Early PET/CT scan is more effective than RECIST in predicting outcome of patients with liver metastases from colorectal cancer treated with preoperative chemotherapy plus bevacizumab

Imaging Considerations before and after Liver-Directed Locoregional Treatments for Metastatic Colorectal Cancer

Colorectal cancer is a leading cause of cancer-related death. Liver metastases will develop in over one-third of patients with colorectal cancer and are a major cause of morbidity and mortality. Even though surgical resection has been considered the mainstay of treatment, only approximately 20% of the patients are surgical candidates. Liver-directed locoregional therapies such as thermal ablation, Yttrium-90 transarterial radioembolization, and stereotactic body radiation therapy are pivotal in managing colorectal liver metastatic disease. Comprehensive pre- and post-intervention imaging, encompassing both anatomic and metabolic assessments, is invaluable for precise treatment planning, staging, treatment response assessment, and the prompt identification of local or distant tumor progression. This review outlines the value of imaging for colorectal liver metastatic disease and offers insights into imaging follow-up after locoregional liver-directed therapy.

Role of PET/Computed Tomography in Gastric and Colorectal Malignancies

This article focuses on the role of PET/computed tomography in evaluating and managing gastric cancer and colorectal cancer. The authors start with describing the common aspects of imaging with 2-deoxy-2-18F-d-glucose, followed by tumor-specific discussions of gastric and colorectal malignancies. Finally, the authors provide a brief overview of non-FDG tracers including their potential clinical applications, and describe future directions in imaging these malignancies.

Extracellular volume fraction can predict the treatment response and survival outcome of colorectal cancer liver metastases

OBJECTIVE

To assess the prognostic value of pre- and post-therapeutic changes in extracellular volume (ECV) fraction of liver metastases (LMs) for treatment response (TR) and survival outcomes in colorectal cancer liver metastases (CRLM).

METHODS

186 LMs were confirmed by pathology or follow-up (Training: 130; Test: 56). We analyzed the changes in ECV fraction of LMs before and after 2 cycles of chemotherapy combined with bevacizumab. After 12 cycles, we evaluated the TR on LMs based on the RECIST v1.1. Relative changes in ECV fraction and Hounsfield Units (HU), defined as ΔECV and ΔHU, were associated with progression-free survival (PFS), overall survival (OS), and TR. We identified TR predictors with multivariate logistic regression and PFS, OS risk factors with COX analysis.

RESULTS

186 LMs were classified as TR lesions (TR+: 84) and non-TR lesions (TR-:102). ΔECV, ΔHUA-E, and texture could distinguish the TR of LMs in training and test set (P < 0.05). ΔECV [Odds ratio (OR): 1.03; 95% Confidence interval (CI): 1.02-1.05, P < 0.01] was an independent predictor of TR-. Area under the curve (AUC), sensitivity and specificity of TR model in training and test set were 0.87, 0.84, 90.14%, 90.32%, 72.88%, 64.00%, respectively. High CRD_score indicates that patients have shorter PFS [Hazard ratio (HR): 2.01; 95%CI: 1.02-3.98, P = 0.045)] and OS (HR: 1.89, 95%CI: 1.04-3.42, P = 0.038).

CONCLUSION

ΔECV can be used as an independent predictor of TR of CRLM chemotherapy combined with bevacizumab.

PET/CT in assessment of colorectal liver metastases: a comprehensive review with emphasis on 18F-FDG

Approximately 25% of those who are diagnosed with colorectal cancer will develop colorectal liver metastases (CRLM) as their illness advances. Despite major improvements in both diagnostic and treatment methods, the prognosis for patients with CRLM is still poor, with low survival rates. Accurate employment of imaging methods is critical in identifying the most effective treatment approach for CRLM. Different imaging modalities are used to evaluate CRLM, including positron emission tomography (PET)/computed tomography (CT). Among the PET radiotracers, fluoro-18-deoxyglucose (18F-FDG), a glucose analog, is commonly used as the primary radiotracer in assessment of CRLM. As the importance of 18F-FDG-PET/CT continues to grow in assessment of CRLM, developing a comprehensive understanding of this subject becomes imperative for healthcare professionals from diverse disciplines. The primary aim of this article is to offer a simplified and comprehensive explanation of PET/CT in the evaluation of CRLM, with a deliberate effort to minimize the use of technical nuclear medicine terminology. This approach intends to provide various healthcare professionals and researchers with a thorough understanding of the subject matter.

Deep radiomics-based fusion model for prediction of bevacizumab treatment response and outcome in patients with colorectal cancer liver metastases: a multicentre cohort study

Background

Accurate tumour response prediction to targeted therapy allows for personalised conversion therapy for patients with unresectable colorectal cancer liver metastases (CRLM). In this study, we aimed to develop and validate a multi-modal deep learning model to predict the efficacy of bevacizumab in patients with initially unresectable CRLM using baseline PET/CT, clinical data, and colonoscopy biopsy specimens.

Methods

In this multicentre cohort study, we retrospectively collected data of 307 patients with CRLM from the BECOME study (NCT01972490) (Zhongshan Hospital of Fudan University, Shanghai) and two independent Chinese cohorts (internal validation cohort from January 1, 2018 to December 31, 2018 at Zhongshan Hospital of Fudan University; external validation cohort from January 1, 2020 to December 31, 2020 at Zhongshan Hospital-Xiamen, Shanghai, and the First Hospital of Wenzhou Medical University, Wenzhou). The main inclusion criteria were that patients with CRLM had pre-treatment PET/CT images as well as colonoscopy specimens. After extracting PET/CT features with deep neural networks (DNN) and selecting related clinical factors using LASSO analysis, a random forest classifier was built as the Deep Radiomics Bevacizumab efficacy predicting model (DERBY). Furthermore, by combining histopathological biomarkers into DERBY, we established DERBY+. The performance of model was evaluated using area under the curve (AUC), sensitivity, specificity, positive predictive value, and negative predictive value.

Findings

DERBY achieved promising performance in predicting bevacizumab sensitivity with an AUC of 0.77 and 95% confidence interval (CI) [0.67-0.87]. After combining histopathological features, we developed DERBY+, which had more robust accuracy for predicting tumour response in external validation cohort (AUC 0.83 and 95% CI [0.75-0.92], sensitivity 80.4%, specificity 76.8%). DERBY+ also had prognostic value: the responders had longer progression-free survival (median progression-free survival: 9.6 vs 6.3 months, p = 0.002) and overall survival (median overall survival: 27.6 vs 18.5 months, p = 0.010) than non-responders.

Interpretation

This multi-modal deep radiomics model, using PET/CT, clinical data and histopathological data, was able to identify patients with bevacizumab-sensitive CRLM, providing a favourable approach for precise patient treatment. To further validate and explore the clinical impact of this work, future prospective studies with larger patient cohorts are warranted.

Funding

The National Natural Science Foundation of China; Fujian Provincial Health Commission Project; Xiamen Science and Technology Agency Program; Clinical Research Plan of SHDC; Shanghai Science and Technology Committee Project; Clinical Research Plan of SHDC; Zhejiang Provincial Natural Science Foundation of China; and National Science Foundation of Xiamen.

FDG PET/CT Depicting Right Iliac Vein Tumor Thrombosis following Low Anterior Resection in Rectal Cancer Patient: A Case Report and Literature Review

Venous tumor thrombus is a rare complication of rectal cancer but is more common in other types of cancer, like renal cell carcinoma and hepatocellular carcinoma. The usual site of tumor thrombus in rectal cancer patients is the inferior mesenteric vein (IMV), which is seldom seen in the common iliac vein, with only a few cases reported till now. We present a case of fluorodeoxyglucose (FDG) avid right iliac vein tumor thrombosis after low anterior resection in a patient with rectal cancer and review the literature.

Early evaluation of liver metastasis using spectral CT to predict outcome in patients with colorectal cancer treated with FOLFOXIRI and bevacizumab

PURPOSE

Early evaluation of the efficacy of first-line chemotherapy combined with bevacizumab in patients with colorectal cancer liver metastasis (CRLM) remains challenging. This study used 2-month post-chemotherapy spectral computed tomography (CT) to predict the overall survival (OS) and response of CRLM patients with bevacizumab-containing therapy.

METHOD

This retrospective analysis was performed in 104 patients with pathologically confirmed CRLM between April 2017 and October 2021. Patients were treated with 5-fluorouracil, leucovorin, oxaliplatin or irinotecan with bevacizumab. Portal venous phase spectral CT was performed on the target liver lesion within 2 months of commencing chemotherapy to demonstrate the iodine concentration (IoD) of the target liver lesion. The patients were classified as responders (R +) or non-responders (R -) according to the Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 at 6 months. Multivariate analysis was performed to determine the relationships of the spectral CT parameters, tumor markers, morphology of target lesions with OS and response. The differences in portal venous phase spectral CT parameters between the R + and R - groups were analyzed. Receiver operating characteristic (ROC) curves were used to evaluate the predictive power of spectral CT parameters.

RESULTS

Of the 104 patients (mean age ± standard deviation: 57.73 years ± 12.56; 60 men) evaluated, 28 (26.9%) were classified as R + . Cox multivariate analysis identified the iodine concentration (hazard ratio [HR]: 1.238; 95% confidence interval [95% CI]: 1.089-1.408; P < 0.001), baseline tumor longest diameter (BLD) (HR: 1.022; 95% CI: 1.005-1.038, P = 0.010), higher baseline CEA (HR: 1.670; 95% CI: 1.016-2.745, P = 0.043), K-RAS mutation (HR: 2.027; 95% CI: 1.192-3.449; P = 0.009), and metachronous liver metastasis (HR: 1.877; 95% CI: 1.179-2.988; P = 0.008) as independent risk factors for patient OS. Logistic multivariate analysis identified the IoD (Odds Ratio [OR]: 2.243; 95% CI: 1.405-4.098; P = 0.002) and clinical N stage of the primary tumor (OR: 4.998; 95% CI: 1.210-25.345; P = 0.035) as independent predictor of R + . Using IoD cutoff values of 4.75 (100ug/cm³) the area under the ROC curve was 0.916, sensitivity and specificity were 80.3% and 96.4%, respectively.

CONCLUSIONS

Spectral CT IoD can predict the OS and response of patients with CRLM after 2 months of treatment with bevacizumab-containing therapy.

Regorafenib monotherapy as second-line treatment of patients with RAS-mutant advanced colorectal cancer (STREAM): an academic, multicenter, single-arm, two-stage, phase II study

BACKGROUND

Maintaining angiogenesis inhibition and switching the chemotherapy backbone represent the current second-line therapy in patients with RAS-mutant metastatic colorectal cancer (mCRC). Regorafenib, an oral multikinase inhibitor, prolonged overall survival (OS) in the chemorefractory setting.

MATERIALS AND METHODS

STREAM was an academic, multicenter, single-arm phase II trial, evaluating the activity of regorafenib in RAS-mutant mCRC, in terms of the rate of patients who were progression-free after 6 months from study entry (6mo-PF). Patients were pretreated with fluoropyrimidine, oxaliplatin, and bevacizumab. According to Simon's two-stage design, ≥18 patients 6mo-PF were needed in the overall population (N = 46). Secondary endpoints were safety, objective response rate (ORR), progression-free survival (PFS), and OS. Early metabolic response by [¹⁸F]2-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography ([¹⁸F]-FDG PET/CT) scan was an exploratory endpoint. EudraCT Number: 2015-001105-13.

RESULTS

The number of patients 6mo-PF was 8/22 at the first stage and 14/46 in the overall population. The ORR was 10.9%, disease control rate was 54.6%, median (m)PFS was 3.6 months [95% confidence interval (CI) 1.9-6.7 months], mOS was 18.9 months (95% CI 10.3-35.3 months), and mPFS2 (from study entry to subsequent-line progression) was 13.3 months (95% CI 8.4-19.7 months). Long benefiter patients (>6mo-PF) significantly more often had a single metastatic site and lung-limited disease. No unexpected toxicity was reported. Grade ≥3 events occurred in 39.1% of patients, with hand-foot syndrome (13%), fatigue, and hyperbilirubinemia (6.5%) occurring mostly. Baseline metabolic assessment was associated with OS in the multivariate analysis, while early metabolic response was not associated with clinical outcomes.

CONCLUSIONS

The study did not meet its primary endpoint. However, regorafenib was well tolerated and did not preclude subsequent treatments. Patients with good prognostic features (single metastatic site and lung-limited disease) reported clinical benefit with regorafenib. The exploratory metabolic analysis suggests that baseline [¹⁸F]-FDG PET/CT might be useful to select patients with a favorable outcome. A chemotherapy-free interval with regorafenib was associated with durable disease control in a selected group of patients with favorable clinical characteristics.

The Value of 18F-FDG-PET-CT Imaging in Treatment Evaluation of Colorectal Liver Metastases: A Systematic Review

(1) Background: Up to 50% of patients with colorectal cancer either have synchronous colorectal liver metastases (CRLM) or develop CRLM over the course of their disease. Surgery and thermal ablation are the most common local treatment options of choice. Despite development and improvement in local treatment options, (local) recurrence remains a significant clinical problem. Many different imaging modalities can be used in the follow-up after treatment of CRLM, lacking evidence-based international consensus on the modality of choice. In this systematic review, we evaluated ¹⁸F-FDG-PET-CT performance after surgical resection, thermal ablation, radioembolization, and neoadjuvant and palliative chemotherapy based on current published literature. (2) Methods: A systematic literature search was performed on the PubMed database. (3) Results: A total of 31 original articles were included in the analysis. Only one suitable study was found describing the role of ¹⁸F-FDG-PET-CT after surgery, which makes it hard to draw a firm conclusion. ¹⁸F-FDG-PET-CT showed to be of additional value in the follow-up after thermal ablation, palliative chemotherapy, and radioembolization. ¹⁸F-FDG-PET-CT was found to be a poor to moderate predictor of pathologic response after neoadjuvant chemotherapy. (4) Conclusions: ¹⁸F-FDG-PET-CT is superior to conventional morphological imaging modalities in the early detection of residual disease after thermal ablation and in the treatment evaluation and prediction of prognosis during palliative chemotherapy and after radioembolization, and ¹⁸F-FDG-PET-CT could be considered in selected cases after neoadjuvant chemotherapy and surgical resection.

Predicting malignancy in patients with adrenal tumors using 18 F-FDG-PET/CT SUVmax

BACKGROUND AND OBJECTIVES

¹⁸ F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸ F-FDG-PET/CT) parameters may help distinguish malignant from benign adrenal tumors, but few have been externally validated or determined based on definitive pathological confirmation. We determined and validated a threshold for ¹⁸ F-FDG-PET/CT maximum standard uptake value (SUVmax) in patients who underwent adrenalectomy for a nonfunctional tumor.

METHODS

Database review identified patients with ¹⁸ F-FDG-PET/CT images available (training cohort), or only SUVmax values (validation cohort). Discriminative accuracy was assessed by area under the curve (AUC), and the optimal cutoff value estimated by maximally selected Wilcoxon rank statistics.

RESULTS

Of identified patients (n = 171), 86 had adrenal metastases, 20 adrenal cortical carcinoma, and 27 adrenal cortical adenoma. In the training cohort (n = 96), SUVmax was significantly higher in malignant versus benign tumors (median 8.3 vs. 3.0, p < .001), with an AUC of 0.857. Tumor size did not differ. The optimal cutoff SUVmax was 4.6 (p < .01). In the validation cohort (n = 75), this cutoff had a sensitivity of 75% and specificity 55%.

CONCLUSIONS

¹⁸ F-FDG-PET/CT SUVmax was associated with malignancy. Validation indicated that SUVmax ≥ 4.6 was suggestive of malignancy, while lower values did not reliably predict benign tumor.

Taiwan Society of Colon and Rectal Surgeons (TSCRS) Consensus for Cytoreduction Selection in Metastatic Colorectal Cancer

BACKGROUND

Taiwan has witnessed a surge in the incidence of colorectal cancer (CRC), of which 40-60% metastasize. Continuous updating of cytoreductive strategies in metastatic CRC (mCRC) has contributed to median overall survival reaching 40 months. In this changing scenario, to standardize the approaches across Taiwan, a group of experts from the Taiwan Society of Colon and Rectal Surgeons (TSCRS) convened to establish evidence- and opinion-based recommendations for defining the criteria of "resectability" in mCRC.

METHODS

Over the course of one-on-one consultations, lasting 30-40 min each, with 30 medical specialists (19 colorectal surgeons, 4 general surgeons, and 7 medical oncologists) from 16 hospitals in Taiwan followed by a 2-h meeting with 8 physician experts (3 general surgeons, 4 colorectal surgeons, and 1 thoracic surgeon), 12 key questions on cytoreduction were addressed. This was further contextualized based on published literature.

RESULTS

The final consensus includes eight recommendations regarding the criteria for metastasis resection, role of local control treatment in liver potentially resectable patients, management of synchronous liver metastases, approach for peritoneal metastasis, place for resection in multiple-organ metastasis, and general criteria for resectability.

CONCLUSIONS

mCRC patients undergoing R0 resection have the greatest survival advantage following surgery. Our role as a multidisciplinary team (MDT) should be to treat potentially resectable mCRC patients as rapidly and safely as possible, and achieve R0 resection as far as possible and for as long as possible (continuum of care). This TSCRS consensus statement aims to help build clinical capacity within the MDTs, while making better use of existing healthcare resources.

Signal changes in T2-weighted MRI of liver metastases under bevacizumab-A practical imaging biomarker?

OBJECTIVE

The purpose of this study was to investigate signal changes in T2-weighted magnetic resonance imaging of liver metastases under treatment with and without bevacizumab-containing chemotherapy and to compare these signal changes to tumor contrast enhancement.

MATERIALS AND METHODS

Retrospective analysis of 44 patients, aged 36-84 years, who underwent liver magnetic resonance imaging including T2-weighted and dynamic contrast enhancement sequences. Patients received bevacizumab-containing (n = 22) or conventional cytotoxic chemotherapy (n = 22). Magnetic resonance imaging was obtained at baseline and at three follow-ups (on average 3, 6 and 9 months after initial treatment). Three independent readers rated the T2 signal intensity and the relative contrast enhancement of the metastases on a 5-point scale.

RESULTS

T2 signal intensity of metastases treated with bevacizumab showed a significant (p<0.001) decrease in T2 signal intensity after initial treatment and exhibit compared to conventionally treated metastases significantly (p<0.001 for each follow-up) hypointense (bevacizumab: 0.70 ± 0.83 before vs. -1.55 ± 0.61, -1.91 ± 0.62, and -1.97 ± 0.52; cytotoxic: 0.73 ± 0.79 before vs. -0.69 ± 0.81, -0.71 ± 0.68, and -0.75 ± 0.65 after 3, 6, and 9 months, respectively). T2 signal intensity was strongly correlated with tumor contrast enhancement (r = 0.71; p<0.001). Intra-observer agreement for T2-signal intensity was substantial (κ = 0.75). The agreement for tumoral contrast enhancement between the readers was considerably lower (κ = 0.39).

CONCLUSION

Liver metastases exhibit considerably hypointense in T2-weighted imaging after treatment with bevacizumab, in contrast to conventionally treated liver metastases. Therefore, T2-weighted imaging seems to reflect the effect of bevacizumab.

Colorectal cancer: Parametric evaluation of morphological, functional and molecular tomographic imaging

Colorectal cancer (CRC) represents one of the leading causes of tumor-related deaths worldwide. Among the various tools at physicians’ disposal for the diagnostic management of the disease, tomographic imaging (e.g., CT, MRI, and hybrid PET imaging) is considered essential. The qualitative and subjective evaluation of tomographic images is the main approach used to obtain valuable clinical information, although this strategy suffers from both intrinsic and operator-dependent limitations. More recently, advanced imaging techniques have been developed with the aim of overcoming these issues. Such techniques, such as diffusion-weighted MRI and perfusion imaging, were designed for the “in vivo” evaluation of specific biological tissue features in order to describe them in terms of quantitative parameters, which could answer questions difficult to address with conventional imaging alone (e.g., questions related to tissue characterization and prognosis). Furthermore, it has been observed that a large amount of numerical and statistical information is buried inside tomographic images, resulting in their invisibility during conventional assessment. This information can be extracted and represented in terms of quantitative parameters through different processes (e.g., texture analysis). Numerous researchers have focused their work on the significance of these quantitative imaging parameters for the management of CRC patients. In this review, we aimed to focus on evidence reported in the academic literature regarding the application of parametric imaging to the diagnosis, staging and prognosis of CRC while discussing future perspectives and present limitations. While the transition from purely anatomical to quantitative tomographic imaging appears achievable for CRC diagnostics, some essential milestones, such as scanning and analysis standardization and the definition of robust cut-off values, must be achieved before quantitative tomographic imaging can be incorporated into daily clinical practice.

Measurement of 18F-FDG PET tumor heterogeneity improves early assessment of response to bevacizumab compared with the standard size and uptake metrics in a colorectal cancer model

PURPOSE

Treatment of metastatic colorectal cancer frequently includes antiangiogenic agents such as bevacizumab. Size measurements are inadequate to assess treatment response to these agents, and newer response assessment criteria are needed. We aimed to evaluate F-FDG PET-derived texture parameters in a preclinical colorectal cancer model as alternative metrics of response to treatment with bevacizumab.

MATERIALS AND METHODS

Fourteen CD1 athymic mice injected in the flank with 5×106 LS174T cells (human colorectal carcinoma) were either untreated controls (n=7) or bevacizumab treated (n=7). After 2 weeks, mice underwent F-FDG PET/CT. Calliper-measured tumor growth (Δvol) and final tumor volume (Volcal), F-FDG PET metabolically active volume (Volmet), mean metabolism (Metmean), and maximum metabolism (Metmax) were measured. Twenty-four texture features were compared between treated and untreated mice. Immunohistochemical mean tumor vascular density was estimated by anti-CD-34 staining after tumor resection.

RESULTS

Treated mice had significantly lower tumor vascular density (P=0.032), confirming the antiangiogenic therapeutic effect of bevacizumab. None of the conventional measures were different between the two groups: Δvol (P=0.9), Volcal (P=0.7), Volmet (P=0.28), Metmax (P=0.7), or Metmean (P=0.32). One texture parameter, GLSZM-SZV (visually indicating that the F-FDG PET images of treated mice comprise uniformly sized clusters of different activity) had significantly different means between the two groups of mice (P=0.001).

CONCLUSION

F-FDG PET derived texture parameters, particularly GLSZM-SZV, may be valid biomarkers of tumor response to treatment with bevacizumab, before change in volume.

A strategy for early detection of response to chemotherapy drugs based on treatment-related changes in the metabolome

We describe a biomarker-based approach to delivering chemotherapy that entails monitoring treatment changes in the circulating metabolome that reflect efficacy. In-vitro, multiple tumor cell lines were exposed to numerous chemotherapeutics. Supernatants were collected at baseline and 72 hours post treatment. MTT assays were used to quantify growth inhibition. Clinical samples were derived from a phase II clinical trial of second-line axitinib in patients with advanced hepatocellular carcinoma. Sera were collected at baseline and 2–4 weeks after treatment initiation. Response to therapy was estimated by CT scan at 8 weeks. Samples were analyzed by gas chromatography-mass spectrometry to identify metabolomic changes associated with response. In vitro, we found drug-specific and generalizable patterns of change in the extracellular metabolome accompany growth inhibition. A cell death signature was also identified. This approach was also applied to clinical samples. While the in vitro signatures were detectable in vivo, a more robust signal was identified clinically that appeared within 4 weeks of administering drug that distinguished individuals with a treatment response. These changes were extinguished as tumor growth resumed. Serial monitoring of the metabolome during chemotherapy is a means to follow treatment efficacy and emergence of resistance, informing the oncologist whether to modify treatment.

18F-FDG PET/CT Is an Early Predictor of Pathologic Tumor Response and Survival After Preoperative Radiochemotherapy with Bevacizumab in High-Risk Locally Advanced Rectal Cancer

There is an unmet need for predictive biomarkers of the clinical benefit of antiangiogenic drugs. The aim of the present study was to prospectively evaluate the value of ¹⁸F-FDG PET/CT performed during and after preoperative chemoradiotherapy with bevacizumab for the prediction of complete pathologic tumor regression and survival in patients with MRI-defined high-risk locally advanced rectal cancer. Methods: Sixty-one patients treated in a nonrandomized phase II study (BRANCH) with concomitant or sequential (4 d before chemoradiotherapy) administration of bevacizumab with preoperative chemoradiotherapy were included. ¹⁸F-FDG PET/CT was performed at baseline, 11 d after the beginning of chemoradiotherapy (early), and before surgery (late). Metabolic changes were compared with pathologic complete tumor regression (TRG1) versus incomplete tumor regression (TRG2-TRG5), progression-free survival, cancer-specific survival, and overall survival. Receiver-operating-characteristic curves were calculated for those ¹⁸F-FDG PET/CT parameters that significantly correlated with TRG1. Results: Early total-lesion glycolysis and its percentage change compared with baseline (ΔTLG-early) could discriminate TRG1 from TRG2-TRG5. Only receiver-operating-characteristic analysis of ΔTLG-early showed an area under the curve greater than 0.7 (0.76), with an optimal cutoff at 59.5% (80% sensitivity, 71.4% specificity), for identifying TRG1. Late metabolic assessment could not discriminate between the 2 groups. After a median follow-up of 98 mo (range, 77-132 mo), metabolic responders (ΔTLG-early ≥ 59.5%) demonstrated a significantly higher 10-y progression-free survival (89.3% vs. 63.6%, P = 0.02) and cancer-specific survival (92.9% vs. 72.6%, P = 0.04) than incomplete metabolic responders. Conclusion: Our results suggest that early metabolic response can act as a surrogate marker of the benefit of antiangiogenic therapy. The findings provide further support for the use of early ¹⁸F-FDG PET/CT evaluation to predict pathologic response and survival in the preoperative treatment of patients with locally advanced rectal cancer. ΔTLG-early showed the best accuracy in predicting tumor regression and may be particularly useful in guiding treatment-modifying decisions during preoperative chemoradiotherapy based on expected response.

Prognostic modeling for patients with colorectal liver metastases incorporating FDG PET radiomic features

OBJECTIVE

We aimed to improve prediction of outcome for patients with colorectal liver metastases, via prognostic models incorporating PET-derived measures, including radiomic features that move beyond conventional standard uptake value (SUV) measures.

PATIENTS AND METHODS

A range of parameters including volumetric and heterogeneity measures were derived from FDG PET images of 52 patients with colorectal intrahepatic-only metastases (29 males and 23 females; mean age 62.9 years [SD 9.8; range 32-82]). The patients underwent PET/CT imaging as part of the clinical workup prior to final decision on treatment. Univariate and multivariate models were implemented, which included statistical considerations (to discourage false discovery and overfitting), to predict overall survival (OS), progression-free survival (PFS) and event-free survival (EFS). Kaplan-Meier survival analyses were performed, where the subjects were divided into high-risk and low-risk groups, from which the hazard ratios (HR) were computed via Cox proportional hazards regression.

RESULTS

Commonly-invoked SUV metrics performed relatively poorly for different prediction tasks (SUVmax HR = 1.48, 0.83 and 1.16; SUVpeak HR = 2.05, 1.93, and 1.64, for OS, PFS and EFS, respectively). By contrast, the number of liver metastases and metabolic tumor volume (MTV) each performed well (with respective HR values of 2.71, 2.61 and 2.42, and 2.62, 1.96 and 2.29, for OS, PFS and EFS). Total lesion glycolysis (TLG) also resulted in similar performance as MTV. Multivariate prognostic modeling incorporating different features (including those quantifying intra-tumor heterogeneity) resulted in further enhanced prediction. Specifically, HR values of 4.29, 4.02 and 3.20 (p-values = 0.00004, 0.0019 and 0.0002) were obtained for OS, PFS and EFS, respectively.

CONCLUSIONS

PET-derived measures beyond commonly invoked SUV parameters hold significant potential towards improved prediction of clinical outcome in patients with liver metastases, especially when utilizing multivariate models.

Predictive value of positron emission tomography for the prognosis of molecularly targeted therapy in solid tumors

Objective

This study aimed at comprehensively exploring the value applying positron emission tomography (PET) to predict the effect of molecularly targeted therapy in solid tumors.

Materials and methods

A systematic search was performed for potentially relevant studies from the time of inception to February 2017. The primary endpoints were progression-free survival (PFS), overall survival (OS), and time to progression (TTP). The results were analyzed by Review Manager version 5.3 (RevMan 5.3) statistical software. Subgroup analyses were implemented based on the type of molecularly targeted agents (monoclonal antibodies arm and small molecular targeted agents arm), mechanism (erlotinib/gefitinib arm and bevacizumab arm), radioactive tracers, type of tumor, and reevaluated PET timing.

Results

Twenty-six studies incorporating 865 individuals were eligible. Compared with PET nonresponse group, PET response group displayed a decrease in maximal standard uptake value (SUVmax), which was associated with a significantly prolonged PFS (HR =0.41, 95% CI [0.29, 0.59]; P<0.00001), OS (HR =0.52, 95% CI [0.40, 0.67]; P<0.00001), and TTP (HR =0.30, 95% CI [0.14, 0.66]; P=0.003). Similar results were obtained in the subgroup analyses of PFS in erlotinib/gefitinib arm and small molecular targeted agents arm; and OS in lung cancer arm, erlotinib/gefitinib arm, bevacizumab arm, small molecular targeted agents arm, monoclonal antibodies arm, 18F-fluorodeoxythymidine (18F-FLT) arm, 18F-fluorodeoxyglucose (18F-FDG) arm, and early PET timing arm.

Conclusion

Our study demonstrated that PET was a favorable approach to predict the prognosis of molecularly targeted therapy for solid tumors. PET assessment within 2 weeks could be useful to predict clinical outcome.

Imaging of the Postoperative Colon

Recognition of postoperative complications is important for the immediate diagnosis and treatment needed for appropriate patient care. Identification of postoperative complications from colon surgery requires not only knowledge of the type of procedure, but also the expected normal postoperative appearance. The purpose of this article is to discuss and review the expected anatomic changes after colorectal surgery, and the appearance of the most common postoperative complications.

A radiologist's point of view in the presurgical and intraoperative setting of colorectal liver metastases

Multidisciplinary management of patients with metastatic colorectal cancer requires in each phase an adequate choice of the most appropriate imaging modality. The first challenging step is liver lesions detection and characterization, using several imaging modality ultrasound, computed tomography, magnetic resonance and positron emission tomography. The criteria to establish the metastases resectability have been modified. Not only the lesions number and site but also the functional volume remnant after surgery and the quality of the nontumoral liver must be taken into account. Radiologists should identify the liver functional volume remnant and during liver surgical procedures should collaborate with the surgeon to identify all lesions, including those that disappeared after the therapy, using intraoperative ultrasound with or without contrast medium.

Repeated Transarterial Chemoembolization with Degradable Starch Microspheres (DSMs-TACE) of Unresectable Hepatocellular Carcinoma: A Prospective Pilot Study

OBJECTIVE

The aims of this study were to: a) evaluate tumor response rates using modified-Response-evaluation-criteria-in-solid-tumors (mRecist) criteria, b) evaluate safety of Degradable Starch Microspheres Trans-arterial-chemo-embolization (DSMs-TACE) for unresectable hepatocellular-carcinoma (HCC) treatment.

MATERIALS AND METHODS

We prospectively enrolled 24 HCC cirrhotic patients (21/3 M/F, mean age 66.3 years) to be treated with repeated DSMs-TACE procedures, performed at 4-6 week intervals on the basis of tumor response and patients tolerance. Clinical and biochemical evaluations were performed before and after each procedure. Treatment response was also assessed by Computed-tomography (CT) or Magnetic-resonance-imaging (MRI)-scan 4-6 weeks following each procedure.

RESULTS

In our experience, DSMs-TACE was both safe and effective. A total of 53 DSMs-TACE procedures were performed (2.2 per patient). No procedure-related death was observed. Complete Response (CR) was observed in 5/24 (20.8%), 4/17 (23.5%) and 5/12 (41.6%) patients after the first, second and third procedure, respectively. At the end of each treatment, all patients experienced at least a partial response. At the end of the repeated procedures, no differences between mono- or bi-lobar disease were observed in patients with CR (64.2% vs 50%; p=ns). In most cases, treatment discontinuation was due to worsening liver function.

CONCLUSION

DSMs-TACE is a valid, well-tolerated alternative treatment to Lipiodol-TACE or DEB-TACE, as it has demonstrated to achieve a relatively high percentage of complete tumor necrosis. CR rates were similar between patients with mono- or bi-lobar disease indicating the possibility of carrying-out repeated procedure in a safe and effective way in both types of patients.

Prospective evaluation of plasma Epstein-Barr virus DNA clearance and fluorodeoxyglucose positron emission scan in assessing early response to chemotherapy in patients with advanced or recurrent nasopharyngeal carcinoma

BACKGROUND

Plasma Epstein-Barr virus (pEBV) DNA and fluorodeoxyglucose positron emission (PET) reflect tumour burden in advanced NPC. This study hypothesised that a dual endpoint based on assessing pEBV DNA clearance and PET response could predict early drug response.

METHODS

Eligible patients underwent a computed tomography (CT) scan and dual PET-CT at baseline, a PET-CT at 4 weeks, and then a CT scan at 10 weeks after starting palliative or induction chemotherapy. Plasma EBV DNA clearance was determined.

RESULTS

Fifty-eight out of 70 enrolled patients completed all imaging and 50/58 had falling pEBV DNA level, which allowed calculation of the clearance. At a median follow-up of 29.1 months, the dual endpoint (pEBV DNA clearance ≤ 10 days and > 50% drop in sum of SUVmax of target lesions) was an independent indicator of overall survival (hazard ratio (HR) = 0.135, 95% CI = 0.039 to 0.466, p = 0.0015) and progression-free survival (HR = 0.136, 95% CI = 0.048 to 0.385, p = 0002). This dual endpoint could predict subsequent response by Response Evaluation Criteria In Solid Tumours (RECIST) criteria at 10 weeks after chemotherapy.

CONCLUSIONS

Early PET-CT response and pEBV DNA clearance could predict survival and subsequent response. This dual endpoint is an innovative tool for assessing early drug response.

Late gadolinium enhancement of colorectal liver metastases post-chemotherapy is associated with tumour fibrosis and overall survival post-hepatectomy

Purpose

To determine whether late gadolinium MRI enhancement of colorectal liver metastases (CRCLM) post-chemotherapy is associated with tumour fibrosis and survival post-hepatectomy.

Materials and methods

The institutional review board approved this retrospective cohort study and waived the requirement for informed consent. A cohort of 121 surgical patients who received preoperative MRI after chemotherapy between 2006-2012 was included in this study. Target tumour enhancement (TTE), defined as the mean contrast-to-noise ratio of up to two target lesions on late-phase gadobutrol-enhanced MRI, was determined by two independent raters. The average TTE was correlated with tumour fibrosis on post-hepatectomy specimens using Spearman correlation and with survival post-hepatectomy using Kaplan-Meier and Cox regression. Inter-rater reliability was determined using relative intra-class correlation coefficients.

Results

In the surgical cohort (mean age: 63.0 years; male: 58%), TTE was associated with tumour fibrosis (r = 0.43, p < 0.001). Strong TTE was associated with improved survival compared to weak TTE (3-year survival: 88.4% vs. 58.8%, p = 0.003) with a hazard ratio of 0.32 (95% CI: 0.14-0.75, p = 0.008), after taking into account known prognostic variables. Inter-rater reliability was very good with a relative intraclass correlation of 0.84 (95% CI: 0.77-0.89).

Conclusion

Late gadolinium MRI enhancement of CRCLM post-chemotherapy is associated with tumour fibrosis and survival.

Key Points

• MRI enhancement of colorectal liver metastases is associated with survival post-hepatectomy

• MRI enhancement of chemotherapy-treated colorectal liver metastases correlates with tumour fibrosis

• Measuring late MRI enhancement using target tumour enhancement is reliable

Surgical Treatment following Chemo-Targeted Therapy with Bevacizumab for Lung Metastasis from Colorectal Carcinoma: Analysis of Safety and Histological Therapeutic Effects in Patients Treated at a Single Institution

Background

Recently, therapeutic strategies for a metastasectomy from colorectal carcinoma after chemo-targeted therapy with bevacizumab have been presented, with which some uncommon but serious adverse events have been reported. However, only few reports have investigated the safety of lung resection after such therapy or the histological effects. We retrospectively analyzed the both of them at our institute.

Methods

Of 69 colorectal carcinoma patients who underwent pulmonary metastasectomy procedures from 2009 to 2014, we investigated 11 who also received chemo-targeted therapy prior to surgery.

Results

In addition to bevacizumab, 5 fluorouracil (FU)/leucovorin + oxaliplatin or capecitabine was given in 6 cases and 5 FU/leucovorin + irinotecan in 5 cases. The mean period from the end of chemo-targeted therapy to surgery was 2.7 ± 0.9 months. The response to therapy shown in imaging findings was progressive disease in 6, stable disease in 3, and partial response in 2 (response rate, 18.2%). The operation modes were wedge resection (n = 8, 72.3%), segmentectomy (n = 2, 1 in bilateral lobes, 1 in the right lobe, 18.2%), and lobectomy (n = 1, left lower lobectomy, 9.1%). All patients safely underwent a complete resection. As for postsurgical complications, chylothorax occurred in 1 case and prolonged pulmonary air leakage in 1 case. The histological effects of chemo-targeted therapy were slight. There was no relationship between histological findings with imaging findings obtained prior to the operation (p = 0.63). The 5-year disease-free survival rate after metastasectomy was 10.9%.

Conclusions

Pulmonary metastasectomy after chemo-targeted therapy for colorectal carcinoma patients obtained acceptable results. In addition, there was no correlation between imaging and histopathologic results following chemo-targeted therapy.

Identifying an early indicator of drug efficacy in patients with metastatic colorectal cancer-a prospective evaluation of circulating tumor cells, 18F-fluorodeoxyglucose positron-emission tomography and the RECIST criteria

Background

This study investigated the predictive and prognostic significance of assessing early drug response with both positron-emission computerized tomography (PET-CT) and circulating tumor cells (CTCs) in patients receiving first-line chemotherapy for metastatic colorectal cancer.

Patients and methods

Eligible patients had PET-CT and CTC analysis at baseline and 4-6 weeks after starting chemotherapy, and then a CT scan at 10-12 weeks to assess the Response Evaluation Criteria In Solid Tumors (RECIST) response. Early response was defined as achieving a dual-endpoint consisting of PET-CT (30% drop in the sum of maximum standard uptake values-SUVmax-of target lesions) and CTC response (CTC < 3 cells/7.5 ml blood) at 4-6 weeks after starting chemotherapy.

Results

About 84 patients were enrolled with a median follow-up of 32.9 months (95% confidence interval, CI, 24.5 months-not reached, NR), and 70 patients (84.3%) completed all assessments. Achieving an early response based on the dual-endpoint was independently associated with progression-free survival (hazard ratio, HR = 0.452, 95% CI 0.267-0.765). The median progression-free survival of early responders was 7.41 months (95% CI, 6.05-9.11) compared with 5.37 months (95% CI, 4.68-6.24) in non-responders (log-rank, P = 0.0167). RECIST response at 10 weeks was independently associated with overall survival (OS) (HR = 0.484, 95% CI, 0.275-0.852). Early response based on the dual-endpoint could predict the subsequent RECIST response with a sensitivity, specificity and positive predictive value of 64%, 70% and 74%, respectively.

Conclusions

Early response based on both PET-CT and CTC analysis has prognostic and probably predictive significance in patients undergoing first-line chemotherapy for metastatic colorectal cancer. Its utility as a new tool for assessing early drug response should be further validated.

Colorectal cancer with Synchronous liver-limited Metastases: the protocol of an Inception Cohort study (CoSMIC)

INTRODUCTION

Colorectal cancer is the fourth most common cancer in the UK and an important cause of cancer-related death. In 20% of patients, there is metastasis to the liver or beyond at the time of diagnosis. The management of synchronous disease is complex. Conventional surgery removes the colorectal primary first, followed by chemotherapy, with resection of liver metastases as a final step. Advances in the availability and safety of liver surgery, anaesthesia and critical care have made two alternative options feasible. The first is synchronous resection of the primary and liver metastases. The second is resection of the metastatic disease as the first step, termed the reverse or liver-first approach. Currently, evidence is inadequate to inform the selection of care pathway for patients with colorectal cancer and synchronous liver-limited metastases. Specifically, optimal pathways are not defined and there is a dearth of prospectively recorded cohort-defining factors influencing treatment selection or outcome.

METHODS AND ANALYSIS

Colorectal cancer with Synchronous liver-limited Metastases: an Inception Cohort (CoSMIC) is an inception cohort study of patients with a new diagnosis of colorectal cancer with synchronous liver-limited metastases. The sequence of treatment received, and factors influencing treatment decisions, will be evaluated against European Society of Medical Oncology guidelines. Clinical data will be collected, and quality of life, morbidity, mortality and long-term outcome compared for different treatment sequences adjusted for prognostic factors. Disease-free survival or progression will be measured at 1, 2 and 5 years. A nested qualitative study will ascertain patient experiences and clinician perspectives on delivery of care.

ETHICS AND DISSEMINATION

The full study protocol was independently peer reviewed by Professor Kees de Jong (University of Maastricht, Holland). CoSMIC has ethical approval from the National Health Service Research Ethics Committee (14/NW/1397). Results will be disseminated to healthcare professionals and patient groups, and may be used to design a definitive trial addressing areas of equipoise in treatment pathways, as well as optimising current pathways to improve outcomes and experiences.

TRIAL REGISTRATION NUMBER

NCT02456285, pre-results.

Total lesion glycolysis (TLG) as an imaging biomarker in metastatic colorectal cancer patients treated with regorafenib

PURPOSE

This study was performed to evaluate whether fluorine-18 fluorodeoxyglucose positron-emission tomography/computed tomography (FDG PET/CT) could predict treatment outcome of regorafenib in metastatic colorectal cancer (mCRC).

METHODS

Previously treated refractory mCRC patients were enrolled into a prospective biomarker study of regorafenib. For this sub-study, the results of FDG PET/CT scans at baseline and after two cycles of treatment were analyzed. Various metabolic parameters obtained from PET images were analyzed in relation to treatment outcome.

RESULTS

A total of 40 patients were evaluable for PET image analysis. Among various PET parameters, total lesion glycolysis (TLG) measured in the same target lesions for RECIST 1.1 analysis were the most significant in predicting prognosis, with the lowest p-value observed in TLG calculated using the margin threshold of 40 % (TLG_{40 %}). Further analysis using TLG_{40 %} showed significantly longer overall survival (OS) in patients with lower baseline TLG_{40 %} (<151.8) (p = 0.003, median 14.2 vs. 9.1 months in <151.8 and ≥151.8, respectively). Patients showing higher decrease in TLG_{40 %} after treatment showed significantly longer progression-free survival (PFS) (p = 0.001, median 8.0 vs. 2.4 months in %ΔTLG_{40 %} < -9.6 % and ≥ -9.6 %, respectively) and OS (p = 0.002, median 16.4 vs. 9.1 months in %ΔTLG_{40 %} < -9.6 % and ≥ -9.6 %, respectively). The same cutoff could discriminate patients with longer survival among the patients who were under the stable disease category according to RECIST 1.1 (median PFS 8.4 vs. 6.8 months, p = 0.020; median OS 18.3 vs. 11.5 months, p = 0.049).

CONCLUSION

Measurement of TLG can predict treatment outcome of regorafenib in mCRC.

Timing and extent of response in colorectal cancer: critical review of current data and implication for future trials

The identification of new surrogate endpoints for advanced colorectal cancer is becoming crucial and, along with drug development, it represents a research field increasingly studied. Although overall survival (OS) remains the strongest trial endpoint available, it requires larger sample size and longer periods of time for an event to happen. Surrogate endpoints such as progression free survival (PFS) or response rate (RR) may overcome these issues but, as such, they need to be prospectively validated before replacing the real endpoints; moreover, they often bear many other limitations. In this narrative review we initially discuss the role of time-to-event endpoints, objective response and response rate as surrogates of OS in the advanced colorectal cancer setting, discussing also how such measures are influenced by the tumor assessment criteria currently employed. We then report recent data published about early tumor shrinkage and deepness of response, which have recently emerged as novel potential endpoint surrogates, discussing their strengths and weaknesses and providing a critical comment. Despite being very compelling, the role of such novel response measures is yet to be confirmed and their surrogacy with OS still needs to be further investigated within larger and well-designed trials.

Surrogate Imaging Biomarkers of Response of Colorectal Liver Metastases After Salvage Radioembolization Using 90Y-Loaded Resin Microspheres

OBJECTIVE

The purpose of the present study is to evaluate Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1, tumor attenuation criteria, Choi criteria, and European Organization for Research and Treatment of Cancer (EORTC) PET criteria as measures of response and subsequent predictors of liver progression-free survival (PFS) after radioembolization (RE) of colorectal liver metastases (CLM). The study also assesses interobserver variability for measuring tumor attenuation using a single 2D ROI on a simple PACS workstation.

MATERIALS AND METHODS

We performed a retrospective review of the clinical RE database at our institution, to identify patients treated in the salvage setting for CLM between December 2009 and March 2013. Response was evaluated on FDG PET scans, with the use of EORTC PET criteria, and on portal venous phase CT scans, with the use of RECIST 1.1, tumor attenuation criteria, and Choi criteria. Two independent blinded observers measured tumor attenuation using a single 2D ROI. The intraclass correlation coefficient (ICC) for interobserver variability was assessed. Kaplan-Meier methodology was used to calculate liver PFS, and the log-rank test was used to assess the response criteria as predictors of liver PFS.

RESULTS

A total of 25 patients with 46 target tumors were enrolled in the study. The ICC was 0.95 at baseline and 0.98 at response evaluation. Among the 25 patients, more responders (i.e., partial response) were identified on the basis of EORTC PET criteria (n = 14), Choi criteria (n = 15), and tumor attenuation criteria (n = 13) than on the basis of RECIST 1.1 (n = 2). The median liver PFS was 3.0 months (95% CI, 2.1-4.0 months). Response identified on the basis of EORTC PET criteria (p < 0.001), Choi criteria (p < 0.001), or tumor attenuation criteria (p = 0.01) predicted liver PFS; however, response identified by RECIST 1.1 did not (p = 0.1).

CONCLUSION

RECIST 1.1 has poor sensitivity for detecting metabolic responses classified by EORTC PET criteria. EORTC PET criteria, Choi criteria, and tumor attenuation criteria appear to be equally reliable surrogate imaging biomarkers of liver PFS after RE in patients with CLM.

Is early response by (18)F-2-fluoro-2-deoxy-D-glucose positron emission tomography-computed tomography a predictor of long-term outcome in patients with metastatic colorectal cancer?

BACKGROUND

Identify in advance responder patients to chemotherapy in metastatic colorectal cancer (CRC) would allow prompt interruption of ineffective therapies in non-responder patients. Hence, predictive markers are sought in numerous trials to detect responder patients, including tumor shrinkage measured by imaging methods. Usually, Response Evaluation Criteria in Solid Tumors (RECIST) is used to evaluate tumor response in metastatic CRC, but these criteria are questionable with use of biological agents associated to chemotherapy. Our aim was correlate early metabolic response by (18)F-2-fluoro-2-deoxy-D-glucose positron emission tomography-computed tomography ((18)FDG-PET-CT) with long-term outcome in metastatic CRC in first-line therapy.

METHODS

We prospectively evaluated 36 patients with metastatic CRC in first-line treatment with 5-fluorouracil, leucovorin (folinic acid), oxaliplatin (FOLFOX) or 5-fluorouracil, leucovorin (folinic acid), irinotecan (FOLFIRI) associated with cetuximab or bevacizumab. (18)FDG-PET-CT was performed at baseline and after two cycles of chemotherapy. The early metabolic response [standardized uptake value (SUV)] was measured to identify responder and non-responder patients and correlated with overall survival (OS) and progression-free survival (PFS).

RESULTS

Median age was 58.5 years (range, 41-74 years). PFS was 15.5 months for responder and 13.3 months for non-responder (P=0.42), OS was 55.7 months for responder and not reached for non-responder. There was no correlation between delta-SUV and clinical and pathological variables analyzed. In the subgroup of patients who did not undergo resection of metastasis (45%), PFS was higher for responders (15.3×6.8 months, P=0.02).

CONCLUSIONS

According to our findings, early response by (18)FDG-PET-CT was not a predictor of long-term outcome for patients with metastatic CRC treated in the first-line chemotherapy with a monoclonal antibody.

Early 18F-FDG PET/CT Evaluation Shows Heterogeneous Metabolic Responses to Anti-EGFR Therapy in Patients with Metastatic Colorectal Cancer

OBJECTIVE

The aim of this pilot study was to explore intrapatient mixed metabolic response and early 18F-FDG PET response evaluation using predefined quantification strategies in patients with advanced KRAS wild-type colorectal adenocarcinoma (mCRC) treated with cetuximab.

METHODS

A 18F-FDG PET was performed at baseline and after 2 cycles of cetuximab. Metabolic response was categorized using thresholds suggested in PERCIST. Quantitative analysis was done for the sum of all target lesions, ≤ 5 lesions and the metabolically most active lesion per PET. Quantitative data were correlated with clinical benefit, according to RECIST v1.1, after two months of treatment.

RESULTS

In nine evaluable patients the total number of target lesions was 34 (1-8 per patient). Mixed metabolic response was observed in three out of seven patients with multiple target lesions, using TLG. Dichotomised metabolic data of the sum of all or ≤ 5 lesions had a concordance with clinical benefit of 89% using SULmax or SULpeak, and 100% using TLG. Evaluating the metabolically most active lesion, concordance was 89% for all three units. Additionally, the decrease in TLG was significantly correlated with PFS for all three quantification strategies.

CONCLUSION

Mixed metabolic response was observed in nearly half of the patients with advanced KRAS wild-type mCRC treated with cetuximab. If ≤ 5 target lesions were evaluated using TLG clinical benefit was predicted correctly for all patients. Moreover, decrease in TLG is significantly correlated with the duration of PFS. Validation of these promising preliminary results in a larger cohort is currently on-going.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01691391.

Diagnostic accuracy of diffusion-weighted magnetic resonance imaging versus positron emission tomography/computed tomography for early response assessment of liver metastases to Y90-radioembolization

Objectives

Patients with hepatic metastases who are candidates for Y90-radioembolization (Y90-RE) usually have advanced tumor stages with involvement of both liver lobes. Per current guidelines, these patients have usually undergone several cycles of potentially hepatotoxic systemic chemotherapy before Y90-RE is at all considered, requiring split (lobar) treatment sessions to reduce hepatic toxicity. Assessing response to Y90-RE early, that is, already after the first lobar session, would be helpful to avoid an ineffective and potentially hepatotoxic second lobar treatment. We investigated the accuracy with which diffusion- weighted magnetic resonance imaging (DWI-MRI) and positron emission tomography/computed tomography (PET/CT) can provide this information.

Methods

An institutional review board–approved prospective intraindividual comparison trial on 35 patients who underwent fluorodeoxyglucose PET/CT and DWI-MRI within 6 weeks before and 6 weeks after Y90-RE to treat secondary-progressive liver metastases from solid cancers (20 colorectal, 13 breast, 2 other) was performed. An increase of minimal apparent diffusion coefficient (ADCmin) or decrease of maximum standard uptake value (SUVmax) by at least 30% was regarded as positive response. Long-term clinical and imaging follow-up was used to distinguish true- from false-response classifications.

Results

On the basis of long-term follow-up, 23 (66%) of 35 patients responded to the Y90 treatment. No significant changes of metastases size or contrast enhancement were observable on pretreatment versus posttreatment CT or magnetic resonance images.However, overall SUVmax decreased from 8.0 ± 3.9 to 5.5 ± 2.2 (P < 0.0001), and ADCmin increased from 0.53 ± 0.13 × 10⁻³ mm²/s to 0.77 ± 0.26 × 10⁻³ mm²/s (P < 0.0001). Pretherapeutic versus posttherapeutic changes of ADCmin and SUVmax correlated moderately (r = −0.53). In 4 of the 35 patients (11%), metastases were fluorodeoxyglucose-negative such that no response assessment was possible by PET. In 25 (71%) of the 35 patients, response classification by PET and DWI-MRI was concordant; in 6 (17%) of the 35, it was discordant. In 5 of the 6 patients with discordant classifications, follow-up confirmed diagnoses made by DWI. The positive predictive value to predict response was 22 (96%) of 23 for MRI and 15 (88%) of 17 for PET. The negative predictive value to predict absence was 11 (92%) of 12 for MRI and 10 (56%) of 18 for PET. Sensitivity for detecting response was significantly higher for MRI (96%; 22/23) than for PET (65%; 15/23) (P < 0.02).

Conclusions

Diffusion-weighted magnetic resonance imaging appears superior to PET/CT for early response assessment in patients with hepatic metastases of common solid tumors. It may be used in between lobar treatment sessions to guide further management of patients who undergo Y90-RE for hepatic metastases.

A randomized phase 3 study on the optimization of the combination of bevacizumab with FOLFOX/OXXEL in the treatment of patients with metastatic colorectal cancer-OBELICS (Optimization of BEvacizumab scheduLIng within Chemotherapy Scheme)

BACKGROUND

Despite the improvements in diagnosis and treatment, colorectal cancer (CRC) is the second cause of cancer deaths in both sexes. Therefore, research in this field remains of great interest. The approval of bevacizumab, a humanized anti-vascular endothelial growth factor (VEGF) monoclonal antibody, in combination with a fluoropyrimidine-based chemotherapy in the treatment of metastatic CRC has changed the oncology practice in this disease. However, the efficacy of bevacizumab-based treatment, has thus far been rather modest. Efforts are ongoing to understand the better way to combine bevacizumab and chemotherapy, and to identify valid predictive biomarkers of benefit to avoid unnecessary and costly therapy to nonresponder patients. The BRANCH study in high-risk locally advanced rectal cancer patients showed that varying bevacizumab schedule may impact on the feasibility and efficacy of chemo-radiotherapy.

METHODS/DESIGN

OBELICS is a multicentre, open-label, randomised phase 3 trial comparing in mCRC patients two treatment arms (1:1): standard concomitant administration of bevacizumab with chemotherapy (mFOLFOX/OXXEL regimen) vs experimental sequential bevacizumab given 4 days before chemotherapy, as first or second treatment line. Primary end point is the objective response rate (ORR) measured according to RECIST criteria. A sample size of 230 patients was calculated allowing reliable assessment in all plausible first-second line case-mix conditions, with a 80% statistical power and 2-sided alpha error of 0.05. Secondary endpoints are progression free-survival (PFS), overall survival (OS), toxicity and quality of life. The evaluation of the potential predictive role of several circulating biomarkers (circulating endothelial cells and progenitors, VEGF and VEGF-R SNPs, cytokines, microRNAs, free circulating DNA) as well as the value of the early [(18)F]-Fluorodeoxyglucose positron emission tomography (FDG-PET) response, are the objectives of the traslational project.

DISCUSSION

Overall this study could optimize bevacizumab scheduling in combination with chemotherapy in mCRC patients. Moreover, correlative studies could improve the knowledge of the mechanisms by which bevacizumab enhance chemotherapy effect and could identify early predictors of response. EudraCT Number: 2011-004997-27 TRIAL REGISTRATION: ClinicalTrials.gove number, NCT01718873.

Tumor histopathology predicts outcomes after resection of colorectal cancer liver metastases treated with and without pre-operative chemotherapy

BACKGROUND AND OBJECTIVES

Study objectives, included determination of: (i) associations between radiologic and pathologic responses of colorectal cancer liver metastases (CRCLM) to chemotherapy; and (ii) whether CRCLM histopathology is associated with recurrence free survival (RFS) after resection among patients not treated with pre-operative chemotherapy (untreated).

METHODS

Demographics, clinicopathologic characteristics, and outcomes among patients who underwent CRCLM resection from 2007 to 2014 were reviewed. Tumor regression grade (TRG) of 1-2 and 4-5 depict low and high proportions of viable tumor relative to fibrosis, respectively.

RESULTS

Of 138 patients, 84 (60.9%) were treated with pre-operative chemotherapy. In these patients, there was no difference in proportions with TRG 1-2 among those with verses without radiologic response (26.9% vs. 18.8%, P = 0.393). TRG 1-2 was associated with superior RFS on univariable (median 15 vs. 6 months, P < 0.001) and multivariable (P = 0.005) analyses. Radiologic response was not associated with RFS. Among untreated patients (n = 54), TRG 4-5 was associated with poor RFS on univariable (median 44 vs. 15 months, P = 0.011) and multivariable (P = 0.012) analyses.

CONCLUSIONS

High proportions of CRCLM fibrosis occur in 20% of patients without radiologic response to chemotherapy. Among untreated patients, high proportion of viable tumor relative to fibrosis is associated with poor RFS after resection. J. Surg. Oncol. 2016;113:456-462. © 2016 Wiley Periodicals, Inc.

Neoadjuvant and conversion treatment of patients with colorectal liver metastasis: the potential role of bevacizumab and other antiangiogenic agents

More than 50 % of patients with colorectal cancer develop liver metastases. Surgical resection is the only available treatment that improves survival in patients with colorectal liver metastases (CRLM). New antiangiogenic targeted therapies, such as bevacizumab, aflibercept, and regorafenib, in combination with neoadjuvant and conversion chemotherapy may lead to improved response rates in this population of patients and increase the proportion of patients eligible for surgical resection. The present review discusses the available data for antiangiogenic targeted agents in this setting. One of these therapies, bevacizumab, which targets the vascular endothelial growth factor (VEGF) has demonstrated good results in this setting. In patients with initially unresectable CRLM, the combination of 5-fluorouracil, leucovorin, and oxaliplatin (FOLFOX) plus bevacizumab has led to high response and resection rates. This combination is also effective for patients with unresectable CRLM. Moreover, the addition of bevacizumab to chemotherapy in the neoadjuvant setting of liver metastasis has a higher impact on pathological response rate. This drug also has a manageable safety profile, and according to recent data, bevacizumab may protect against the sinusoidal dilation provoked in the liver by certain cytotoxic agents. In phase II trials, antiangiogenic therapy has demonstrated benefits in the presurgical treatment of CRLM and may represent a new treatment pathway for these patients.

Prognostic significance of (18)FDG PET/CT in colorectal cancer patients with liver metastases: a meta-analysis

Background

The role of 18-fluorodeoxyglucose positron emission tomography CT (¹⁸FDG PET/CT), as a prognostic factor for survival in colorectal cancer patients with liver metastases, is still controversial. We sought to perform a meta-analysis of the literature to address this issue.

Methods

A systematic literature search was performed to identify the studies that associated ¹⁸FDG PET/CT to clinical survival outcomes of patients with liver metastases. Methodological qualities of the included studies were also assessed. The summarized hazard ratio (HR) was estimated by using fixed- or random-effect model according to heterogeneity between trails.

Results

By analyzing a total of 867 patients from 15 studies, we found that PET/CT for metabolic response to the therapy was capable of predicting event-free survival (EFS) and overall survival (OS) with statistical significance, and the HR was 0.45 (95 % confidence interval [CI], 0.26–0.78) and 0.36 (95 % CI, 0.18–0.71), respectively. Furthermore, pre-treatment ¹⁸FDG PET/CT with high standardized uptake value (SUV) was also significantly associated with poorer OS HR, 1.24; (95 % CI, 1.06–1.45). However, we did not find a statistically significant effect of post-treatment SUV for predicting OS HR, 1.68; (95 % CI, 0.63–4.52).

Conclusions

The present meta-analysis confirms that ¹⁸FDG PET/CT is a useful tool to help predict survival outcomes in patients with liver metastases.

Electronic supplementary material

The online version of this article (doi:10.1186/s40644-015-0055-z) contains supplementary material, which is available to authorized users.

The Prognostic Significance of Metabolic Response Heterogeneity in Metastatic Colorectal Cancer

Background

Tumoral heterogeneity is a major determinant of resistance in solid tumors. FDG-PET/CT can identify early during chemotherapy non-responsive lesions within the whole body tumor load. This prospective multicentric proof-of-concept study explores intra-individual metabolic response (mR) heterogeneity as a treatment efficacy biomarker in chemorefractory metastatic colorectal cancer (mCRC).

Methods

Standardized FDG-PET/CT was performed at baseline and after the first cycle of combined sorafenib (600mg/day for 21 days, then 800mg/day) and capecitabine (1700 mg/m²/day administered D1-14 every 21 days). MR assessment was categorized according to the proportion of metabolically non-responding (non-mR) lesions (stable FDG uptake with SUVmax decrease <15%) among all measurable lesions.

Results

Ninety-two patients were included. The median overall survival (OS) and progression-free survival (PFS) were 8.2 months (95% CI: 6.8–10.5) and 4.2 months (95% CI: 3.4–4.8) respectively. In the 79 assessable patients, early PET-CT showed no metabolically refractory lesion in 47%, a heterogeneous mR with at least one non-mR lesion in 32%, and a consistent non-mR or early disease progression in 21%. On exploratory analysis, patients without any non-mR lesion showed a significantly longer PFS (HR 0.34; 95% CI: 0.21–0.56, P-value <0.001) and OS (HR 0.58; 95% CI: 0.36–0.92, P-value 0.02) compared to the other patients. The proportion of non-mR lesions within the tumor load did not impact PFS/OS.

Conclusion

The presence of at least one metabolically refractory lesion is associated with a poorer outcome in advanced mCRC patients treated with combined sorafenib-capecitabine. Early detection of treatment-induced mR heterogeneity may represent an important predictive efficacy biomarker in mCRC.

Trial Registration

ClinicalTrials.gov NCT01290926

Positron Emission Tomography for the Response Evaluation following Treatment with Chemotherapy in Patients Affected by Colorectal Liver Metastases: A Selected Review

The aim of the present paper is to review the scientific literature concerning the usefulness of (18)F-FDG PET/CT in the evaluation of response to chemotherapy in patients affected by liver metastases from colorectal cancer. Material and Methods. Studies were identified by searching PubMed electronic databases. Both prospective and retrospective studies were included. Information regarding the figure of merit of PET for the evaluation of therapy response was extracted and analyzed. Results. Existing data suggests that (18)F-FDG PET/CT may have an outstanding role in evaluating the response. The sensitivity of PET in detecting therapy response seems to be greater than conventional imaging (CT and MRI). PET/CT response is strictly related to better overall survival and progression-free survival. Conclusions. PET/CT is more than a promising technique to assess the response to chemotherapy in colorectal and liver metastases. However, to be fully validated, this examination needs further studies by recruiting more patients.

Prognostic and predictive response factors in colorectal cancer patients: Between hope and reality

Colorectal cancer (CRC) represents one of the most commonly diagnosed cancers worldwide. It is the second leading cause of cancer death in Western Countries. In the last decade the survival of patients with metastatic CRC has improved dramatically. Due to the advent of new drugs (irinotecan and oxaliplatin) and target therapies (i.e., bevacizumab, cetuximab and panitumab), the median overall survival has risen from about 12 mo in the mid nineties to 30 mo recently. Many questions needing of right collocations and more clearness still exist regarding the prognostic factors and the predictive factors of response to therapy. Despite advances in dosing and scheduling of chemotherapy in both adjuvant and advanced settings, and a greater emphasis on early detection, the outlook still remains poor for most patients. Molecular analyses have shown that the natural history of all CRCs is not the same. Individual patients with same stage tumours may have different long term prognosis and response to therapy. In addition, some prognostic variables are likely to be more important than others. Here we review the role of prognostic factors and predictive factors according to the recently published English literature.

Nonsurgical giant cell tumour of the tendon sheath or of the diffuse type: are MRI or 18F-FDG PET/CT able to provide an accurate prediction of long-term outcome?

PURPOSE

To investigate whether MRI (RECIST 1.1, WHO criteria and the volumetric approach) or (18)F-FDG PET/CT (PERCIST 1.0) are able to predict long-term outcome in nonsurgical patients with giant cell tumour of the tendon sheath or of the diffuse type (GCT-TS/DT).

METHODS

Fifteen "nonsurgical" patients with a histological diagnosis of GCT-TS/DT were divided into two groups: symptomatic patients receiving targeted therapy and asymptomatic untreated patients. All 15 patients were evaluated by MRI of whom 10 were treated, and a subgroup of 7 patients were evaluated by PET/CT of whom 4 were treated. Early evolution was assessed according to MRI and PET/CT scans at baseline and during follow-up. Cohen's kappa coefficient was used to evaluate the degree of agreement between PERCIST 1.0, RECIST 1.1, WHO criteria, volumetric approaches and the reference standard (long-term outcome, delay 505 ± 457 days). The response rate in symptomatic patients with GCT-TS/DT receiving targeted therapy was also assessed in a larger population that included additional patients obtained from a review of the literature.

RESULTS

The kappa coefficients for agreement between RECIST/WHO/volumetric criteria and outcome (15 patients) were respectively: 0.35 (p = 0.06), 0.26 (p = 0.17) and 0.26 (p = 0.17). In the PET/CT subgroup (7 patients), PERCIST was in perfect agreement with the late symptomatic evolution (kappa = 1, p < 0.05). In the treated symptomatic group including the additional patients from the literature the response rates to targeted therapies according to late symptomatic assessment, and PERCIST and RECIST criteria were: 65 % (22/34), 77 % (10/13) and 26 % (10/39).

CONCLUSION

(18)F-FDG PET/CT with PERCIST is a promising approach to the prediction of the long-term outcome in GCT-TS/DT and may avoid unnecessary treatments, toxicity and costs. On MRI, WHO and volumetric approaches are not more effective than RECIST using the current thresholds.