Radioembolization of renal cell carcinoma using yttrium-90 microspheres

Ablative Radioembolization (SIRT) of a Large Inoperable Renal Cell Carcinoma Invading the Liver That Resulted in Hematuria Control and Complete Necrosis by mRECIST Criteria

ABSTRACT

We report the successful application of radioembolization (SIRT) in a 77-year-old man with end-stage renal disease on hemodialysis and repeated episodes of macroscopic hematuria due to a large renal cell carcinoma of the right kidney extending to liver segment VI. A compassionate SIRT therapy was performed with resin microspheres through the upper pole renal artery and the feeding segmental artery of liver segment VI. Hematuria was resolved after treatment, and 4 months later, a follow-up CT scan revealed tumor size reduction and complete tumor necrosis (Response Evaluation Criteria in Solid Tumors criteria). Ablative SIRT therapy could be a safe and efficient option in a large inoperable RCC.

Partial Radiation Nephrectomy Using 90 Y Resin Microspheres: A Treatment Option for Renal Tumors With Malignant Characteristics in Patients Not Candidates for Surgery

ABSTRACT

Contrast-enhancing renal masses are likely to be malignant in over 90% of cases due to the high diagnostic accuracy of abdominal imaging. In this situation, tumor biopsy is unnecessary and should be managed as a renal cell carcinoma. Resection remains the only potentially curative treatment. However, as in the case herein presented, comorbidities can prevent surgical resection. Radioembolization with 90 Y microspheres is an intra-arterial procedure capable of delivering high doses of radiation to tumors. The present case demonstrates the concept of partial radiation nephrectomy in treating renal tumors with malignant characteristics in patients not amenable to surgery.

Extrahepatic Applications of Yttrium-90 Radioembolization

While initially described and now accepted as treatment for primary and secondary malignancies in the liver, radioembolization therapy has expanded to include treatment for other disease pathologies and other organ systems. Advantages and limitations for these treatments exist and must be compared against more traditional treatments for these processes. This article provides an overview of the current applications for radioembolization outside of the liver, for both malignant and nonmalignant disease.

Effects of Yttrium-90 selective internal radiation therapy on non-conventional liver tumors

The liver is a common site of metastasis, with essentially all metastatic malignancies having been known to spread to the liver. Nearly half of all patients with extrahepatic primary cancer have hepatic metastases. The severe prognostic implications of hepatic metastases have made surgical resection an important first line treatment in management. However, limitations such as the presence of extrahepatic spread or poor functional hepatic reserve exclude the majority of patients as surgical candidates, leaving chemotherapy and locoregional therapies as next best options. Selective internal radiation therapy (SIRT) is a form of catheter-based locoregional cancer treatment modality for unresectable tumors, involving trans-arterial injection of microspheres embedded with a radio-isotope Yttrium-90. The therapeutic radiation dose is selectively delivered as the microspheres permanently embed themselves within the tumor vascular bed. Use of SIRT has been conventionally aimed at treating primary hepatic tumors (hepatocellular carcinoma) or colorectal and neuroendocrine metastases. Numerous reviews are available for these tumor types. However, little is known or reviewed on non-colorectal or non-neuroendocrine primaries. Therefore, the aim of this paper is to systematically review the current literature to evaluate the effects of Yttrium-90 radioembolization on non-conventional liver tumors including those secondary to breast cancer, cholangiocarcinoma, ocular and percutaneous melanoma, pancreatic cancer, renal cell carcinoma, and lung cancer.

Transcatheter renal interventions: a review of established and emerging procedures

Catheter-based interventions play an important role in the multidisciplinary management of renal pathology. The array of procedures available to interventional radiologists (IRs) includes established techniques such as angioplasty, stenting, embolization, thrombolysis, and thrombectomy for treatment of renovascular disease, as well as embolization of renal neoplasms and emerging therapies such as transcatheter renal artery sympathectomy for treatment of resistant hypertension. Here, we present an overview of these minimally invasive therapies, with an emphasis on interventional technique and clinical outcomes of the procedure.

Beyond hepatocellular carcinoma and colorectal metastasis: the expanding applications of radioembolization

As a relatively safe outpatient procedure, radioembolization can potentially be used to treat any type of tumor within the liver, primary or metastatic. The safety and effectiveness of radioembolization in the treatment of hepatocellular carcinoma (HCC) and metastatic colorectal cancer (mCRC) has led many groups to explore its application in other malignancies. Moreover, other organs, such as the lungs and kidneys, have been explored as targets for therapy. Although the most data for radioembolization is related to HCC and mCRC, there is increasing experience and data regarding metastatic disease to the liver for other primary tumors. We review the current state of liver-directed therapy with radioembolization outside of HCC and mCRC, including metastatic neuroendocrine, breast, and melanoma, as well as limited experiences with other primary malignancies. Applications of radioembolization related to these other cancers and new trends and future directions will be discussed. With increasing use and availability of radioembolization, it promises to serve an expanding role in the repertoire of tools available for treating and managing oncologic disease.

Post-radioembolization yttrium-90 PET/CT - part 2: dose-response and tumor predictive dosimetry for resin microspheres

Background

Coincidence imaging of low-abundance yttrium-90 (⁹⁰Y) internal pair production by positron emission tomography with integrated computed tomography (PET/CT) achieves high-resolution imaging of post-radioembolization microsphere biodistribution. Part 2 analyzes tumor and non-target tissue dose-response by ⁹⁰Y PET quantification and evaluates the accuracy of tumor ^99mTc macroaggregated albumin (MAA) single-photon emission computed tomography with integrated CT (SPECT/CT) predictive dosimetry.

Methods

Retrospective dose quantification of ⁹⁰Y resin microspheres was performed on the same 23-patient data set in part 1. Phantom studies were performed to assure quantitative accuracy of our time-of-flight lutetium-yttrium-oxyorthosilicate system. Dose-responses were analyzed using ⁹⁰Y dose-volume histograms (DVHs) by PET voxel dosimetry or mean absorbed doses by Medical Internal Radiation Dose macrodosimetry, correlated to follow-up imaging or clinical findings. Intended tumor mean doses by predictive dosimetry were compared to doses by ⁹⁰Y PET.

Results

Phantom studies demonstrated near-perfect detector linearity and high tumor quantitative accuracy. For hepatocellular carcinomas, complete responses were generally achieved at D₇₀ > 100 Gy (D₇₀, minimum dose to 70% tumor volume), whereas incomplete responses were generally at D₇₀ < 100 Gy; smaller tumors (<80 cm³) achieved D₇₀ > 100 Gy more easily than larger tumors. There was complete response in a cholangiocarcinoma at D₇₀ 90 Gy and partial response in an adrenal gastrointestinal stromal tumor metastasis at D₇₀ 53 Gy. In two patients, a mean dose of 18 Gy to the stomach was asymptomatic, 49 Gy caused gastritis, 65 Gy caused ulceration, and 53 Gy caused duodenitis. In one patient, a bilateral kidney mean dose of 9 Gy (V₂₀ 8%) did not cause clinically relevant nephrotoxicity. Under near-ideal dosimetric conditions, there was excellent correlation between intended tumor mean doses by predictive dosimetry and those by ⁹⁰Y PET, with a low median relative error of +3.8% (95% confidence interval, -1.2% to +13.2%).

Conclusions

Tumor and non-target tissue absorbed dose quantification by ⁹⁰Y PET is accurate and yields radiobiologically meaningful dose-response information to guide adjuvant or mitigative action. Tumor ^99mTc MAA SPECT/CT predictive dosimetry is feasible. ⁹⁰Y DVHs may guide future techniques in predictive dosimetry.

Post-radioembolization yttrium-90 PET/CT - part 1: diagnostic reporting

Background

Yttrium-90 (⁹⁰Y) positron emission tomography with integrated computed tomography (PET/CT) represents a technological leap from ⁹⁰Y bremsstrahlung single-photon emission computed tomography with integrated computed tomography (SPECT/CT) by coincidence imaging of low abundance internal pair production. Encouraged by favorable early experiences, we implemented post-radioembolization ⁹⁰Y PET/CT as an adjunct to ⁹⁰Y bremsstrahlung SPECT/CT in diagnostic reporting.

Methods

This is a retrospective review of all paired ⁹⁰Y PET/CT and ⁹⁰Y bremsstrahlung SPECT/CT scans over a 1-year period. We compared image resolution, ability to confirm technical success, detection of non-target activity, and providing conclusive information about ⁹⁰Y activity within targeted tumor vascular thrombosis. ⁹⁰Y resin microspheres were used. ⁹⁰Y PET/CT was performed on a conventional time-of-flight lutetium-yttrium-oxyorthosilicate scanner with minor modifications to acquisition and reconstruction parameters. Specific findings on ⁹⁰Y PET/CT were corroborated by ⁹⁰Y bremsstrahlung SPECT/CT, ^99mTc macroaggregated albumin SPECT/CT, follow-up diagnostic imaging or review of clinical records.

Results

Diagnostic reporting recommendations were developed from our collective experience across 44 paired scans. Emphasis on the continuity of care improved overall diagnostic accuracy and reporting confidence of the operator. With proper technique, the presence of background noise did not pose a problem for diagnostic reporting. A counter-intuitive but effective technique of detecting non-target activity is proposed, based on the pattern of activity and its relation to underlying anatomy, instead of its visual intensity. In a sub-analysis of 23 patients with a median follow-up of 5.4 months, ⁹⁰Y PET/CT consistently outperformed ⁹⁰Y bremsstrahlung SPECT/CT in all aspects of qualitative analysis, including assessment for non-target activity and tumor vascular thrombosis. Parts of viscera closely adjacent to the liver remain challenging for non-target activity detection, compounded by a tendency for mis-registration.

Conclusions

Adherence to proper diagnostic reporting technique and emphasis on continuity of care are vital to the clinical utility of post-radioembolization ⁹⁰Y PET/CT. ⁹⁰Y PET/CT is superior to ⁹⁰Y bremsstrahlung SPECT/CT for the assessment of target and non-target activity.