In vivo assessment of the gastric mucosal tolerance dose after single fraction, small volume irradiation of liver malignancies by computed tomography–guided, high-dose-rate brachytherapy

Local tumor control of intermediate and advanced stage hepatocellular carcinoma after local ablative treatment with image-guided interstitial high-dose-rate brachytherapy: A subgroup analysis of 286 HCC nodules

PURPOSE

Image-guided interstitial high-dose-rate brachytherapy (iBT) has been demonstrated to offer high local tumor control rates (LTC) of >90% after local ablation of intermediate and advanced hepatocellular carcinoma (HCC; BCLC B and C). The purpose of this study was to show the efficacy of iBT stratified by subgroups and to identify clinical characteristics associated with superior local tumor control (LTC) based on a highly heterogenous patient population METHODS AND MATERIALS: A cumulative number of 286 HCC nodules in 107 patients were retrospectively analyzed. Clinical and imaging follow-ups were conducted every 3 months after treatment. Analyzed clinical factors were: etiology, presence of liver cirrhosis, radiographic features, lesion size, pretreatment, administered dose, presence of portal hypertension, portal vein thrombosis, and level of alpha-fetoprotein (AFP).

RESULTS

LTC rate was 88.8% for a median follow-up of 14.3 months (range 3-81 months; 95% CI: 85-92%). Median minimal enclosing tumor dose (D100) was 16.1 Gy (range 7.1-30.3 Gy; reference dose 15 Gy). Subgroup analysis showed significant fewer local recurrences for alcoholic liver disease (ALD)-related HCCs compared to those related to other causes of liver cirrhosis (nonalcoholic fatty liver disease, virus-related liver cirrhosis and other causes) (p = 0.015). LTC was significantly lower after prior surgical resection (p = 0.046). No significant variance was observed for the applied D100 in each group or for all other clinical factors tested.

CONCLUSIONS

IBT achieves high LTC rates across treated subgroups. However, further studies should particularly address the possible impact of underlying etiology on local recurrence with emphasis on a possible higher radiosensitivity of ALD-related HCCs.

Narrative Review of High-Dose-Rate Interstitial Brachytherapy in Primary or Secondary Liver Tumors

The optimal management of intrahepatic malignancies involves a multidisciplinary approach. Although surgical resection has been considered the only curative approach, the use of several minimally invasive ablative techniques has dramatically increased the last two decades, mainly due to the fact that they provide similar oncological results with significantly decreased morbidity. Among these modalities, interstitial liver brachytherapy, probably the most flexible liver ablative method, with excellent clinical data on its safety and effectiveness, is frequently not even mentioned as an option in the current peer reviewed literature and guidelines. Brachytherapy is a type of radiotherapy utilizing radionuclides that are directly inserted into the tumor. Compared to external beam radiation therapy, brachytherapy has the potential to deliver an ablative radiation dose over a short period of time, with the advantage of a rapid dose fall-off, that allows for sparing of adjacent healthy tissue. For numerous malignancies such as skin, gynecological, breast, prostate, head and neck, bladder, liver and soft-tissue tumors, brachytherapy as a monotherapy or combined with external beam radiation therapy, has become a standard treatment for many decades. This review article aims to describe the high-dose-rate liver brachytherapy technique, its selection criteria, present its advantages and disadvantages, as well as the available clinical data, in order to help physicians to explore and hopefully introduce liver brachytherapy into their clinical routine.

Multi-modal and sequential treatment of liver cancer and its impact on the gastrointestinal tract

Hepatic tumors include hepatocellular cancer (HCC) and cholangiocarcinoma (CC), a small subgroup of tumors (approx. 1%) are classified as combined hepatocellularcholangiocellular carcinomas. Different stage-dependent therapeutic approaches comprise resection, local ablative techniques, locoregional therapies, systemic treatment, liver transplantation in selected cases and possible combination of these treatment modalities. This review summarizes current knowledge on multi-modal treatment strategies for liver cancer focusing on gastrointestinal side effects.

Treatment of metastatic gastric adenocarcinoma with image-guided high-dose rate, interstitial brachytherapy as second-line or salvage therapy

PURPOSE

We aimed to evaluate the safety and effectiveness of image-guided high-dose rate interstitial brachytherapy (iBT) for the treatment of patients with hepatic, lymphatic, and pancreatic metastases originating from gastric cancer, an entity rarely surgically treatable with curative intent.

METHODS

Twelve patients with a cumulative number of 36 metastases (29 liver, 2 pancreatic, 5 lymph node) from histologically proven gastric adenocarcinoma received iBT between 2010 and 2016 and were retrospectively analyzed. Every patient underwent palliative chemotherapy prior to iBT. The iBT procedure employs a temporarily, intratumorally placed iridium-192 source in a single fraction with the goal of tumor cell eradication. Effectiveness was assessed clinically and by radiologic imaging every three months.

RESULTS

Local tumor control was achieved in 32 of all treated metastases (89%). Four lesions showed a local recurrence after 7 months. Lesion sizes varied from 9 to 102 mm with a median of 20 mm. The median progression-free survival was 6.6 months (range, 1.8-46.8 months). The median overall survival was 11.4 months (range, 5-47 months). One patient suffered a major complication following iBT, hepatic hematoma and abscess (Common Terminology Criteria for Adverse Events grade 3), successfully dealt with by transcutaneous drainage.

CONCLUSION

iBT is an overall safe procedure, which facilitates high rates of local tumor control in treatment of metastatic gastric adenocarcinoma. Compared with surgical metastasectomy, similar overall survival rates could be achieved in our patient collective after iBT application.

Efficacy and safety of percutaneous computed tomography-guided high-dose-rate interstitial brachytherapy in treatment of oligometastatic lymph node metastases of retroperitoneal space

Purpose

To assess efficacy, safety, and outcome of computed tomography (CT)-guided high-dose-rate (HDR) interstitial brachytherapy in patients with oligometastatic lymph node metastases of the retroperitoneal space.

Material and methods

24 patients with a total of 47 retroperitoneal lymph node metastases from different primary tumors were treated with CT-guided interstitial brachytherapy using an ¹⁹²Ir source (single fraction irradiation). Every three months after treatment, clinical and imaging follow-up were conducted to evaluate local control and safety.

Results

Median follow-up was 9.6 months (range, 2.9-39.0 months). Local tumor control rate was 95.7%. The median diameter of the gross tumor volume was 2.2 cm (range, 1-8.6 cm), treated with a median D₁₀₀ (minimal enclosing tumor dose) of 14.9 Gy (range, 4.5-20.6 Gy). One severe adverse event (grade three) was recorded.

Cumulative median progression-free survival was 4.2 months (range, 1.4-23.7 months), and cumulative median overall survival after interstitial brachytherapy was 15.9 months (range, 3.8-39.0 months).

Conclusions

CT-guided HDR interstitial brachytherapy is a safe and feasible method for local ablation of oligometastatic lymph node metastases of the retroperitoneal space, and might provide a well-tolerated additional therapeutic option in the multidisciplinary management of selected patients.

Treatment of hepatic pancreatic ductal adenocarcinoma metastases with high-dose-rate image-guided interstitial brachytherapy: a single center experience

Purpose

To evaluate the efficacy and safety of image-guided (computed tomography/magnetic resonance imaging – CT/MRI) high-dose-rate (HDR) interstitial brachytherapy (iBT) as a salvage maneuver for the treatment of hepatic metastases originating from hepatic pancreatic ductal adenocarcinoma (PDAC). PDAC metastases present a major and unresolved problem, and any surgical approach or local therapeutic intervention remains extremely controversial.

Material and methods

A cumulative number of 45 hepatic PDAC metastases in 16 patients were treated and retrospectively analyzed. Synchronous metastatic spread was observed in five patients, metachronous in eleven. 14 patients had resection of the pancreatic primary prior to iBT: eight Whipple/PPPD and six distal pancreatectomy procedures. The hepatic metastases were progressing under chemotherapy, thus iBT was applied as a salvage maneuver with the intention of local tumor control and prolonged survival. iBT is applied interstitially, with temporarily introduced ¹⁹²Ir source in a single fraction HDR irradiation regime to eradicate vital tumor cells. Response to treatment was assessed clinically with CT/MRI every three months.

Results

Local tumor control was achieved in 87% of all treated metastases. The median diameter of the irradiated lesions was 2.2 cm (range, 1-11.2 cm), the median irradiation dose was 21 Gy (range, 5-29.1 Gy). Median progression-free survival (PFS) after iBT was 3.4 months (range, 1.5-19.6 months), the median overall survival (OS) after iBT was 8.9 months (range, 3.1-29.3 months). Three major complications (CTCAE grade 3) occurred following iBT: three cases of liver abscess, which were successfully resolved with drainage and antibiotics.

Conclusions

Overall, iBT is a safe procedure, which enables excellent rates of local tumor control and presents a viable anti-neoplastic treatment option as a salvage therapy for metastatic PDAC patients.

Comparative analysis between interstitial brachytherapy and stereotactic body irradiation for local ablation in liver malignancies

PURPOSE

Interstitial high-dose-rate brachytherapy (BT) is an alternative treatment option to stereotactic body radiotherapy (SBRT) for the ablative treatment of liver malignancies. The aim of the present comparative planning study was to reveal the possibilities and limitations of both techniques with regard to dosimetric properties.

METHODS AND MATERIALS

Eighty-five consecutive patients with liver malignancy diagnosis were treated with interstitial BT between 12/2008 and 09/2009. The prescription dose of BT varied between 15 and 20 Gy, depending on histology. For dosimetric comparison, virtual SBRT treatment plans were generated using the original BT planning CTs. Additional margins reflecting the respiratory tumor motion were added to the target volumes for SBRT planning.

RESULTS

The mean PTV_BT was 34.7 cm³ (0.5-410.0 cm³) vs. a mean PTV_SBRT of 73.2 cm³ (6.1-593.4 cm³). Regarding the minimum peripheral dose (D_99.9), BT achieved the targeted prescription dose of 15 Gy/20 Gy better without violating organ at risk constraints. The dose exposure of the liver was significantly influenced by treatment modality. The liver exposure to 5 Gy was statistically lower with 611 ± 43 cm³ for BT as compared with 694 ± 37 cm³ for SBRT plans (20-Gy group, p = 0.001), corresponding to 41.8% vs. 45.9% liver volume, respectively.

CONCLUSIONS

To the best of our knowledge, this is the first report on the comparison of clinically treated liver BT treatments with virtually planned SBRT treatments. The planning study showed a superior outcome of BT regarding dose coverage of the target volume and exposed liver volume. Nevertheless, further studies are needed to determine ideal applicability for each treatment approach.

First report on extended distance between tumor lesion and adjacent organs at risk using interventionally applied balloon catheters: a simple procedure to optimize clinical target volume covering effective isodose in interstitial high-dose-rate brachytherapy of liver malignomas

Purpose

Organs at risk (OARs), which are very close to a clinical target volume (CTV), can compromise effective tumor irradiation. The present study investigated the feasibility and safety of a novel approach, in particular, the extent of the dosimetric effect of distancing CTV from adjacent OARs by means of interventionally applied balloon catheters.

Material and methods

Patients with peripheral hepatic malignancies, in whom the critical proximity of an OAR to the CTV in the assessment by contrast-enhanced magnetic resonance imaging (MRI) scans and the preplanning process were included. Additionally, patients underwent placement of an interventional balloon catheter during computed tomography (CT)-guided application of interstitial brachytherapy (iBT) catheters inserted into the tissue between hepatic capsule and adjacent OAR. The virtual position of an OAR without balloon catheter was anticipated and contoured in addition to contouring of CTV and OAR. The calculated dose values for CTV as well as 1 cc of the relevant OAR (D_1cc) with and without balloon were recorded. The D_1cc of the realized irradiation plan was statistically compared to the D_1cc of the virtually contoured OARs.

Results

In 31 cases, at least one balloon catheter was administered. The mean D_1cc of the OAR in the group with balloon(s) was 12.6 Gy compared with 16 Gy in the virtual cohort without the device, therefore significantly lower (p < 0.001). Overall, there were no acute complications. Severe (> 2 CTCAEv4.03) late complications observed in 3/31 (9.6%) patients during follow-up period after brachytherapy were most certainly not due to the balloon application. Side effects were probably associated with pre-existing serious diseases and potentially additional local late effects of the irradiation in general rather than with the balloon catheters.

Conclusions

The distancing of the adjacent OARs allows a higher D₁₀₀ value of CTV, therefore allowing for more efficient local control.

Treatment of metastatic, imatinib refractory, gastrointestinal stroma tumor with image-guided high-dose-rate interstitial brachytherapy

PURPOSE

Evaluation of efficacy and safety of CT- or MRI-guided high-dose-rate interstitial brachytherapy (iBT) in the treatment of advanced, imatinib refractory, metastatic gastrointestinal stroma tumors (GISTs) was the objective of this retrospective study.

METHODS AND MATERIALS

A cumulative number of 40 unresectable metastases (30 hepatic, 10 peritoneal) were treated with iBT in 10 selected patients with histologically proven GISTs. Six patients had peritoneal disease, and 5 patients were even progressing under sunitinib (second line)-thus iBT was applied as a salvage maneuver. IBT uses an interstitially introduced ¹⁹²iridium source in a high-dose-rate irradiation regime to destroy vital cells in a single fraction. Response to treatment was assessed clinically and with acquisition of MRI/CT every 3 months.

RESULTS

Local tumor control was reached in 97.5% of all treated metastases during a median time of 25 months-only one local relapse was observed during followup. The median diameter of the irradiated lesions was 2.4 cm (range 0.6-11.2 cm); a median dose of 15 Gy (range 6.7-21.96 Gy) was applied. The median progression-free survival after iBT was 6.8 (range 3.0-20.2) months; the median overall survival was 37.3 months (range 11.4-89.7). Two major complications (Common Terminology for Adverse Events grade 3) occurred following the intervention: local hemorrhage and pneumothorax, successfully dealt with by angiographic embolization and pleural drainage, respectively.

CONCLUSIONS

In selected patients with metastatic, imatinib refractory GISTs, iBT safely enables high rates of local tumor control and presents an alternative, anti-neoplastic treatment option even in a salvage situation.

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.

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.

Reporting small bowel dose in cervix cancer high-dose-rate brachytherapy

Small bowel (SB) is an organ at risk (OAR) that may potentially develop toxicity after radiotherapy for cervix cancer. However, its dose from brachytherapy (BT) is not systematically reported as in other OARs, even with image-guided brachytherapy (IGBT). This study aims to introduce consideration of quantified objectives for SB in BT plan optimization and to evaluate the feasibility of sparing SB while maintaining adequate target coverage. In all, 13 patients were included in this retrospective study. All patients were treated with external beam radiotherapy (EBRT) 45Gy in 25 fractions followed by high dose rate (HDR)-BT boost of 28Gy in 4 fractions using tandem/ring applicator. Magnetic resonance imaging (MRI) and computed tomographic (CT) images were obtained to define the gross tumor volume (GTV), high-risk clinical target volume (HR-CTV) and OARs (rectum, bladder, sigmoid colon, and SB). Treatment plans were generated for each patient using GEC-ESTRO recommendations based on the first CT/MRI. Treatment plans were revised to reduce SB dose when the [Formula: see text] dose to SB was > 5Gy, while maintaining other OAR constraints. For the 7 patients with 2 sets of CT and MRI studies, the interfraction variation of the most exposed SB was analyzed. Plan revisions were done in 6 of 13 cases owing to high [Formula: see text] of SB. An average reduction of 19% in [Formula: see text] was achieved. Meeting SB and other OAR constraints resulted in less than optimal target coverage in 2 patients (D90 of HR-CTV < 77Gyαβ10). The highest interfraction variation was observed for SB at 16 ± 59%, as opposed to 28 ± 27% for rectum and 21 ± 16% for bladder. Prospective reporting of SB dose could provide data required to establish a potential correlation with radiation-induced late complication for SB.

Gastric injury from (90)Y to left hepatic lobe tumors adjacent to the stomach: fact or fiction?

PURPOSE

Radioembolization with (90)Y microspheres is a locoregional radiation therapy for unresectable hepatic neoplasm. Non-target delivery of (90)Y microspheres resulting in gastrointestinal (GI) symptoms is a recognized complication; there is minimal knowledge regarding the radiation effect to the gastric wall from left hepatic lobe (90)Y treatments. Our aim was to study the incidence of GI complications when the target tissue (hepatic parenchyma ± tumor) is in close proximity to the gastric wall. We hypothesized that liver (tumor) to stomach proximity does not correlate with increased toxicity.

METHODS

Between November 2011 and September 2013, we studied all patients who underwent left lobe radioembolization with (90)Y glass microspheres. With Institutional Review Board (IRB) approval, we retrospectively reviewed MRI/CT images of these patients, identifying a subset of patients with the left hepatic lobe <1 cm from the gastric wall. Patients were seen in clinic 1 month posttreatment and subsequently at 3-month intervals. Short- and long-term gastric adverse events were tabulated.

RESULTS

Ninety-seven patients successfully underwent left hepatic lobe (90)Y microsphere radioembolization in which the average distance from the liver to the stomach wall was 1.0 ± 2.8 mm. The average dose for patients who received radioembolization to the left hepatic lobe was 109 ± 57 Gy. Fifty patients had tumor within 1 cm of the gastric wall. The average dose for patients who received radioembolization to the left hepatic lobe with tumor within 1 cm of the gastric wall was 121 ± 41 Gy. There were no reportable or recordable medical events. Of the patients, 34% reported abdominal pain that was grade 1-2; 65% of the patients reported no abdominal pain. None of the 97 patients developed a clinically evident GI ulcer.

CONCLUSION

Patients with left lobe tumors adjacent to or abutting the stomach do not exhibit acute or chronic radiation effects following radioembolization with glass microspheres.

Safety of a Scout Dose Preceding Hepatic Radioembolization with 166Ho Microspheres

Before (166)Ho radioembolization, a small batch of the same type of microspheres is administered as a scout dose instead of the conventional (99m)Tc-macroaggregated albumin ((99m)Tc-MAA). The (166)Ho scout dose provides a more accurate and precise lung shunt assessment. However, in contrast to (99m)Tc-MAA, an unintended extrahepatic deposition of this β-emitting scout dose could inflict radiation damage, the extent of which we aimed to quantify in this study.

METHODS

All patients eligible for radioembolization in our institute between January 2011 and March 2014 were reviewed. Of the extrahepatic depositions of (99m)Tc-MAA on SPECT, the amount and volume were measured. These were used to calculate the theoretic absorbed dose in the case a (166)Ho scout dose had been used. The extrahepatic activity was measured as the sum of all voxels of the deposition. Volumes were measured using a threshold technique including all voxels from the maximum voxel intensity up to a certain percentage. The threshold needed to obtain the true volume was studied in a phantom study.

RESULTS

In the phantom study, a threshold of 40% was found to overestimate the volume, with the consequence of underestimating the absorbed dose. Of 160 patients, 32 patients (34 cases) of extrahepatic deposition were identified. The depositions contained a median of 1.3% (range, 0.1%-19.5%) of the administered activity in a median volume of 6.8 mL (range, 1.1-42 mL). The use of a scout dose of 250 MBq of (166)Ho microspheres in these cases would theoretically have resulted in a median absorbed dose of 6.0 Gy (range, 0.9-374 Gy). The dose exceeded a limit of 49 Gy (reported in 2013) in 2 of 34 cases (5.9%; 95% confidence interval, 0.7%-20.1%) or 2 of 160 (1.3%; 95% confidence interval, 0.1%-4.7%) of all patients. In these 2 patients with a large absorbed dose (112 and 374 Gy), the culprit vessel was identified in 1 case.

CONCLUSION

Extrahepatic deposition of a (166)Ho scout dose seems to be theoretically safe in most patients. Its safety in clinical practice is being evaluated in ongoing clinical trials.

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.

Eradicative brachytherapy with hyaluronate gel injection into pararectal space in treatment of bulky vaginal stump recurrence of uterine cancer

The purpose of this study is to develop a procedure for eradicative brachytherapy that can deliver a curative boost dose to bulky (>4 cm) vaginal stump recurrence of uterine cancer without risk of damaging surrounding organs. We separated risk organs (the rectum and sigmoid) from the target during brachytherapy, with a hyaluronate gel injection into the pararectal space via the percutaneous paraperineal approach under local anesthesia. The rectum anchored to the sacrum by native ligament was expected to shift posteriorly. We encountered a patient with bulky stump recurrence of uterine cancer, approximately 8 cm in maximum diameter. She was complaining of abdominal pain and constipation due to bowel encasement. Following 50 Gy of external beam radiotherapy, we applied a single fraction of brachytherapy under gel separation and delivered 14.5 Gy (50.8 GyE: equivalent dose in 2-Gy fraction calculated with linear quadratic model at α/β = 3) to the target. The gel injection procedure was completed in 30 min without complications. A total irradiation dose of 100.8 GyE was delivered to the target and the cumulative minimum dose to the most irradiated rectosigmoidal volume of 2 cc (cumulative D(2cc)) was calculated as 58.5 GyE with gel injection, and was estimated to be 96 GyE without. Over three years, the local stump tumor has completely disappeared, with no complications. Brachytherapy with a pararectal gel injection can be a safe and effective eradicative option for bulky vaginal stump recurrence.

[Update on interstitial brachytherapy]

CLINICAL/METHODICAL ISSUE

Minimally invasive treatment procedures, such as image-guided local tumour ablation have gained increasing relevance in oncologic concepts. Limitations of thermal ablation procedures have led to the development of percutaneous, computed tomography (CT) guided brachytherapy.

STANDARD RADIOLOGICAL METHODS

Thermal ablation procedures, such as radiofrequency ablation (RFA) and laser-induced thermotherapy (LITT) show limitations regarding maximum tumour size (<5 cm), cooling effects of adjacent vessels and surrounding risk structures.

METHODICAL INNOVATIONS

The image-guided interstitial brachytherapy allows the single application of high-dose rate (HDR) irradiation with an extensive protracted cytotoxic effect. Adjacent risk structures play a minor role due to the steep dose gradient outside the clinical target volume.

PERFORMANCE

Studies using CT-guided brachytherapy resulted in a local tumour control rate of approximately 90% after 12 months in the treatment of hepatocellular carcinoma (HCC) and 70-90% in the treatment of colorectal metastases or cholangiocellular carcinoma (CCC). Similar response rates were also seen in the treatment of metastases of renal cell carcinoma (RCC), non-small cell lung cancer (NSCLC) or neuroendocrine tumours. In colorectal liver metastases and HCC the method has proven to have a positive impact on prognosis.

ACHIEVEMENTS

In contrast to thermal ablation the method can be used without restriction with respect to tumour location. Cooling effects do not play a role. It has already been applied in more than 5,000 cases and it is used in clinical routine.

PRACTICAL RECOMMENDATIONS

Image-guided brachytherapy is safe and effective and has found its way into the clinical routine.

Computed tomography-guided brachytherapy for liver cancer

Limitations of thermal liver cancer ablation have led to the development of percutaneous, catheter-based brachytherapy for the treatment of liver malignancies. Computed tomography (CT)-guided brachytherapy has been used to treat primary and metastatic liver cancers, including very large tumors >10 cm. Cooling effects by adjacent blood vessels are not a concern in brachytherapy, and the method may be used safely in tumors unsuitable for thermal ablation that are close to the liver hilum due to the relatively high radiation tolerance of bile duct. CT scanning is used for dosimetry planning after catheter implantation and also to guide the catheter placement itself. Major complications, including postinterventional bleeding, are rare despite frequent application of this technique in a salvage situation. Patients with liver cirrhosis have an increased risk for complications. Prospective trials of CT-guided brachytherapy have been performed with promising survival rates for liver metastases and hepatocellular carcinoma, respectively. In this article, the radiobiological and technical properties of CT-guided brachytherapy, appropriate patients for treatment, and prospective trials that have been published to date are reviewed.

Reirradiation of paraaortic lymph node metastasis by brachytherapy with hyaluronate injection via paravertebral approach: With DVH comparison to IMRT

PURPOSE/INTRODUCTION: To safely irradiate retroperitoneal targets as paraaortic lymph node by separating abdominal at-risk organs from the target during irradiation, we created a percutaneous paravertebral approach of high-dose-rate brachytherapy with hyaluronate gel injection (HGI). We report a case treated with this technique.

METHODS AND MATERIALS

We encountered a patient with symptomatic regrowth of paraaortic lymph node metastasis from prostatic cancer. He had previously received 58.4Gy of radiotherapy to the same region 12 months prior. Brachytherapy needles and a HGI needle were deployed via the paravertebral approach under local anesthesia at our outpatient clinic.

RESULTS

A single dose of 22.5Gy (equivalent to 60.94Gy in 2Gy per fraction schedule calculated at α/β=10) was delivered to the target, with preservation of the surrounding small intestine by HGI with D(2cc) (minimum dose to the most irradiated volume of 2mL) of 5.05Gy. Therapeutic ratio was 3.64 times higher for this brachytherapy plan compared with an intensity-modulated radiation therapy plan. At followup at 1 year after brachytherapy, the symptoms had disappeared, tumor size had reduced with no fluorodeoxyglucose accumulation, and prostate-specific antigen level had decreased.

CONCLUSION

We consider that high-dose-rate brachytherapy with the HGI procedure offers effective treatment even in this type of reirradiation situation.

Value of diffusion weighted MR imaging as an early surrogate parameter for evaluation of tumor response to high-dose-rate brachytherapy of colorectal liver metastases

Background

To assess the value of diffusion weighted imaging (DWI) as an early surrogate parameter for treatment response of colorectal liver metastases to image-guided single-fraction ¹⁹²Ir-high-dose-rate brachytherapy (HDR-BT).

Methods

Thirty patients with a total of 43 metastases underwent CT- or MRI-guided HDR-BT. In 13 of these patients a total of 15 additional lesions were identified, which were not treated at the initial session and served for comparison. Magnetic resonance imaging (MRI) including breathhold echoplanar DWI sequences was performed prior to therapy (baseline MRI), 2 days after HDR-BT (early MRI) as well as after 3 months (follow-up MRI). Tumor volume (TV) and intratumoral apparent diffusion coefficient (ADC) were measured independently by two radiologists. Statistical analysis was performed using univariate comparison, ANOVA and paired t test as well as Pearson's correlation.

Results

At early MRI no changes of TV and ADC were found for non-treated colorectal liver metastases. In contrast, mean TV of liver lesions treated with HDR-BT increased by 8.8% (p = 0.054) while mean tumor ADC decreased significantly by 11.4% (p < 0.001). At follow-up MRI mean TV of non-treated metastases increased by 50.8% (p = 0.027) without significant change of mean ADC values. In contrast, mean TV of treated lesions decreased by 47.0% (p = 0.026) while the mean ADC increased inversely by 28.6% compared to baseline values (p < 0.001; Pearson's correlation coefficient of r = -0.257; p < 0.001).

Conclusions

DWI is a promising imaging biomarker for early prediction of tumor response in patients with colorectal liver metastases treated with HDR-BT, yet the optimal interval between therapy and early follow-up needs to be elucidated.

Treatment of hepatic metastases of breast cancer with CT-guided interstitial brachytherapy - a phase II-study

PURPOSE

The aim of the study was the evaluation of feasibility, safety and effectiveness of interstitial brachytherapy for the treatment of hepatic metastases of breast cancer.

MATERIALS AND METHODS

Forty-one consecutive patients with 115 unresectable hepatic metastases of breast cancer were included in this phase-II-trial. They were treated in 69 interventions of CT-guided-interstitial-brachytherapy of the liver. Brachytherapy was applied as a single fraction high-dose-irradiation (15-25Gy (Gray)) using a (192)Ir-source of 10Ci. Nineteen patients presented systemically pretreated extrahepatic tumors. Primary endpoints were complications, local tumor control and progression-free survival.

RESULTS

The median tumor diameter was 4.6 cm (1.5-11 cm). The median irradiation time per intervention was 26.5 min (range: 7-47 min). The applied median minimal dose at the CTV (clinical target volume) margin was 18.5 Gy (12-25 Gy). In 69 interventions and during the postinterventional period, one major complication (symptomatic post-interventional bleeding) (1.5%) and six minor complications occurred (8.7%). The median follow-up time was 18 months (range: 1-56). After 6, 12 and 18 months, local tumor control was 97%, 93.5% and 93.5%, intra- and extrahepatic progression free survival was 53%, 40% and 27%, and overall survival was 97%, 79% and 60%, respectively.

CONCLUSION

CT-guided-brachytherapy is safe and effective for the treatment of liver metastases of breast cancer.

[Normal tissue tolerance to external beam radiation therapy: the stomach]

In the following article, we will discuss general issues relating to acute and late gastric's radiation toxicities. The tolerance of the stomach to complete or partial organ irradiation is more unappreciated than for most other organs. We consulted the Medline database via PubMed and used the key words gastric--radiotherapy--toxicity. Currently, 60 Gy or less is prescribed in gastric radiation therapy. Acute clinical toxicity symptoms are predominantly nausea and vomiting. Although there is a general agreement that the whole stomach tolerance is for doses of 40 to 45 Gy without unacceptable complication, it is well established that a stomach dose of 35 Gy increases the risk of ulcer complications.

Radiation dose-volume effects in the stomach and small bowel

Published data suggest that the risk of moderately severe (>or=Grade 3) radiation-induced acute small-bowel toxicity can be predicted with a threshold model whereby for a given dose level, D, if the volume receiving that dose or greater (VD) exceeds a threshold quantity, the risk of toxicity escalates. Estimates of VD depend on the means of structure segmenting (e.g., V15 = 120 cc if individual bowel loops are outlined or V45 = 195 cc if entire peritoneal potential space of bowel is outlined). A similar predictive model of acute toxicity is not available for stomach. Late small-bowel/stomach toxicity is likely related to maximum dose and/or volume threshold parameters qualitatively similar to those related to acute toxicity risk. Concurrent chemotherapy has been associated with a higher risk of acute toxicity, and a history of abdominal surgery has been associated with a higher risk of late toxicity.

Peptic ulcer disease

Peptic ulcer disease had a tremendous effect on morbidity and mortality until the last decades of the 20th century, when epidemiological trends started to point to an impressive fall in its incidence. Two important developments are associated with the decrease in rates of peptic ulcer disease: the discovery of effective and potent acid suppressants, and of Helicobacter pylori. With the discovery of H pylori infection, the causes, pathogenesis, and treatment of peptic ulcer disease have been rewritten. We focus on this revolution of understanding and management of peptic ulcer disease over the past 25 years. Despite substantial advances, this disease remains an important clinical problem, largely because of the increasingly widespread use of non-steroidal anti-inflammatory drugs (NSAIDs) and low-dose aspirin. We discuss the role of these agents in the causes of ulcer disease and therapeutic and preventive strategies for drug-induced ulcers. The rare but increasingly problematic H pylori-negative NSAID-negative ulcer is also examined.

Changes in transcriptome after in vivo exposure to ionising radiation reveal a highly specialised liver response

PURPOSE

To identify transcriptional gene-networks involved in the early in vivo response of liver cells to radiation exposure and improve our understanding of the molecular processes responsible for tissue radiosensitivity.

MATERIALS AND METHODS

Transcriptome variations of liver RNA samples were measured 3 hours post-irradiation using microarray technology. The results were confirmed and extended using real-time polymerase-chain-reaction (RT-PCR).

RESULTS

We identified quantitative changes in the expression of 126 genes, most of which were observed for the first time. We show that some modifications, such as the upregulation of the cyclin-dependent kinase inhibitor 1A (Cdkn1A) gene, persisted for at least two months after the initial exposure. Other genes regulated by the transformation-related protein 53 (Trp53/p53) such as Bcl2-associated X protein (Bax) or etoposide-induced-2.4 (Ei24/PIG8) were not upregulated. Grouping differentially expressed genes into functional categories revealed that the primary response of liver cells to radiation exposure was the enhancement of oxidoreductase activity and inhibition of cell proliferation, involving cell cycle progression and apoptosis-related genes.

CONCLUSIONS

The data provides evidence of gene expression modifications associated with the hepatic response to radiation exposure. One of the main differences observed with radiation-sensitive tissues such as the spleen was cell proliferation. The comparison of our data with transcriptome modifications in different biological models enabled the identification of networks of genes that might be co-regulated. Overall, our expression data revealed genes and cellular pathways that might help to improve our understanding of the molecular basis underlying tissue radiosensitivity and to identify possible targets for novel therapeutic strategies.

Helicobacter pylori-negative nonsteroidal anti-inflammatory drug-negative ulcer

The most important clinical point for dyspeptic H pylori-negative NSAID-absent negative ulcers is to adequately ensure that these common risk factors are indeed absent. Once that is done, further investigations to include the rare causes of ulcer disease need to be performed and exclusion of underlying malignancy ensured. The possibility of the Zollinger Ellison syndrome should be considered, remembering that proton pump inhibitor therapy will mitigate its classical, clinical features.

How I manage H. pylori-negative, NSAID/aspirin-negative peptic ulcers

The first and most important action on encountering a patient with unexplained gastric or duodenal ulceration is to double check that they are truly H. pylori negative and also not taking any ulcerogenic medicines. Once the patient is confirmed to be H. pylori negative and NSAID negative, ensure that biopsies of the ulcer-whether gastric or duodenal-and of the surrounding gastric and duodenal mucosa are obtained to exclude underlying malignancy/lymphoma, Crohn's disease, and unusual infectious agents. If the etiology of the ulceration remains unexplained, an underlying gastrinoma should be considered and excluded. Patients with idiopathic ulcers should be maintained on proton pump inhibitor therapy, and higher doses may be required to control acid secretion and prevent ulcer relapse in these H. pylori-uninfected subjects.

Techniques of interventional tumor therapy

INTRODUCTION

The last few years have seen the rapid development of new image-guided interventions for the local treatment of malignant tumors. The goal of this article is to provide an overview of the techniques that are most commonly used today in interventional oncology.

METHODS

Selective literature review on the current state of image-guided interventional techniques for local tumor therapy.

RESULTS

While surgery, radiation oncology, and systemic chemotherapy are still the three main pillars of tumor therapy, a broad range of minimally invasive, image-guided techniques for local tumor treatment is now available. These may be categorized as percutaneous injection of a toxic substance, transarterial embolization, thermal ablation, and internal radiotherapy. The choice of treatment depends on the type, location, and size of tumor. The greatest amount of clinical experience to date has been gathered in the treatment of primary and secondary hepatic malignancy, but there are interventional treatment options for virtually all regions of the body. At present, the utility of this form of treatment is limited for very large or multiple tumors; novel therapeutic options for these situations are now being studied.

DISCUSSION

The outcome of treatment depends on a judicious determination of the indication for it. The indication should be established by interdisciplinary consensus after all treatment options have been considered.

Brachytherapy of liver metastases

Brachytherapy for the treatment of liver metastases is a novel approach. In this procedure, techniques of locally ablative treatment in interventional radiology and radiation therapy are combined. After computed tomography (CT)-guided percutaneous implantation of catheters into the hepatic tumor, the irradiation is performed in an afterloading technique. This minimally invasive procedure offers circumscriptive high-dose rate irradiation of the lesion to treat in a single session, irrespective of breathing motion or potential cooling effects of neighboring vessels. Good local control rates have been achieved in several tumor entities, including both secondary and primary malignancies of the liver. This article gives an overview of the application technique, possible adverse events, and outcome with special attention to the pancreatic cancer scenario.