Validation of Several SUV-Based Parameters Derived from 18F-FDG PET for Prediction of Survival After SIRT of Hepatic Metastases from Colorectal Cancer

Transarterial Radioembolization in the TACOME Trial: Dosimetric Analysis and Clinical Features in Predicting Response and Overall Survival

In this multicenter retrospective study, we aimed to analyze the dose-response and survival relationships and estimate the tumor absorbed radiation dose required to achieve response in colorectal cancer liver metastases treated with 90Y glass microspheres. Methods: Patients with metastatic colorectal cancer treated with 90Y glass microspheres were included in this retrospective study. Mean perfused volume, mean estimated perfused volume absorbed dose, mean estimated tumor absorbed dose (ETAD), mean estimated perfused normal liver absorbed dose, and mean estimated whole liver absorbed dose were calculated using [99mTc]-macroaggregated albumin SPECT images. Treatment to response was evaluated by [18F]-FDG PET images. Results: In total, 176 patients (112 men and 64 women) were included in the analysis. A strong correlation was found between mean ETAD and response to treatment (P = 0.001). The cutoff values to predict a response were calculated as 109 Gy (sensitivity, 68%; specificity, 73%; area under the curve, 0.728; P = 0.001) for mean estimated perfused volume absorbed dose and 152 Gy (sensitivity, 93%; specificity, 89%; area under the curve, 0.945; P = 0.001) for mean ETAD. The median overall survival (OS) of patients with a mean ETAD higher than 152 Gy was significantly longer than that of the remaining patients, at 18.1 mo (95% CI, 15.7-20.4 mo) versus 12.8 mo (95% CI, 10.6-15.0 mo; P = 0.030). Further analysis using maximally selected rank statistics to better predict OS showed that patients with a minimum mean ETAD of 203 Gy had OS 6.4 mo longer than the OS of those with a lower mean ETAD (P = 0.022). Conclusion: A mean radiation dose to the tumor of at least 152 Gy may predict a metabolic response. Although a threshold of 152 Gy predicted longer OS, a mean ETAD of 203 Gy, when achievable, predicted even longer OS than found for those with a mean ETAD of less than 203 Gy.

Assessment of Hypoxia Before Radioembolization Treatment With 18F-FMISO PET: ARTE-MISO Trial

BACKGROUND

Transarterial radioembolization (TARE) is a therapeutic option for patients with liver tumors. However, factors responsible for treatment resistance in TARE remain largely unknown. In this study, we aimed to investigate the role of hypoxia in the treatment response of liver tumors using 18F-FMISO PET imaging before TARE.

PATIENTS AND METHODS

This single-center prospective study included 25 patients with primary or metastatic liver tumors imaged with 18F-FMISO PET/CT before TARE and treated with 90Y resin microspheres. Posttreatment response was assessed with 18F-FDG PET imaging. Hypoxia status was evaluated by calculating the tumor-to-muscle (T/M) and tumor-to-blood pool (T/BP) ratios. Absorbed dose metrics were derived from 90Y PET/MRI imaging post-procedure. Lesions were categorized by response as complete responders (CR), partial responders (PR), stable disease (SD), and progressive disease (PD). Statistical analyses included ROC curve analysis, χ2 tests, and regression models to determine predictors of treatment response.

RESULTS

Among 25 patients (mean age: 60.4 ± 12 y, 56% males), 54 18F-FDG-avid lesions were evaluated. The median absorbed dose (Dmean) was 114.8 Gy for CR, 98.9 Gy for PR, 56.7 Gy for SD, and 78.3 Gy for PD. Significant differences in Dmean (P = 0.013) and T/BP ratios (P = 0.011) were observed between responder and nonresponder groups. High Dmean lesions (>89 Gy) had a response rate of 86%, compared with 56% in low Dmean lesions. Hypoxic lesions (T/BP >1.29) showed a 57% response rate, while non-hypoxic lesions (T/BP <1.29) showed a 91% response rate. In combined analyses, while non-hypoxic/high Dmean lesions had the highest response rates (93%), hypoxic/low-dose had the lowest response rate (39%).

CONCLUSIONS

In this study, we have observed that both mean absorbed radiation dose and hypoxia status are significant predictors of response to treatment after radioembolization of liver tumors. While larger studies are needed to confirm these findings, this pilot study may pave the way for further personalized treatments to achieve better results for radioembolization.

Transarterial Radioembolisation with Y90 Resin Microspheres and the Effect of Reimbursement Criteria in France: Final Results of the CIRT-FR Prospective Observational Study

PURPOSE

This analysis of the CIRSE Registry for SIR-Spheres Therapy in France, CIRT-FR, reports on real-world outcomes of transarterial radioembolisation (TARE) with Y90 resin microspheres for hepatocellular carcinoma (HCC) and colorectal cancer liver metastases (CRLM) patients in France, focusing on safety, effectiveness and health-related quality of life (HRQoL). Results on patients treated based on national reimbursement criteria are discussed here.

METHODS

Prospective, multicentre, observational study of HCC and CRLM patients treated between August 2017 and July 2020 with TARE Y90 resin microspheres. Patients were assigned to different analysis groups based on reimbursement recommendations. Follow-up period was at least 24 months with patient data collected every 3 months.

RESULTS

In total, 252 (193 HCC, 59 CRLM) patients of CIRT-FR were included in the analysis. No differences in effectiveness, safety and HRQoL were found between analysis groups based on reimbursement recommendations. Median overall survival for HCC and CRLM was 19.0 (95% CI, 16.1-22.4) and 10.8 (95% CI, 8.0-13.5) months, respectively. Serious procedure-related adverse events occurred in 13% of the patients. HRQoL generally remained stable, with some fluctuations in function scores and symptoms.

CONCLUSION

In our cohorts, patients performed similarly regarding clinical outcomes irrespective of their analysis group based on reimbursement recommendations. Our results suggest that instead of restrictive reimbursement criteria, more decision-making power in selecting suitable patient groups could be given to multidisciplinary tumour boards. Results confirm that TARE with Y90 resin microspheres is an effective and safe treatment for liver cancer, with maintained HRQoL in most patients.

Recommendations for the management of yttrium-90 radioembolization in the treatment of patients with colorectal cancer liver metastases: a multidisciplinary review

PURPOSE

Strategies for the treatment of liver metastases from colon cancer (lmCRC) are constantly evolving. Radioembolization with yttrium 90 (Y-90 TARE) has made significant advancements in treating liver tumors and is now considered a potential option allowing for future resection. This study reviewed the scientific evidence and developed recommendations for using Y-90 TARE as a treatment strategy for patients with unresectable lmCRC.

METHODS

A multidisciplinary scientific committee, consisting of experts in medical oncology, hepatobiliary surgery, radiology, and nuclear medicine, all with extensive experience in treating patients with ImCRC with Y-90 TARE, led this project. The committee established the criteria for conducting a comprehensive literature review on Y-90 TARE in the treatment of lmCRC. The data extraction process involved addressing initial preliminary inquiries, which were consolidated into a final set of questions.

RESULTS

This review offers recommendations for treating patients with lmCRC using Y-90 TARE, addressing four areas covering ten common questions: 1) General issues (multidisciplinary tumor committee, indications for treatment, contraindications); 2) Previous process (predictive biomarkers for patient selection, preintervention tests, published evidence); 3) Procedure (standard procedure); and 4) Post-intervention follow-up (potential toxicity and its management, parameters for evaluation, quality of life).

CONCLUSIONS

Based on the insights of the multidisciplinary committee, this document offers a comprehensive overview of the technical aspects involved in the management of Y-90 TARE. It synthesizes recommendations for applying Y-90 TARE across various phases of the treatment process.

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.

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.

Prospective Evaluation of Immune Activation Associated with Response to Radioembolization Assessed with PET/CT in Women with Breast Cancer Liver Metastasis

Background The impact of transarterial radioembolization (TARE) of breast cancer liver metastasis (BCLM) on antitumor immunity is unknown, which hinders the optimal selection of candidates for TARE. Purpose To determine whether response to TARE at PET/CT in participants with BCLM is associated with specific immune markers (cytokines and immune cell populations). Materials and Methods This prospective pilot study enrolled 23 women with BCLM who planned to undergo TARE (June 2018 to February 2020). Peripheral blood and liver tumor biopsies were collected at baseline and 1-2 months after TARE. Monocyte, myeloid-derived suppressor cell (MDSC), interleukin (IL), and tumor-infiltrating lymphocyte (TIL) levels were assessed with use of gene expression studies and flow cytometry, and immune checkpoint and cell surface marker levels with immunohistochemistry. Modified PET Response Criteria in Solid Tumors was used to determine complete response (CR) in treated tissue. After log-transformation, immune marker levels before and after TARE were compared using paired t tests. Association with CR was assessed with Wilcoxon rank-sum or unpaired t tests. Results Twenty women were included. After TARE, peripheral IL-6 (geometric mean, 1.0 vs 1.6 pg/mL; P = .02), IL-10 (0.2 vs 0.4 pg/mL; P = .001), and IL-15 (1.9 vs 2.4 pg/mL; P = .01) increased. In biopsy tissue, lymphocyte activation gene 3-positive CD4+ TILs (15% vs 31%; P < .001) increased. Eight of 20 participants (40% [exact 95% CI: 19, 64]) achieved CR. Participants with CR had lower baseline peripheral monocytes (10% vs 29%; P < .001) and MDSCs (1% vs 5%; P < .001) and higher programmed cell death protein (PD) 1-positive CD4+ TILs (59% vs 26%; P = .006) at flow cytometry and higher PD-1+ staining in tumor (2% vs 1%; P = .046). Conclusion Complete response to transarterial radioembolization was associated with lower baseline cytokine, monocyte, and myeloid-derived suppressor cell levels and higher programmed cell death protein 1-positive tumor-infiltrating lymphocyte levels. © RSNA, 2022 Online supplemental material is available for this article.

Metabolic tumor volume predicts long-term survival after transplantation for unresectable colorectal liver metastases: 15 years of experience from the SECA study

OBJECTIVE

To report 15 years of experience with metabolic tumor volume (MTV) of liver metastases from the preoperative 18F-FDG PET/CT to predict long-term survival after liver transplantation (LT) for unresectable colorectal liver metastases (CRLM).

METHODS

The preoperative 18F-FDG PET/CT from all SECA 1 and 2 patients was evaluated. MTV was obtained from all liver metastases. The patients were divided into one group with low MTV (< 70 cm3) and one group with high MTV (> 70 cm3) based on a receiver operating characteristic analysis. Overall survival (OS), disease-free survival (DFS) and post recurrence survival (PRS) for patients with low versus high MTV were compared using the Kaplan-Meier method and log rank test. Clinopathological features between the two groups were compared by a nonparametric Mann-Whitney U test for continuous and Fishers exact test for categorical data.

RESULTS

At total of 40 patients were included. Patients with low MTV had significantly longer OS (p < 0.001), DFS (p < 0.001) and PRS (p = 0.006) compared to patients with high values. The patients with high MTV had higher CEA levels, number of liver metastases, size of the largest liver metastasis, N-stage, number of chemotherapy lines and more frequently progression of disease at LT compared to the patients with low MTV.

CONCLUSION

MTV of liver metastases is highly predictive of long-term OS, DFS and PRS after LT for unresectable CRLM and should be implemented in risk stratification prior to LT.

EANM procedure guideline for the treatment of liver cancer and liver metastases with intra-arterial radioactive compounds

Primary liver tumours (i.e. hepatocellular carcinoma (HCC) or intrahepatic cholangiocarcinoma (ICC)) are among the most frequent cancers worldwide. However, only 10-20% of patients are amenable to curative treatment, such as resection or transplant. Liver metastases are most frequently caused by colorectal cancer, which accounts for the second most cancer-related deaths in Europe. In both primary and secondary tumours, radioembolization has been shown to be a safe and effective treatment option. The vast potential of personalized dosimetry has also been shown, resulting in markedly increased response rates and overall survival. In a rapidly evolving therapeutic landscape, the role of radioembolization will be subject to changes. Therefore, the decision for radioembolization should be taken by a multidisciplinary tumour board in accordance with the current clinical guidelines. The purpose of this procedure guideline is to assist the nuclear medicine physician in treating and managing patients undergoing radioembolization treatment. PREAMBLE: The European Association of Nuclear Medicine (EANM) is a professional non-profit medical association that facilitates communication worldwide among individuals pursuing clinical and research excellence in nuclear medicine. The EANM was founded in 1985. These guidelines are intended to assist practitioners in providing appropriate nuclear medicine care for patients. They are not inflexible rules or requirements of practice and are not intended, nor should they be used, to establish a legal standard of care. The ultimate judgment regarding the propriety of any specific procedure or course of action must be made by medical professionals taking into account the unique circumstances of each case. Thus, there is no implication that an approach differing from the guidelines, standing alone, is below the standard of care. To the contrary, a conscientious practitioner may responsibly adopt a course of action different from that set out in the guidelines when, in the reasonable judgment of the practitioner, such course of action is indicated by the condition of the patient, limitations of available resources or advances in knowledge or technology subsequent to publication of the guidelines. The practice of medicine involves not only the science but also the art of dealing with the prevention, diagnosis, alleviation and treatment of disease. The variety and complexity of human conditions make it impossible to always reach the most appropriate diagnosis or to predict with certainty a particular response to treatment. Therefore, it should be recognised that adherence to these guidelines will not ensure an accurate diagnosis or a successful outcome. All that should be expected is that the practitioner will follow a reasonable course of action based on current knowledge, available resources and the needs of the patient to deliver effective and safe medical care. The sole purpose of these guidelines is to assist practitioners in achieving this objective.

Role of Resin Microsphere Y90 Dosimetry in Predicting Objective Tumor Response, Survival and Treatment Related Toxicity in Surgically Unresectable Colorectal Liver Metastasis: A Retrospective Single Institution Study

Simple Summary

Colorectal liver metastases are difficult to treat, with only a minority of patients eligible for surgical resection. Yttrium-90 selective internal radiation therapy is an alternative treatment currently used for patients who have progressed on chemotherapy. A technique called dosimetry allows clinicians to analyze how much radiation was delivered to target lesions post-treatment. The aim of this study is to evaluate the relationship of various dosimetric parameters with objective tumor response, overall survival, and treatment related toxicity with the potential goal of optimizing Yttrium-90 treatment in this patient population. Additionally, other potential predictors of survival outcomes, including clinical and demographic factors, were also evaluated. We found that delivering a mean tumor dose ≥100 Gy when using resin microspheres was significantly associated with objective tumor response and prolonged overall survival. In this study, no mean non-tumoral liver dose threshold was found to predict treatment related toxicity.

Abstract

Purpose: To Evaluate the correlation between tumor dosimetric parameters with objective tumor response (OR) and overall survival (OS) in patients with surgically unresectable colorectal liver metastasis (CRLM) undergoing resin-based Ytrrium-90 selective internal radiation therapy (Y90 SIRT). Materials and Methods: 45 consecutive patients with CRLM underwent resin-based Y90 SIRT in one or both hepatic lobes (66 treated lobes total). Dose volume histograms were created with MIM Sureplan^® v.6.9 using post-treatment SPECT/CT. Dosimetry analyses were based on the cumulative volume of the five largest tumors in each treatment session and non-tumoral liver (NTL) dose. Receiver operating characteristic (ROC) curve was used to evaluate tumor dosimetric factors in predicting OR by Response Evaluation Criteria for Solid Tumors at 3 months post-Y90. Additionally, ROC curve was used to evaluate non-tumoral liver dose as a predictor of grade ≥ 3 liver toxicity and radioembolization induced liver disease (REILD) 3 months post Y90. To minimize for potential confounding demographic and clinical factors, univariate and multivariate analysis of survival with mean tumor dose as one of the factors were also performed. Kaplan-Meier estimation was used for OS analysis from initial Y90 SIRT. Results: 26 out of 45 patients had OR with a median OS of 17.2 months versus 6.8 months for patients without OR (p < 0.001). Mean tumor dose (TD) of the five largest tumors was the strongest predictor of OR with an area under the curve of 0.73 (p < 0.001). Minimum TD, and TD to 30%, 50%, and 70% of tumor volume also predicted OR (p’s < 0.05). Mean TD ≥ 100 Gy predicted a significantly prolonged median OS of 19 vs. 11 months for those receiving TD < 100 Gy (p = 0.016). On univariate analysis, mean TD < 100 Gy, presence of any genomic mutation, presence of MAPK pathway mutation, bilobar hepatic metastases and diffuse metastatic disease (>10 lesions per liver lobe) were found to be predictors of shorter median OS. On multivariate analysis, mean TD < 100 Gy, presence of any genomic mutation, and diffuse hepatic metastatic disease were found to be independent predictors of shorter OS. Overall, six (13.3%) patients developed grade ≥ 3 liver toxicity post Y90 of whom two (4.4%) patients developed REILD. No dose threshold predicting grade ≥ 3 liver toxicity or REILD was identified. Conclusions: Mean TD ≥ 100 Gy in patients with unresectable CRLM undergoing resin-based Y90 SIRT predicts OR and prolonged OS.

[18F]FDG PET/MRI enables early chemotherapy response prediction in pancreatic ductal adenocarcinoma

Purpose

In this prospective exploratory study, we evaluated the feasibility of [¹⁸F]fluorodeoxyglucose ([¹⁸F]FDG) PET/MRI-based chemotherapy response prediction in pancreatic ductal adenocarcinoma at two weeks upon therapy onset.

Material and methods

In a mixed cohort, seventeen patients treated with chemotherapy in neoadjuvant or palliative intent were enrolled. All patients were imaged by [¹⁸F]FDG PET/MRI before and two weeks after onset of chemotherapy. Response per RECIST1.1 was then assessed at 3 months [¹⁸F]FDG PET/MRI-derived parameters (MTV_50%, TLG_50%, MTV_2.5, TLG_2.5, SUV_max, SUV_peak, ADC_max, ADC_mean and ADC_min) were assessed, using multiple t-test, Man–Whitney-U test and Fisher’s exact test for binary features.

Results

At 72 ± 43 days, twelve patients were classified as responders and five patients as non-responders. An increase in ∆MTV_50% and ∆ADC (≥ 20% and 15%, respectively) and a decrease in ∆TLG_50% (≤ 20%) at 2 weeks after chemotherapy onset enabled prediction of responders and non-responders, respectively. Parameter combinations (∆TLG_50% and ∆ADC_max or ∆MTV_50% and ∆ADC_max) further improved discrimination.

Conclusion

Multiparametric [¹⁸F]FDG PET/MRI-derived parameters, in particular indicators of a change in tumor glycolysis and cellularity, may enable very early chemotherapy response prediction. Further prospective studies in larger patient cohorts are recommended to their clinical impact.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13550-021-00808-4.

Systematic review and network meta-analyses of third-line treatments for metastatic colorectal cancer

BACKGROUND

Limited treatment options are available in chemotherapy-refractory metastatic colorectal cancer (mCRC). The objective was to conduct a systematic literature review (SLR) and exploratory network meta-analysis (NMA) to compare the tolerability and effectiveness of SIRT with Y-90 resin microspheres, regorafenib, TAS-102 (trifluridine/tipiracil), and best supportive care (BSC) as third-line treatment in patients with mCRC.

METHODS

An SLR was conducted to identify studies comparing two or more of the treatments and reporting overall survival (OS), progression-free survival, tumor response, or adverse event (AE) incidence. An exploratory NMA was conducted to compare hazard ratios (HRs) for OS using Markov chain Monte Carlo (MCMC) techniques.

RESULTS

Seven studies were identified in the SLR: two double-blind randomized-controlled trials (RCT) for each drug, one open-label RCT, and two non-randomized comparative studies for SIRT. Patient selection criteria differed between studies, with SIRT studies including patients with liver-dominant colorectal metastases. Nausea and vomiting were more frequent with TAS-102 than regorafenib or SIRT; diarrhea was more common with TAS-102 and regorafenib than SIRT. The exploratory NMA suggested that all active treatments improved OS, with HRs of 0.48 (95% CrI 0.30-0.78) for SIRT with Y-90 resin microspheres, 0.63 (0.38-1.03) for TAS-102, and 0.67 (0.40-1.08) for regorafenib each compared to BSC.

CONCLUSIONS

Regorafenib, TAS-102 and SIRT using Y-90 resin microspheres are more effective than BSC in third-line treatment of mCRC; however, study heterogeneity made comparisons between active treatments challenging. SIRT is a viable treatment for third-line mCRC and its favorable AE profile should be considered in the therapeutic decision-making process.

Role of imaging biomarkers for prognostic prediction in patients with pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive tumours. PDAC has a poor prognosis; therefore, it is necessary to perform further risk stratification. Identifying prognostic factors before treatment might help to implement suitable and personalised treatment for individuals and avoid side effects. Conventional staging systems and tumour biomarkers are fundamental to establish prognosis; however, they have obvious limitations. Novel imaging biomarkers extracted from advanced imaging techniques offer opportunities to evaluate underlying tumour physiological characteristics, such as mutational status, cellular composition, local microenvironment, tumour metabolism, and biological behaviour. Thus, imaging biomarkers might help the decision making of oncologists and surgeons. The present review discusses the functions of imaging biomarkers for prognostic prediction in patients with PDAC and their potential value for further translation in clinical practice.

ePAD: An Image Annotation and Analysis Platform for Quantitative Imaging

Medical imaging is critical for assessing the response of patients to new cancer therapies. Quantitative lesion assessment on images is time-consuming, and adopting new promising quantitative imaging biomarkers of response in clinical trials is challenging. The electronic Physician Annotation Device (ePAD) is a freely available web-based zero-footprint software application for viewing, annotation, and quantitative analysis of radiology images designed to meet the challenges of quantitative evaluation of cancer lesions. For imaging researchers, ePAD calculates a variety of quantitative imaging biomarkers that they can analyze and compare in ePAD to identify potential candidates as surrogate endpoints in clinical trials. For clinicians, ePAD provides clinical decision support tools for evaluating cancer response through reports summarizing changes in tumor burden based on different imaging biomarkers. As a workflow management and study oversight tool, ePAD lets clinical trial project administrators create worklists for users and oversee the progress of annotations created by research groups. To support interoperability of image annotations, ePAD writes all image annotations and results of quantitative imaging analyses in standardized file formats, and it supports migration of annotations from various propriety formats. ePAD also provides a plugin architecture supporting MATLAB server-side modules in addition to client-side plugins, permitting the community to extend the ePAD platform in various ways for new cancer use cases. We present an overview of ePAD as a platform for medical image annotation and quantitative analysis. We also discuss use cases and collaborations with different groups in the Quantitative Imaging Network and future directions.

PET/CT Imaging Characteristics After Radioembolization of Hepatic Metastasis from Breast Cancer

PURPOSE

To define positron emission tomography/computed tomography (PET/CT) imaging characteristics during follow-up of patients with metastatic breast cancer (MBC) treated with yttrium-90 (Y90) radioembolization (RE).

MATERIALS AND METHODS

From January 2011 to October 2017, 30 MBC patients underwent 38 Y90 glass or resin RE treatments. Pre-RE PET/CT was performed on average 51 days before RE. There were 68 PET/CTs performed after treatment. Response was assessed using modified PERCIST criteria focusing on the hepatic territory treated with RE, normalizing SUVpeak to the mean SUV of liver uninvolved by tumor. An objective response (OR) was defined as a decrease in SUVpeak by at least 30%.

RESULTS

Of the 68 post-RE scans, 6 were performed at 0-30 days, 15 at 31-60 days, 9 at 61-90 days, 13 at 91-120 days, 14 scans at 121-180 days, and 11 scans at > 180 days after RE. Of the 30 patients, 25 (83%) achieved OR on at least one follow-up. Median survival was 15 months after the first RE administration. Highest response rates occurred at 30-90 days, with over 75% of cases demonstrating OR at that time. After 180 days, OR was seen in only 25%. There was a median TTP of 169 days among responders.

CONCLUSION

In MBC, follow-up PET/CT after RE demonstrates optimal response rates at 30-90 days, with progression noted after 180 days. These results help to guide the timing of imaging and also to inform patients of expected outcomes after RE.

Additional Local Therapy for Liver Metastases in Patients with Metastatic Castration-Resistant Prostate Cancer Receiving Systemic PSMA-Targeted Therapy

The aim of this study was to evaluate the efficacy of ¹⁷⁷Lu-prostate-specific membrane antigen (PSMA)-617 (¹⁷⁷Lu-PSMA) and selective internal radiation therapy (SIRT) for the treatment of liver metastases of castration-resistant prostate cancer. Methods: Safety and survival of patients with metastatic castration-resistant prostate cancer and liver metastases assigned to ¹⁷⁷Lu-PSMA alone (n = 31) or in combination with SIRT (n = 5) were retrospectively analyzed. Additionally, a subgroup (n = 10) was analyzed using morphologic and molecular response criteria. Results: Median estimated survival was 5.7 mo for ¹⁷⁷Lu-PSMA alone and 8.4 mo for combined sequential ¹⁷⁷Lu-PSMA and SIRT. ¹⁷⁷Lu-PSMA achieved discordant therapy responses with both regressive and progressive liver metastases in the same patient (best vs. worst responding metastases per patient: -35% vs. +63% diameter change; P < 0.05). SIRT was superior to ¹⁷⁷Lu-PSMA for the treatment of liver metastases (0% vs. 56% progression). Conclusion: The combination of ¹⁷⁷Lu-PSMA and SIRT is efficient and feasible for the treatment of advanced prostate cancer. ¹⁷⁷Lu-PSMA alone seems to have limited response rates in the treatment of liver metastases.

18 F-NaF PET/CT IMAGING IN FIBROUS DYSPLASIA OF BONE

Fibrous dysplasia (FD) is a mosaic skeletal disorder resulting in fractures, deformity, and functional impairment. Clinical evaluation has been limited by a lack of surrogate endpoints capable of quantitating disease activity. The purpose of this study was to investigate the utility of ¹⁸ F-NaF PET/CT imaging in quantifying disease activity in patients with FD. Fifteen consecutively evaluated subjects underwent whole-body ¹⁸ F-NaF PET/CT scans, and FD burden was assessed by quantifying FD-related ¹⁸ F-NaF activity. ¹⁸ F-NaF PET/CT parameters obtained included (i) SUV_max (standardized uptake value [SUV] of the FD lesion with the highest uptake); (ii) SUV_mean (average SUV of all ¹⁸ F-NaF-positive FD lesions); (iii) total volume of all ¹⁸ F-NaF-positive FD lesions (TV); and (iv) total FD lesion activity determined as the product of TV multiplied by SUV_mean (TA =  TV ×  SUV_mean ) (TA). Skeletal outcomes, functional outcomes, and bone turnover markers were correlated with ¹⁸ F-NaF PET/CT parameters. TV and TA of extracranial FD lesions correlated strongly with skeletal outcomes including fractures and surgeries (p values ≤ 0.003). Subjects with impaired ambulation and scoliosis had significantly higher TV and TA values (P < 0.05), obtained from extracranial and spinal lesions, respectively. Craniofacial surgeries correlated with TV and TA of skull FD lesions (P < 0.001). Bone turnover markers, including alkaline phosphatase, N-telopeptides, and osteocalcin, were strongly correlated with TV and TA (P < 0.05) extracted from FD lesions in the entire skeleton. No associations were identified with SUV_max or SUV_mean . Bone pain and age did not correlate with ¹⁸ F-NaF PET/CT parameters. FD burden evaluated by ¹⁸ F-NaF-PET/CT facilitates accurate assessment of FD activity, and correlates quantitatively with clinically-relevant skeletal outcomes. © 2019 American Society for Bone and Mineral Research.

The Evolving Role of PET-Based Novel Quantitative Techniques in the Interventional Radiology Procedures of the Liver

Interventional radiology procedures have revolutionized the treatment of cancer and interventional oncology is now the fourth pillar of cancer care. The article discusses the importance of fluorodeoxyglucose (FDG)-PET imaging, and dual time-point imaging in the context of PET/computed tomography as applied to treatments of liver malignancy. The necessary paradigm shift in the adoption of novel segmentation methodologies to express global disease burden is explored.

Significance of Metabolic Tumor Volume and Total Lesion Glycolysis Measured Using ¹⁸F-FDG PET/CT in Locally Advanced and Metastatic Gallbladder Carcinoma

PURPOSE

This study aimed to determine the prognostic value of new quantitative parameters of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT), including metabolic tumor volume (MTV), in patients with locally advanced and metastatic gallbladder cancer (GBC).

MATERIALS AND METHODS

In total, 83 patients initially diagnosed with locally advanced and metastatic GBC and who underwent ¹⁸F-FDG PET/CT at the time of initial diagnosis were retrospectively reviewed. The metabolic volume-based PET parameters of primary tumors and metastatic lesions were measured, including maximum and average standardized uptake values (SUV), MTV, and total lesion glycolysis. An overall survival (OS) analysis was performed using the Kaplan-Meier method with PET and clinical parameters. A Cox proportional hazards regression analysis was performed to determine independent prognostic factors.

RESULTS

In univariate analysis, pathologic differentiation (p<0.001), performance status (PS; p=0.003), C-reactive protein (CRP) level (p=0.009), and PET-related SUV_{mt max} (the highest SUV among the metastatic lesions) (p=0.040) and MTV_total (the sum of the MTVs of both the primary and metastatic lesions) (p=0.031), were significant for OS. In multivariate analysis, MTV_total (hazard ratio: 2.07; 95% confidence interval: 1.23-3.48; p=0.006) remained significant for the prediction of OS, as did differentiation (p=0.001), PS (p=0.001), and CRP (p=0.039).

CONCLUSION

In locally advanced and metastatic GBC, volume-based PET/CT parameters of the total tumor burden of malignancy, such as MTV_total, were found to be useful for the identification of patients with poor prognosis.

Predictive Value of [18F]FDG PET/CT for Lymph Node Metastasis in Rectal Cancer

[18F]Fluorodeoxyglucose ([18F]FDG) Positron emission tomography/computed tomography (PET/CT) is commonly used for rectal cancer staging, but improved diagnostic methods for nodal metastases are needed. We aimed to evaluate whether the combination model of the metabolic tumor volume of primary tumor (T_MTV) and maximum standardized uptake value of lymph node (N_SUVmax) on pretreatment [18F]FDG PET/CT could improve nodal metastases prediction in rectal cancer. We enrolled a total of 166 rectal cancer patients who underwent pretreatment [18F]FDG PET/CT and surgical resection without neoadjuvant treatment between January 2009 and August 2016. Visual and semiquantitative PET/CT parameters were obtained. Associations between clinicopathological, PET/CT-derived variables and nodal metastases were evaluated by logistic regression analysis. Nodal metastases were confirmed histologically in 68 of the 166 patients (41%). Uni- and multivariate analyses demonstrated T_MTV and N_SUVmax were independent predictive factors for nodal metastases. The c-statistics of the combination model was 0.806 (Standard Error, 0.034; 95% Confidence Interval, 0.737-0.863), which showed significant improvement compared to T_MTV (0.698, P = 0.0002) or N_SUVmax (0.720, P = 0.0008) alone. T_MTV and N_SUVmax are independently correlated with nodal metastases. Furthermore, the combination model showed improved performance for risk prediction; thus, [18F]FDG PET/CT might have a role in rectal cancer staging and treatment planning.

Volumetric and texture analysis of pretherapeutic 18F-FDG PET can predict overall survival in medullary thyroid cancer patients treated with Vandetanib

PURPOSE

The metabolically most active lesion in 2-deoxy-2-(¹⁸F)fluoro-D-glucose (¹⁸F-FDG) PET/CT can predict progression-free survival (PFS) in patients with medullary thyroid carcinoma (MTC) starting treatment with the tyrosine kinase inhibitor (TKI) vandetanib. However, this metric failed in overall survival (OS) prediction. In the present proof of concept study, we aimed to explore the prognostic value of intratumoral textural features (TF) as well as volumetric parameters (total lesion glycolysis, TLG) derived by pre-therapeutic ¹⁸F-FDG PET.

METHODS

Eighteen patients with progressive MTC underwent baseline ¹⁸F-FDG PET/CT prior to and 3 months after vandetanib initiation. By manual segmentation of the tumor burden at baseline and follow-up PET, intratumoral TF and TLG were computed. The ability of TLG, imaging-based TF, and clinical parameters (including age, tumor marker doubling times, prior therapies and RET (rearranged during transfection) mutational status) for prediction of both PFS and OS were evaluated.

RESULTS

The TF Complexity and the volumetric parameter TLG obtained at baseline prior to TKI initiation successfully differentiated between low- and high-risk patients. Complexity allocated 10/18 patients to the high-risk group with an OS of 3.3 y (vs. low-risk group, OS = 5.3 y, 8/18, AUC = 0.78, P = 0.03). Baseline TLG designated 11/18 patients to the high-risk group (OS = 3.5 y vs. low-risk group, OS = 5 y, 7/18, AUC = 0.83, P = 0.005). The Hazard Ratio for cancer-related death was 6.1 for Complexity (TLG, 9.5). Among investigated clinical parameters, the age at initiation of TKI treatment reached significance for PFS prediction (P = 0.02, OS, n.s.).

CONCLUSIONS

The TF Complexity and the volumetric parameter TLG are both independent parameters for OS prediction.

Usefulness of FDG PET/CT derived parameters in prediction of histopathological finding during the surgery in patients with pancreatic adenocarcinoma

Purpose

Pancreatic cancer is the 4th most common cause of cancer death in Japan and exhibits a 5-year overall survival rate of approximately 7%. The accurate diagnosis of pancreatic cancer is important for determining the optimal management strategy. Fludeoxyglucose-positron emission tomography (FDG PET) integrated with computed tomography (¹⁸F-FDG PET/CT) has emerged as a powerful imaging tool for detecting and evaluating various cancers, and it is used for staging, detecting local recurrence and distant metastasis, measuring therapeutic effects, and predicting prognosis in pancreatic cancer patients.

Lately, FDG PET/CT-derived parameters, such as standardized uptake values (SUV), the metabolic tumor volume (MTV), and total lesion glycolysis (TLG), have been suggested as prognostic factors for various types of cancer, including pancreatic cancer. However, there is no consensus regarding the best parameters for evaluating patient prognosis, operability, etc. The purpose of this study was to examine the differences between operable and non-operable pancreatic cancer using FDG PET/CT-derived parameters, and to investigate whether volumetric parameters (TLG and the MTV) are superior to SUV-based parameters for predicting infiltration status/determining operability.

Materials and methods

We conducted a retrospective study of the cases of 48 patients with clinically proven pancreatic adenocarcinoma, who underwent FDG PET/CT imaging before treatment. In the operable group, the surgical specimens were subjected to histopathological examinations, and the cases were separated into those exhibiting less and greater infiltration. SUVmax, SUVpeak, the tumor background ratio (TBR), TLG, and the MTV were compared between these groups as well as between the operable and non-operable groups.

Results

Venous infiltration showed significant associations with several metabolic parameters (SUVmax, SUVpeak, and the TBR). However, it did not display any significant associations with volumetric parameters, such as TLG or the MTV. None of the FDG PET/CT-derived parameters exhibited significant associations with lymphatic or neural infiltration. Significant differences in volumetric parameters, such as the MTV and TLG, were detected between the operable and non-operable subgroups.

Conclusions

Metabolic ¹⁸F-FDG PET/CT-derived parameters, such as SUVmax, SUVpeak, and the TBR, are useful for predicting venous infiltration status in patients with operable pancreatic adenocarcinoma.

Factors Affecting Oncologic Outcomes of 90Y Radioembolization of Heavily Pre-Treated Patients With Colon Cancer Liver Metastases

INTRODUCTION

The purpose of this study was to identify predictors of overall (OS) and liver progression-free survival (LPFS) following Yttrium-90 radioembolization (RAE) of heavily pretreated patients with colorectal cancer liver metastases (CLM), as well as to create and validate a predictive nomogram for OS.

MATERIALS AND METHODS

Metabolic, anatomic, laboratory, pathologic, genetic, primary disease, and procedure-related factors, as well as pre- and post-RAE therapies in 103 patients with CLM treated with RAE from September 15, 2009 to March 21, 2017 were analyzed. LPFS was defined by Response Evaluation Criteria In Solid Tumors 1.1 and European Organization for Research and Treatment of Cancer criteria. Prognosticators of OS and LPFS were selected using univariate Cox regression, adjusted for clustering and competing risk analysis (for LPFS), and subsequently tested in multivariate analysis (MVA). The nomogram was built using R statistical software and internally validated using bootstrap resampling.

RESULTS

Patients received RAE at a median of 30.9 months (range, 3.4-161.7 months) after detection of CLM. The median OS and LPFS were 11.3 months (95% confidence interval, 7.9-15.1 months) and 4 months (95% confidence interval, 3.3-4.8 months), respectively. Of the 40 parameters tested, 6 were independently associated with OS in MVA. These baseline parameters included number of extrahepatic disease sites (P < .001), carcinoembryonic antigen (P < .001), albumin (P = .005), alanine aminotransferase level (P < .001), tumor differentiation level (P < .001), and the sum of the 2 largest tumor diameters (P < .001). The 1-year OS of patients with total points of < 25 versus > 80 was 90% and 10%, respectively. Bootstrap resampling showed good discrimination (optimism corrected c-index = 0.745) and calibration (mean absolute prediction error = 0.299) of the nomogram. Only baseline maximum standardized uptake value was significant in MVA for LPFS prediction (P < .001; SHR = 1.06).

CONCLUSION

The developed nomogram included 6 pre-RAE parameters and provided good prediction of survival post-RAE in heavily pretreated patients. Baseline maximum standardized uptake value was the single significant predictor of LPFS.

Association of PI3K Pathway Mutations with Early Positron-Emission Tomography/CT Imaging Response after Radioembolization for Breast Cancer Liver Metastases: Results of a Single-Center Retrospective Pilot Study

PURPOSE

To describe imaging response and survival after radioembolization for metastatic breast cancer and to delineate genetic predictors of imaging responses and outcomes.

MATERIALS AND METHODS

This retrospective study included 31 women (average age, 52 y) with liver metastasis from invasive ductal carcinoma who underwent resin and glass radioembolization (average cumulative dose, 2.0 GBq ± 1.8) between January 2011 and September 2017 after receiving ≥ 3 lines of chemotherapy. Twenty-four underwent genetic profiling with MSK-IMPACT or Sequenom; 26 had positron-emission tomography (PET)/CT imaging before and after treatment. Survival after the first radioembolization and 2-4-month PET/CT imaging response were assessed. Laboratory and imaging features were assessed to determine variables predictive of outcomes. Unpaired Student t tests and Fisher exact tests were used to compare responders and nonresponders categorized by changes in fluorodeoxyglucose avidity. Kaplan-Meier survival analysis was used to determine the impact of predictors on survival after radioembolization.

RESULTS

Median survival after radioembolization was 11 months (range, 1-49 mo). Most patients (18 of 26; 69%) had complete or partial response based on changes in fluorodeoxyglucose avidity. Imaging response was associated with longer survival (P = .005). Whereas 100% of patients with PI3K pathway mutations showed an imaging response, only 45% of wild-type patients showed a response (P = .01). Median survival did not differ between PI3K pathway wild-type (10.9 mo) and mutant (undefined) patients (P = .50).

CONCLUSIONS

These preliminary data suggest that genomic profiling may predict which patients with metastatic breast cancer benefit most from radioembolization. PI3K pathway mutations are associated with improved imaging response, which is associated with longer survival.

Early Response Assessment in Pancreatic Ductal Adenocarcinoma Through Integrated PET/MRI

OBJECTIVE

The purpose of this study is to investigate early changes in ¹⁸F-FDG PET/MRI metrics after treatment in patients with advanced pancreatic ductal adenocarcinoma (PDAC) and to correlate those changes with eventual tumor response at standard-of-care CT.

SUBJECTS AND METHODS

Thirteen patients with advanced PDAC underwent integrated FDG PET/MRI before and 4 weeks after treatment initiation. Patients were classified as responders or nonresponders according to Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 at subsequent CT performed 8-12 weeks after treatment initiation. Changes in the primary tumor's maximum standardized uptake value (SUV_max), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) determined at PET and apparent diffusion coefficient (ADC) determined at DWI at 4 weeks were compared between responders and nonresponders.

RESULTS

Seven patients had a partial response according to RECIST, and six did not. Responders displayed significantly greater decreases in MTV (p = 0.003) and TLG (p = 0.006) in the primary pancreatic tumor at 4 weeks. Responders also displayed a greater increase in the mean (p = 0.004) and minimum (p = 0.024) ADC of the primary tumors. Tumor size change at 4 weeks was not significantly different between responders and nonresponders (p = 0.11). PET responders enjoyed longer progression-free survival (PFS) (p = 0.0004) and overall survival (OS) (p = 0.013) than did nonresponders, using either a 60% reduction in MTV or 65% reduction in TLG as a threshold. MRI responders had significantly longer PFS (p = 0.0002) and OS (p = 0.027) than did nonresponders, using a 20% increase in either mean or minimum ADC as a threshold.

CONCLUSION

Integrated PET/MRI can provide early response assessment in patients with advanced PDAC, thus potentially allowing early treatment adaptation in nonresponders.

Importance of 18F-FDG PET/CT to select patients with nonresectable colorectal liver metastases for liver transplantation

OBJECTIVE

The aim of this study was to evaluate fluorine-18-fluorodeoxyglucose (F-FDG) PET/CT for the selection of patients with nonresectable colorectal liver metastases (NCLM) for liver transplantation (LT). In the secondary cancer study, we reported an improved 5-year overall survival in patients treated with LT for NCLM (56%) compared with chemotherapy (9%). However, many patients were rejected for LT owing to the detection of extrahepatic disease at preoperative imaging.

PATIENTS AND METHODS

F-FDG PET/CT and contrast-enhanced computed tomography (ceCT) examinations before tentative LT for NCLM were assessed, and findings contraindicating LT were registered. Maximum, mean and peak standardized uptake values; tumor-to-background ratio; metabolic tumor volume; and total lesion glycolysis were measured and calculated for all liver metastases. Overall survival was calculated by the Kaplan-Meier method.

RESULTS

Thirty-two patients excluded by F-FDG PET/CT and/or ceCT before tentative LT for NCLM were identified. F-FDG PET/CT from 20 of the 32 excluded patients revealed extrahepatic disease. Eight of the other 12 patients had a negative F-FDG PET/CT finding but were excluded by ceCT. Ten patients were excluded by F-FDG PET/CT only. Four patients were excluded owing to detected malignancy from frozen sections at the start of the intended transplant operation. Tumor-to-background ratio of the liver metastases was significantly higher in patients where F-FDG PET/CT detected extrahepatic disease (P=0.03). The median (range) survival after exclusion was 16 (0-52) months.

CONCLUSION

The ability of F-FDG PET/CT to detect extrahepatic disease before LT for NCLM is vital to establish LT as a treatment option.

Diffusion-weighted MRI Is Superior to PET/CT in Predicting Survival of Patients Undergoing 90Y Radioembolization of Hepatic Metastases

Purpose To determine the relationship between diffusion-weighted (DW) liver MR images obtained 4-6 weeks after lobar yttrium 90 (⁹⁰Y) treatment and overall survival in comparison with PET/CT or established oncologic factors known to affect survival. Materials and Methods The institutional review board approved this prospective intraindividual comparative study in 36 consecutive patients (25 women) with liver-dominant metastases (20 colorectal, 14 breast, two other) (mean age, 60 years ± 10 [standard deviation]) who underwent fluorine 18 (¹⁸F) fluorodeoxyglucose (FDG) PET/CT and DW MRI before and 4-6 weeks after ⁹⁰Y radioembolization. DW MRI response was defined as a mean minimal apparent diffusion coefficient increase of more than 30%; PET/CT response was defined as a mean maximal standardized uptake value decrease of more than 30%. Kaplan-Meier curves, log-rank test, and multivariable Cox regression analyses were used to compare patient survival as a function of imaging and Response Evaluation Criteria in Solid Tumors (RECIST) response, pretreatment Eastern Cooperative Oncology Group (ECOG) performance status (PS) (0 vs 1), hepatic tumor load (<25% vs ≥25%), and presence versus absence of extrahepatic disease. Results Thirty-five of the 36 patients were observed until death (median survival, 36 weeks). Response was observed with PET/CT in 18 of 36 patients (50%). Median survival was 39 weeks in patients who responded to PET/CT versus 27 weeks in those who did not (P = .60). Response was observed with DW MRI in 24 of 36 patients (67%). Median survival was 53 weeks in DW MRI responders versus 20 weeks in nonresponders (P = .01). At multivariable analysis, DW MRI response was the only independent predictor of survival (P < .01). Response based on RECIST parameters, ECOG PS, hepatic tumor load, and presence of extrahepatic metastases did not correlate with survival. Conclusion In patients with hepatic metastases undergoing ⁹⁰Y radioembolization, prediction of response to therapy with DW MRI was superior to that with PET/CT and established oncologic factors.

The prognostic value of 18F-FDG PET/CT prior to liver transplantation for nonresectable colorectal liver metastases

PURPOSE

The main objective of this study was to evaluate the prognostic value of volumetric and metabolic information derivied from F-18 fluorodeoxyglucose positron emission tomography (18F-FDG PET) in combination with computed tomography (CT) prior to liver transplantation (LT) in patients with nonresectable colorectal liver metastases (CLM). Due to scarcity of liver grafts, prognostic information enabling selection of candidates who will gain the highest survival after LT is of vital importance. 18F-FDG PET/CT was a part of the preoperative study protocol. Patients without evidence of extrahepatic malignant disease on 18F-FDG PET/CT who also fulfilled all the other inclusion criteria underwent LT.

METHODS

The preoperative 18F-FDG PET/CT examinations of all patients included in the SECA (secondary cancer) study were retrospectively assessed. Maximum, mean and peak standardized uptake values (SUVmax, SUVmean and SUVpeak), tumor to background (T/B) ratio, metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were measured and calculated for all liver metastases. Total MTV and TLG were calculated for each patient. Cut-off values were determined for each of these parameters by using receiver operating characteristic (ROC) analysis dividing the patients into two groups. One, three and five-year overall survival (OS) and disease free survival (DFS) for patients over and under the cut-off value were compared by using the Kaplan-Meier method and log rank test.

RESULTS

Twenty-three patients underwent LT in the SECA study. Total MTV and TLG under the cut-off values were significantly correlated to improved OS at three and five years (p = 0.027 and 0.026) and DFS (p = 0.01). One, three and five-year OS and DFS were not significantly related to SUVmax, SUVmean, SUVpeak or T/B-ratio.

CONCLUSION

Total MTV and TLG from 18F FDG PET/CT prior to LT for nonresectable CLM were significantly correlated to improved three and five-year OS and DFS and can potentially improve the patient selection for LT.

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.

Prognostic value of metabolic indices and bone marrow uptake pattern on preoperative 18F-FDG PET/CT in pediatric patients with neuroblastoma

PURPOSE

To evaluate the prognostic value of metabolic parameters and bone marrow uptake (BMU) patterns on pretherapeutic 18-F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) in pediatric patients with neuroblastoma (NB).

PATIENTS AND METHODS

Forty-seven pediatric patients with newly diagnosed neuroblastoma who underwent 18F-FDG PET/CT were retrospectively reviewed. Clinicopathological factors and metabolic parameters including maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), total lesion glycolysis (TLG) and bone marrow uptake patterns on PET/CT were compared to predict recurrence-free survival (RFS) and overall survival (OS) by univariate and multivariate analysis.

RESULTS

During the follow-up period, 27 (57.4%) patients experienced recurrence. MTV (P = 0.001), TLG (P = 0.004) and BMU patterns (P = 0.025) remained significant predictive factors for tumor recurrence, along with tumor size, histology, stage, lactate dehydrogenase (LDH) and other distant metastasis (except bone metastasis). Univariate analysis showed that histology, stage, tumor size (>37.25 cm), other distant metastasis, MTV (>88.10cm³) and TLG (>1045.2 g) and BMU patterns correlated with both RFS and OS (P < 0.05). On multivariate analysis, TLG remained the only independent prognostic factor for RFS (P = 0.016) and OS (P = 0.012), and BMU patterns and MTV were statistically significant for OS (P = 0.024 and P = 0.038, respectively).

CONCLUSION

Pretherapeutic 18F-FDG PET/CT can provide reliable prognostic information for neuroblastoma pediatric patients, and patients with high MTV, TLG and focal bone marrow (unifocal and multifocal) uptake on PET/CT may have inferior outcomes during subsequent treatment.

Present and future roles of FDG-PET/CT imaging in the management of gastrointestinal cancer: an update

Positron emission tomography/computed tomography (PET/CT) integrated with 2-[18F]fluoro-2-deoxy-D-glucose (FDG) is a useful tool for acquisition of both glucose metabolism and anatomic imaging data, as only a single device and one diagnostic session is required, thus opening a new field in clinical oncologic imaging. FDG-PET/CT has been successfully used for initial staging, restaging, assessment of early treatment response, evaluation of metastatic disease response, and prognostication of intestinal cancer as well as various malignant tumors. We reviewed the current status and role of FDG-PET/CT for management of patients with esophageal cancer, gastric cancer, and colorectal cancer, with focus on both its usefulness and limitations.

Recommendations for SIR-Spheres Y-90 resin microspheres in chemotherapy-refractory/intolerant colorectal liver metastases

A Spanish expert panel reviewed current evidence for the use of SIR-Spheres Y-90 resin microspheres in patients with chemotherapy refractory/intolerant unresectable colorectal liver metastases. Substantial evidence for its efficacy and safety is available from a randomized controlled study, retrospective comparative studies and several single arm studies. Clinical evidence data obtained from more than 1500 patients have led to the inclusion of selective internal radiation therapy in the 2016 ESMO Clinical Guidelines as third-line treatment. This publication results from an expert panel meeting, where published evidence and author's experiences were shared to position SIR-Spheres Y-90 resin microspheres in Spain for the treatment of chemotherapy refractory/intolerant unresectable colorectal liver metastases, and second, to define the patient subgroup that will benefit the most with this treatment.

Predictors and prognosticators for survival with Yttrium-90 radioembolization therapy for unresectable colorectal cancer liver metastasis

This critical review aims to explore predictive and prognostic biomarkers of Yttrium-90 (Y90) radioembolization therapy of colorectal liver metastases. A brief overview of established predictive and prognostic molecular and genetic biomarkers in colorectal cancer therapies will be discussed. A review of the literature on imaging modalities, genetic, metabolic and other molecular markers and the subsequent outcomes in post-Y90 treatment will be presented. How these biomarkers and future biomarker research can inform locoregional treatment decisions in the clinical setting of metastatic colorectal cancer lesions of the liver will be explored. There are opportunities for personalized cancer treatment in the setting of Y90 radioembolization. The ability to predict tumor response after Ytrium-90 radioembolization therapy can greatly impact clinical decision making and enhance treatment outcomes, therefore further research into the field is needed.

Role of the pretreatment 18F-fluorodeoxyglucose positron emission tomography maximal standardized uptake value in predicting outcomes of colon liver metastases and that value's association with Beclin-1 expression

The current study sought to evaluate the predictive and prognostic performance of the maximum standardized uptake value (SUV_max) prior to treatment in 43 patients with colon cancer and unresectable liver metastases. Patients with colon cancer who underwent ¹⁸F-FDG-PET/computed tomography (CT) scans for staging before the start of first-line 5-fluorouracil-based chemotherapy were retrospectively analyzed. Expression of Beclin-1 in cancer cells was evaluated in primary tumors using immunohistochemical staining. The pretreatment SUV_max for liver metastases was not able to predict progression-free survival but was significantly associated with poorer overall survival, with a hazard ratio of 2.05 (95 % CI, 1.016-4.155). Moreover, a negative correlation was noted between SUV_max and expression of a marker of autophagy - Beclin-1 (rho = -0.42, p = 0.006). This suggests that the pretreatment SUV_max in ¹⁸F-FDG PET/CT is a useful tool to help predict survival outcome in patients with colon cancer and unresectable liver metastases and may significantly distinguish between patients with low and high levels of Beclin-1 expression (AUC = 0.809, 95% CI: 0.670-0.948, p = 0.001).

Radiotherapy response evaluation using FDG PET-CT-established and emerging applications

Radiation therapy is a common component of curative cancer treatment. However, there is a significant incidence of treatment failure. In these cases, salvage surgical options are sometimes appropriate. Accurate assessment of response and early recognition of treatment success or failure is therefore critical to guide treatment decisions and impacts on survival and the morbidity of treatment. Traditionally, treatment response has depended upon the anatomical measurement of disease. However, this may not correlate well with the presence of disease, especially after radiotherapy. Combined positron emission tomography (PET) and CT imaging employs radioactive tracers to identify molecular characteristics of tissues. PET imaging exploits the fact that malignancies have characteristic molecular profiles which differ compared with surrounding tissues. The complementary anatomical and functional information facilitates accurate non-invasive assessment of surrogate biomarkers of disease activity.

A Lesion-Based Response Prediction Model Using Pretherapy PET/CT Image Features for Y90 Radioembolization to Hepatic Malignancies

We present a probabilistic approach to identify patients with primary and secondary hepatic malignancies as responders or nonresponders to yttrium-90 radioembolization therapy. Recent advances in computer-aided detection have decreased false-negative and false-positive rates of perceived abnormalities; however, there is limited research in using similar concepts to predict treatment response. Our approach is driven by the goal of precision medicine to determine pretherapy fluorine-18-2-fluoro-2-deoxy-d-glucose positron emission tomography and computed tomography imaging parameters to facilitate the identification of patients who would benefit most from yttrium-90 radioembolization therapy, while avoiding complex and costly procedures for those who would not. Our algorithm seeks to predict a patient's response by discovering common co-occurring image patterns in the lesions of baseline fluorine-18-2-fluoro-2-deoxy-d-glucose positron emission tomography and computed tomography scans by extracting invariant shape and texture features. The extracted imaging features were represented as a distribution of each subject based on the bag-of-feature paradigm. The distribution was applied in a multinomial naive Bayes classifier to predict whether a patient would be a responder or nonresponder to yttrium-90 radioembolization therapy based on the imaging features of a pretherapy fluorine-18-2-fluoro-2-deoxy-d-glucose positron emission tomography and computed tomography scan. Comprehensive published criteria were used to determine lesion-based clinical treatment response based on fluorine-18-2-fluoro-2-deoxy-d-glucose positron emission tomography and computed tomography imaging findings. Our results show that the model is able to predict a patient with liver cancer as a responder or nonresponder to yttrium-90 radioembolization therapy with a sensitivity of 0.791 using extracted invariant imaging features from the pretherapy fluorine-18-2-fluoro-2-deoxy-d-glucose positron emission tomography and computed tomography test. The sensitivity increased to 0.821 when combining extracted invariant image features with variable features of tumor volume.

Standardized Added Metabolic Activity Predicts Survival After Intra-arterial Resin-Based 90Y Radioembolization Therapy in Unresectable Chemorefractory Metastatic Colorectal Cancer to the Liver

PURPOSE

Standardized added metabolic (SAM) activity is a functional objective measurement of the total tumoral metabolic activity that avoids partial volume effect and thresholding, which limit conventional PET parameters. The purpose of this study is to investigate the role of SAM in predicting survival in unresectable, chemorefractory colorectal hepatic metastatic disease treated with resin-based Y radioembolization.

MATERIALS AND METHODS

This is a prospective correlative study of patients with unresectable, chemorefractory colorectal liver metastasis who underwent F-FDG PET/CT and CT/MRI before and after Y. Target RECIST, PERCIST, change in total glycolytic activity (ΔTGA), and ΔSAM treatment response were assessed. Percentage changes in diameter, SUVpeak, TGA, and SAM were calculated pre- and post-Y therapy and objective response was defined as >30% change (responders). Survival analysis by Kaplan-Meier, log-rank, and Cox proportional hazard models were performed and significance was set at <0.05.

RESULTS

Sixteen patients (mean age of 61.6) were enrolled and performed a total of 20 Y therapies. After Y, target ΔSAM showed an objective response rate of 40% vs. 35%, 30%, and 22.2% based on target ΔTGA, PERCIST, and RECIST criteria, respectively. Median overall survival (OS) of the cohort after Y was 9.2 months (CI 95% 2.2-16.2). Patients demonstrating objective response based on ΔSAM had a median OS of 22.7 months (CI 95% 12.4-33.0) vs. 6.7 (CI 95% 4.2-9.2) in non-responders (P = 0.007). On multivariate analysis, hazard ratios for the objective response group based on target ΔSAM were 0.01 (P = 0.03) vs. 0.05 (P = 0.08), 0.20 (P = 0.29), and 0.91 (P = 0.98) based on target ΔTGA, PERCIST, and RECIST criteria, respectively.

CONCLUSIONS

In unresectable colorectal liver metastatic disease refractory to standard chemotherapy, ΔSAM predicted OS for assessment of response following Y radioembolization therapy, whereas RECIST, PERCIST, and ΔTGA did not.

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.

Quantitative Measurements of Enhancement on Preprocedure Triphasic CT Can Predict Response of Colorectal Liver Metastases to Radioembolization

OBJECTIVE

Colorectal liver metastases (CLM) have a variable response to radioembolization. This may be due at least partly to differences in tumor arterial perfusion. The present study examines whether quantitative measurements of enhancement on preprocedure triphasic CT can be used to predict the response of CLM to radioembolization.

MATERIALS AND METHODS

We retrospectively reviewed patients with CLM treated with radioembolization who underwent pretreatment PET/CT and triphasic CT examinations and posttreatment PET/CT examinations. A total of 31 consecutive patients with 60 target tumors were included in the present study. For each tumor, we calculated the hepatic artery coefficient (HAC), portal vein coefficient (PVC), and arterial enhancement fraction (AEF) based on enhancement measurements on pretreatment triphasic CT. HAC and PVC are estimates of the hepatic artery and portal vein blood supply. AEF, which is the arterial phase enhancement divided by the portal phase enhancement, provides an estimate of the hepatic artery blood supply as a fraction of the total blood supply. For each tumor, the metabolic response to radioembolization was based on findings from the initial follow-up PET/CT scan obtained at 4-8 weeks after treatment.

RESULTS

A total of 55% of CLM had a complete or partial metabolic response. Arterial phase enhancement, the HAC, and the PVC did not predict which tumors responded to radioembolization. However, the AEF was statistically significantly greater in tumors with a complete or partial metabolic response than in tumors with no metabolic response (i.e., those with stable disease or disease progression) (p = 0.038). An AEF of less than 0.4 was associated with a 40% response rate, whereas an AEF greater than 0.75 was associated with a 78% response rate.

CONCLUSION

Response to radioembolization can be predicted using the AEF calculated from the preprocedure triphasic CT.

Metabolic tumor volume and total lesion glycolysis on FDG-PET/CT can predict overall survival after (90)Y radioembolization of colorectal liver metastases: A comparison with SUVmax, SUVpeak, and RECIST 1.0

PURPOSE

To compare the performance of 4 metrics of metabolic response on FDG-PET/CT against RECIST 1.0 for determining response and predicting overall survival (OS) following (90)Y resin microspheres radioembolization of colorectal liver metastases (CLM).

METHODS

We conducted an IRB-waived retrospective review of our radioembolization database to identify patients with unresectable CLM treated between December 2009 and December 2013. We included patients who had both PET/CT and contrast enhanced CT (CECT) available at baseline and on the first follow-up post-radioembolization. On baseline CECT up to five target tumors were chosen per patient according to RECIST 1.0. Four metrics of FDG-avidity (SUVmax, SUVpeak, metabolic tumor volume (MTV), and total lesion glycolysis (TLG)) on PET/CT were measured for the same target tumors. Using RECIST 1.0, patients were classified as no progression (partial response or stable disease) and progression. For each PET metric, a cut-off point of ≥30% decrease was chosen to define response. OS was calculated from the time of radioembolization using Kaplan-Meier methodology. The log-rank test was used for univariate analysis to identify predictors of OS.

RESULTS

The study enrolled 49 patients with 119 target tumors; a median of 2 (range: 1-5) tumors were selected per patient. Median OS was 12.7 months (95%CI: 7.2-16.7). Response by MTV (P=0.035) and TLG (P=0.044) reached statistical significance in predicting OS. Response by SUVmax (P=0.21), SUVpeak (P=0.20) or no progression by RECIST 1.0 (P=0.44) did not predict OS.

CONCLUSION

Metabolic response based on changes in MTV and TLG can predict OS post-radioembolization of CLM.

Preoperative Volume-Based PET Parameter, MTV2.5, as a Potential Surrogate Marker for Tumor Biology and Recurrence in Resected Pancreatic Cancer

This study aims to evaluate the role of volume-based positron emission tomography parameters as potential surrogate markers for tumor recurrence in resected pancreatic cancer. Between January 2008 and October 2012, medical records of patients who underwent surgical resection for pancreatic ductal adenocarcinoma and completed ¹⁸F-fluorodeoxyglucose positron emission tomography/CT as a part of preoperative staging work-up were retrospectively reviewed. Not only clinicopathologic variables but also positron emission tomography parameters such as SUVmax, MTV2.5 (metabolic tumor volume), and TLG (total lesion glycolysis) were obtained. Twenty-six patients were women and 31 were men with a mean age of 62.9 ± 9.1 years. All patients were preoperatively determined to resectable pancreatic cancer except 1 case with borderline resectability. R0 resection was achieved in all patients and 45 patients (78.9%) received postoperative adjuvant chemotherapy with or without radiation therapy. Median overall disease-free survival was 12.8 months with a median overall disease-specific survival of 25.1 months. SUVmax did not correlate with radiologic tumor size (P = 0.501); however, MTV2.5 (P = 0.001) and TLG (P = 0.009) were significantly associated with radiologic tumor size. In addition, MTV2.5 (P < 0.001) and TLG (P < 0.001) were significantly correlated with a tumor differentiation. There were no significant differences in TLG and SUVmax according to lymph node ratio; only MTV2.5 was related to lymph node ratio with marginal significance (P = 0.055). In multivariate analysis, lymph node ratio (Exp [β] = 2.425, P = 0.025) and MTV2.5 (Exp[β] = 2.273, P = 0.034) were identified as independent predictors of tumor recurrence following margin-negative resection. Even after tumor size-matched analysis, MTV2.5 was still identified as significant prognostic factor in resected pancreatic cancer (P < 0.05). However, preoperative neoadjuvant treatment attenuated adverse oncologic impact of high preoperative MTV2.5 (P = 0.210). Preoperatively determined volume-based PET parameter, MTV2.5, can potentially be used as a surrogate marker to estimate tumor biology and tumor recurrence. Individual treatment strategies for pancreatic cancer can be suggested based on patients' preoperative MTV2.5.

Safety, Efficacy, and Prognostic Factors After Radioembolization of Hepatic Metastases from Breast Cancer: A Large Single-Center Experience in 81 Patients

The present study evaluated safety, efficacy, and prognostic factors for (90)Y-yttrium microsphere radioembolization of unresectable liver metastases from breast cancer.

METHODS

Eighty-one patients were treated with radioembolization. Acute toxicity was monitored through daily physical examination and serum tests until 3 d after radioembolization; late toxicity was evaluated until 12 wk after radioembolization. Overall survival and response according to (18)F-FDG PET (>30% decrease of tracer uptake) and CA15-3 serum level (any decline) were recorded. Pretherapeutic characteristics, including pretreatment history, liver function tests, and PET/CT parameters, were assessed by univariate and subsequent multivariate Cox regression for predicting patient survival.

RESULTS

A toxicity grade of 3 or more based on clinical symptoms, bilirubin, ulcer, pancreatitis, ascites, or radioembolization-induced liver disease occurred in 10% or less of patients. Two patients eventually died from radioembolization-induced liver disease. Sequential lobar treatment and absence of prior angiosuppressive therapy were both associated with a lower rate of serious adverse events. On the basis of PET/CA15-3 criteria, 52/61% of patients responded to treatment. Median overall survival after radioembolization was 35 wk (interquartile range, 41 wk). Pretherapeutic tumor burden of the liver greater than 50% or more (P< 0.001; hazard ratio, 5.67; 95% confidence interval, 2.41-13.34) and a transaminase toxicity grade of 2 or more (P= 0.009; hazard ratio, 2.15; 95% confidence interval, 1.21-3.80) independently predicted short survival.

CONCLUSION

Radioembolization for breast cancer liver metastases shows encouraging local response rates with low incidence of serious adverse events, especially in those patients with sequential lobar treatment or without prior angiosuppressive therapy. High hepatic tumor burden and liver transaminase levels at baseline indicate poor outcome.