lt;0.01). Left-sided primary tumors were more frequent in EOCRC (73% vs 57%, p&amp;lt;0.01). Among stage I-III, EOCRC was associated with longer OS compared to LOCRC (HR:1.43, 95%CI 1.07-1.91, p=0.01). Among stage IV CRC, no differences were observed in OS between EOCRC and LOCRC in a multivariate analysis including RAS/BRAF mutation (mt), MSI and liver, lung and peritoneal metastasis (HR: 1.01, 95% CI 0.8-1.28, p=0.92). The proportion of BRAF mt was higher in LOCRC (15 vs 7%, p&amp;lt;0.01), mainly in stage I-III (17% vs 7%, p=0.01). This association is significant after adjusting for tumor sidedness (OR: 1.77 95% CI 1.19-2.63, p&amp;lt;0.01). BRAF V600E mt is more frequent in LOCRC (11 vs 3%, p&amp;lt;0.01). APC and PI3KCA mt are more common in EOCRC, but only among right-sided tumors. There were not significant differences in copy number alterations or structural variants. APC, TP53, KRAS, BRAF and PI3KCA were analyzed according to stage. Among EOCRC, TP53 mt was more frequent in stage IV vs I-III (79 vs 70%, p=0.02). In LOCRC, both TP53 (76% vs 69%, p=0.01) and KRAS mt (47 vs 38%, p&amp;lt;0.01) were more frequent in stage IV vs I-III. Effect modification of the association between these genes and OS by age of onset was explored using an interaction test in stage IV and I-III. APC mt in stage I-III conferred better prognosis in EOCRC (HR 0.31 (0.18-0.51) for EOCRC; HR 0.72 (0.51-1.01) for LOCRC; interaction p&amp;lt;0.01). Conclusions: EOCRC does not show significant genomic differences from LOCRC except for lower frequency of BRAF mt. For right-sided tumors, APC and PI3KCA mt are more common in EOCRC. APC mt in stage I-III is associated with a better prognosis in EOCRC. Further characterization of the biology of EOCRC beyond genomic profiling is needed. Citation Format: Enrique Sanz Garcia, Eric Chen, Marios Giannakis, Gregory J. Riely, Jeremy L. Warner, Michele L. LeNoue-Newton, Jessica Weiss, Katrina Hueniken, Kenneth L. Kehl, Deborah Schrag, Andrea Cercek, Kimmie Ng, AACR GENIE BPC Core Team . Genomic characteristics and clinical outcomes of early onset colorectal cancer (EOCRC): Findings from AACR Project GENIE Biopharma Collaborative registry [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1177.

Association of primary tumor location with long-term oncological prognosis following hepatectomy for hepatocellular carcinoma:A multicenter propensity score matching analysis

PurposeThere is a striking laterality in the site of hepatocellular carcinoma (HCC), with a strong predominance for the right side; however, the impact of primary tumor location on long-term prognosis after hepatectomy of HCC remains unclear. This study aimed to investigate the effect of primary tumor location on long-term oncological prognosis after hepatectomy for HCC. Patients and methodsData of consecutive patients undergoing curative hepatectomy for HCC between 2008 and 2017 were analyzed. Overall survival (OS) and recurrence-free survival (RFS) of left-sided HCC (LS group) and right-sided HCC (RS group) were compared by using propensity score matching (PSM) analysis. COX regression analysis was performed to assess the adjusted effect of tumor location on long-term oncological prognosis. ResultsOf the 2799 included patients, 707 (25.3%) and 2092 (74.7%) were in the LS and RS groups, respectively. Using PSM analysis, 650 matched pairs of patients were created. In the PSM cohort, median OS (66.0 vs. 72.0 months, P = 0.001) and RFS (28.0 vs. 51.0 months, P < 0.001) were worse among patients in the LS group compared to individuals in the RS group. After further adjustment for other confounders using multivariable COX regression analyses, HCC located on the left side remained independently associated with worse OS and RFS. ConclusionTumors located on the left side are associated with poorer OS and RFS after hepatectomy for HCC. Careful surgical options selection and frequent follow-up to improve long-term survival may be justified for HCC patients with left-sided primary tumors.

Sidedness and addition of chemotherapy associated with treatment outcomes of regorafenib for metastatic colorectal cancer (mCRC).

36 Background: Regorafenib is one of the options of salvage treatment for mCRC. We aimed to explore the prognostic factors of such regorafenib treatment. Methods: We searched the database of National Health Insurance, Taiwan for patients who initiated regorafenib treatment for mCRC from September 1, 2015, to December 31, 2018. Database interrogation of National Death Registry, Taiwan and Taiwan Cancer Registry was conducted for survival data and clinicopathological variables, respectively. Results: A total of 3,643 patients were included in the analysis. The median age was 61.2 years. The primary tumor was left-sided and KRAS mutant in 75.3% and 54.5% of patients, respectively; 28.9% of patients received chemotherapy simultaneously, with irinotecan as the most common companion. The median time to treatment discontinuation (TTD) was 2.3 months (95% confidence interval [CI]: 95% CI: 2.3-2.3), and the median overall survival (OS) was 7.2 months (95% CI: 6.9-7.4). Patients with left-sided primary tumors, compared with patients with right-sided tumors, exhibited significantly longer TTD (median, 2.4 vs. 2.1 months, p &lt; 0.001) and OS (median, 7.6 vs. 6.1 months, p &lt; 0.001). By contrast, TTD and OS of patients under regorafenib treatment were similar regardless the KRAS mutation status ( p = 0.415 and 0.643, respectively). Patients who received chemotherapy along with regorafenib, compared with patients who did not, also exhibited significantly longer TTD (median, 2.6 vs. 2.2 months, p &lt; 0.001) and OS (median, 8.3 vs. 6.7 months, p &lt; 0.001). In multivariate analysis adjusting age, sex, time from colorectal cancer diagnosis, hospital level, KRAS mutation, and initial regorafenib dose, left-sidedness of the primary tumor remained a predictor for better TTD (hazard ratio [HR]: 0.88, p = 0.002) and OS (HR: 0.92, p = 0.048), as well as addition of chemotherapy (for TTD, HR: 0.86, p &lt; 0.001; for OS, HR: 0.76, p &lt; 0.001). Due to the interaction between sidedness and KRAS mutation, we established separate Cox models and found that left-sided primary tumor was an independent predictor for better TTD and OS for KRAS wild-type tumors, but not for KRAS mutant tumors. Conclusions: In this population-wide cohort study, left-sided primary tumor and addition of chemotherapy were associated with better TTD and OS of regorafenib treatment for mCRC.

A phase II single-arm study of the FGFR inhibitor pemigatinib in patients with metastatic colorectal cancer (mCRC) harboring FGF/FGFR alterations.

139 Background: The fibroblast growth factor receptor (FGFR) pathway plays a key role in cellular proliferation, migration, survival and angiogenesis. Aberrant signaling through FGFR in colorectal cancer and other malignancies results from gene amplification or mutation, chromosomal translocation or ligand-dependent activation of the receptors. Pemigatinib is an oral inhibitor of FGFR1-3 with proven efficacy in FGFR-altered cholangiocarcinoma and myeloid/lymphoid neoplasms, among others. We hypothesized that pemigatinib would improve response rates compared to historical controls in patients with refractory FGF/FGFR-altered mCRC. Methods: ACCRU-GI-1701 was a multicenter, single-arm, Simon’s two-stage phase II clinical trial (NCT04096417) of the FGFR inhibitor pemigatinib in patients (pts) with FGF/FGFR-altered mCRC. Eligible pts had received prior fluoropyrimidine, oxaliplatin, irinotecan, and anti-VEGF/anti-EGFR/anti-PD-1 if eligible. Pts received pemigatinib 13.5 mg once daily on d1-21 of each cycle, with option to escalate to 18 mg in c2 if well tolerated. The primary endpoint was (unconfirmed) objective response (OR). A sample size of 21 evaluable pts would provide 82% power to detect a true OR rate of 20% or greater compared to a historical control of 5 % with a one-sided type I error rate of 0.1. A prespecified interim analysis for futility was planned after 12 evaluable patients. Results: A total of 14 patients were enrolled in the first stage of the study, and all were evaluable for the primary endpoint. No OR were observed (out of 12) crossing the futility boundary and resulting in permanent closure of the study. Among all enrolled patients, median age was 60.5 years, 71.4% were male, 92.9% Caucasian, 42.9% with no prior exposure to TAS-102 or regorafenib, and 64.3% with left-sided primary tumors. Treated patients all had tumors with FGFR1-4 mutations and/or FGF/FGFR amplifications by tissue- and/or blood-based molecular testing; no FGFR translocations were present. OR rate for this study was 0% (95% CI, 0-23.2%), with one patient achieving stable disease as best response. Median progression-free survival was 9.1 weeks (95% CI, 7.9-not evaluable [NE]), and median overall survival was 7.9 months (95% CI, 3.4-NE). Grade 3+ adverse events (AE) were seen in 42.9% of treated patients (including 1 grade 5 AE). Most commonly occurring AEs of any grade were anemia, hyperphosphatemia, alkaline phosphatase increased, aspartate aminotransferase increase, and fatigue. Conclusions: Pemigatinib demonstrated evidence of safety but not clinical activity in this population of patients with FGF/FGFR-altered mCRC. It is unknown whether pemigatinib would be active in mCRC patients with FGFR translocations/fusions as these were not represented in our trial. Translational studies are planned to investigate mechanisms of resistance to this therapy. Clinical trial information: NCT04096417 .

Compliance with Therapeutic Goods Association prescribing information: weekly or second weekly cetuximab for the treatment of metastatic colorectal cancer.

Treatment with cetuximab provides a survival benefit for patients with RAS wild-type metastatic colorectal cancer (mCRC). Practice-defining cetuximab studies utilised weekly (q1w) administration. More convenient second weekly (q2w) administration is supported by pharmacokinetic data and a recent meta-analysis, but large head-to-head studies have not been conducted. Therapeutic Goods Association (TGA) prescribing information states cetuximab be administered q1w for all indications. To assess the real-world use of q1w versus q2w cetuximab schedule and any difference in outcomes. We analysed data from a prospective mCRC database at seven Melbourne hospitals from January 2010 to August 2019. Characteristics and outcomes for cetuximab-treated patients were examined, comparing q1w versus q2w schedules. Progression-free survival (PFS) and overall survival (OS) were the primary endpoints. Of 214 eligible patients, 103 (48%) received q1w and 111 (52%) received q2w cetuximab. Q2w cetuximab has been used in >70% of patients from 2015. Q2w was more commonly used in public patients (70% vs 13% in private, P < 0.001), in left-sided primary tumours (83% vs 68%, P=0.025) and in combination with chemotherapy (73% q2w vs 40% q1w, P< 0.001). Q2w treatment was less common in BRAFV600E mutated tumours (4% vs 13%, P=0.001). PFS was similar across all lines of therapy, including when analyses were limited to a left-sided primary and there was no difference in OS in multivariate analysis. This real-world analysis shows q2w cetuximab has become the dominant method of administration, despite TGA guidance. Our outcome data adds to other data supporting the use of q2w cetuximab as the standard option. Consideration could be given to modifying current TGA advice.