Computed-tomography-guided high-dose-rate brachytherapy (CT-HDRBT) ablation of metastases adjacent to the liver hilum

CT-guided high-dose-rate brachytherapy ablation of HCC patients with portal vein tumor thrombosis

BACKGROUND

We assessed the safety and efficacy of computed tomography (CT)-guided high-dose-rate (HDR) brachytherapy in treating hepatocellular carcinoma (HCC) with portal vein tumor thrombosis (PVTT).

METHODS

From January 2010 to January 2022, 56 patients (median age 67.5 years) with HCC and PVTT underwent 64 procedures. PVTT was further classified according to the Japan liver cancer study group into VP1-VP4. Tumor response was evaluated by cross-sectional imaging 6 weeks after CT-guided HDR brachytherapy and every 3 months thereafter. Local tumor control (LTC), progression-free survival (PFS), and overall survival (OS) were assessed using Kaplan-Meier curves. The severity of procedure-related complications was classified according to the Society of Interventional Radiology guidelines.

RESULTS

Patients were available for imaging evaluation for a median follow-up of 14.0 months. The median diameter of the largest lesion was 56 mm. Estimated median PFS, LTC, and OS were 7.0 (95% CI 5.0-13.0), 14.0 (95% CI 7.0-21.0), and 20.0 (95% CI 13.0-26.0) months respectively. Actuarial 1-, 2-, and 3-year OS rates were 66%, 41%, and 27%, respectively. Subclassified for VP1, VP2, VP3, and VP4 estimated OS was 38.0 (95% CI 9.0-Not-a-number), 21.5 (95% CI 15.0-25.0), 15.0 (95% CI 7.0-33.0), and 13.0 (95% CI 6.0-34.0) months, respectively. Considering the 64 procedures, we recorded no complications for 49 (76.6%), mild-to-moderate complications for 12 (18.8%), and major complications for 3 (4.7%).

CONCLUSION

CT-guided HDR brachytherapy was safe and effective for locoregional treatment in patients with advanced HCC due to PVTT, achieving long-lasting local tumor control.

RELEVANCE STATEMENT

CT-guided HDR brachytherapy is an option to be considered for locoregional treatment of patients with advanced HCC due to PVTT.

KEY POINTS

Evaluation of CT-guided high-dose-rate (HDR) brachytherapy in treating HCC patients with portal vein tumor thrombosis (PVTT). Median OS was 20.0 months ranging between 13.0 and 38.0 months. CT-guided HDR brachytherapy seems to be a safe and effective treatment option in HCC patients with PVTT.

Decision-Tree Models Indicative of Microvascular Invasion on MRI Predict Survival in Patients with Hepatocellular Carcinoma Following Tumor Ablation

Purpose

Histological microvascular invasion (MVI) is a risk factor for poor survival and early recurrence in hepatocellular carcinoma (HCC) after surgery. Its prognostic value in the setting of locoregional therapies (LRT), where no tissue samples are obtained, remains unknown. This study aims to establish CT-derived indices indicative of MVI on liver MRI with superior soft tissue contrast and evaluate their association with patient survival after ablation via interstitial brachytherapy (iBT) versus iBT combined with prior conventional transarterial chemoembolization (cTACE).

Patients and Methods

Ninety-five consecutive patients, who underwent ablation via iBT alone (n = 47) or combined with cTACE (n = 48), were retrospectively included between 01/2016 and 12/2017. All patients received contrast-enhanced MRI prior to LRT. Overall (OS), progression-free survival (PFS), and time-to-progression (TTP) were assessed. Decision-tree models to determine Radiogenomic Venous Invasion (RVI) and Two-Trait Predictor of Venous Invasion (TTPVI) on baseline MRI were established, validated on an external test set (TCGA-LIHC), and applied in the study cohorts to investigate their prognostic value for patient survival. Statistics included Fisher's exact and t-test, Kaplan-Meier and cox-regression analysis, area under the receiver operating characteristic curve (AUC-ROC) and Pearson's correlation.

Results

OS, PFS, and TTP were similar in both treatment groups. In the external dataset, RVI showed low sensitivity but relatively high specificity (AUC-ROC = 0.53), and TTPVI high sensitivity but only low specificity (AUC-ROC = 0.61) for histological MVI. In patients following iBT alone, positive RVI and TTPVI traits were associated with poorer OS (RVI: p < 0.01; TTPVI: p = 0.08), PFS (p = 0.04; p = 0.04), and TTP (p = 0.14; p = 0.03), respectively. However, when patients with combined cTACE and iBT were stratified by RVI or TTPVI, no differences in OS (p = 0.75; p = 0.55), PFS (p = 0.70; p = 0.43), or TTP (p = 0.33; p = 0.27) were observed.

Conclusion

The study underscores the role of non-invasive imaging biomarkers indicative of MVI to identify patients, who would potentially benefit from embolotherapy via cTACE prior to ablation rather than ablation alone.

Effectiveness and safety of computed tomography-guided high-dose-rate brachytherapy in treating recurrent hepatocellular carcinoma not amenable to repeated resection or radiofrequency ablation

PURPOSE

To assess the efficacy and safety of computed tomography (CT)-guided high-dose-rate HDR) brachytherapy in treating recurrent hepatocellular carcinoma (HCC) not amenable to repeated resection or radiofrequency ablation.

MATERIALS AND METHODS

From January 2010 to January 2022, 38 patients (mean age, 70.1 years; SD ± 9.0 years) with 79 nodular and four diffuse intrahepatic HCC recurrences not amenable to repeated resection or radiofrequency ablation underwent CT-guided HDR brachytheapy in our department. Tumor response was evaluated by cross-sectional imaging 6 weeks after CT-guided HDR brachytherapy and every 3 months thereafter. Local tumor control (LTC), progression-free survival (PFS) and overall survival (OS) were assessed using Kaplan-Meier curves (KPCs). Severity of procedure-related complications (PRCs) was classified as recommended by the Society of Interventional Radiology (SIR).

RESULTS

Patients were available for MRI evaluation for a mean follow-up of 33.1 months (SD, ±21.6 mm, range 4-86 months; median 29 months). Patients had a mean of 2.3 (SD, ±1.4) intrahepatic tumors. Mean tumor diameter was 43.2 mm (SD, ±19.6 mm). 13 of 38 (34.2%) patients showed local tumor progression after CT-guided HDR brachytherapy. Mean LTC was 29.3 months (SD, ±22.1). Distant tumor progression was seen in 12 patients (31.6%). The mean PFS was 20.8 months (SD, ±22.1). Estimated 1-, 3-, and 5-year PFS rates were 65.1%, 35.1% and 22.5%, respectively. 13 patients died during the follow-up period. Mean OS was 35.4 months (SD, ±21.7). Estimated 1-, 3-, and 5-year OS rates were 91.5%, 77.4% and 58.0%, respectively. SIR grade 1 complications were recorded in 8.6% (5/38) and SIR grade 2 complications in 3.4% (2/58) of interventions.

CONCLUSION

CT-guided HDR brachytherapy is a safe and efficient therapeutic option for managing large or critically located HCC recurrences in the remaining liver after prior hepatic resection.

CT-guided High-Dose-Rate Brachytherapy versus Transarterial Chemoembolization in Patients with Unresectable Hepatocellular Carcinoma

Background CT-guided high-dose-rate (HDR) brachytherapy (hereafter, HDR brachytherapy) has been shown to be safe and effective for patients with unresectable hepatocellular carcinoma (HCC), but studies comparing this therapy with other local-regional therapies are scarce. Purpose To compare patient outcomes of HDR brachytherapy and transarterial chemoembolization (TACE) in patients with unresectable HCC. Materials and Methods This multi-institutional retrospective study included consecutive treatment-naive adult patients with unresectable HCC who underwent either HDR brachytherapy or TACE between January 2010 and December 2022. Overall survival (OS) and progression-free survival (PFS) were compared between patients matched for clinical and tumor characteristics by propensity score matching. Not all patients who underwent TACE had PFS available; thus, a different set of patients was used for PFS and OS analysis for this treatment. Hazard ratios (HRs) were calculated from Kaplan-Meier survival curves. Results After propensity matching, 150 patients who underwent HDR brachytherapy (median age, 71 years [IQR, 63-77 years]; 117 males) and 150 patients who underwent TACE (OS analysis median age, 70 years [IQR, 63-77 years]; 119 male; PFS analysis median age, 68 years [IQR: 63-76 years]; 119 male) were analyzed. Hazard of death was higher in the TACE versus HDR brachytherapy group (HR, 4.04; P < .001). Median estimated PFS was 32.8 months (95% CI: 12.5, 58.7) in the HDR brachytherapy group and 11.6 months (95% CI: 4.9, 22.7) in the TACE group. Hazard of disease progression was higher in the TACE versus HDR brachytherapy group (HR, 2.23; P < .001). Conclusion In selected treatment-naive patients with unresectable HCC, treatment with CT-guided HDR brachytherapy led to improved OS and PFS compared with TACE. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Chapiro in this issue.

Interventional oncology of liver tumors: how it all started and where are we now

Liver was the very first organ for which interventional procedures were applied for the local treatment of primary and secondary malignancies. In this paper, the history of Interventional Oncology of liver, from the very beginning to the current situation, is summarized, including both percutaneous and intravascular procedures, and together with the evolution of the techniques for image guidance. The main ongoing developments, such as new techniques, combined interventional treatments and association of local interventions with new drugs are briefly described, too.

The American Brachytherapy Society consensus statement for permanent implant brachytherapy using Yttrium-90 microsphere radioembolization for liver tumors

PURPOSE

To develop a multidisciplinary consensus for high quality multidisciplinary implementation of brachytherapy using Yttrium-90 (90Y) microspheres transarterial radioembolization (90Y TARE) for primary and metastatic cancers in the liver.

METHODS AND MATERIALS

Members of the American Brachytherapy Society (ABS) and colleagues with multidisciplinary expertise in liver tumor therapy formulated guidelines for 90Y TARE for unresectable primary liver malignancies and unresectable metastatic cancer to the liver. The consensus is provided on the most recent literature and clinical experience.

RESULTS

The ABS strongly recommends the use of 90Y microsphere brachytherapy for the definitive/palliative treatment of unresectable liver cancer when recommended by the multidisciplinary team. A quality management program must be implemented at the start of 90Y TARE program development and follow-up data should be tracked for efficacy and toxicity. Patient-specific dosimetry optimized for treatment intent is recommended when conducting 90Y TARE. Implementation in patients on systemic therapy should account for factors that may enhance treatment related toxicity without delaying treatment inappropriately. Further management and salvage therapy options including retreatment with 90Y TARE should be carefully considered.

CONCLUSIONS

ABS consensus for implementing a safe 90Y TARE program for liver cancer in the multidisciplinary setting is presented. It builds on previous guidelines to include recommendations for appropriate implementation based on current literature and practices in experienced centers. Practitioners and cooperative groups are encouraged to use this document as a guide to formulate their clinical practices and to adopt the most recent dose reporting policies that are critical for a unified outcome analysis of future effectiveness studies.

Comparison of intrahepatic progression patterns of hepatocellular carcinoma and colorectal liver metastases following CT-guided high dose-rate brachytherapy

Introduction:

Given the metachronous and multifocal occurrence of hepatocellular carcinoma (HCC) and colorectal cancer metastases in the liver (CRLM), this study aimed to compare intrahepatic progression patterns after computed tomography (CT)-guided high dose-rate brachytherapy.

Patients and methods:

This retrospective analysis included 164 patients (114 HCC, 50 CRLM) treated with brachytherapy between January 2016 and January 2018. Patients received multiparametric magnetic resonance imaging (MRI) before, and about 8 weeks after brachytherapy, then every 3 months for the first, and every 6 months for the following years, until progression or death. MRI scans were assessed for local or distant intrahepatic tumor progression according to RECIST 1.1 and electronic medical records were reviewed prior to therapy. The primary endpoint was progression-free survival (PFS). Specifically, local and distant intra-hepatic PFS were assessed to determine differences between the intrahepatic progression patterns of HCC and CRLM. Secondary endpoints included the identification of predictors of PFS, time to progression (TTP), and overall survival (OS). Statistics included Kaplan–Meier analysis and univariate and multivariate Cox regression modeling.

Results:

PFS was longer in HCC [11.30 (1.33–35.37) months] than in CRLM patients [8.03 (0.73–19.80) months, p = 0.048], respectively. Specifically, local recurrence occurred later in HCC [PFS: 36.83 (1.33–40.27) months] than CRLM patients [PFS: 12.43 (0.73–21.90) months, p = 0.001]. In contrast, distant intrahepatic progression occurred earlier in HCC [PFS: 13.50 (1.33–27.80) months] than in CRLM patients [PFS: 19.80 (1.43–19.80) months, p = 0.456] but without statistical significance. Multivariate Cox regression confirmed tumor type and patient age as independent predictors for PFS.

Conclusion:

Brachytherapy proved to achieve better local tumor control and overall PFS in patients with unresectable HCC as compared to those with CRLM. However, distant progression preceded local recurrence in HCC. As a result, these findings may help design disease-specific surveillance strategies and personalized treatment planning that highlights the strengths of brachytherapy. They may also help elucidate the potential benefits of combinations with other loco-regional or systemic therapies.

Review of brachytherapy complications - Upper gastrointestinal tract

While brachytherapy applications are not widely used for cancer diagnoses in the upper GI tract (including the esophagus, liver, stomach, and pancreas), they have a clear role in palliation and symptom management and occasionally definitive locoregional treatment. With the increasing use of image-guided techniques, the incidence of side effects and complications has shown to be lower than many other alternative treatment modalities, making brachytherapy approaches a preferred treatment option. This review examines procedural complications and acute and chronic adverse effects from radiation associated with esophageal, hepatobiliary, and pancreatic brachytherapy and their management.

Simulated accuracy assessment of small footprint body-mounted probe alignment device for MRI-guided cryotherapy of abdominal lesions

PURPOSE

Magnetic resonance imaging (MRI)-guided percutaneous cryotherapy of abdominal lesions, an established procedure, uses MRI to guide and monitor the cryoablation of lesions. Methods to precisely guide cryotherapy probes with a minimum amount of trial-and-error are yet to be established. To aid physicians in attaining precise probe alignment without trial-and-error, a body-mounted motorized cryotherapy-probe alignment device (BMCPAD) with motion compensation was clinically tested in this study. The study also compared the contribution of body motion and organ motion compensation to the guidance accuracy of a body-mounted probe alignment device.

METHODS

The accuracy of guidance using the BMCPAD was prospectively measured during MRI-guided percutaneous cryotherapies before insertion of the probes. Clinical parameters including patient age, types of anesthesia, depths of the target, and organ sites of target were collected. By using MR images of the target organs and fiducial markers embedded in the BMCPAD, we retrospectively simulated the guidance accuracy with body motion compensation, organ motion compensation, and no compensation. The collected data were analyzed to test the impact of motion compensation on the guidance accuracy.

RESULTS

Thirty-seven physical guidance of probes were prospectively recorded for sixteen completed cases. The accuracy of physical guidance using the BMCPAD was 13.4 ± 11.1 mm. The simulated accuracy of guidance with body motion compensation, organ motion compensation, and no compensation was 2.4 ± 2.9 mm, 2.2 ± 1.6 mm, and 3.5 ± 2.9 mm, respectively. Data analysis revealed that the body motion compensation and organ motion compensation individually impacted the improvement in the accuracy of simulated guidance. Moreover, the difference in the accuracy of guidance either by body motion compensation or organ motion compensation was not statistically significant. The major clinical parameters impacting the accuracy of guidance were the body and organ motions. Patient age, types of anesthesia, depths of the target, and organ sites of target did not influence the accuracy of guidance using BMCPAD. The magnitude of body surface movement and organ movement exhibited mutual statistical correlation.

CONCLUSIONS

The BMCPAD demonstrated guidance accuracy comparable to that of previously reported devices for CT-guided procedures. The analysis using simulated motion compensation revealed that body motion compensation and organ motion compensation individually impact the improvement in the accuracy of device-guided cryotherapy probe alignment. Considering the correlation between body and organ movements, we also determined that body motion compensation using the ring fiducial markers in the BMCPAD can be solely used to address both body and organ motions in MRI-guided cryotherapy.

Tumor Seeding along the Puncture Tract in CT-Guided Interstitial High-Dose-Rate Brachytherapy

PURPOSE

To quantify the occurrence of tumor seeding in computed tomography (CT)-guided high-dose-rate brachytherapy (HDRBT) and to identify potential risk factors.

MATERIALS AND METHODS

CT-HDRBT is a minimally invasive therapeutic option for local ablation of unresectable tumors. The procedure involves CT-guided placement of an enclosed catheter and high-dose-rate brachytherapy using iridium-192. Transcutaneous puncture of a tumor with subsequent retraction of the applicator has the potential risk of tumor seeding along the puncture tract. A total of 1,765 consecutive CT-HDRBT procedures were performed at this center between 2006 and 2017 and were retrospectively analyzed. In addition, a distinction was made between whether the puncture tract was irradiated or not. Follow-up imaging datasets were evaluated for tumor seeding along the former puncture tracts. Descriptive and exploratory statistical analyses of the data were performed.

RESULTS

Tumor seeding was observed in 25 cases (25 of 1,765 cases [1.5%]). A total of 0.008 cases occurred per person-age. Patient age was identified as a potential risk factor with an odds ratio of 1.046 (95% confidence interval, 1.003-1.091; P = .04). There were no differences between whether the puncture tract was irradiated or not (P = .552).

CONCLUSIONS

Tumor seeding along the puncture tract can occur in CT-HDRBT but is rare.

Needle track seeding in hepatocellular carcinoma after local ablation by high-dose-rate brachytherapy: a retrospective study of 588 catheter placements

Purpose

Needle track seeding in the local treatment of hepatocellular carcinoma (HCC) is not yet evaluated for catheter-based high-dose-rate brachytherapy (HDR-BT), a novel local ablative technique.

Material and methods

We report a retrospective analysis of 100 patients treated on 233 HCC lesions by HDR-BT (using 588 catheters in total). No needle or catheter track irradiation was used. Minimum required follow-up with imaging was 6 months. In case of suspected needle track seeding (intra- and/or extrahepatic) in follow-up, image fusion of follow-up CT/MRI with 3D irradiation plan was used to verify the location of a new tumor deposit within the path of a brachytherapy catheter at the time of treatment.

Results

We identified 9 needle track metastases, corresponding to a catheter-based risk of 1.5% for any location of occurrence. A total of 7 metastases were located within the liver (catheter-based risk, 1.2%), and 2 metastases were located extrahepatic (catheter-based risk, 0.3%). Eight out of 9 needle track metastases were successfully treated by further HDR-BT.

Conclusions

The risk for needle track seeding after interstitial HDR-BT of HCC is comparable to previous reports of percutaneous biopsies and radiofrequency ablation (RFA), especially in case of extrahepatic needle track metastases. To compensate for the risk of seeding, a track irradiation technique similar to track ablation in RFA should be implemented in clinical routine.

Combined Systemic Chemotherapy and CT-Guided High-Dose-Rate Brachytherapy for Isolated Local Manifestation of Pancreatic Cancer after Surgical Resection

BACKGROUND

Prospective data on the optimal management of patients with pancreatic ductal adenocarcinoma (PDA) and isolated local manifestation (ILM) after surgery are lacking. Hence, no statements with respect to this entity have been released from most international guidelines including European Society for Medical Oncology, National Comprehensive Cancer Network, and American Society for Clinical Oncology.

METHODS

We report for the first time a case-series of 3 patients with PDA and ILM receiving combined systemic chemotherapy and CT-guided high-dose-rate interstitial brachytherapy (CT-HDRBT).

RESULTS

CT-HDRBT allowed in all patients with pronounced chemotherapy-induced side effects either a pause of cytostatic treatment or de-escalation to a "maintenance" therapy (dose reduction, interval prolongation, scheme modification with withdrawal of most toxic drugs).

CONCLUSION

Combining CT-HDRBT to systemic chemotherapy in patients with PDA and ILM is feasible and safe. As for patients with PDA and ILM no standard of care exists, designing an appropriate randomized prospective trial for this highly selected group of patients is challenging.

Local ablation or radioembolization of colorectal cancer metastases: comorbidities or older age do not affect overall survival

Background

Local ablative techniques are emerging in patients with oligometastatic disease from colorectal carcinoma, commonly described as less invasive than surgical methods. This single arm cohort seeks to determine whether such methods are suitable in patients with comorbidities or higher age.

Methods

Two hundred sixty-six patients received radiofrequency ablation (RFA), CT-guided high-dose rate brachytherapy (HDR-BT) or Y90-radioembolization (Y90-RE) during treatment of metastatic colorectal cancer (mCRC). This cohort comprised of patients with heterogenous disease stages from single liver lesions to multiple organ systems involvement commonly following multiple chemotherapy lines. Data was reviewed retrospectively for patient demographics, previous therapies, initial or disease stages at first intervention, comorbidities and mortality. Comorbidity was measured using the Charlson Comorbidity Index (CCI) and age-adjusted Charlson Index (CACI) excluding mCRC as the index disease. Kaplan-Meier survival analysis and Cox regression were used for statistical analysis.

Results

Overall median survival of 266 patients was 14 months. Age ≥ 70 years did not influence survival after local therapies. Similarly, CCI or CACI did not affect the patients prognoses in multivariate analyses. Moderate or severe renal insufficiency (n = 12; p = 0.005) was the only single comorbidity identified to negatively affect the outcome after local therapy.

Conclusion

Interventional procedures for mCRC may be performed safely even in elderly and comorbid patients. In severe renal insufficiency, the use of invasive techniques should be limited to selected cases.

Endoluminal and Interstitial Brachytherapy for the Treatment of Gastrointestinal Malignancies: a Systematic Review

Radiation therapy is an integral component in the multimodality management of many gastrointestinal (GI) cancers at all stages of clinical presentation. With recent advances in technology and radiation delivery, external beam radiation therapy (EBRT) can be delivered with reduced toxicity. However, despite these advances, EBRT doses are still limited by the presence of radiosensitive serial structures near clinical targets in the GI tract. Relative to EBRT techniques, brachytherapy techniques have a lower integral dose and more rapid fall-off, allowing for high-dose delivery with little normal tissue exposure. Given the unique characteristics of brachytherapy, it is an attractive strategy to treat GI malignancies. This review addresses the application of both high-dose rate brachytherapy (HDRBT) and low-dose rate brachytherapy (LDRBT) to multiple GI malignancies for both definitive and palliative management.

Management of unresectable intrahepatic cholangiocarcinoma: how do we decide among the various liver-directed treatments?

Intrahepatic cholangiocarcinoma often causes death due to obstruction of the biliary system or interruption of the vascular supply of the liver. This fact emphasizes the critical need for local tumor control in this disease. Successful local tumor control has traditionally been achievable through surgical resection for the small proportion of patients with operable tumors. Technological advances in radiation oncology and in interventional radiology have enabled the delivery of ablative radiation doses or other cytotoxic therapies for tumors in the liver. In some cases, this has translated into substantial prolongation of life for patients with this disease, but the indications for these different treatment options are still the subject of ongoing debate. Here, we review the technological advances and clinical studies that are changing the way intrahepatic cholangiocarcinoma is managed, and discuss ways to achieve individualized treatment of patients.

Image-guided high-dose-rate brachytherapy of head and neck - a case series study

Purpose

The aim of the study was the evaluation of image guided transdermal application of interstitial brachytherapy in patients undergoing repeated irradiation for relapsed local tumor of the head and neck area.

Material and methods

The article describes transdermal application of interstitial high-dose-rate (HDR) brachytherapy in 4 patients treated due to relapsed local tumor in soft palate, submandibular area, laryngopharynx, as well as pterygoid muscles and maxillary sinus. The application was conducted under continuous computed tomography (CT)-image guidance (CT fluoroscopy). Patients qualified for this type of treatment had neoplastic lesions located deep under the skin surface. Because of their location, access to the lesions was limited, and the risk of damaging the adjacent tissues such as vessels and nerves was high. The following parameters have been evaluated: clinical response using RECIST 1.1, incidence of perisurgical complications using CTCAE 4.0 and the frequency of occurrence of radiotherapy related early morbidity using RTOG.

Results

Various radiation schemes were used, from 3 to 5 fractions of 3.5-5 Gy. The median total dose (D₉₀) was 20.6 Gy. Biologic effective dose (BED) and equivalent 2 Gy (DEQ₂) median doses were 30.4 Gy and 25.3 Gy, respectively. In the follow-up period of 3-7 months (the median value of 3.5 months), 2 patients had partial regression of the disease and in 2 others the neoplastic process was stabilized. None of the patients had serious complications of treatment (of 3^rd degree or higher).

Conclusions

Computed tomography-image guided brachytherapy proved to be a safe method of treatment in patients with local relapse in sites, in which traditional visually controlled application was impossible due to risk of complications. Despite short observation period and small study group, it seems justified to conduct prospective studies for the evaluation of efficacy and safety of CT-image guided brachytherapy.

Image-guided high-dose-rate brachytherapy of malignancies in various inner organs - technique, indications, and perspectives

In the last few years, minimally invasive tumor ablation performed by interventional radiologists has gained increasing relevance in oncologic patient care. Limitations of thermal ablation techniques such as radiofrequency ablation (RFA), microwave ablation (MWA), and laser-induced thermotherapy (LITT), including large tumor size, cooling effects of adjacent vessels, and tumor location near thermosensitive structures, have led to the development of image-guided high-dose-rate (HDR) brachytherapy, especially for the treatment of liver malignancies. This article reviews technical properties of image-guided brachytherapy, indications and its current clinical role in multimodal cancer treatment. Furthermore, perspectives of this novel therapy option will be discussed.

Activity-based cost analysis of hepatic tumor ablation using CT-guided high-dose rate brachytherapy or CT-guided radiofrequency ablation in hepatocellular carcinoma

Purpose

To analyse and compare the costs of hepatic tumor ablation with computed tomography (CT)-guided high-dose rate brachytherapy (CT-HDRBT) and CT-guided radiofrequency ablation (CT-RFA) as two alternative minimally invasive treatment options of hepatocellular carcinoma (HCC).

Materials and methods

An activity based process model was created determining working steps and required staff of CT-RFA and CT-HDRBT. Prorated costs of equipment use (purchase, depreciation, and maintenance), costs of staff, and expenditure for disposables were identified in a sample of 20 patients (10 treated by CT-RFA and 10 by CT-HDRBT) and compared. A sensitivity and break even analysis was performed to analyse the dependence of costs on the number of patients treated annually with both methods.

Results

Costs of CT-RFA were nearly stable with mean overall costs of approximately 1909 €, 1847 €, 1816 € and 1801 € per patient when treating 25, 50, 100 or 200 patients annually, as the main factor influencing the costs of this procedure was the single-use RFA probe. Mean costs of CT-HDRBT decreased significantly per patient ablation with a rising number of patients treated annually, with prorated costs of 3442 €, 1962 €, 1222 € and 852 € when treating 25, 50, 100 or 200 patients, due to low costs of single-use disposables compared to high annual fix-costs which proportionally decreased per patient with a higher number of patients treated annually. A break-even between both methods was reached when treating at least 55 patients annually.

Conclusion

Although CT-HDRBT is a more complex procedure with more staff involved, it can be performed at lower costs per patient from the perspective of the medical provider when treating more than 55 patients compared to CT-RFA, mainly due to lower costs for disposables and a decreasing percentage of fixed costs with an increasing number of treatments.

Image-guided high-dose-rate brachytherapy: preliminary outcomes and toxicity of a joint interventional radiology and radiation oncology technique for achieving local control in challenging cases

PURPOSE

To determine the ability of image-guided high-dose-rate brachytherapy (IG-HDR) to provide local control (LC) of lesions in non-traditional locations for patients with heavily pre-treated malignancies.

MATERIAL AND METHODS

This retrospective series included 18 patients treated between 2012 and 2014 with IG-HDR, either in combination with external beam radiotherapy (EBRT; n = 9) or as monotherapy (n = 9). Lesions were located in the pelvis (n = 5), extremity (n = 2), abdomen/retroperitoneum (n = 9), and head/neck (n = 2). All cases were performed in conjunction between interventional radiology and radiation oncology. Toxicity was graded based on CTCAE v4.0 and local failure was determined by RECIST criteria. Kaplan-Meier analysis was performed for LC and overall survival.

RESULTS

The median follow-up was 11.9 months. Two patients had localized disease at presentation; the remainder had recurrent and/or metastatic disease. Seven patients had prior EBRT, with a median equivalent dose in 2 Gy fractions (EQD2) of 47.0 Gy. The median total EQD2s were 34 Gy and 60.9 Gy for patients treated with monotherapy or combination therapy, respectively. Image-guided high-dose rate brachytherapy was delivered in one to six fractions. Six patients had local failures at a median interval of 5.27 months with a one-year LC rate of 59.3% and a one-year overall survival of 40.7%. Six patients died from their disease at a median interval of 6.85 months from the end of treatment. There were no grade ≥ 3 acute toxicities but two patients had serious long term toxicities.

CONCLUSIONS

We demonstrate a good one year LC rate of nearly 60%, and a favorable toxicity profile when utilizing IG-HDR to deliver high doses of radiation with high precision into targets not readily accessible by other forms of local therapy. These preliminary results suggest that further studies utilizing this approach may be considered for patients with difficult to access lesions that require LC.

CT-guided high-dose-rate brachytherapy in the interdisciplinary treatment of patients with liver metastases of pancreatic cancer

BACKGROUND

CT-guided high-dose-rate brachytherapy (CT-HDRBT) is an interventional radiologic technique for local ablation of primary and secondary malignomas applying a radiation source through a brachycatheter percutaneously into the targeted lesion. The aim of this study was to assess local tumor control, safety and efficacy of CT-HDRBT in the treatment of liver metastases of pancreatic cancer.

METHODS

Twenty consecutive patients with 49 unresectable liver metastases of pancreatic cancer were included in this retrospective trial and treated with CT-HDRBT, applied as a single fraction high-dose irradiation (15-20 Gy) using a 192Ir-source. Primary endpoint was local tumor control and secondary endpoints were complications, progression-free survival and overall survival.

RESULTS

The mean tumor diameter was 29 mm (range 10-73). The mean irradiation time was 20 minutes (range 7-42). The mean coverage of the clinical target volume was 98% (range 88%-100%). The mean D100 was 18.1 Gy and the median D100 was 19.78 Gy. Three major complications occurred with post-interventional abscesses, three of which were seen in 15 patients with biliodigestive anastomosis (20%) and overall 15%. The mean follow-up time was 13.7 months (range 1.4-55.0). The median progression-free survival was 4.9 months (range 1.4-42.9, mean 9.4). Local recurrence occurred in 5 (10%) of 49 metastases treated. The median overall survival after CT-HDRBT was 8.6 months (range 1.5-55.3). Eleven patients received chemotherapy after ablation with a median progression-free survival of 4.9 months (mean 12.9). Nine patients did not receive chemotherapy after intervention with a median progression-free survival of 3.2 months (mean 5.0). The rate of local tumor control was 91% in both groups after 12 months.

CONCLUSION

CT-HDRBT was safe and effective for the treatment of liver metastases of pancreatic cancer.

Extending the Frontiers Beyond Thermal Ablation by Radiofrequency Ablation: SBRT, Brachytherapy, SIRT (Radioembolization)

Metastatic spread of the primary is still defined as the systemic stage of disease in treatment guidelines for various solid tumors. This definition is the rationale for systemic therapy. Interestingly and despite the concept of systemic involvement, surgical resection as a local treatment has proven to yield long-term outcomes in a subset of patients with limited metastatic disease, supporting the concept of oligometastatic disease. Radiofrequency ablation has yielded favorable outcomes in patients with hepatocellular carcinoma and colorectal metastases, and some studies indicate its prognostic potential in combined treatments with systemic therapies. However, some significant technical limitations apply, such as size limitation, heat sink effects, and unpredictable heat distribution to adjacent risk structures. Interventional and non-invasive radiotherapeutic techniques may overcome these limitations, expanding the options for oligometastatic patients and cytoreductive concepts. Current data suggest very high local control rates even in large tumors at any given location in the human body. The article focusses on the characteristics and possibilities of stereotactic body radiation therapy, interstitial high-dose-rate brachytherapy, and Yttrium-90 radioembolization. In this article, we discuss the differences of the technical preferences as well as their impact on indications. Current data is presented and discussed with a focus on application in oligometastatic or cytoreductive concepts in different tumor biologies.

Efficacy and safety of image-guided interstitial single fraction high-dose-rate brachytherapy in the management of metastatic malignant melanoma

PURPOSE

Computed tomography (CT) or magnetic resonance imaging (MRI) guided brachytherapy provides high tumor control rates in hepatocellular carcinoma (HCC) and colorectal liver metastases. In contrast to thermal ablation methods such as radiofrequency ablation (RFA), much less restrictions apply with respect to tumor location or size. In this study, we determined the efficacy and safety of CT- or MRI-guided brachytherapy in metastatic melanoma.

MATERIAL AND METHODS

Fifty-two metastases of malignant melanoma in 14 patients were included in this retrospective study. Local tumor control and safety were evaluated as primary and secondary endpoints. Furthermore, we evaluated overall survival and progression free survival. Tumor locations were liver (n = 31), lung (n = 15), adrenal (n = 3), lymph nodes (n = 2), and kidney (n = 1). Treatment planning was performed using three-dimensional CT or MRI data acquired after percutaneous applicator positioning under CT or open MRI guidance. Subsequently, single fraction high-dose-rate (HDR) brachytherapy was applied using a (192)Iridium source. Clinical and cross-sectional follow-up were performed every 3 months post intervention.

RESULTS

The median diameter of treated lesions was 1.5 cm (range: 0.7-10 cm). Doses between 15 and 20 Gy were applied (median dose: 19.9 Gy). The mean irradiation time ranged between 7-45 minutes. After treatment, there was one patient with a cholangitis. After a median follow up of five months, the median local tumor control was 90%. The median overall survival of the patients was 8 months. The median progression free survival of the patients was 6 months.

CONCLUSIONS

Image-guided HDR brachytherapy is a safe and effective treatment procedure in metastatic malignant melanoma.