Diffusion-weighted MRI monitoring of pancreatic cancer response to radiofrequency heat-enhanced intratumor chemotherapy

Multiparametric detection and outcome prediction of pancreatic cancer involving dual-energy CT, diffusion-weighted MRI, and radiomics

BACKGROUND

The advent of next-generation computed tomography (CT)- and magnetic resonance imaging (MRI) opened many new perspectives in the evaluation of tumor characteristics. An increasing body of evidence suggests the incorporation of quantitative imaging biomarkers into clinical decision-making to provide mineable tissue information. The present study sought to evaluate the diagnostic and predictive value of a multiparametric approach involving radiomics texture analysis, dual-energy CT-derived iodine concentration (DECT-IC), and diffusion-weighted MRI (DWI) in participants with histologically proven pancreatic cancer.

METHODS

In this study, a total of 143 participants (63 years ± 13, 48 females) who underwent third-generation dual-source DECT and DWI between November 2014 and October 2022 were included. Among these, 83 received a final diagnosis of pancreatic cancer, 20 had pancreatitis, and 40 had no evidence of pancreatic pathologies. Data comparisons were performed using chi-square statistic tests, one-way ANOVA, or two-tailed Student's t-test. For the assessment of the association of texture features with overall survival, receiver operating characteristics analysis and Cox regression tests were used.

RESULTS

Malignant pancreatic tissue differed significantly from normal or inflamed tissue regarding radiomics features (overall P < .001, respectively) and iodine uptake (overall P < .001, respectively). The performance for the distinction of malignant from normal or inflamed pancreatic tissue ranged between an AUC of ≥ 0.995 (95% CI, 0.955-1.0; P < .001) for radiomics features, ≥ 0.852 (95% CI, 0.767-0.914; P < .001) for DECT-IC, and ≥ 0.690 (95% CI, 0.587-0.780; P = .01) for DWI, respectively. During a follow-up of 14 ± 12 months (range, 10-44 months), the multiparametric approach showed a moderate prognostic power to predict all-cause mortality (c-index = 0.778 [95% CI, 0.697-0.864], P = .01).

CONCLUSIONS

Our reported multiparametric approach allowed for accurate discrimination of pancreatic cancer and revealed great potential to provide independent prognostic information on all-cause mortality.

Radiofrequency Hyperthermia Enhances Locally Delivered Oncolytic Immuno-Virotherapy for Pancreatic Adenocarcinoma

PURPOSE

To investigate the effect of radiofrequency hyperthermia (RFH)-enhanced oncolytic immuno-virotherapy on in vitro pancreatic adenocarcinoma cell line and in vivo rat pancreatic cancer model.

MATERIALS AND METHODS

Rat pancreatic adenocarcinoma cell line and 24 Lewis rats with orthotopic pancreatic adenocarcinomas underwent treatment with either (1) oncolytic virotherapy (talimogene laherparepvec [T-VEC]) plus RFH at 42 °C for 30 min; (2) oncolytic virotherapy-only; (3) RFH-only; or (4) saline (control). MTS assays and flow cytometry were used to analyze tumor cell viability and apoptosis levels 24 h after treatment. In the in vivo studies, bioluminescence optical/x-ray imaging and ultrasound imaging was used to assess tumor viability and size 7 and 14 days after treatment. Histopathologic analysis was performed after hematoxylin and eosin staining, TUNEL, Ki-67, and immunohistochemical staining with CD8 and ANK61.

RESULTS

Combination therapy (T-VEC + RFH) induced decreased cell viability and increased cell apoptosis compared to T-VEC alone, RFH alone, or control. Optical/x-ray imaging and ultrasound imaging demonstrated decreased tumor bioluminescent signal and tumor volume relative to baseline after combination therapy compared to T-VEC alone, RFH alone, or control. Histopathology demonstrated decreased tumor volume and cell proliferation, increased CD8⁺ T cell and NK cell infiltration in tumors treated with the combination therapy compared to other three groups.

CONCLUSION

RFH enhances locally delivered oncolytic immuno-virotherapy for pancreatic adenocarcinoma, with decreased cell viability and increased apoptosis observed after combination therapy in vitro, and decreased cell viability and tumor volume and increased immune cell infiltrate observed after combination therapy in vivo.

Magnetic Fields and Cancer: Epidemiology, Cellular Biology, and Theranostics

Humans are exposed to a complex mix of man-made electric and magnetic fields (MFs) at many different frequencies, at home and at work. Epidemiological studies indicate that there is a positive relationship between residential/domestic and occupational exposure to extremely low frequency electromagnetic fields and some types of cancer, although some other studies indicate no relationship. In this review, after an introduction on the MF definition and a description of natural/anthropogenic sources, the epidemiology of residential/domestic and occupational exposure to MFs and cancer is reviewed, with reference to leukemia, brain, and breast cancer. The in vivo and in vitro effects of MFs on cancer are reviewed considering both human and animal cells, with particular reference to the involvement of reactive oxygen species (ROS). MF application on cancer diagnostic and therapy (theranostic) are also reviewed by describing the use of different magnetic resonance imaging (MRI) applications for the detection of several cancers. Finally, the use of magnetic nanoparticles is described in terms of treatment of cancer by nanomedical applications for the precise delivery of anticancer drugs, nanosurgery by magnetomechanic methods, and selective killing of cancer cells by magnetic hyperthermia. The supplementary tables provide quantitative data and methodologies in epidemiological and cell biology studies. Although scientists do not generally agree that there is a cause-effect relationship between exposure to MF and cancer, MFs might not be the direct cause of cancer but may contribute to produce ROS and generate oxidative stress, which could trigger or enhance the expression of oncogenes.

Natural killer cell-based adoptive transfer immunotherapy for pancreatic ductal adenocarcinoma in a KrasLSL-G12D p53LSL-R172H Pdx1-Cre mouse model

Natural killer (NK) cells play a pivotal role in host immunity against different malignancies, including pancreatic ductal adenocarcinoma (PDAC). Our study aimed to evaluate the antitumor effects of NK cell-based adoptive transfer immunotherapy for PDAC in an orthotopic mouse model. Orthotopic Kras^LSL-G12D p53^LSL-R172H Pdx1-Cre (KPC) mice were used to evaluate the therapeutic efficacy. Mouse NK cells (LNK cells) (1×10⁶) were intravenously injected to tumor-bearing mice once a week for 3 weeks. MRI measurements (tumor volume and apparent diffusion coefficient (ADC) values) and survival were compared between control and LNK treated tumors. Flow cytometry and enzyme-linked immunosorbent assay (ELISA) were used to determine LNK cells cytotoxicity and IFN-γ level, respectively. LNK cells can produce a higher level of IFN-γ and more effectively lyse PDAC cells compared with spleen NK cells in vitro. LNK-cell adoptive transfer therapy elicited potent in vivo antitumor activity, resulting in delayed tumor growth (P=0.033) in KPC mice. The ADC values at the last timepoint ((0.94±0.06)×10^-3 mm²/s) were significantly higher than that at first timepoint ((0.75±0.04)×10^-3 mm²/s) in treated tumors (P<0.001). ADC values were significantly different between control group and treated tumors at the last time point ((0.75±0.09)×10^-3 mm²/s vs (0.94±0.06)×10^-3 mm²/s, P=0.004) in KPC mice. Our data demonstrate the potential of NK cell-based adoptive transfer immunotherapy for PDAC treatment.

Bridging the translational gap: Implementation of multimodal small animal imaging strategies for tumor burden assessment in a co-clinical trial

In designing co-clinical cancer studies, preclinical imaging brings unique challenges that emphasize the gap between man and mouse. Our group is developing quantitative imaging methods for the preclinical arm of a co-clinical trial studying immunotherapy and radiotherapy in a soft tissue sarcoma model. In line with treatment for patients enrolled in the clinical trial SU2C-SARC032, primary mouse sarcomas are imaged with multi-contrast micro-MRI (T1 weighted, T2 weighted, and T1 with contrast) before and after immune checkpoint inhibition and pre-operative radiation therapy. Similar to the patients, after surgery the mice will be screened for lung metastases with micro-CT using respiratory gating. A systems evaluation was undertaken to establish a quantitative baseline for both the MR and micro-CT systems against which others systems might be compared. We have constructed imaging protocols which provide clinically-relevant resolution and contrast in a genetically engineered mouse model of sarcoma. We have employed tools in 3D Slicer for semi-automated segmentation of both MR and micro-CT images to measure tumor volumes efficiently and reliably in a large number of animals. Assessment of tumor burden in the resulting images was precise, repeatable, and reproducible. Furthermore, we have implemented a publicly accessible platform for sharing imaging data collected during the study, as well as protocols, supporting information, and data analyses. In doing so, we aim to improve the clinical relevance of small animal imaging and begin establishing standards for preclinical imaging of tumors from the perspective of a co-clinical trial.

PET/CT in brachytherapy early response evaluation of pancreatic ductal adenocarcinoma xenografts: comparison with apparent diffusion coefficient from diffusion-weighted MR imaging

OBJECTIVE

To evaluate the feasibility of using PET/CT and diffusion-weighted magnetic resonance imaging (DW-MRI) to monitor the early response of pancreatic ductal adenocarcinoma (PDAC) xenografts to brachytherapy, and to determine whether maximum standardized uptake value (SUVmax) correlate with apparent diffusion coefficient (ADC).

MATERIALS AND METHODS

SW1990 human PDAC were subcutaneously implanted in 20 nude mice. They were randomly divided into 125-Iodine (125I) seeds and blank seeds group. PET/CT and DW-MRI were performed at pretreatment and 5 days after therapy. SUVmax and ADC values were calculated, respectively. The correlation between SUVmax and ADC values was analyzed by the Pearson correlation test.

RESULTS

The SUVmax were significantly decreased between pretreatment and 5 days after 125I seeds treatment (p < 0.001) and between two groups (p < 0.001). And the ADC values were significantly increased between pretreatment and 5 days after 125I seeds treatment (p < 0.001) and between two groups (p < 0.001). While in the bank seeds group, there were no significantly difference between pretreatment and after treatment in SUVmax and ADC values (p = 0.057; p = 0.397). SUVmax and ADC correlated significantly and negatively before treatment in both groups (r = - 0.964, R2 = 0.929, p < 0.001; r = - 0.917, R2 = 0.841, p < 0.001) and after treatment in the blank seeds group (r = - 0.944, R2 = 0.891, p < 0.001). But after 125I seeds treatment there was no significant correlation between SUVmax and ADC (r = - 0.388, R2 = 0.151, p = 0.268).

CONCLUSION

The PET/CT and DW-MRI are capable of monitoring the early response of PDAC xenografts to brachytherapy. The significantly inverse correlation between pretreatment SUVmax and ADC suggests that PET/CT and DW-MRI might play complementary roles for therapy assessment.

Intratumoral radiofrequency hyperthermia-enhanced chemotherapy of liposomal doxorubicin on hepatocellular carcinoma

PURPOSE

To investigate the possibility of using radiofrequency hyperthermia (RFH) to enhance intratumoral therapeutic effect of liposomal doxorubicin on hepatocellular carcinoma (HCC) via an interventional molecular imaging approach.

MATERIALS AND METHODS

For both in-vitro confirmation and in-vivo validation, Luciferase/mCherry-labeled human HCC cells (HepG2) and mice subcutaneous hepatic cancer xenografts were treated by: (i) combination therapy of liposomal doxorubicin plus RFH at 42°C; (ii) liposomal doxorubicin alone; (iii) RFH at 42°C alone; (iv) phosphate buffered saline (PBS) as a control. For in-vitro confirmation, MTS assay, confocal microscopy, optical imaging and flow cytometry were used to evaluate and compare cell viabilities and apoptosis among different treatment groups. For in vivo validation, liposomal doxorubicin was directly injected into the tumor and RFH was performed subsequently under ultrasound imaging guidance. Changes of tumor sizes were quantified using ultrasound imaging and bioluminescence signal intensities after treatments were measured by optical imaging over 14 days, which were correlated with subsequent histology analysis.

RESULTS

Of in vitro experiments, MTS assay demonstrated the lowest cell proliferation in combination therapy group compared with the other three groups (25.0 ± 5.6% vs 49.7 ± 5.2% vs 94.2 ± 3.9% vs 100%, respectively, P < 0.001). Flow cytometry showed the highest percentage of early apoptotic HepG2 cells in combination therapy compared to the other three groups (37.9 ± 3.2% vs 32.2 ± 1.7% vs 2.9 ± 1.7% vs 1.8 ± 0.7%, respectively, P < 0.001). Of in vivo experiments, optical imaging demonstrated a significantly decreased bioluminescence signal intensities in the combination therapy group, compared with the other three groups (0.53 ± 0.10 VS 1.4 ± 0.5 VS 2.8 ± 0.8 VS 3.0 ± 0.3, P < 0.05). Ultrasound images showed the smallest tumor volumes of the combination therapy group, in comparison to other control groups (0.7 ± 0.1 VS 1.8 ± 0.4 VS 3.0 ± 0.8 VS 3.3 ± 0.3, P < 0.05). Both histologic correlation confirmed imaging findings.

CONCLUSION

RFH can enhance intratumoral therapy with liposomal doxorubicin for HCC, which is effectively monitored by ultrasound imaging and optical imaging techniques. This concept may provide new avenues for eradicating the residual tumor cells when combining RFA with interventional molecular imaging guided direct intratumoral chemotherapy of HCC.

Early Response Assessment in Pancreatic Ductal Adenocarcinoma Through Integrated PET/MRI

OBJECTIVE

The purpose of this study is to investigate early changes in ¹⁸F-FDG PET/MRI metrics after treatment in patients with advanced pancreatic ductal adenocarcinoma (PDAC) and to correlate those changes with eventual tumor response at standard-of-care CT.

SUBJECTS AND METHODS

Thirteen patients with advanced PDAC underwent integrated FDG PET/MRI before and 4 weeks after treatment initiation. Patients were classified as responders or nonresponders according to Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 at subsequent CT performed 8-12 weeks after treatment initiation. Changes in the primary tumor's maximum standardized uptake value (SUV_max), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) determined at PET and apparent diffusion coefficient (ADC) determined at DWI at 4 weeks were compared between responders and nonresponders.

RESULTS

Seven patients had a partial response according to RECIST, and six did not. Responders displayed significantly greater decreases in MTV (p = 0.003) and TLG (p = 0.006) in the primary pancreatic tumor at 4 weeks. Responders also displayed a greater increase in the mean (p = 0.004) and minimum (p = 0.024) ADC of the primary tumors. Tumor size change at 4 weeks was not significantly different between responders and nonresponders (p = 0.11). PET responders enjoyed longer progression-free survival (PFS) (p = 0.0004) and overall survival (OS) (p = 0.013) than did nonresponders, using either a 60% reduction in MTV or 65% reduction in TLG as a threshold. MRI responders had significantly longer PFS (p = 0.0002) and OS (p = 0.027) than did nonresponders, using a 20% increase in either mean or minimum ADC as a threshold.

CONCLUSION

Integrated PET/MRI can provide early response assessment in patients with advanced PDAC, thus potentially allowing early treatment adaptation in nonresponders.

Intratumoral radiofrequency hyperthermia-enhanced direct chemotherapy of pancreatic cancer

Purpose

To investigate the technical feasibility of using ultrasound-guided intratumoral radiofrequency hyperthermia (RFH) to enhance local chemotherapy of rat orthotopic pancreatic cancers.

Materials and Methods

Orthotopic pancreatic cancer masses were established by inoculating luciferase/mCherry labeled-pancreatic cancer cells into the pancreatic tails of Lewis model rats via a laparotomy approach. Twenty-four rats with pancreatic cancer and 24 mice with subcutaneous pancreatic cancer xenografts in four study groups (n = 6/group) received various treatments: i) combination therapy of intratumoral MR imaging-heating-guidewire-mediated RFH (42^oC) plus local chemotherapy (gemcitabine); ii) intratumoral chemotherapy alone; iii) RFH alone; and (iv)phosphate-buffered saline (PBS). Transcutaneous ultrasound imaging was used to guide the treatment and subsequently follow changes in tumor sizes. Bioluminescence optical imaging was performed to follow photon signal changes. Sonographic and optical findings were correlated with histology at 14 days.

Results

Optical imaging demonstrated a significantly decreased bioluminescence signal in mice with combination therapy group, compared with the other control groups (0.51±0.18 VS 1.6±0.4 VS 3.18±0.9 VS 3.5±0.96, p < 0.05). Ultrasound imaging showed the smallest tumor volumes of both mice and rat group with the combination therapy, compared with other control groups (0.62±0.16 VS 1.25±0.19 VS 2.28±0.25 VS 2.64±0.26, p < 0.05) and (0.75±0.18 VS 1.31±0.30 VS 1.61±0.28 VS 1.72±0.28, p < 0.05). Both imaging findings were confirmed by histologic correlation.

Conclusion

Intratumoral RFH can augment the chemotherapeutic effect in an orthotopic pancreatic cancer model.

Radiofrequency hyperthermia promotes the therapeutic effects on chemotherapeutic-resistant breast cancer when combined with heat shock protein promoter-controlled HSV-TK gene therapy: Toward imaging-guided interventional gene therapy

Objective

Gene therapy is a frontier in modern medicine. In the present study, we explored a new technique for the effective treatment of multidrug-resistant (MDR) breast cancer by combining fully the advantages of multidisciplinary fields, including image-guided minimally invasive interventional oncology, radiofrequency technology, and direct intratumoral gene therapy.

Results

Combination treatment with P_HSP-TK plus RFH resulted in significantly higher TK gene transfection/expression, as well as a lower cell proliferation rate and a higher cell apoptosis index, than those of control groups. In vivo validation experiments with MRI confirmed that combination therapy resulted in a significant reduction of relative tumor volume compared with those of control animals, which was supported by the results of histologic and apoptosis analyses.

Materials and methods

The heat shock protein promoter (P_HSP) was used to precisely control the overexpression of thymidine kinase (TK) (P_HSP-TK). Serial in vitro experiments were performed to confirm whether radiofrequency hyperthermia (RFH) could enhance P_HSP-TK transfection and expression in a MDR breast cancer cell line (MCF7/Adr). Serial in vivo experiments were then carried out to validate the feasibility of the new technique, termed interventional RFH-enhanced direct intratumoral P_HSP-TK gene therapy. The therapeutic effect of combination therapy was evaluated by MRI and confirmed by subsequent laboratory correlation.

Conclusions

This study has established “proof-of-principle” of a new technique, interventional RFH-enhanced local gene therapy for MDR breast cancer, which may open new avenues for the effective management of MDR breast cancers via the simultaneous integration of interventional oncology, RF technology, and direct intratumoral gene therapy.

Radiofrequency heat-enhanced direct intratumoral chemotherapy for prostate cancer

A novel, minimally invasive interventional technique, radiofrequency heat (RFH), has been suggested to improve the efficacy of chemotherapy for solid organ tumors. However, the treatment for prostate cancer has not been completely characterized. The aim of the present study was to investigate the in vitro and in vivo efficiency of chemotherapy in combination with RFH for the treatment of prostate cancer. The following four treatment groups were included: i) No treatment (control); ii) RFH-only; iii) chemotherapy (docetaxel)-only; and iv) combination therapy of docetaxel and RFH in human prostate cancer (HPC) cell lines and mice with HPC xenografts. In the in vitro experiments, a heating guidewire was attached under the bottom of the last chamber of the four-chamber cell culture slide, and was then connected to a radiofrequency (RF) generator. In the in vivo experiments, a tumor model was generated by subcutaneously injecting human prostate cancer cells into 24 male nu/nu mice. RFH was conducted by inserting the 0.022-inch heating-guidewire into the tumor. The follow-up magnetic resonance imaging demonstrated a significant reduction in the average tumor size in animals treated with combination therapy compared with those receiving RFH-only and chemotherapy-only. The number of apoptotic cells and the average apoptotic index of the combination therapy group were significantly higher compared with those of the other three treatment groups. In conclusion, the results of the present study suggested that RFH is able to increase the therapeutic efficiency of docetaxel in prostate cancer, and this study serves as a foundation for the future development of an interventional molecular image-guided local treatment strategy for prostate cancer that integrates RF technology, interventional oncology and direct intratumoral chemotherapy, as a replacement for systemic chemotherapy.

The clinical benefit of hyperthermia in pancreatic cancer: a systematic review

OBJECTIVE

In pancreatic cancer, which is therapy resistant due to its hypoxic microenvironment, hyperthermia may enhance the effect of radio(chemo)therapy. The aim of this systematic review is to investigate the validity of the hypothesis that hyperthermia added to radiotherapy and/or chemotherapy improves treatment outcome for pancreatic cancer patients.

METHODS AND MATERIALS

We searched MEDLINE and Embase, supplemented by handsearching, for clinical studies involving hyperthermia in pancreatic cancer patients. The quality of studies was evaluated using the Oxford Centre for Evidence-Based Medicine levels of evidence. Primary outcome was treatment efficacy; we calculated overall response rate and the weighted estimate of the population median overall survival (m_p) and compared these between hyperthermia and control cohorts.

RESULTS

Overall, 14 studies were included, with 395 patients with locally advanced and/or metastatic pancreatic cancer of whom 248 received hyperthermia. Patients were treated with regional (n = 189), intraoperative (n = 39) or whole-body hyperthermia (n = 20), combined with chemotherapy, radiotherapy or both. Quality of the studies was low, with level of evidence 3 (five studies) and 4. The six studies including a control group showed a longer m_p in the hyperthermia groups than in the control groups (11.7 vs. 5.6 months). Overall response rate, reported in three studies with a control group, was also better for the hyperthermia groups (43.9% vs. 35.3%).

CONCLUSIONS

Hyperthermia, when added to chemotherapy and/or radiotherapy, may positively affect treatment outcome for patients with pancreatic cancer. However, the quality of the reviewed studies was limited and future randomised controlled trials are needed to establish efficacy.

Multi-modality imaging-monitored creation of rat orthotopic pancreatic head cancer with obstructive jaundice

Purpose

To investigate the feasibility of using multi-modality imaging to monitor the creation of rat models with orthotopic pancreatic head cancer with obstructive jaundice.

Results

27 of 52 rats (51.92%) developed pancreatic head cancer. The tumor formation rate was significantly higher in the animal group receiving bioluminescent tumor, compared to the group receiving non-bioluminescent donor tumors [78.1% (25/32 rats) vs 10.0% (2/20 rats), P = 0.0001]. Both ultrasound imaging and MRI clearly characterized the orthotopic tumors. Laboratory biochemistry test for those rats with obstructive jaundice showed elevated levels of bilirubin, aspartate transaminase (AST), alkaline phosphatase (ALT) and gamma-glutamyl transpeptidase (λ-GGT), compared with those rats without jaundice (P < 0.05). Correlative pathology confirmed that all tumors were ductal adenocarcinomas, and located in pancreatic head regions.

Materials and Methods

Rat pancreatic adenocarcinoma cells (DSL-6A/C1) were first transfected with lentivirus/mCherry-luciferase genes, and then subcutaneously implanted into flanks of donor immunocompetent Lewis rats, to create pancreatic tumor tissues. The tumor tissues from donor rats with either bioluminescence signal or without the signal were then transplanted into the pancreatic heads of 52 recipient Lewis rats. Bioluminescence optical and ultrasound imaging, as well as magnetic resonance imaging (MRI), were performed to follow up the tumor formation and growth in these tumor-transplanted rats. Physical examination and biochemistry test were used to discern the rats with obstructive jaundice. The rats were euthanized for subsequent histologic correlation and confirmation.

Conclusions

We successfully created a new rat model with orthotopic pancreatic head cancer, which can be accurately monitored and visualized by different imaging modalities.

Radiofrequency hyperthermia-enhanced herpes simplex virus-thymidine kinase/ganciclovir direct intratumoral gene therapy of hepatocellular carcinoma

PURPOSE

To determine the feasibility of using radiofrequency hyperthermia (RFH) and to enhance the therapeutic effect of herpes simplex virus-thymidine kinase/ganciclovir (HSV-TK/GCV) for the treatment of hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Human HCC cells (HepG2) were first transfected with lentivirus/luciferase. For both in vitro confirmation and in vivo validation, luciferase-labeled HCC cells and HCC tumour xenografts on mice received different treatments: (i) combination therapy of intratumoral HSV-TK/GCV-mediated gene therapy plus magnetic resonance imaging heating guidewire (MRIHG)-mediated RFH; (ii) gene therapy only; (iii) RFH only; and (iv) phosphate-buffered saline (PBS) as control. Cell proliferation was quantified. Tumour changes were monitored by ultrasound imaging and bioluminescence optical imaging before and at days 7 and 14 after treatments, which were correlated with subsequent histology.

RESULTS

In vitro, the lowest cell proliferation was seen in the combination therapy group compared with control groups (29 ± 6% vs. 56 ± 9%, 93 ± 4%, and 100 ± 5%, p < .05). Ultrasound imaging of treated animal xenografts showed smaller relative tumour volume in combination therapy group than those in three control groups (0.74 ± 0.19 vs. 1.79 ± 0.24, 3.14 ± 0.49 and 3.22 ± 0.52, p < .05). Optical imaging demonstrated significant decrease of bioluminescence signals of tumours in the combination therapy group, compared to those in three control groups (1.2 ± 0.1 vs. 1.9 ± 0.2% vs. 3.3 ± 0.6% vs. 3.5 ± 0.4%, p < .05). These imaging findings were correlated well with histologic confirmation.

CONCLUSION

RFH can enhance HSV-TK/GCV-mediated gene therapy of HepG2 cell line and mice human HCC xenografts, which may open new avenues for effective management of HCC using MR/RFH integrated interventional gene therapy.

Radiofrequency hyperthermia-enhanced herpes simplex virus-thymidine kinase/ganciclovir direct intratumoral gene therapy of esophageal squamous cancers

Despite recent advances in surgical technique and treatment strategies for esophageal cancer (EC), to effectively manage the advanced (metastatic or disseminated) and recurrent EC still remain a great challenge. The aim of this study was to determine the feasibility of using intra-esophagus radiofrequency hyperthermia to enhance local HSV-TK/ganciclovir-mediated suicide gene therapy of an innovative animal models with orthotopic esophageal squamous cancers. Human esophageal squamous cancer (ESCa) cells were labeled with lentivirus/luciferase. ESCa cells and nude rats with orthotopic ESCa were divided into in four groups (n = 6/group) and treated with: i) combination therapy of MR imaging-heating-guidewire-mediated radiofrequency hyperthermia ((RFH, 42°C) plus local HSV-TK/GCV; ii) HSV-TK/GCV alone; iii) RFH alone; and (iv) phosphate-buffered saline (PBS). Bioluminescence optical imaging and transcutaneous ultrasound imaging were used to follow up bioluminescence signal and size changes of tumors among different groups over two weeks, which were correlated with subsequent histology. We demonstrated that combination therapy of RFH with gene therapy resulted in the lowest cell proliferation (37.5±8.6%, P<0.0001), rendered the smallest relative tumor volume (0.90±0.15, P<0.01), and relative bioluminescence optical imaging photon signal intensity (0.81±0.17, P<0.01) of orthotopic esophageal cancers, compared with groups treated with gene therapy alone, RFH alone and PBS. Our study indicated that intra-esophageal radiofrequency hyperthermia could enhance the HSV-TK-mediated effect on esophageal squamous cancers.

Orthotopic Esophageal Cancers: Intraesophageal Hyperthermia-enhanced Direct Chemotherapy in Rats

Purpose To determine the feasibility of using intraesophageal radiofrequency (RF) hyperthermia to enhance local chemotherapy in a rat model with orthotopic esophageal squamous cancers. Materials and Methods The animal protocol was approved by the institutional animal care and use committee and the institutional review board. Human esophageal squamous cancer cells were transduced with luciferase lentiviral particles. Cancer cells, mice with subcutaneous cancer esophageal xenografts, and nude rats with orthotopic esophageal cancers in four study groups of six animals per group were treated with (a) combination therapy of magnetic resonance imaging heating guidewire-mediated RF hyperthermia (42°C) plus local chemotherapy (cisplatin and 5-fluorouracil), (b) chemotherapy alone, (c) RF hyperthermia alone, and (d) phosphate-buffered saline. Bioluminescent optical imaging and transcutaneous ultrasonographic imaging were used to observe bioluminescence signal and changes in tumor size among the groups over 2 weeks, which were correlated with subsequent histologic results. The nonparametric Mann-Whitney U test was used for comparisons of variables. Results Compared with chemotherapy alone, RF hyperthermia alone, and phosphate-buffered saline, combination therapy with RF hyperthermia and chemotherapy induced the lowest cell proliferation (relative absorbance of formazan: 23.4% ± 7, 44.6% ± 7.5, 95.8% ± 2, 100%, respectively; P < .0001), rendered the smallest relative tumor volume (0.65 mm³ ± 0.15, P < .0001) and relative bioluminescence optical imaging photon signal (0.57 × 10⁷ photons per second per square millimeter ± 0.15, P < .001) of mice with esophageal cancer xenografts, as well as the smallest relative tumor volume (0.68 mm³ ± 0.13, P < .05) and relative photon signal (0.56 × 10⁷ photons per second per square millimeter ± 0.11. P < .001) of rat orthotopic esophageal cancers. Conclusion Intraesophageal RF hyperthermia can enhance the effect of chemotherapy on esophageal squamous cell cancers. ^© RSNA, 2016.

Predicting liver metastasis of gastrointestinal tract cancer by diffusion-weighted imaging of apparent diffusion coefficient values

AIM: To determine if efficacy of chemotherapy on liver metastasis of gastrointestinal tract cancer can be predicted by apparent diffusion coefficient (ADC) values of diffusion-weighted imaging (DWI).

METHODS: In total, 86 patients with liver metastasis of gastrointestinal tract cancer (156 metastatic lesions) diagnosed in our hospital were included in this study. The maximum diameters of these tumors were compared with each other before treatment, 2 wk after treatment, and 12 wk after treatment. Selected patients were classified as the effective group and the ineffective group, depending on the maximum diameter of the tumor after 12 wk of treatment; and the ADC values at different treatment times between the two groups were compared. Spearman rank correlation was used to analyze the relationship between ADC value and tumor diameter. Receiver operating characteristic curve (ROC curve) was used to analyze the ADC values before treatment to predict the patient’s sensitivity and specificity degree of efficacy to the chemotherapy.

RESULTS: There was no difference in age between the two groups and in maximum tumor diameter before treatment and 2 wk after treatment. However, after 12 wk of treatment, maximum tumor diameter in the effective group was significantly lower than that in the ineffective group (P < 0.05). Before treatment, ADC values in the ineffective group were significantly higher than those in the effective group (P < 0.05). There was no difference in ADC values between the effective and ineffective groups after 2 and 12 wk of treatment. However, ADC values were significantly higher after 2 and 12 wk of treatment compared to before treatment in the effective group (P < 0.05). Spearman rank correlation analysis showed that ADC value before treatment and the reduced percentage of the maximum tumor diameter after 12 wk of treatment were negatively correlated, while the increase in the percentage of the ADC value 12 wk after treatment and the decrease in the percentage of the maximum tumor diameter were significantly positively correlated. The results of the ROC curve showed that ADC value with a chemotherapy ineffective threshold value of 1.14 × 10^-3 mm²/s before treatment had a sensitivity and specificity of 94.3% and 76.7%, respectively.

CONCLUSION: DWI ADC values can be used to predict the response of patients with liver metastasis of gastrointestinal tract cancer to chemotherapy with high sensitivity and relatively high specificity.

Molecular Imaging-Guided Interventional Hyperthermia in Treatment of Breast Cancer

Breast cancer is the most frequent malignancy in women worldwide. Although it is commonly treated via chemotherapy, responses vary among its subtypes, some of which are relatively insensitive to chemotherapeutic drugs. Recent studies have shown that hyperthermia can enhance the effects of chemotherapy in patients with refractory breast cancer or without surgical indications. Recent advances in molecular imaging may not only improve early diagnosis but may also facilitate the development and response assessment of targeted therapies. Combining advanced techniques such as molecular imaging and hyperthermia-integrated chemotherapy should open new avenues for effective management of breast cancer.

Radiofrequency heat-enhanced chemotherapy for breast cancer: towards interventional molecular image-guided chemotherapy

Breast cancer is the most common malignancy in women worldwide. Recent developments in minimally invasive interventional radiology techniques have significantly improved breast cancer treatment. This study aimed to develop a novel technique for the local management of breast cancers using radiofrequency heat (RFH). We performed both in vitro experiments using human breast cancer cells and in vivo validation in xenograft animal models with magnetic resonance imaging (MRI) and pathological correlation to investigate the feasibility of our approach. Four treatment groups, including (1) no treatment (control), (2) RFH-only, (3) chemo (doxorubicin)-only, and (4) combination therapy with both doxorubicin and RFH, were conducted in each experiment. In vitro combination therapy significantly decreased breast cancer cell proliferation while increased their apoptosis index compared to the other three groups. MRI demonstrated a significant tumor size reduction in animals treated with combination therapy compared to those receiving other treatments in vivo. Such result was further confirmed by pathological examination. In conclusion, our findings suggests that RFH can enhance the therapeutic efficiency of doxorubicin on breast cancers, thus establishing the basis for future development of interventional molecular image-guided local chemotherapy for breast malignancies.