Yttrium-90 transarterial radioembolization for liver metastases from medullary thyroid cancer

Objectives

Liver metastases occur in 45% of patients with advanced metastatic medullary thyroid cancer (MTC). Transarterial radioembolization (TARE) has been proposed to treat liver metastases (LM), especially in neuroendocrine tumors. The aim of this study was to investigate the biochemical (calcitonin and carcino-embryonic antigen) and objective response of liver metastases from MTC to TARE.

Methods

TARE is an internal radiotherapy in which microspheres loaded with β-emitting yttrium-90 (90Y) are delivered into the hepatic arteries that supply blood to LM. Eight patients with progressive multiple LM underwent TARE and were followed prospectively. They were clinically, biochemically and radiologically evaluated at 1, 4, 12 and 18 months after TARE.

Results

Two patients were excluded from the analysis due to severe liver injury and death due to extrahepatic disease progression, respectively. One month after TARE, a statistically significant (P = 0.02) reduction of calcitonin was observed in all patients and remained clinically relevant during follow-up; reduction of CEA, although not significant, was found in all patients. Significant reduction of liver tumor mass was observed 1, 4 and 12 months after TARE (P = 0.007, P = 0.004, P = 0.002, respectively). After 1 month, three of six patients showed partial response (PR) and three of six stable disease (SD) according to RECIST 1.1, while five of six patients had a PR and one of six a SD according to mRECIST. The clinical response remained relevant 18 months after TARE. Excluding one patient, all others showed only a slight and transient increase in liver enzymes.

Conclusions

TARE is effective in LM treatment of MTC. The absence of severe complications and the good tolerability make TARE a valid therapeutic strategy when liver LM are multiple and progressive.

Expected and Unexpected Imaging Findings after 90Y Transarterial Radioembolization for Liver Tumors

Transarterial radioembolization (TARE), also called radioembolization or selective internal radiation therapy, is an interventional radiology technique used to treat primary liver tumors and liver metastases. The aim of this therapy is to deliver tumoricidal doses of radiation to liver tumors while selecting a safe radiation dose limit for nontumoral liver and lung tissue. Hence, correct treatment planning is essential to obtaining good results. However, this treatment invariably results in some degree of irradiation of normal liver parenchyma, inducing different radiologic findings that may affect follow-up image interpretation. When evaluating treatment response, the treated area size, tumor necrosis, devascularization, and changes seen at functional MRI must be taken into account. Unlike with other interventional procedures, with TARE, it can take several months for the tumor response to become evident. Ideally, responding lesions will show reduced size and decreased enhancement 3-6 months after treatment. In addition, during follow-up, there are many imaging findings related to the procedure itself (eg, peritumoral edema, inflammation, ring enhancement, hepatic fibrosis, and capsular retraction) that can make image interpretation and response evaluation difficult. Possible complications, either hepatic or extrahepatic, also can occur and include biliary injuries, hepatic abscess, radioembolization-induced liver disease, and radiation pneumonitis or dermatitis. A complete understanding of these possible posttreatment changes is essential for correct radiologic interpretations during the follow-up of patients who have undergone TARE. ^©RSNA, 2019.

Current state of the art imaging approaches for colorectal liver metastasis

One of the most common cancers worldwide, colorectal cancer (CRC) has been associated with significant morbidity and mortality and therefore represents an enormous burden to the health care system. Recent advances in CRC treatments have provided patients with primary and metastatic CRC a better long-term prognosis. The presence of synchronous or metachronous metastasis has been associated, however, with worse survival. The most common site of metastatic disease is the liver. A variety of treatment modalities aimed at targeting colorectal liver metastases (CRLM) has been demonstrated to improve the prognosis of these patients. Loco-regional approaches such as surgical resection and tumor ablation (operative and percutaneous) can provide patients with a chance at long-term disease control and even cure in select populations. Patient selection is important in defining the most suitable treatment option for CRLM in order to provide the best possible survival benefit while avoiding unnecessary interventions and adverse events. Medical imaging plays a crucial role in evaluating the characteristics of CRLMs and disease resectability. Size of tumors, proximity to adjacent anatomical structures, and volume of the unaffected liver are among the most important imaging parameters to determine the suitability of patients for surgical management or other appropriate treatment approaches. We herein provide a comprehensive overview of current-state-of-the-art imaging in the management of CRLM, including staging, treatment planning, response and survival assessment, and post-treatment surveillance. Computed tomography (CT) scan and magnetic resonance imaging (MRI) are two most commonly used techniques, which can be used solely or in combination with functional imaging modalities such as positron emission tomography (PET) and diffusion weighted imaging (DWI). Providing up-to-date evidence on advantages and disadvantages of imaging modalities and tumor assessment criteria, the current review offers a practice guide to assist providers in choosing the most suitable imaging approach for patients with CRLM.

Prognostic Importance of the Presence of Early Metabolic Response and Absence of Extrahepatic Metastasis After Selective Internal Radiation Therapy in Colorectal Cancer Liver Metastasis

AIMS

In this study, the authors aimed to identify prognostic factors after selective internal radiation therapy (SIRT) for colorectal cancer (CRC) liver metastasis.

METHODS

Forty-nine (28 male, 21 female; mean age: 64.6 ± 10.8) patients who received SIRT for CRC liver metastasis were studied. Effects of number (<5 vs. ≥5), maximum dimension, and standardized uptake value (SUV) of liver metastases, liver tumor load (<25% vs. 26%-50% vs. 51%-75%), presence of extrahepatic disease, and metabolic early response on overall survival were analyzed.

RESULTS

Mean follow-up time was 44.1 ± 27.5 months. Overall survival time was calculated as 10.03 ± 1.61 (95% CI; 6.86-13.20) months. SUV (0.004) of liver metastases, early metabolic response (p = 0.015), and presence of extrahepatic metastasis (p = 0.001) were identified as significant factors influencing overall survival. The hazard ratio was 1:2.3 for the presence of extrahepatic metastasis and 1:2.7 for the absence of early metabolic response.

CONCLUSION

These findings suggest that patients with CRC liver metastasis who have lower SUV at presentation and early metabolic response have better outcomes after SIRT.

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.

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.

Hepatic imaging response to radioembolization with yttrium-90-labeled resin microspheres for tumor progression during systemic chemotherapy in patients with colorectal liver metastases

BACKGROUND

To assess response and the impact of imaging artifacts following radioembolization with yttrium-90-labeled resin microspheres ((90)Y-RE) based on the findings from a central independent review of patients with liver-dominant metastatic colorectal cancer (mCRC).

METHODS

Patients with mCRC who received (90)Y-RE (SIR-Spheres(®); Sirtex Medical, Sydney, Australia) at nine US institutions between July 2002 and December 2011 were included in the analysis. Tumor response was assessed at baseline and 3 months using either the Response Evaluation Criteria in Solid Tumors (RECIST) version 1.0 or 1.1. For each lesion, known artifacts affecting the interpretation of response (peri-tumoral edema and necrosis) were documented. Survivals (Kaplan-Meier analyses) were compared in responders [partial response (PR)] and non-responders [stable (SD) or progressive disease (PD)].

RESULTS

Overall, 195 patients (mean age 62 years) received (90)Y-RE after a median of 2 (range, 1-6) lines of prior chemotherapy. Using RECIST 1.0 and RECIST 1.1, 7.6% and 6.9% of patients were partial responders, 47.3% and 48.1% had SD, and 55.0% and 55.0% PD, respectively. RECIST 1.0 and RECIST 1.1 showed excellent agreement {Kappa =0.915 [95% confidence interval (CI): 0.856-0.975]}. Peri-tumoral edema was documented in 32.8%, necrosis in 48.1% and both in 57.3% of cases (using RECIST 1.0). Although baseline characteristics were similar in responders and non-responders (P>0.05), responders survived significantly longer in an analysis according to RECIST 1.0: PR median (95% CI) 25.2 (range, 9.2-49.4) months vs. SD 15.8 (range, 9.3-21.1) months vs. PD 7.1 (range, 6.0-9.5) months (P<0.0001).

CONCLUSIONS

RECIST 1.0 and RECIST 1.1 imaging responses provide equivalent interpretations in the assessment of hepatic tumors following (90)Y-RE. Radiologic lesion responses at 3 months must be interpreted with caution due to the significant proportion of patients with peri-tumoral edema and necrosis, which may lead to an under-estimation of PR/SD. Nevertheless, 3-month radiologic responses were predictive of prolonged survival.

Imaging tumor response following liver-directed intra-arterial therapy

Liver-directed intra-arterial therapies are palliative treatment options for patients with unresectable liver cancer; their use has also resulted in patients being downstaged leading to curative resection and transplantation. These intra-arterial therapies include transarterial embolization, conventional transarterial chemoembolization (TACE), drug-eluting bead TACE and radioembolization. Assessment of imaging response following these liver-directed intra-arterial therapies is challenging but pivotal for patient management. Size measurements based on computed tomography or magnetic resonance imaging (MRI) have been traditionally used to assess tumor response to therapy. However, these anatomic changes lag behind functional changes and may require months to occur. Further, these intra-arterial therapies cause acute tumor necrosis, which may result in a paradoxical increase in tumor size on early follow-up imaging despite complete cell death or necrosis. This concept is unique comparing to changes seen following systemic chemotherapy. The recent development of functional imaging techniques including diffusion-weighted MRI (DW MRI) and positron emission tomography (PET) allow for early assessment of treatment response and even prediction of overall tumor response to intra-arterial therapies. Although the results of DW MRI and PET studies are promising, the impact of these imaging modalities to assess treatment response has been limited without standardized protocols. The aim of this review article is to delineate the best practice for assessing tumor response in patients with primary or secondary hepatic malignancies undergoing intra-arterial therapies.

The role of 18F-FDG-PET and PET/CT in patients with colorectal liver metastases undergoing selective internal radiation therapy with yttrium-90: a first evidence-based review

PURPOSE

To provide a first evidence-based review of the literature on the role of fluorine-18-fluorodeoxyglucose positron emission tomography and positron emission tomography/computed tomography (FDG-PET and PET/CT) in patients with colorectal liver metastases (CRLM) undergoing selective internal radiation therapy (SIRT) with yttrium-90 ((90)Y) microspheres.

METHODS

A comprehensive computer literature search was conducted to find relevant published articles on whole-body FDG-PET or PET/CT in patients with CRLM undergoing SIRT.

RESULTS

We identified 19 studies including 833 patients with CRLM undergoing SIRT. The role of FDG-PET or PET/CT was analysed in treatment planning, treatment response evaluation, and as prognostic tool.

CONCLUSION

FDG-PET and PET/CT provide additional information in treatment evaluation of CRLM patients treated with SIRT and may have a role in treatment planning and patient selection. FDG-PET/CT is emerging as good prognostic tool in these patients.