Marc Van den Eynde

Feasibility of 90Y TOF PET-based dosimetry in liver metastasis therapy using SIR-Spheres

Purpose90Y-labelled compounds used in targeted radiotherapy are usually imaged with SPECT by recording the bremsstrahlung X-rays of the β decay. The continuous shape of the X-ray spectrum induces the presence of a significant fraction of scatter rays in the acquisition energy window, reducing the accuracy of biodistribution and of dosimetry assessments.MethodsThe aim of this paper is to use instead the low branch of e− e+ pair production in the 90Y decay. After administration of 90Y-labelled SIR-Spheres by catheterization of both liver lobes, the activity distribution is obtained by 90Y time-of-flight (TOF) PET imaging. The activity distribution is convolved with a dose irradiation kernel in order to derive the regional dosimetry distribution.ResultsEvaluation on an anatomical phantom showed that the method provided an accurate dosimetry assessment. Preliminary results on a patient demonstrated a high-resolution absorbed dose distribution with a clear correlation with tumour response.ConclusionThis supports the implementation of 90Y PET in selective internal radiation therapy of the liver.

International validation of the consensus Immunoscore for the classification of colon cancer: a prognostic and accuracy study

BACKGROUND The estimation of risk of recurrence for patients with colon carcinoma must be improved. A robust immune score quantification is needed to introduce immune parameters into cancer classification. The aim of the study was to assess the prognostic value of total tumour-infiltrating T-cell counts and cytotoxic tumour-infiltrating T-cells counts with the consensus Immunoscore assay in patients with stage I-III colon cancer. METHODS An international consortium of 14 centres in 13 countries, led by the Society for Immunotherapy of Cancer, assessed the Immunoscore assay in patients with TNM stage I-III colon cancer. Patients were randomly assigned to a training set, an internal validation set, or an external validation set. Paraffin sections of the colon tumour and invasive margin from each patient were processed by immunohistochemistry, and the densities of CD3+ and cytotoxic CD8+ T cells in the tumour and in the invasive margin were quantified by digital pathology. An Immunoscore for each patient was derived from the mean of four density percentiles. The primary endpoint was to evaluate the prognostic value of the Immunoscore for time to recurrence, defined as time from surgery to disease recurrence. Stratified multivariable Cox models were used to assess the associations between Immunoscore and outcomes, adjusting for potential confounders. Harrells C-statistics was used to assess model performance. FINDINGS Tissue samples from 3539 patients were processed, and samples from 2681 patients were included in the analyses after quality controls (700 patients in the training set, 636 patients in the internal validation set, and 1345 patients in the external validation set). The Immunoscore assay showed a high level of reproducibility between observers and centres (r=0·97 for colon tumour; r=0·97 for invasive margin; p<0·0001). In the training set, patients with a high Immunoscore had the lowest risk of recurrence at 5 years (14 [8%] patients with a high Immunoscore vs 65 (19%) patients with an intermediate Immunoscore vs 51 (32%) patients with a low Immunoscore; hazard ratio [HR] for high vs low Immunoscore 0·20, 95% CI 0·10-0·38; p<0·0001). The findings were confirmed in the two validation sets (n=1981). In the stratified Cox multivariable analysis, the Immunoscore association with time to recurrence was independent of patient age, sex, T stage, N stage, microsatellite instability, and existing prognostic factors (p<0·0001). Of 1434 patients with stage II cancer, the difference in risk of recurrence at 5 years was significant (HR for high vs low Immunoscore 0·33, 95% CI 0·21-0·52; p<0·0001), including in Cox multivariable analysis (p<0·0001). Immunoscore had the highest relative contribution to the risk of all clinical parameters, including the American Joint Committee on Cancer and Union for International Cancer Control TNM classification system. INTERPRETATION The Immunoscore provides a reliable estimate of the risk of recurrence in patients with colon cancer. These results support the implementation of the consensus Immunoscore as a new component of a TNM-Immune classification of cancer. FUNDING French National Institute of Health and Medical Research, the LabEx Immuno-oncology, the Transcan ERAnet Immunoscore European project, Association pour la Recherche contre le Cancer, CARPEM, AP-HP, Institut National du Cancer, Italian Association for Cancer Research, national grants and the Society for Immunotherapy of Cancer.

Sinusoidal obstruction syndrome (SOS) related to chemotherapy for colorectal liver metastases: factors predictive of severe SOS lesions and protective effect of bevacizumab

OBJECTIVES The most frequent presentation of chemotherapy-related toxicity in colorectal liver metastases (CRLM) is sinusoidal obstruction syndrome (SOS). The purpose of the present study was to identify preoperative factors predictive of SOS and to establish associations between type of chemotherapy and severity of SOS. METHODS A retrospective study was carried out in a tertiary academic referral hospital. Patients suffering from CRLM who had undergone resection of at least one liver segment were included. Grading of SOS on the non-tumoral liver parenchyma was accomplished according to the Rubbia-Brandt criteria. A total of 151 patients were enrolled and divided into four groups according to the severity of SOS (grades 0-3). RESULTS Multivariate analysis identified oxaliplatin and 5-fluorouracil as chemotherapeutic agents responsible for severe SOS lesions (P < 0.001 and P = 0.005, respectively). Bevacizumab was identified as having a protective effect against the occurrence of SOS lesions (P = 0.005). Univariate analysis identified the score on the aspartate aminotransferase : platelets ratio index (APRI) as the most significant biological factor predictive of severe SOS lesions. Splenomegaly is also significantly associated with the occurrence of severe SOS lesions. CONCLUSIONS The APRI score and splenomegaly are effective as factors predictive of SOS. Bevacizumab has a protective effect against SOS.

Radiological imaging markers predicting clinical outcome in patients with metastatic colorectal carcinoma treated with regorafenib: post hoc analysis of the CORRECT phase III trial (RadioCORRECT study)

Objective To identify imaging markers predicting clinical outcomes to regorafenib in metastatic colorectal carcinoma (mCRC). Methods The RadioCORRECT study is a post hoc analysis of a cohort of patients with mCRC treated within the phase III placebo-controlled CORRECT trial of regorafenib. Baseline and week 8 contrast-enhanced CT were used to assess response by RECIST 1.1, changes in the sum of target lesion diameters (ΔSTL), lung metastases cavitation and liver metastases density. Primary and secondary objectives were to develop ex novo univariable and multivariable models to predict overall survival (OS) and progression-free survival (PFS), respectively. Results 202 patients were enrolled, 134 (66.3%) treated with regorafenib and 68 (33.7%) with placebo. In the univariate analysis, PFS predictors were lung metastases cavitation at baseline (HR 0.50, 95% CI 0.27 to 0.92, p=0.03) and at week 8 (HR 0.58, 95% CI 0.36 to 0.93, p=0.02). Baseline cavitation (HR 0.23, 95% CI 0.08 to 0.66, p=0.007), RECIST 1.1 (HR 0.23, 95% CI 0.14 to 0.4, p <0.0001) and ΔSTL (HR 1.16, 95% CI 1.06 to 1.27, p=0.002) predicted OS. We found an increase of 9% of diameter as the best threshold for discriminating OS (HR 2.64, 95% CI 1.61 to 4.34, p <0.001). In the multivariate analysis, baseline and week 8 cavitation remained significant PFS predictors. Baseline cavitation, RECIST 1.1 and ΔSTL remained predictors of OS in exploratory multivariable models. Assessment of liver metastases density did not predict clinical outcome. Conclusions RECIST 1.1 and ΔSTL predict favourable outcome to regorafenib. In contrast to liver metastases density that failed to be a predictor, lung metastases cavitation represents a novel radiological marker of favourable outcome that deserves consideration.

Regorafenib induced severe toxic hepatitis: characterization and discussion.

Regorafenib is the first small‐molecule multikinase inhibitor which showed survival benefits in pretreated metastatic colorectal cancer (mCRC) patients. Besides classical adverse events of this drug class, hepatotoxicity has been described as a frequent side effect.

Evolution of Metastases in Space and Time under Immune Selection

We examined how the immune microenvironment molds tumor evolution at different metastatic organs in a longitudinal dataset of colorectal cancer. Through multiplexed analyses, we showed that clonal evolution patterns during metastatic progression depend on the immune contexture at the metastatic site. Genetic evidence of neoantigen depletion was observed in the sites with high Immunoscore and spatial proximity between Ki67+ tumor cells and CD3+ cells. The immunoedited tumor clones were eliminated and did not recur, while progressing clones were immune privileged, despite the presence of tumor-infiltrating lymphocytes. Characterization of immune-privileged metastases revealed tumor-intrinsic and tumor-extrinsic mechanisms of escape. The lowest recurrence risk was associated with high Immunoscore, occurrence of immunoediting, and low tumor burden. We propose a parallel selection model of metastatic progression, where branched evolution could be traced back to immune-escaping clones. The findings could inform the understanding of cancer dissemination and the development of immunotherapeutics.