Metastatic Colorectal Adenocarcinoma Research Articles

Minimal Residual Disease using a Plasma-Only Circulating Tumor DNA Assay to Predict Recurrence of Metastatic Colorectal Cancer Following Curative Intent Treatment.

Minimal residual disease (MRD) detection identifies patients with colorectal adenocarcinoma (CRC) likely to recur following definitive treatment. We evaluated a plasma only MRD assay to predict recurrence and survival in metastatic CRC patients undergoing curative intent procedures (surgery and/or radiotherapy), with or without (neo)adjuvant chemotherapy. The primary objective of this study was to assess the correlation of post-procedure tumor cfDNA detection status with radiographic disease recurrence (RFS). Pre- and post-procedure longitudinal samples were collected from 53 patients and analyzed with a multiomic MRD assay detecting circulating tumor DNA (ctDNA) from genomic and epigenomic signals. Pre- and post-procedure ctDNA detection correlated with recurrence-free and overall survival. 230/233 samples from 52 patients were successfully analyzed. At the time of data cutoff, 36 (69.2%) patients recurred with median follow-up of 31 months. 19/42 patients (45.2%) with ctDNA analyzed 3 weeks post-procedure had detectable ctDNA. ctDNA detection 3 weeks post-procedure was associated with shorter median RFS (HR 5.27; 95% CI, 2.31-12.0, p<0.0001) and overall survival (OS) (HR 12.83; 95% CI, 3.6-45.9, p<0.0001). Pre-procedure ctDNA detection status was not associated with RFS but was associated with improved OS (HR 4.65; 95% CI, 1.4-15.2, p=0.0111). Undetectable ctDNA pre-procedure had notable long-term overall survival, >90% 3 years post-procedure. In this cohort of oligometastatic CRC, detection of ctDNA pre- or post-procedure was associated with inferior outcomes even after accounting for prognostic clinicopathologic variables. This suggests ctDNA may enhance current risk stratification methods helping evaluate novel treatments and surveillance strategies toward improving patient outcomes.

Abstract 5977: A first-in-human, open-label, multi-center phase 1 study of TST003, a GREM 1 inhibitor, in subjects with locally advanced or metastatic solid tumors

Abstract Background: Gremlin-1 (GREM1), a member of the TGF-β superfamily, plays a key role in EMT, and cancer cell proliferation by binding to BMPs. GREM1 is widely expressed in various human cancers and TME stromal cells. Overexpression of GREM1 is correlated with poor prognosis. TST003 is a novel humanized IgG1 monoclonal antibody targeting GREM1 with high affinity and selectivity, and it blocks GREM1 binding to BMP2/4 resulting in enhanced BMP signaling. This study will investigate TST003’s safety, tolerability, and preliminary anti-tumor activity in patients with advanced solid tumors. Objectives: The primary objectives are to evaluate the safety and tolerability and determine the maximum tolerated dose and/or optimal biologic dose(s) of TST003. Secondary objectives include pharmacokinetic, pharmacodynamic and preliminary anti-tumor activity of TST003. A comprehensive biomarker plan will be implemented to analyze GREM1 expression, BMP signaling pathway, and tumor microenvironment with tumor tissues (including tumor cells, CAFs, Teff, Treg, MDSCs and TAMs), as well as circulating tumor DNA to explore the correlation among drug exposure, pharmacodynamic markers and clinical outcomes. Method: This is a first in human Phase 1 study in locally advanced or metastatic solid tumor subjects having tumor progression during or after prior therapies and have no standard therapy that could confer clinical benefit. It comprises of the Part 1 Dose Escalation and the Part 2 Pharmacodynamic Cohorts. Part 1 will evaluate sequential dose levels of 1, 3, 10, 20 and 30 mg/kg TST003 iv., every three weeks as a single agent. The traditional “3+3” design were used for dose escalation of the first two cohorts (1 and 3 mg/kg), and Bayesian Optimal Interval (BOIN) Design with prespecified cohort size of 3 is used in the following cohorts. Part 2 will include 2 pharmacodynamic cohorts to evaluate the pharmacokinetic (PK) profile, pharmacodynamic (PD) markers, preliminary tumor response, as well as safety of TST003 as monotherapy in locally advanced or metastatic colorectal adenocarcinoma (CRC) subjects. The 2 doses used in the pharmacodynamic cohorts will be chosen from Part 1 and are expected to be within the pharmacologically active range based on nonclinical PK/PD modeling and available clinical PK/PD data from the ongoing study. Baseline GREM1 expression will be analyzed by immunohistochemistry. In each pharmacodynamic cohort, around 13-18 subjects will be enrolled to ensure at least 7 GREM1 positive subjects. Eligible subjects will receive TST003 until unacceptable toxicity or disease progression by RECIST v1.1. The enrollment is ongoing in clinical centers in the US and China. No significant safety signals were reported in the first few patients treated with TST003. Clinical Trial Information: NCT05731271. Study Sponsor: Suzhou Transcenta Therapeutics Co., Ltd. Citation Format: Ismael Rodriguez Rivera, Lin Shen, Shivaani Kummar, Minal Barve, Caroline Germa, Chuan Qi, Lei Chen, Jenny Milata, Jenny Yao, Li Shen, Xuelian Zhu. A first-in-human, open-label, multi-center phase 1 study of TST003, a GREM 1 inhibitor, in subjects with locally advanced or metastatic solid tumors [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 5977.

Immune checkpoint blockade combined with targeted therapies to provide disease control in mismatch repair-proficient colorectal cancer with peritoneal metastases.

133 Background: Metastatic colorectal adenocarcinoma (mCRC) with proficient mismatch repair (pMMR) is associated with poor response to cytotoxic chemotherapy in the refractory setting, with a median overall survival (OS) of 10.8 months. Recent immunotherapy (IO) regimens utilizing a combination of immune checkpoint blockade (ICB) and tyrosine kinase inhibitors (TKIs) that suppress tumor-associated macrophages (TAMs) have shown promise for extra-hepatic, but not hepatic metastases. However, few studies include patients with peritoneal metastases (PMs) and the response rate of PMs to these therapies is unknown. We sought to examine the disease control rates (DCR) and OS of patients treated with PM who were treated with ICB regimens. Methods: Patients with pMMR tumors treated with ICB and TKI after progression on 1st and 2nd-line therapy from 2015 to 2022 were identified. Date of start of therapy, end of therapy, last follow up and vital status were determined from the medical record. Radiographic disease response within each metastasis site at 6 months and at last follow-up on therapy was determined for each patient. Overall survival was estimated using the Kaplan-Meier method. Results: A total of 93 patients treated with an ICB and TKI after at least two lines of cytotoxic systemic therapy were identified. Five were excluded due to dMMR/MSI-H status and eight due to lack of follow-up. A total of 33 patients with PM, with or without other metastases, had a median follow-up on therapy of 6.1 months and median follow-up until death or censoring of 9.8 months. Median OS was 15.1 (9.7-29.5) months, and 18-month survival was 43% (95%CI: 24-62%). OS was not associated with either BRAF (HR 0.98, 0.38-2.6, p=0.98) or RAS (HR 1.50, 0.62- 3.63, p=0.37) mutation status. Partial response of PM was noted in 5 patients (15%), stable disease in 14 (42%) and progressive disease in 14 (42%), resulting in DCR of 57%. Disease control for all metastatic sites was noted in 9 (27%) of patients, and median OS was not reached at 2 years. Median OS for patients without peritoneal progression was 22.0 months [12.3-NR], and PM progression was associated with worse OS (HR 0.66, p=0.024). A total of 32 patients with any metastatic site were treated for at least 6 months. Median follow-up was 16.1 months for this cohort. DCR at 6 months for CRLM was 23% (3/13), PM was 58% (14/24, p=0.08 vs CRLM) and for LM was 62% (8/13, p=0.11 vs CRLM). Conclusions: Response to ICB and targeted therapy combinations can vary widely by metastatic site, with liver trending towards less response than peritoneum or lung. Disease control in the peritoneum can be achieved in the majority of patients, and median OS compares favorably to standard-of-care therapy in the refractory setting. Patients with peritoneal disease should be included in future trials of ICBs as treatment options are otherwise limited.

A Phase 1 Study of Cabozantinib and Trifluridine/Tipiracil in Metastatic Colorectal Adenocarcinoma

IntroductionThis study determined the safety and recommended phase 2 dose (RP2D) of the multikinase inhibitor cabozantinib in combination with trifluridine/tipiracil (FTD/TPI) in refractory metastatic colorectal carcinoma (mCRC). Patients and MethodsSingle institution investigator-initiated phase 1 study using 3+3 design. Eligible mCRC patients had received prior standard regimens. Cabozantinib was given orally (p.o.) at 20 mg (dose level [DL] 0) or 40 mg (DL 1) daily on days 1-28, and FTD/TPI p.o. at 35 mg/m2 on days 1-5 and 8-12 every 28 days. Prophylactic growth-factor support was allowed. ResultsFifteen patients were enrolled. Median age 56 years (31-80), male (12/15), ECOG 0/1 = 9/6. Three patients were treated at DL 0 and another nine were treated at DL 1, none exhibiting a DLT. Most common any grade (G) treatment related adverse events (TRAE) were diarrhea (50%), nausea (42%), neutropenia (42%), fatigue (33%), and rash (25%). G3-4 TRAE were neutropenia (25%) and thrombocytopenia, hypokalemia, and weight loss (each 8%). No serious TRAE or G5 were reported. The RP2D was determined to be DL 1. Median PFS was 3.8 months (95% CI 1.9-6.8) and disease control rate was 86.7%. ConclusionThe combination of cabozantinib and FTD/TPI is feasible and tolerable at standard doses with the use of growth factors and showed encouraging clinical activity in refractory mCRC. ClinicalTrials.GovNCT04868773.

96P Tyrosine kinase inhibitor (TKI) plus PD-1 blockade in TKI-responsive MSS/pMMR metastatic colorectal adenocarcinoma (mCRC): Updated results of TRAP study

96P Tyrosine kinase inhibitor (TKI) plus PD-1 blockade in TKI-responsive MSS/pMMR metastatic colorectal adenocarcinoma (mCRC): Updated results of TRAP study

A nomogram based on ultrasonographic features and clinical indicators for differentiating mass-forming intrahepatic cholangiocarcinoma and liver metastatic colorectal adenocarcinoma.

This study aimed to develop and validate a nomogram based on ultrasonographic features and clinical indicators to differentiate mass-forming intrahepatic cholangiocarcinoma (MF-ICC) from hepatic metastatic colorectal adenocarcinoma. A total of 343 patients with pathologically confirmed MF-ICC or metastatic colorectal adenocarcinoma were enrolled between October 2018 and July 2022. Patients were randomly assigned to training and validation sets at a ratio of 7:3. Preoperative ultrasound features and clinical indicators were retrieved. Univariate logistic regression analysis was employed to select relevant features. Multivariate logistic regression analysis was used to establish a predictive model, which was presented as a nomogram in training sets. The model's performance was assessed in terms of discrimination, calibration, and clinical usefulness. The study included 169 patients with MF-ICC and 174 with liver metastatic colorectal adenocarcinoma, assigned to training (n=238) and validation (n=105) cohorts. The nomogram incorporated ultrasound features (tumor size, lesion number, echogenicity, tumor necrosis, and rim arterial phase hyperenhancement) and clinical information (serum levels of CEA, CA19-9, CA125). The nomogram demonstrated promising performance in differentiating these two entities in both training and validation sets, with an AUC value of 0.937 (95%CI: 0.907,0.969) and 0.916 (95%CI: 0.863,0.968), respectively. The Hosmer-Lemeshow test and calibration curves confirmed good consistency between predictions and observations. Additionally, decision curve analysis confirmed the nomogram's high clinical practicability. The nomogram based on ultrasound features and clinical indicators demonstrated good discrimination performance in differentiating MF-ICC from metastatic colorectal adenocarcinoma, which may enhance clinical decision-making process in managing these challenging diagnostic scenarios.

Primary Rectal Tumor With Extensive Choriocarcinoma Differentiation in a Woman With Lung, Liver and Disseminated Peritoneal Disease: A Primary Rectal Adenocarcinoma With Extensive Choriocarcinoma Differentiation or Primary Rectal Choriocarcinoma?

Primary rectal adenocarcinoma with extensive choriocarcinomatous differentiation is a rare neoplasm, with only sporadic cases reported worldwide. The prognosis is typically poor, and no standard therapy has been established for this tumor. We report a case of a 63-year-old woman who presented with lower abdominal and pelvic discomfort, as well as rectal bleeding. Endoscopy revealed a rectal tumor. She was diagnosed with primary rectal adenocarcinoma with extensive choriocarcinomatous differentiation, accompanied by liver metastasis and peritoneal carcinomatosis. The immunohistochemical profile demonstrated strong and diffuse positivity for keratin (AE1/AE3), beta-human chorionic gonadotropin (β-HCG), p53, MYC, p16, and Ki-67. Molecular analysis indicated mutations in KRAS, TP53, and PI3KCA. Despite the tumor's profile, the serum β-HCG level was not elevated. A chemotherapy regimen for metastatic colorectal adenocarcinoma was initiated, but there was a poor response, with rapid tumor progression. The patient survived for only 5 months postdiagnosis. We discuss the histopathological, immunohistochemical, and molecular findings, emphasizing their relevance to the differential diagnosis of neoplasms with choriocarcinomatous differentiation.

Superior vena cava and tricuspid valve tumoral thrombosis in a 54‐year‐old female with metastatic colorectal adenocarcinoma: A rare case report

Superior vena cava and tricuspid valve tumoral thrombosis in a 54‐year‐old female with metastatic colorectal adenocarcinoma: <scp>A</scp> rare case report

S2090 Underrecognized Risk of Severe Acute Necrotizing Pancreatitis in Metastatic Colorectal Adenocarcinoma Patients After Percutaneous Transhepatic Biliary Intervention: A Palliative Care Conundrum

S2090 Underrecognized Risk of Severe Acute Necrotizing Pancreatitis in Metastatic Colorectal Adenocarcinoma Patients After Percutaneous Transhepatic Biliary Intervention: A Palliative Care Conundrum

Development and validation of a decision tree for distinguishing pulmonary adenocarcinomas with mucinous features and metastatic colorectal adenocarcinoma.

Diagnosis of mucinous carcinomas in the lung on transbronchial biopsy or fine-needle aspiration (FNA) samples can be difficult for the pathologist, because primary and metastatic tumors can have similar morphological, immunohistochemical, and molecular characteristics. Correct diagnosis is key to determine appropriate therapy and to distinguish primary from metastatic disease. This distinction often falls to the pathologist in patients with a history of mucinous adenocarcinoma of the colon. Despite its drawbacks, immunohistochemistry is often employed to help assign a primary site for mucinous adenocarcinomas in the lung. However, the published data in this regard is limited to studies that use only a handful of markers. The authors examined the staining characteristics and heterogeneity of CK7, TTF-1, NapsinA, CK20, CDX2, and SATB2 in resection specimens of pulmonary adenocarcinomas with mucinous features and metastatic colorectal adenocarcinoma. Based on the heterogeneity, sensitivity, and specificity in this cohort, the authors developed a decision tree based on TTF-1, SATB2, CDX2, and CK7 to categorize tumors as primary or metastatic lesions. Validation of the decision tree in FNA specimens from the lungs and lung-draining lymph nodes showed 84% concurrence in cases from the lung and 100% concurrence in cases from the lymph node. In cases where the algorithm assigned a primary site, it was 95% accurate compared to the multidisciplinary diagnosis. This method holds promise in distinguishing primary versus metastatic lesions in resection, biopsy, and FNA samples from the lungs.

Establishment and characterization of a novel cell line and xenotransplant mouse model derived from feline colorectal adenocarcinoma.

Colorectal adenocarcinoma is an aggressive malignant tumor in cats that frequently metastasizes to the lymph nodes and/or distant organs. However, research on feline colorectal adenocarcinoma is limited, and experimental models have not been established. A novel cell line, FeLeco-G7, was established from the lymph node of a 12-year-old spayed female Maine Coon cat with metastatic colorectal adenocarcinoma. FeLeco-G7 cells were polygonal with abundant cytoplasm and adherent growth. The population-doubling time was approximately 28.3 hours, and the mean number of chromosomes was 37.6±0.1 per cell (ranging between 32 and 41). Consistent with the original tumor, FeLeco-G7 cells were immunopositive for cytokeratin (CK) 20 and CDX2, and immunonegative for CD10 and CK7. Nuclear accumulation of β-catenin was rarely observed. Mutation analysis suggested TP53 gene alterations. A subcutaneous injection of FeLeco-G7 cells into immunodeficient mice resulted in the formation of a mass at the injection site without the development of metastatic lesions. An orthotopic (intrarectal) transplantation of FeLeco-G7 cells caused cachexia and diffuse involvement of the rectal mucosa in one of the 3 mice and the formation of masses around the rectum in the other 2 mice. Metastases to the regional lymph nodes and lungs were detected in three of the 3 and one of the 3 mice, respectively. The histological findings and immunohistochemical features of these masses were similar to those of the original tumor. These results suggest that FeLeco-G7 cells and the orthotopically transplanted mouse model are valuable tools for further molecular and therapeutic research on feline colorectal adenocarcinoma.

Sintilimab plus bevacizumab, oxaliplatin and capecitabine as first-line therapy in RAS-mutant, microsatellite stable, unresectable metastatic colorectal cancer: an open-label, single-arm, phase II trial

Microsatellite stable (MSS) and RAS-mutant metastatic colorectal cancer (mCRC) patients are characterized by an immunosuppressive microenvironment and a low response rate to immunotherapy. Chemotherapy and anti-angiogenesis therapy have been reported to potentially promote immunotherapy response. This study aims to assess the preliminary anti-tumor activity and safety of sintilimab plus bevacizumab, oxaliplatin and capecitabine as a treatment option for patients with RAS-mutant MSS mCRC. This study was an open-label, single-arm, phase II trial in China. Patients with unresectable, RAS-mutant and MSS metastatic colorectal adenocarcinoma received treatment by intravenous sintilimab (200mg, day 1) plus bevacizumab (7.5mg/kg, day 1), oxaliplatin (135mg/m2, day 1) and oral capecitabine (1g/m2, day 1-14) in each 21-day cycle. The primary endpoints included objective response rate (ORR) and adverse events. Biomarker analysis was performed to identify potential predictors of good response to treatment. This study is registered with ClinicalTrials.gov, number NCT04194359. Between April 2021 and December 2021, 25 patients were enrolled. Two (8%) patients showed complete response (CR), 19 (76%) had partial response (PR) and 4 (16%) presented with stable disease. ORR reached 84% (95% CI, 63.9-95.5) and the disease control rate was 100% (95% CI, 86.3-100). The median progression-free survival (PFS) was 18.2 months for the full analysis set. The most common treatment-related adverse events (TRAEs) in all grades were anemia (21/25, 84%), neutropenia (20/25, 80%), and hand-foot syndrome (14/25, 56%). The most frequent grade 3 or 4 TRAEs were neutropenia (3/25, 12%) and increased alanine transaminase (2/25, 8%). No grade 5 adverse events occurred. In the exploration of biomarkers, 5 patients could be characterized as TTN/OBSCN "double-hit" after treatment, and the copy number variants burden was significantly decreased in tumor tissues after treatment compared with the baseline. Nanostring panel RNA sequencing analysis indicated a better tumor immune microenvironment cell infiltration in CR/PR patients compared with non-CR/PR patients as well as the PFS-long (≥12.5 months) group compared with the PFS-short group. Combination treatment with sintilimab plus bevacizumab, oxaliplatin and capecitabine as first-line treatment demonstrated a promising antitumor activity and a manageable safety profile in RAS-mutant, MSS and unresectable mCRC. Exploratory biomarker assessment analysis showed that some RAS-mutant and MSS patients changed into "immune-hot" subtype after the treatment. This study was supported by the Key R&D Program of Zhejiang Province (2021C03125 to Ying Yuan), the National Natural Science Foundation of China (81872481 to Ying Yuan, 82072624 to Kefeng Ding), the Fundamental Research Funds for the Central Universities (No. 226-2022-00009 to Kefeng Ding), and the Zhejiang Provincial Natural Science Foundation of China (No. LY22H160024 to Hanguang Hu).

Fruquintinib versus placebo in patients with refractory metastatic colorectal cancer (FRESCO-2): an international, multicentre, randomised, double-blind, phase 3 study

There is a paucity of effective systemic therapy options for patients with advanced, chemotherapy-refractory colorectal cancer. We aimed to evaluate the efficacy and safety of fruquintinib, a highly selective and potent oral inhibitor of vascular endothelial growth factor receptors (VEGFRs) 1, 2, and 3, in patients with heavily pretreated metastatic colorectal cancer. We conducted an international, randomised, double-blind, placebo-controlled, phase 3 study (FRESCO-2) at 124 hospitals and cancer centres across 14 countries. We included patients aged 18 years or older (≥20 years in Japan) with histologically or cytologically documented metastatic colorectal adenocarcinoma who had received all current standard approved cytotoxic and targeted therapies and progressed on or were intolerant to trifluridine-tipiracil or regorafenib, or both. Eligible patients were randomly assigned (2:1) to receive fruquintinib (5 mg capsule) or matched placebo orally once daily on days 1-21 in 28-day cycles, plus best supportive care. Stratification factors were previous trifluridine-tipiracil or regorafenib, or both, RAS mutation status, and duration of metastatic disease. Patients, investigators, study site personnel, and sponsors, except for selected sponsor pharmacovigilance personnel, were masked to study group assignments. The primary endpoint was overall survival, defined as the time from randomisation to death from any cause. A non-binding futility analysis was done when approximately one-third of the expected overall survival events had occurred. Final analysis occurred after 480 overall survival events. This study is registered with ClinicalTrials.gov, NCT04322539, and EudraCT, 2020-000158-88, and is ongoing but not recruiting. Between Aug 12, 2020, and Dec 2, 2021, 934 patients were assessed for eligibility and 691 were enrolled and randomly assigned to receive fruquintinib (n=461) or placebo (n=230). Patients had received a median of 4 lines (IQR 3-6) of previous systemic therapy for metastatic disease, and 502 (73%) of 691 patients had received more than 3 lines. Median overall survival was 7·4 months (95% CI 6·7-8·2) in the fruquintinib group versus 4·8 months (4·0-5·8) in the placebo group (hazard ratio 0·66, 95% CI 0·55-0·80; p<0·0001). Grade 3 or worse adverse events occurred in 286 (63%) of 456 patients who received fruquintinib and 116 (50%) of 230 who received placebo; the most common grade 3 or worse adverse events in the fruquintinib group included hypertension (n=62 [14%]), asthenia (n=35 [8%]), and hand-foot syndrome (n=29 [6%]). There was one treatment-related death in each group (intestinal perforation in the fruquintinib group and cardiac arrest in the placebo group). Fruquintinib treatment resulted in a significant and clinically meaningful benefit in overall survival compared with placebo in patients with refractory metastatic colorectal cancer. These data support the use of fruquintinib as a global treatment option for patients with refractory metastatic colorectal cancer. Ongoing analysis of the quality of life data will further establish the clinical benefit of fruquintinib in this patient population. HUTCHMED.

Influence of levothyroxine concomitant treatment on treatment responses and outcomes in patients with metastatic colorectal adenocarcinoma.

e15593 Background: Hypothyroidism is the most common thyroid disorder and levothyroxine is the mainstay treatment. Levothyroxine is mainly used to restore the euthyroid clinical and biochemical status in the gland. Recent literature has correlated chronic hormonal treatment with adverse effects on bone and heart function, as well as correlated with an increased risk of tumor onset. Data available in the literature are controversial, therefore the aim of our study was to evaluate the correlation between chronic levothyroxine intake and outcomes and response to first line treatments in patients affected by metastatic colorectal cancer. Methods: We retrospectively collected the data from 139 patients with metastatic colorectal adenocarcinoma, belonging to the Medical Oncology Department of the University Hospital of Cagliari from 2016 to 2019. All patients enrolled in the study had received metastatic first-line treatment with doublet or triplet chemotherapy associated with anti-VEGF or anti-EGR monoclonal antibody. Patients with ECOG PS ≤1 with no more than two relevant comorbidities were included in the study. The primary objective of the study was median overall survival (mOS) and secondary objectives were: median progression free progression (PFS), median overall survival (mOS) differences between RAS wild type and mutant tumour. BRAF mutant tumors were excluded from the evaluation. Results: Median age was 65 years (±10), 51% were male and 49% were female. 63% patients had an ECOG-PS 0, while 37% had an ECOG-PS 1. 67% developed from the left colon; 33% from the right colon and the transverse colon. All patients had synchronous metastases. 18% patients took levothyroxine and 82% patients did not take it. Among the patients receiving levothyroxine therapy, 64% had a RAS wild type and 36% a RAS mutated. Levothyroxine treated patients showed a significantly lower median OS than not treated patients (15 months versus not reached, p = 0,0001). Levothyroxine treated patients also showed a significantly lower median PFS than non treated patients (6 versus 8 months, p = 0,035). Within levothyroxine treated pts, no statistically significant differences were found in mOS and mPFS between RAS wt and RAS mut (mOS 15 versus 14 months, respectively, p = 0.9; mPFS 8 versus 7 months, respectively, p = 0,7). Conclusions: The results show a possible correlation between levothyroxine therapy and outcomes in mCRC. This would deserve further study to understand further biological-molecular aspects, to date partially explained by preclinical studies, in order to clarify some of the possible underlying mechanisms.

P-166 Influence of levothyroxine concomitant treatment on treatment responses and outcomes in patients with metastatic colorectal adenocarcinoma

P-166 Influence of levothyroxine concomitant treatment on treatment responses and outcomes in patients with metastatic colorectal adenocarcinoma

The ideal reporting of RAS testing in colorectal adenocarcinoma: a pathologists' perspective.

RAS gene mutational status represents an imperative predictive biomarker to be tested in the clinical management of metastatic colorectal adenocarcinoma. Even if it is one of the most studied biomarkers in the era of precision medicine, several pre-analytical and analytical factors may still impasse an adequate reporting of RAS status in clinical practice, with significant therapeutic consequences. Thus, pathologists should be aware on the main topics related to this molecular evaluation: (i) adopt diagnostic limit of detections adequate to avoid the interference of sub-clonal cancer cell populations; (ii) choose the most adequate diagnostic strategy according to the available sample and its qualification for molecular testing; (iii) provide all the information regarding the mutation detected, since many RAS mutation-specific targeted therapeutic approaches are in development and will enter into routine clinical practice. In this review, we give a comprehensive description of the current scenario about RAS gene mutational testing in the clinic focusing on the pathologist's role in patient selection for targeted therapies.

Metastatic colorectal adenocarcinoma tumor purity assessment from whole exome sequencing data.

Tumors rich in stroma are associated with advanced stage and poor prognosis in colorectal adenocarcinoma (CRC). Abundance of stromal cells also has implications for genomic analysis of patient tumors as it may prevent detection of somatic mutations. As part of our efforts to interrogate stroma-cancer cell interactions and to identify actionable therapeutic targets in metastatic CRC, we aimed to determine the proportion of stroma embedded in hepatic CRC metastases by performing computational tumor purity analysis based on whole exome sequencing data (WES). Unlike previous studies focusing on histopathologically prescreened samples, we used an unbiased in-house collection of tumor specimens. WES from CRC liver metastasis samples were utilized to evaluate stromal content and to assess the performance of three in silico tumor purity tools, ABSOLUTE, Sequenza and PureCN. Matching tumor derived organoids were analyzed as a high purity control as they are enriched in cancer cells. Computational purity estimates were compared to those from a histopathological assessment conducted by a board-certified pathologist. According to all computational methods, metastatic specimens had a median tumor purity of 30% whereas the organoids were enriched for cancer cells with a median purity estimate of 94%. In line with this, variant allele frequencies (VAFs) of oncogenes and tumor suppressor genes were undetectable or low in most patient tumors, but higher in matching organoid cultures. Positive correlation was observed between VAFs and in silico tumor purity estimates. Sequenza and PureCN produced concordant results whereas ABSOLUTE yielded lower purity estimates for all samples. Our data shows that unbiased sample selection combined with molecular, computational, and histopathological tumor purity assessment is critical to determine the level of stroma embedded in metastatic colorectal adenocarcinoma.

PINK1 Immunoexpression Predicts Survival in Patients Undergoing Hepatic Resection for Colorectal Liver Metastases.

PTEN-induced kinase-1 (PINK1) is the initiator of the canonical mitophagy pathway. Our aim was to study the immunoexpression of PINK1 in surgical specimens from ninety patients with metastatic colorectal adenocarcinoma (CRC) to the liver (CRLM). Tissue arrays were produced, and immunohistochemical studies were analyzed by the H-Score method. The mean immunoexpression of PINK1 in normal tissues was between 40 to 100 points. In tumoral tissues, positive PINK1 immunoexpression was observed in all samples, and no differences were noted between CRCs. In CRLMs, a significant under-expression was noted for PINK1 from the rectum (71.3 ± 30.8; p < 0.042) compared to other sites. Altered PINK1 immunoexpression in CRCs, either higher than 100 points or lower than 40 points, was associated with worse overall survival (OS) (p < 0.012) due to a shorter post-metastatic survival (PMS) (p < 0.023), and it was found to be a significant independent predictor of prognosis in a multivariate model for OS and PMS (HR = 1.972, 95% CI 0.971-4.005; p = 0.022. HR = 2.023, 95% CI 1.003-4.091; p = 0.037, respectively). In conclusion, altered PINK1 immunoexpression determined in CRCs with resected CRLM predicts a worse prognosis, possibly due to the abnormal function of mitophagy.

Metastatic Colorectal Cancer to the Right Ventricle

Colorectal cancer (CRC) is the third most common cancer worldwide. Cardiac metastasis from CRC is extremely rare with only a few cases reported, with the clinical presentation being silent in over 90% of cases. Here we discuss a case of 62 -year-old male who presented with abdominal pain, distention,and weight loss. Computed Tomography (CT) chest/abdomen showed a multiseptated left hepatic lobe lesion, bilateral lung nodules, and a mass-like hypodensity in the right ventricle (RV). A transesophageal echocardiogram (TEE) confirmed the RV mass with normal cardiac function. A liver biopsy showed metastatic colorectal adenocarcinoma. Two months after diagnosis, the patient developed progressive abdominal distention, shortness of breath, and pedal edema. Hospice care was initiated after he did not tolerate palliative chemotherapy, and he passed away three months later. Metastatic cardiac involvement secondary to CRC is extremely uncommon. From 1948 to 2007, the incidence of cardiac metastasis was noted to be 2.3 - 18.3% in the literature. The clinical presentation is silent in 90% of cases. Symptoms can range from being asymptomatic to chronic fatigue and shortness of breath due to reduced cardiac output, to sudden cardiac death from embolization of metastatic tumor. Metastatic cardiac tumors progress rapidly and have poor outcomes. It is crucial to recognize the underestimated prevalence of cardiac metastasis as it may have implications for the management and prognosis of CRC. Given the asymptomatic presentation of cardiac metastasis in the context of CRC, future integration of genetic sequencing may help delineate further guidelines on screening for cardiac metastasis.

ICGC-ARGO precision medicine: an update on targeted therapy based on longitudinal analysis of tumour heterogeneity and evolution in colorectal cancer

We previously reported two patients with metastatic colorectal adenocarcinoma who, after referral to the precision medicine tumour board, had tissue and longitudinal liquid biopsies and responded to targeted therapy based on their molecular profile. These patients are from the SCRUM-MONSTAR programme, a nationwide genome-screening project in Japan that is part of the International Cancer Genome Consortium–Accelerating Research in Genomic Oncology. Here, we summarise the clinical history of the two patients and report an update on clinical course and longitudinal molecular assessment using circulating-tumour DNA (ctDNA) sequencing.