Dosimetric study for breathing-induced motion effects in an abdominal pancreas phantom for carbon ion mini-beam radiotherapy.

BACKGROUND: Particle mini-beam therapy exhibits promise in sparing healthy tissue through spatial fractionation, particularly notable for heavy ions, further enhancing the already favorable differential biological effectiveness at both target and entrance regions. However, breathing-induced organ motion affects particle mini-beam irradiation schemes since the organ displacements exceed the mini-beam structure dimensions, decreasing the advantages of spatial fractionation. PURPOSE: In this study, the impact of breathing-induced organ motion on the dose distribution was examined at the target and organs at risk(OARs) during carbon ion mini-beam irradiation for pancreatic cancer. METHODS: As a first step, the carbon ion mini-beam pattern was characterized with Monte Carlo simulations. To analyze the impact of breathing-induced organ motion on the dose distribution of a virtual pancreas tumor as target and related OARs, the anthropomorphic Pancreas Phantom for Ion beam Therapy (PPIeT) was irradiated with carbon ions. A mini-beam collimator was used to deliver a spatially fractionated dose distribution. During irradiation, varying breathing motion amplitudes were induced, ranging from 5 to 15 mm. Post-irradiation, the 2D dose pattern was analyzed, focusing on the full width at half maximum (FWHM), center-to-center distance (ctc), and the peak-to-valley dose ratio (PVDR). RESULTS: The mini-beam pattern was visible within OARs, while in the virtual pancreas tumor a more homogeneous dose distribution was achieved. Applied motion affected the mini-beam pattern within the kidney, one of the OARs, reducing the PVDR from 3.78  ± $\pm$  0.12 to 1.478  ± $\pm$  0.070 for the 15 mm motion amplitude. In the immobile OARs including the spine and the skin at the back, the PVDR did not change within 3.4% comparing reference and motion conditions. CONCLUSIONS: This study provides an initial understanding of how breathing-induced organ motion affects spatial fractionation during carbon ion irradiation, using an anthropomorphic phantom. A decrease in the PVDR was observed in the right kidney when breathing-induced motion was applied, potentially increasing the risk of damage to OARs. Therefore, further studies are needed to explore the clinical viability of mini-beam radiotherapy with carbon ions when irradiating abdominal regions.

Unrecognized digestive toxicities of radiation therapy.

The aim of this article is to review unrecognized toxicities resulting from radiation therapy of digestive neoplasms. Due to their precocious occurrence, acute toxicities are well-known by radiation oncologist, and their treatment well-established. Thus, acute toxicities will not be described in this review. We will focus on incidence, diagnosis, and management of late and uncommon toxicities occurring in the digestive tract and digestive organs. Prevention, by respecting healthy tissues constraints, is the main tool to reduce incidence of those rare complications. Nonetheless, once installed, late toxicities remain a major burden in terms of quality of life and can even be life threatening. Hence, information and education about their diagnosis and management is important.

The role of radiotherapy in locally advanced pancreatic cancer.

At diagnosis, about 15% of patients with pancreatic cancer present with a resectable tumour, 50% have a metastatic tumour, and 35% a locally advanced tumour, non-metastatic but unresectable due to vascular invasion, or borderline resectable. Despite the technical progress made in the field of radiation therapy and the improvement of the efficacy of chemotherapy, the prognosis of these patients remains very poor. Recently, the role of radiation therapy in the management of pancreatic cancer has been much debated. This review aims to evaluate the role of radiation therapy for patients with locally advanced tumours.

Dosimetric and radiobiological comparison of treatment plan between CyberKnife and EDGE in stereotactic body radiotherapy for pancreatic cancer.

To perform a comparison of the different stereotactic body radiotherapy (SBRT) plans between the Varian EDGE and CyberKnife (CK) systems for locally advanced unresectable pancreatic cancer. Fifteen patients with pancreatic cancer were selected in this study. The median planning target volume (PTV) was 28.688 cm3 (5.736-49.246 cm3). The SBRT plans for the EDGE and CK were generated in the Eclipse and Multiplan systems respectively with the same contouring and dose constrains for PTV and organs at risk (OARs). Dose distributions in PTV were evaluated in terms of coverage, conformity index (CI), new conformity index (nCI), homogeneity index (HI), and gradient index (GI). OARs, including spinal cord, bowel, stomach, duodenum and kidneys were statistically evaluated by different dose-volume metrics and equivalent uniform dose (EUD). The volume covered by the different isodose lines (ISDL) ranging from 10 to 100% for normal tissue were also analyzed. All SBRT plans for EDGE and CK met the dose constraints for PTV and OARs. For the PTV, the dosimetric metrics in EDGE plans were lower than that in CK, except that D99 and GI were slightly higher. The EDGE plans with lower CI, nCI and HI were superior to generate more conformal and homogeneous dose distribution for PTV. For the normal tissue, the CK plans were better at OARs sparing. The radiobiological indices EUD of spinal cord, duodenum, stomach, and kidneys were lower for CK plans, except that liver were higher. The volumes of normal tissue covered by medium ISDLs (with range of 20-70%) were lower for CK plans while that covered by high and low ISDLs were lower for EDGE plans. This study indicated that both EDGE and CK generated equivalent plan quality, and both systems can be considered as beneficial techniques for SBRT of pancreatic cancer. EDGE plans offered more conformal and homogeneous dose distribution for PTV, while the CK plans could minimize the exposure of OARs.

Laser Treatment of Pancreatic Cancer with Immunostimulating Interstitial Laser Thermotherapy Protocol: Safety and Feasibility Results From Two Phase 2a Studies.

PURPOSE: Ablative techniques have emerged as new potential therapeutic options for patients with locally advanced pancreatic cancer (LAPC). We explored the safety and feasibility of using TRANBERG|Thermal Therapy System (Clinical Laserthermia Systems AB, Lund, Sweden) in feedback mode for immunostimulating Interstitial Laser Thermotherapy (imILT) protocol, the newest ablative technique introduced for the treatment of LAPC. METHODS: The safety and feasibility results after the use of imILT protocol treatment in 15 patients of a prospective series of postsystemic therapy LAPC in two high-volume European institutions, the General and Pancreatic Unit of the Pancreas Institute, of the University of Verona, Italy, and the Department of Surgical Oncology of the Institut Paoli-Calmettes of Marseille, France, were assessed. RESULTS: The mean age was 66 ± 5 years, with a mean tumor size of 34.6 (±8) mm. The median number of cycles of pre-imILT chemotherapy was 6 (6-12). The procedure was performed in 13 of 15 (86.6%) cases; indeed, in two cases, the procedure was not performed; in one, the procedure was considered technically demanding; in the other, liver metastases were found intraoperatively. In all treated cases, the procedure was completed. Three late pancreatic fistulas developed over four overall adverse events (26.6%) and were attributed to imILT. Mortality was nil. A learning curve is necessary to interpret and manage the laser parameters. CONCLUSIONS: Safety, feasibility, and device handling outcomes of using TRANBERG|Thermal Therapy System with temperature probes in feedback mode and imILT protocol on LAPC were not satisfactory. The metastatic setting may be appropriate to evaluate the hypothetic abscopal effect.#NCT02702986 and #NCT02973217.

Patterns of Failure After Neoadjuvant Stereotactic Body Radiation Therapy or Fractionated Chemoradiation in Resectable and Borderline Resectable Pancreatic Cancer.

OBJECTIVES: The goal of this study was to compare outcomes of patients with borderline and resectable pancreatic cancer treated with neoadjuvant stereotactic body radiation therapy (SBRT) versus fractionated chemoradiation. METHODS: Patients with borderline or resectable pancreatic cancer treated with neoadjuvant intent between November 2011 and December 2017 were reviewed. The SBRT volume/dose was 33 Gy in 5 fractions to gross tumor plus abutting vessel with or without 25 Gy in 5 fractions to pancreatic head/body and celiac/superior mesenteric artery. Fractionated chemoradiation volume/dose was 50.4 Gy in 28 fractions to gross tumor, superior mesenteric/celiac arteries, and enlarged lymph nodes with concurrent bolus 5-FU, leucovorin, oxaliplatin, irinotecan or gemcitabine/nab-paclitaxel. Failure patterns, local recurrence-free survival (LRFS), progression-free survival (PFS), and overall survival were assessed. RESULTS: Forty-three patients were reviewed (18 SBRTs and 25 fractionated). Among patients who underwent resection, patients treated with fractionated chemoradiation had improved LRFS (12-month LRFS, 86% vs 62%, P = 0.003) and PFS (median PFS, 23 months vs 11 months, P = 0.006) compared with SBRT. There was no difference in overall survival. CONCLUSIONS: Stereotactic body radiation therapy may result in inferior LRFS and PFS compared with fractionated chemoradiation, likely because of under coverage of high-risk vascular targets.

Advances in borderline resectable pancreatic adenocarcinoma.

Pancreatic adenocarcinoma is one of the most lethal cancers in oncology. Pancreatic cancer is the third most common cause of cancer-related mortality in the United States. As the years have progressed, the importance of a multidisciplinary and multimodal approach to pancreatic cancer care has been recognized and is now recommended in all major society guidelines. A subset of pancreatic cancer, borderline resectable pancreatic cancer (BRPC), has emerged as a distinct clinical entity for which specialized treatment plans are now being developed. The medical oncologist, surgical oncologist, and radiation oncologist must work jointly to help deliver the best clinical outcome for the patient with pancreatic cancer. In this discussion, we describe the current state of surgical, locoregional therapies and systemic therapy in BRPC.

Radiation as a Single-Modality Treatment in Localized Pancreatic Cancer.

OBJECTIVES: Locally advanced pancreatic cancer (LAPC) is managed with multimodality therapy. We aim to evaluate the outcome of single-modality radiation therapy for LAPC. METHODS: Locally advanced pancreatic cancer patients were identified between 2004 and 2013 using the National Cancer Database excluding patients who received chemotherapy or surgery. RESULTS: A total of 6590 patients were included. The mean age was 73.5 (range, 28-90) years, 83.2% were white, and 54.4% were female. Tumors of 4 cm or greater (>T3 stage) accounted for 52.7%. The median radiation dose was 39.6 Gy. Stereotactic body radiation (SBRT) delivered to 64 patients and external-beam/intensity modulated radiotherapy in 416 patients. Radiation therapy was associated with improved overall survival (OS) compared with no treatment in univariate and multivariable analyses. The medians OS for patients who received SBRT, external-beam/intensity modulated radiotherapy, or no radiation were 8.6, 6.7, and 3.4 months, respectively (P < 0.001). There is a significant difference in 12-month OS for the SBRT cohort (31.9%; 95% confidence interval [CI], 20.9%-43.5%) compared with patients who received no radiation (15.1%; 95% CI, 14.2%-16.0%), and on multivariable analysis (hazard ratio, 0.50; 95% CI, 0.38-0.65; P < 0.001). CONCLUSIONS: The current study suggests potential benefit for radiation therapy alone in comparison with no treatment in LAPC.

Comparison of antioxidative effects between radon and thoron inhalation in mouse organs.

Radon therapy has been traditionally performed globally for oxidative stress-related diseases. Many researchers have studied the beneficial effects of radon exposure in living organisms. However, the effects of thoron, a radioisotope of radon, have not been fully examined. In this study, we aimed to compare the biological effects of radon and thoron inhalation on mouse organs with a focus on oxidative stress. Male BALB/c mice were randomly divided into 15 groups: sham inhalation, radon inhalation at a dose of 500 Bq/m3 or 2000 Bq/m3, and thoron inhalation at a dose of 500 Bq/m3 or 2000 Bq/m3 were carried out. Immediately after inhalation, mouse tissues were excised for biochemical assays. The results showed a significant increase in superoxide dismutase and total glutathione, and a significant decrease in lipid peroxide following thoron inhalation under several conditions. Additionally, similar effects were observed for different doses and inhalation times between radon and thoron. Our results suggest that thoron inhalation also exerts antioxidative effects against oxidative stress in organs. However, the inhalation conditions should be carefully analyzed because of the differences in physical characteristics between radon and thoron.

Advances in cancer cachexia: Intersection between affected organs, mediators, and pharmacological interventions.

Advanced cancer patients exhibit cachexia, a condition characterized by a significant reduction in the body weight predominantly from loss of skeletal muscle and adipose tissue. Cachexia is one of the major causes of morbidity and mortality in cancer patients. Decreased food intake and multi-organ energy imbalance in cancer patients worsen the cachexia syndrome. Cachectic cancer patients have a low tolerance for chemo- and radiation therapies and also have a reduced quality of life. The presence of tumors and the current treatment options for cancer further exacerbate the cachexia condition, which remains an unmet medical need. The onset of cachexia involves crosstalk between different organs leading to muscle wasting. Recent advancements in understanding the molecular mechanisms of skeletal muscle atrophy/hypertrophy and adipose tissue wasting/browning provide a platform for the development of new targeted therapies. Therefore, a better understanding of this multifactorial disorder will help to improve the quality of life of cachectic patients. In this review, we summarize the metabolic mediators of cachexia, their molecular functions, affected organs especially with respect to muscle atrophy and adipose browning and then discuss advanced therapeutic approaches to cancer cachexia.

Effect of Pulsed Focused Ultrasound on the Native Pancreas.

Pulsed focused ultrasound (pFUS) utilizes short cycles of sound waves to mechanically shake cells within tissues which, in turn, causes transient local increases in cytokines, growth factors and cell adhesion molecules. Although the effect of pFUS has been investigated in several different organs including the kidney, muscle and heart, its effect on the pancreas has not been investigated. In the present work, we applied pFUS to the rodent pancreas with the following parameters: 1.1-MHz frequency, 5-Hz pulse repetition frequency, 5% duty cycle, 10-ms pulse length, 160-s duration. Low-intensity pFUS had a spatial average temporal average intensity of 11.5 W/cm2 and a negative peak pressure of 3 MPa; high-intensity pFUS had a spatial average temporal average intensity of 18.5 W/cm2 and negative peak pressure of 4 MPa. Here we found that pFUS changed the expression of several cytokines while having no effect on the underlying tissue histology or health of pancreatic cells (as reflected by no significant change in plasma levels of amylase and lipase). Furthermore, we found that this effect on cytokine expression in the pancreas was acoustic intensity dependent; while pFUS at low intensities turned off the expression of several cytokines, at high intensities it had the opposite effect and turned on the expression of these cytokines. The ability to non-invasively manipulate the microenvironment of the pancreas using sound waves could have profound implications for priming and modulating this organ for the application of cellular therapies in the context of both regenerative medicine (i.e., diabetes and pancreatitis) and oncology (i.e., pancreatic cancer).

Therapeutic Ultrasound-Induced Insulin Release in Vivo.

The tolerability and efficacy of low-frequency, low-intensity therapeutic ultrasound-induced insulin release was investigated in a pre-clinical in vivo murine model. The treatment groups received a single 5-min continuous sonication at 1 MHz and 1.0 W/cm2. Insulin and glucagon levels in the serum were determined using enzyme-linked immunosorbent assay. The pancreas was excised and sectioned for histologic analysis. In terminal studies, we observed a moderate (∼50 pM) but significant increase in blood insulin concentration in vivo immediately after sonication compared with a decrease of approximately 60 pM in sham animals (n < 6, p < 0.005). No difference was observed in the change in glucose or glucagon concentrations between groups. Comparisons of hematoxylin and eosin-stained terminal and survival pancreatic tissue revealed no visible differences or evidence of damage. This study is the first step in assessing the translational potential of therapeutic ultrasound as a treatment for early stages of type 2 diabetes.

Radiation Dose and Volume to the Pancreas and Subsequent Risk of Diabetes Mellitus: A Report from the Childhood Cancer Survivor Study.

BACKGROUND: Childhood cancer survivors exposed to abdominal radiation (abdRT) are at increased risk for diabetes mellitus, but the association between risk and radiation dose and volume is unclear. METHODS: Participants included 20 762 5-year survivors of childhood cancer (4568 exposed to abdRT) and 4853 siblings. For abdRT, we estimated maximum dose to abdomen; mean doses for whole pancreas, pancreatic head, body, tail; and percent pancreas volume receiving no less than 10, 20, and 30 Gy. Relative risks (RRs) were estimated with a Poisson model using generalized estimating equations, adjusted for attained age. All statistical tests were two-sided. RESULTS: Survivors exposed to abdRT (median age = 31.6 years, range = 10.2-58.3 years) were 2.92-fold more likely than siblings (95% confidence interval [CI] = 2.02 to 4.23) and 1.60-times more likely than survivors not exposed to abdRT (95%CI = 1.24 to 2.05) to develop diabetes. Among survivors treated with abdRT, greater attained age (RRper 10 years = 2.11, 95% CI = 1.70 to 2.62), higher body mass index (RRBMI 30+ = 5.00, 95% CI = 3.19 to 7.83 with referenceBMI 18.5-24.9), and increasing pancreatic tail dose were associated with increased diabetes risk in a multivariable model; an interaction was identified between younger age at cancer diagnosis and pancreatic tail dose with much higher diabetes risk associated with increasing pancreatic tail dose among those diagnosed at the youngest ages (P < .001). Radiation dose and volume to other regions of the pancreas were not statistically significantly associated with risk. CONCLUSIONS: Among survivors treated with abdRT, diabetes risk was associated with higher pancreatic tail dose, especially at younger ages. Targeted interventions are needed to improve cardiometabolic health among those at highest risk.

RETROSPECTIVE ASSESSMENT OF CLINICAL-MORPHOLOGICAL CHANGES OF THE HEPATOBILIARY SYSTEM IN LIVER CIRRHOSIS OF THE CHORNOBYL NPP ACCIDENT CLEAN-UP WORKERS. / RETROSPEKTYVNA OTsINKA KLINIKO-MORFOLOGIChNYKh ZMIN GEPATOBILIARNOÏ SYSTEMY PRY TsYROZI PEChINKY V UChASNYKIV LIKVIDATsIÏ NASLIDKIV ChORNOBYL'S'KOÏ KATASTROFY.

OBJECTIVE: to retrospectively characterize changes in the hepatobiliary system in liver cirrhosis (LC) in the clean-up workers of the Chornobyl NPP accident and to determine the factors of disease progression according to the expert materials of the Central Interagency Expert Commission on Establishing the Causal Relationship of the Diseases with the influence of factors of Chornobyl NPP accident. MATERIALS AND METHODS: Based on the data of 60 cases of the Central Interagency Expert Committee on establishing the causal link of diseases with the impact of the Chornobyl NPP accident, the factors of development, concomitant pathology and indicators of the hepatobiliary system status in 49 deceased and 11 alive clean-up workers with LC were investigated. RESULTS: A retrospective study of the morphological changes of the hepatobiliary system in the clean-up workers with LC showed that the main pathologic anatomical diagnosis in 37.8 % of cases was small-nodal LC, in 8.9 % - micromacronodular, in 4.4 % - large-nodal, in 2.2 % - primary biliary LC, in the other 40 % of cases - LC with uncer- tain nodal structure, as well as 2 (4.4 %) cases of fatty liver and 1 case (2.2 %) of portal cirrhosis against the back- ground of fatty liver. Pathomorphological changes were characterized by expressed growth of fibrous tissue with replacement of the liver parenchyma (fields of fibrosis), increase in size and impaired structure of the liver, thick- ening and tightening of its capsule, fibrotic changes in other organs - gastric mucosa, pancreas, spleen, lungs, heart. Histological examination revealed lobe structure abnormalities, false lobules, periportal fibrosis, lymphoid-lympho- cytic infiltration, diffuse fatty small-sized and large-drop dystrophy, and hepatocyte atrophy. Common inflammato- ry processes and fibrotic changes of other organs and systems: cardiovascular, urinary, bronchopulmonary, stomach, pancreas and spleen made the course of the LC more severe. The most frequent were cardiovascular diseases, signi- ficantly more frequent among the deceased than alive patients: hypertension - 67.3 % and 45.5 %, p < 0.05, coro- nary heart disease - 57.1 % and 18 %, p < 0.05. In most cases, the cause of death in the clean-up workers with LC was hepatic and cellular failure (53.3 %), which together with hepatic-renal failure (17.8 %) made 71.1 %. CONCLUSION: Changes in the hepatobiliary system of change in in the clean-up workers with LC were characterized by marked growth of fibrotic tissue with replacement of the parenchyma and impaired liver structure, fibrotic changes in other organs, diffuse fatty small and large droplet dystrophy and atrophy of hepatocytes. The severe course of the LC with the manifestation of the disease at the stage of decompensation was due to a vague clinical picture, lack of subjective symptoms of liver disease, slow, steadily progressing development, lack of or inadequate examination and treatment, a significant number of concomitant pathology of other organs and systems. The fac- tors of the development of LC in the clean-up workers were the long course of chronic liver disease, numerous con- comitant pathology, long stay in the accident zone, the effect of ionizing radiation, as well as the lack of dispensa- ry supervision and adequate treatment.

The Anatomical Pattern of the Proximal Jejunal Vein as a Prognostic Factor in Patients With Pancreatic Head Cancer Treated With Preoperative Chemoradiation Therapy.

BACKGROUND/AIM: The significance of the anatomical variations of proximal jejunal vein [the so-called 1st jejunal vein (J1v)] has been reported from a technical standpoint. The aim of this study was to retrospectively investigate the prognostic impact of the anatomical variations of J1v in the surgical treatment of resectable pancreatic cancer (PC). PATIENTS AND METHODS: A total of 49 patients with resectable PC located in the uncinate process were included in this study. The J1v converging pattern was divided into 2 groups in terms of its relation to the SMA (i.e., the J1v status): i) group D: the J1v travels posterior to the SMA; ii) group V: the J1v travels anterior to the SMA. The associations between the J1v status and surgical outcome were assessed. RESULTS: The 5-year survival rate after resection in group V (35%) was significantly lower than that in group D (70%) (p=0.029), and the J1v status of group V was the only independent negative prognostic factor (HR=5.49; 95% CI=1.69-19.3; p=0.005). CONCLUSION: The J1v converging pattern is a significant prognostic variable in patients with PC located in the uncinate process: the J1v status of group V was significantly associated with impaired survival.

Split-bolus vs. multiphasic contrast bolus protocol in patients with pancreatic cancer or cholangiocarcinoma.

PURPOSE: To investigate the image quality, diagnostic accuracy, and dose reduction potential of a split-bolus protocol(SBP) compared with a multiphasic protocol(MPP) in the detection of recurrent or progressive pancreatic ductal adenocarcinoma(PDAC) or cholangiocarcinoma(CC) using contrast- enhanced computed tomography(CECT). MATERIALS AND METHODS: This prospective study included 56 patients who underwent CECT, 28 with our institutional standard MPP(100 ml contrast bolus) and 28 with a novel SBP(110 ml). Radiation exposure was determined in terms of total dose- length product(DLP) and computed tomography dose index(CTDI). Image quality was measured objectively by analysis of attenuation in Hounsfield units(HU) in regions of interest(ROIs) and subjectively by two blinded readers using a Likert scale. Diagnostic accuracy and interreader variability were tested. RESULTS: The total DLP of the SBP group(498.1 ± 43.7 mGy*cm) was significantly lower than in the MPP group(1,092.5 ± 106.9 mGy*cm; p < 0.001). The SBP showed higher contrast enhancement of all critical anatomical structures including portal vein, liver, and pancreas compared with the MPP, except for the aorta(SBP: 326.9 ± 15.7 HU vs. MPP: 246.7 ± 12.2 HU; p < 0.001). Subjective analysis revealed poorer image quality ratings for important landmarks with the MPP (resection surface: p = 0.624, portal vein: p = 0.395, liver p = 0.361). The two blinded readers correlated significantly. Sensitivity, specificity, positive and negative predictive values (PPV/NPV), and overall interreader variabilities correlated significantly. Furthermore, significantly fewer slices per exam were required for the SBP(1,823 vs. 3,235; p < 0.001). CONCLUSION: The SBP provides the same image quality and diagnostic accuracy as an MPP while significantly lowering radiation exposure in CT follow-up of PDAC or CC.

Perfusion CT to Assess Response to Neoadjuvant Chemotherapy and Radiation Therapy in Pancreatic Ductal Adenocarcinoma: Initial Experience.

BackgroundChange in tumor size at CT is insufficient for reliable assessment of treatment response after neoadjuvant chemotherapy and radiation therapy (CRT) and shows poor correlation with histologic grading of response.PurposeTo investigate the use of perfusion CT to predict the response of pancreatic ductal adenocarcinoma (PDA) to CRT.Materials and MethodsBetween June 2016 and May 2018, study participants with biopsy-proven PDA were prospectively recruited to undergo perfusion CT before and after planned CRT. Blood flow (BF), blood volume (BV), and permeability-surface area product (PSP) were quantified from CT images. Participants were categorized into responders and nonresponders according to therapy response. The Mann-Whitney test was used to compare the baseline perfusion values between responders and nonresponders, and the Wilcoxon matched-pairs signed rank test was used to compare perfusion values before and after CRT.ResultsThe final cohort of 21 participants (median age, 68 years; interquartile range [IQR], 65-72 years; eight men) underwent dynamic perfusion (dual-source) CT before neoadjuvant CRT. All participants underwent pancreatectomy. Eighteen participants underwent post-CRT perfusion CT. Baseline BF was higher in responders (n = 10) than in nonresponders (n = 11) (median, 44 [IQR, 39-56] vs 28 [IQR, 16-52] mL/100 g/min; P = .04), while BV and PSP were similar between groups (median BV, 4.3 [IQR, 3.5-6.9] vs 2.0 [IQR, 1.6-6.5] mL/100 g, P = .15; median PSP, 25 [IQR, 21-30] vs 20 [IQR, 10-34] mL/100 g/min, P = .31). Response Evaluation Criteria in Solid Tumors (RECIST) and carbohydrate antigen (CA) 19-9 showed no correlation with perfusion parameters (eg, RECIST and BF: r = 0.05, P = .84, 95% confidence interval [CI]: -0.40, 0.48; CA 19-9 and BF: r = 0.06, P = .78, 95% CI: -0.39, 0.49) or histopathologic response (r = 0.16, P = .47, 95% CI: -0.3, 0.57 and r = 0.09, P = .71, 95% CI: -0.37, 0.51, respectively). For responders, perfusion parameters increased after CRT (eg, median BF, 54 [IQR, 42-73] vs 43 [IQR, 28-53] mL/100 g/min; P = .04). The perfusion change in nonresponders was not significant (median BF, 43 [IQR, 28-53] vs 33 [IQR, 16-52] mL/100 g/min; P = .06).ConclusionPerfusion CT may be useful in helping predict the histopathologic response to therapy in pancreatic ductal adenocarcinoma.© RSNA, 2019See also the editorial by Sinitsyn in this issue.

Percutaneous Irreversible Electroporation as First-line Treatment of Locally Advanced Pancreatic Cancer.

BACKGROUND/AIM: Irreversible electroporation (IRE) has recently been used as an experimental ablation treatment following systemic chemotherapy in locally advanced pancreatic cancer (LAPC). The primary aim of this study was to evaluate survival of LAPC patients after IRE prior to chemotherapy. The secondary aim was to examine the complication rates. PATIENTS AND METHODS: Twenty-four patients with LAPC were included and treated with percutaneous ultrasound-guided IRE under general anesthesia. Survival data from the National Quality Registry for Pancreatic and Periampullary Cancer for LAPC during the same period were used for comparison. RESULTS: The median survival after diagnosis was 13.3 months in the IRE group compared to 9.9 months in the registry group (p=0.511). Six patients had a severe complication after IRE treatment. CONCLUSION: No obvious gain in survival was observed with IRE as the first line treatment of LAPC and IRE was associated with severe complications. This study does not support percutaneous IRE in this setting.

Comparison of pancreatic respiratory motion management with three abdominal corsets for particle radiation therapy: Case study.

BACKGROUND AND PURPOSE: Abdominal organ motion seriously compromises the targeting accuracy for particle therapy in patients with pancreatic adenocarcinoma. This study compares three different abdominal corsets regarding their ability to reduce pancreatic motion and their potential usability in particle therapy. MATERIALS AND METHODS: A patient-individualized polyurethane (PU), a semi-individualized polyethylene (PE), and a patient-individualized three-dimensional-scan based polyethylene (3D-PE) corset were manufactured for one healthy volunteer. Time-resolved volumetric four-dimensional-magnetic resonance imaging (4D-MRI) and single-slice two-dimensional (2D) cine-MRI scans were acquired on two consecutive days to compare free-breathing motion patterns with and without corsets. The corset material properties, such as thickness variance, material homogeneity in Hounsfield units (HU) on computed tomography (CT) scans, and manufacturing features were compared. The water equivalent ratio (WER) of corset material samples was measured using a multi-layer ionization chamber for proton energies of 150 and 200 MeV. RESULTS: All corsets reduced the pancreatic motion on average by 9.6 mm in inferior-superior and by 3.2 mm in anterior-posterior direction. With corset, the breathing frequency was approximately doubled and the day-to-day motion variations were reduced. The WER measurements showed an average value of 0.993 and 0.956 for the PE and 3DPE corset, respectively, and of 0.298 for the PU corset. The PE and 3DPE corsets showed a constant thickness of 2.8 ± 0.2 and 3.8 ± 0.2 mm, respectively and a homogeneous material composition with a standard deviation (SD) of 31 and 32 HU, respectively. The PU corset showed a variable thickness of 4.2 - 25.6 mm and a heterogeneous structure with air inclusions with an SD of 113 HU. CONCLUSION: Abdominal corsets may be effective devices to reduce pancreatic motion. For particle therapy, PE-based corsets are preferred over PU-based corset due to their material homogeneity and constant thickness.

Irreversible electroporation versus radiotherapy after induction chemotherapy on survival in patients with locally advanced pancreatic cancer: a propensity score analysis.

BACKGROUND: Locally advanced pancreatic cancer (LAPC) represents more than one third of pancreatic cancers and owns poor survival after the standard chemotherapy. Irreversible electroporation (IRE) is a novel method and has been recently used in LAPC. The aim of this study was to compare the efficacy of IRE and radiotherapy after induction chemotherapy for patients with LAPC. METHODS: From August 2015 to August 2017, a total of 76 patients with biopsy proven LAPC and who had received IRE or radiotherapy after chemotherapy were included. Thirty-two pairs of patients were selected through propensity score matching (PSM) analysis and the efficacy of two treatments was compared. RESULTS: Before PSM analysis, after induction chemotherapy, patients with LAPC benefited more in terms of overall survival (OS) and progression free survival (PFS) from IRE, compared with radiotherapy (2-year OS rates, 53.5% vs 26.9%, p = 0.039; 2-year PFS rates, 28.4% vs 13.3%, p = 0.045). After PSM analysis, the survival benefits of OS and PFS of patients after induction chemotherapy followed by IRE were more obvious than those of patients treated with radiotherapy (2-year OS rates, 53.5% vs 20.7%, p = 0.011; 2-year PFS rates, 28.4% vs 5.6%, p = 0.004). Multivariate Cox regression analysis indicated that IRE after induction chemotherapy was identified as a significant favourable factor for both OS and PFS in both the whole and matched cohort. CONCLUSIONS: Induction chemotherapy followed by IRE is superior to induction chemotherapy followed by radiotherapy for treating LAPC. A randomized clinical trial comparing the efficacy of IRE and radiotherapy after the induction chemotherapy is therefore considerable.