Yttrium-90 Radiation Segmentectomy of Hepatocellular Carcinoma: A Comparative Study of the Effectiveness, Safety, and Dosimetry of Glass-Based versus Resin-Based Microspheres

PURPOSE

To evaluate the differences in safety, effectiveness, and dosimetry between glass-based and resin-based ablative yttrium-90 (90Y) transarterial radioembolization (TARE) of hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Using the modified Response Evaluation Criteria in Solid Tumors and Common Terminology Criteria for Adverse Events, both tumor response and adverse events (AEs) were assessed at 3 months after 90Y-TARE. Post procedure 90Y-bremsstrahlung single-photon emission computed tomography/computed tomography voxel-based dosimetry analysis was used to create tumor dose (TD) and normal tissue dose (NTD) volume histograms, and to calculate tumor particle loading and specific activity. The TD and NTD receiver operating characteristic curves evaluated the dose threshold able to predict objective (partial or complete) and complete tumor responses in addition to any-grade and grade ≥3 AE incidences. The chi-square test and Student t-test were used to assess variable differences where appropriate.

RESULTS

Between 2019 and 2020, 81 patients with HCC (20 in the resin-based cohort and 61 in the glass-based cohort) underwent ablative 90Y-TARE. The resin-based cohort had more males (89% vs 65%, P = .03), lower tumor-to-normal ratio (1.81 ± 0.39 vs 2.22 ± 0.94, P = .03), higher tumor particle loading (40,172 particles/mL ± 28,039 vs 17,081 particles/mL ± 12,555, P = .0001), lower specific activity (158 Bq/particle ± 3 vs 1,058 Bq/particle ± 331, P = .001), and lower mean TD (308 Gy ± 210 vs 794 Gy ± 523, P = .0002) than the glass-based cohort. No significant differences in baseline characteristics or posttreatment AEs were noted. The overall objective and complete response rates were 85% (95% resin-based vs 82% glass-based; P = .1) and 65% (95% resin-based vs 56% glass-based; P = .003), respectively. The mean TD thresholds able to predict the objective and complete responses were 176 Gy and 247 Gy for resin-based radioembolization and 290 Gy and 481 Gy for glass-based radioembolization, respectively. A maximum NTD of 999 Gy predicted any-grade AEs in glass-based ablative 90Y-TARE.

CONCLUSIONS

Compared with glass-based ablative 90Y-TARE, resin-based ablative 90Y-TARE can offer comparable safety and effectiveness profiles for patients with HCC. The impact of the significantly different tumor particle loading, particle specific activities, and delivered TDs on tumor response outcomes merits further investigation.

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.

Assessing the Status of Mentorship Programs in Interventional Radiology Residency Training: Results of a 2018 Survey

RATIONALE AND OBJECTIVES

To assess the prevalence and structure of mentorship programs in interventional radiology (IR) residency programs.

MATERIALS AND METHODS

A 12-question anonymous survey was distributed via email to all 78 program directors (PDs) of United States IR residency programs. The survey included information about the presence or absence of a formal mentorship program at their institution, how the program functions, potential barriers to implementation, and future plans for mentorship.

RESULTS

Twenty-three of 78 integrated IR residency PDs completed the survey (response rate 29.5%). Thirteen of 23 reports that they currently have a formal mentorship program in place and 11 of 13 report no direct departmental support for mentorship. Of those that do not have a mentorship program in place, 5 of 10 report that implementation is underway. These programs report that the absence of a mentorship program is due to a lack of dedicated time and financial support. While 8 of 23 PDs were unaware of the Society of Interventional Radiology Mentor Match program, 6of 23 were registered as mentors through it. Nearly all PDs reported interest in receiving mentoring resources from SIR with the most popular choices being a dedicated mentorship educational course at the SIR annual meeting and regular mentorship articles and practical tips in publications such as IR quarterly.

CONCLUSIONS

Despite involvement of many IR PDs in mentorship, numerous residency programs lack a formal mentorship program. Of those with a program, most don't receive direct departmental support and those without a program cite lack of time and financial support as barriers to effective implementation.

Systematic Review of Contemporary Evidence for the Management of T1 Renal Cell Carcinoma: What IRs Need to Know for Kidney Cancer Tumor Boards

Renal cell carcinoma is a relatively common malignancy, with 60 to 70 thousand cases a year in the United States alone. Increased utilization of cross-sectional imaging has led to an increase in the number of early renal cell cancers seen by the medical establishment. In addition, certain patient populations have an increased risk of developing kidney cancers which may mandate aggressive screening protocols. This article discusses the epidemiology of renal cell cancers; discusses the current management guidelines from multiple specialty societies; discusses some of the surgical and interventional techniques used in the treatment of such lesions; and provides a review of the literature regarding treatments of early-stage renal cell cancers.