Citations

A 35-year-old female patient with hypothyroidism and Ehler-Danlos syndrome presents with fatigue, abdominal distension, and dyspnea. What is your diagnosis?

Abstract Background Tumor microenvironment (TME) characteristics including tumor stroma ratio (TSR), tumor budding (TB), and tumor-infiltrating lymphocytes (TILs) were examined in resected gastric cancer. These TME features have been shown to indicate metastatic potential in colon cancer, and intestinal-type gastric cancer (IGC) has pathological similarities with that malignancy. Methods TSR, TB, and TILs were quantified in routine histological sections from 493 patients with IGC who underwent radical resection at 2 university hospitals in China from 2010 to 2016. TME variables were dichotomized as follows: TSR (50%), TILs (median), TB per international guidelines (4 buds/0.785mm2), and platelet-lymphocyte ratio (PLR) per survival ROC. Association of TME features with patient clinicopathological characteristics, time-to-recurrence (TTR), and cancer-specific-survival (CSS) were examined using univariate and multivariate analysis, including a relative contribution analysis by Cox regression. Results Patients whose tumors showed high TSR or high TB or low TILs were each significantly associated with increased T and N stage, higher histological grade, and poorer TTR and CSS at 5 years. Only TSR and N stage were independently associated with TTR and CSS after adjustment for covariates. PLR was only independently associated with TTR after adjustment for covariates. Among the variables examined, only TSR was significantly associated with both TTR (HR 1.72, 95% CI, 1.14-2.60, P = .01) and CSS (HR 1.62, 95% CI, 1.05-2.51, P = .03) multivariately. Relative contribution to TTR revealed that the top 3 contributors were N stage (45.1%), TSR (22.5%), and PLR (12.9%), while the top 3 contributors to CSS were N stage (59.9%), TSR (14.7%), and PLR (10.9%). Conclusions Among the examined TME features, TSR was the most robust for prognostication and was significantly associated with both TTR and CSS. Furthermore, the relative contribution of TSR to patient TTR and CSS was second only to nodal status.

e15589 Background: Most patients with mCRC eventually develop disease progression or intolerance to first- and second-line therapy. Fruquintinib, a selective oral tyrosine kinase inhibitor of VEGFRs 1, 2, and 3, has emerged as a novel treatment option for refractory mCRC. We conducted a meta-analysis to assess the safety and efficacy of Fruquintinib for the treatment of refractory mCRC compared to placebo in specific patient subgroups of interest. Methods: We systematically searched PubMed, EMBASE, and Cochrane databases for randomized controlled trials (RCTs) reporting Fruquintinib efficacy. The data extraction followed PRISMA guidelines and our protocol was registered in PROSPERO (CRD42023477783). Summary hazard ratios (HRs) of overall survival (OS) and progression-free survival (PFS) were calculated using a random-effects model. The likelihood of Fruquintinib being associated with adverse events (AEs) was expressed by odds ratios (ORs). Results: Of the 1138 studies yielded by the search, three were included, totaling 1178 patients, of whom 786 (67%) received Fruquintinib. This meta-analysis of three randomized trials assessed the clinical outcomes of Fruquintinib in the intervention group compared with placebo in refractory mCRC. Pooled results from all three studies suggested the superiority of Fruquintinib in PFS (HR: 0.29 [0.25, 0.34], 95% CI, I² = 10%, p < 0.01) and OS (HR: 0.66 [0.57, 0.76], 95% CI, p < 0.01). Notably, subgroup analysis showed that Fruquintinib was associated with improved PFS in patients with prior use of VEGF inhibitors (HR: 0.32 [0.27, 0.38], 95% CI, p < 0.01) and those with more than three prior lines of treatment (HR: 0.37 [0.25, 0.53], 95% CI, p < 0.01), RAS wild-type status (HR: 0.25 [0.13, 0.35], 95% CI, p < 0.01), or RAS mutated (HR: 0.33 [0.28, 0.40], 95% CI, p < 0.01). In the safety analysis, fruquintinib and placebo showed no significant differences in serious AEs; nonetheless, the VEGFR inhibitor was associated with more frequent grade ≥ 3 AEs (OR: 3.13 [1.15, 8.53], 95% CI, p = 0.03). Conclusions: This meta-analysis supports the efficacy of Fruquintinib for refractory mCRC regardless of previous use of VEGF inhibitors, the number of previous treatment lines, and gene RAS mutational status, without a significant increase in serious adverse events. [Table: see text]

544 Background: Biliary tract cancer (BTC) is an aggressive malignancy with poor prognosis and limited treatment options. The prevalence of HER2 amplification in BTC has been reported to be 5-20%, and clinical trials suggested the clinical benefit of HER2-targeted treatment in this disease subpopulation. In a global collaboration, we investigated the comprehensive clinico-molecular characterization as well as the efficacy of anti-HER2 therapy in HER2-amplified BTC. Methods: Patients with advanced BTC who received systemic therapy were included from the GOZILA and MONSTAR studies in Japan and from the COLOMATE trial in the US. Genomic alterations were detected by tissue next-generation sequencing (NGS), including FoundationOne CDx and TempuslxT, and plasma circulating tumor DNA NGS including Guardant360 and FoundationOne Liquid CDx. The clinico-molecular characteristics were evaluated in an exploratory cohort comprised of patients from Japan, whereas the efficacy of anti-HER2 therapy was assessed in a biomarker selected cohort with patients from both Japan and the US. Results: Of 439 patients included in the exploratory cohort, 43 (10%) had HER2 amplification. BTC with primary tumor location in the gallbladder accounted for 58% of primary sites of patients with HER2 amplification. TP53 mutation (84% vs 61%, p=0.003) and BRAF amplification (9% vs 2%, p=0.030) were significantly more frequent in patients with HER2 amplification compared to those without, and no KRAS mutation co-occurred with HER2 amplification. There was no significant difference in overall survival (OS) between patients with and without HER2 amplification (17.7 months [M] vs 16.9 M, hazard ratio [HR] 0.95, 95% confidence interval [CI] 0.65-1.40, p=0.799). Of 58 patients with HER2-amplified BTC included in the biomarker selected cohort (43 Japan, 15 US), 27 (47%) received anti-HER2 therapy. The median OS of patients treated with anti-HER2 therapy was significantly longer than that of patients who did not receive anti-HER2 therapy (24.3 M vs. 12.1 M, HR 0.43, 95% CI 0.23-0.82, p=0.011). Multivariate analysis also identified anti-HER2 therapy as an independent prognostic factor for OS (HR 0.42, 95% CI 0.20-0.85, p=0.015). Conclusions: HER2 amplifications were found in 10% of advanced BTC and did not represent an independent predictive factor for OS. Of clinical significance, patients with HER2-amplified BTC derive a significant benefit from anti-HER2 therapy.

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.

Background: Due to lacking evidence on surveillance for gastric cancer (GC), this study aimed to determine the optimal postsurgical surveillance strategy for pathological stage (pStage) II/III GC patients and compare its cost-effectiveness with traditional surveillance strategies. Methods: Prospectively collected data from stage II/III GC patients (n=1661) who underwent upfront surgery at a large-volume tertiary cancer center in China (FJMUUH cohort) between January 2010 and October 2015. For external validation, two independent cohorts were included, which were composed of 380 stage II/III GC patients at an tertiary cancer center in U.S.A (Mayo cohort) between July 1991 and July 2012 and 270 stage II/III GC patients at another tertiary cancer center in China (QUAH cohort) between May 2010 and October 2014. Random forest models were used to predict dynamic recurrence hazards and to construct individual surveillance strategies for stage II/III GC. Cost-effectiveness was assessed by the Markov model. Results: The median follow-up period of the FJMUUH, the Mayo, and QUAH cohorts were 55, 158, and 70 months, respectively. In the FJMUUH cohort, the 5-year recurrence risk was higher in pStage III compared with pStage II GC patients (P<0.001). Our novel individual surveillance strategy achieved optimal cost-effectiveness for pStage II GC patients (ICER =$490/QALY). The most intensive NCCN surveillance guideline was more cost-effective (ICER =$983/QALY) for pStage III GC patients. The external validations confirmed our results. Conclusion: For patients with pStage II GC, individualized risk-based surveillance outperformed the JGCTG and NCCN surveillance guidelines. However, the NCCN surveillance guideline may be more suitable for patients with pStage III GC. Even though our results are limited by the retrospective study design, the authors believe that our findings should be considered when recommending postoperative surveillance for stage II/III GC with upfront surgery in the absence of a randomized clinical trial.

3531 Background: Homologous recombination deficient (HRD) colorectal cancer (CRC) has improved overall survival (OS) when exposed to DNA damaging agents (DDA) oxaliplatin (OX) and irinotecan (IR). However, this OS benefit is only observed in HRD mutated CRC. Low expression of wild type (WT) BRCA1 RNA displays prolonged OS in ovarian cancer; this finding has not been investigated in CRC or outside BRCA. We investigate if low expression of WT HR genes is associated with prolonged OS in response to DDA. Methods: A total of 12,860 CRC patients tumor biopsies were analyzed by next-generation sequencing (592, NextSeq; WES, WTS NovaSeq). Patients with HRD mutations and MSI-H were excluded (N = 935). 11,925 patients were included in the analysis. A total of 11 core ( BARD1, BLM, BRCA1, BRCA2, BRIP1, MRE11, NBN, PALB2, RAD50, RAD51, RAD51B) and 7 related ( BAP1, WRN, DNMT3A, ERCC1, FANCA, FANCF, RECQL4) HR genes were analyzed. Samples were classified by RNA expression percentiles within the studied cohort. Real world OS was extracted from insurance claims and calculated using Kaplan-Meier estimates for molecularly defined cohorts from first of OX or IR to last contact. Results: OS benefit is seen in low RNA expression (bottom 10%) compared to high expression (top 10%) of all core WT HR genes except RAD51B, BARD1 and BRCA2 in response to IR. We observe a progressively longer OS with lower associated RNA expression in response to DDA. OS of nearly 7 years was observed in low expressing BRCA1 and RAD51 following IR exposure and 4.5-year OS benefit when compared to high expression of these genes. OS benefit in response to OX was less robust but significantly prolonged in BRCA1 and BRIP1 (Table). Patients harboring HRD mutations had similar OS to WT HR RNA low (bottom 10%) in response to OX (HR = 0.75; p = 0.1) and IR (HR = 0.82; p = 0.36). Conclusions: Here we report a novel subclass of CRC defined as patients with low RNA expressing WT HR genes that exhibit differential sensitivity to DDA. Significantly longer survival is noted in CRC with low expression BRCA1, RAD51 and BLM, while post-OX survival was significantly prolonged with low expression of BRCA1, BRIP1 and FANCA. Further characterization of sensitive HR genes will better predict DDA sensitivity and impact treatment sequencing. [Table: see text]

Colorectal cancer (CRC) is the third most common malignancy worldwide. It is projected to increase by 3.2 million new cases and account for 1.6 million deaths by 2040. Mortality is largely due to limited treatment options for patients who present with advanced disease. Thus, the development of effective and tolerable therapies is crucial. Chemotherapy has been the backbone of systemic treatment of advanced CRC, but utility has been limited because of invariable resistance to therapy, narrow mechanisms of action, and unfavorable toxicity profile. Tumors that are mismatch repair-deficient have demonstrated remarkable response to immune checkpoint inhibitor therapy. However, most CRC tumors are mismatch repair-proficient and represent an unmet medical need. Although ERBB2 amplification occurs only in a few cases, it is associated with left-sided tumors and a higher incidence of brain metastasis. Numerous combinations of HER2 inhibitors have demonstrated efficacy, and antibody-drug conjugates against HER2 represent innovative strategies in this area. The KRAS protein has been classically considered undruggable. Fortunately, new agents targeting KRAS G12C mutation represent a paradigm shift in the management of affected patients and could lead the advancement in drug development for the more common KRAS mutations. Furthermore, aberrant DNA damage response is present in 15%-20% of CRCs, and emerging innovative combinations with poly (ADP-ribose) polymerase (PARP) inhibitors could improve the current therapeutic landscape. Multiple novel biomarker-driven approaches in the management of patients with advanced CRC tumors are reviewed in this article.

225 Background: HR deficient (HRD) CRC has improved outcomes following exposure to DNA damaging agent (DDA) (irinotecan, IR; oxaliplatin, OX) compared to HRP CRC. Low expression of wild type (WT) BRCA1 mRNA is associated with prolonged OS in ovarian cancer; however, this finding has not been investigated in CRC or outside of BRCA. Here, we examine the effect of low expression of HR genes in HRP CRC on post-DDA survival. Methods: 12,860 CRC samples were analyzed by NGS (592, NextSeq; WES, NovaSeq) and WTS (NovaSeq) at Caris Life Sciences (Phoenix, AZ). Samples were classified by RNA expression percentiles. Real world OS was extracted from insurance claims and calculated using Kaplan-Meier estimates for molecularly defined cohorts from first of OX or IR to last contact. Results: Post-IR survival was prolonged with low expression of ATM, CHEK2 and PALB2 in WT ATM, PALB2, and CHEK2 WT CRC, respectively (bottom vs. top 10%, bottom vs. top 25%; p<0.05). Notably, low PALB2 expression (bottom 10%) showed a 14.5-month post-IR benefit compared to high PALB2 expression (top 10%) in WT PALB2 CRC (p=0.003). Post-OX survival was not significantly prolonged with low expression of CHEK2 in WT CHEK2 CRC (bottom 10% vs top 10%, bottom 25% vs top 25%) but was with low expression of ATM (+9.7 months, p=0.02) and PALB2 (+5.6 months, p=0.03) in WT ATM and PALB2 CRC, respectively (all bottom 25% vs top 25%). Conclusions: Here we report the first findings to suggest a novel subclass of CRC defined as the low expression of mRNA of non-mutated HRD genes that exhibit sensitivity to DDA. Low expression of WT ATM, CHEK2, and PALB2 correlates with prolonged OS following IR, post-OX survival was prolonged with low expression of ATM and PALB2. Further characterization defining sensitivity of low expressing HRP genes to DDA may help guide treatment considerations in HRP CRC. [Table: see text]