Regional hyperthermia for soft tissue sarcoma - a survey on current practice, controversies and consensus among 12 European centers.

PURPOSE: To analyze the current practice of regional hyperthermia (RHT) for soft tissue sarcoma (STS) at 12 European centers to provide an overview, find consensuses and identify controversies necessary for future guidelines and clinical trials. METHODS: In this cross-sectional survey study, a 27-item questionnaire assessing clinical subjects and procedural details on RHT for STS was distributed to 12 European cancer centers for RHT. RESULTS: We have identified seven controversies and five consensus points. Of 12 centers, 6 offer both, RHT with chemotherapy (CTX) or with radiotherapy (RT). Two centers only offer RHT with CTX and four centers only offer RHT with RT. All 12 centers apply RHT for localized, high-risk STS of the extremities, trunk wall and retroperitoneum. However, eight centers also use RHT in metastatic STS, five in palliative STS, eight for superficial STS and six for low-grade STS. Pretherapeutic imaging for RHT treatment planning is used by 10 centers, 9 centers set 40-43 °C as the intratumoral target temperature, and all centers use skin detectors or probes in body orifices for thermometry. DISCUSSION: There is disagreement regarding the integration of RHT in contemporary interdisciplinary care of STS patients. Many clinical controversies exist that require a standardized consensus guideline and innovative study ideas. At the same time, our data has shown that existing guidelines and decades of experience with the technique of RHT have mostly standardized procedural aspects. CONCLUSIONS: The provided results may serve as a basis for future guidelines and inform future clinical trials for RHT in STS patients.

Regional hyperthermia with cisplatin added to gemcitabine versus gemcitabine in patients with resected pancreatic ductal adenocarcinoma: The HEAT randomised clinical trial.

BACKGROUND: Regional hyperthermia (RHT) with cisplatin added to gemcitabine showed efficacy in gemcitabine-pre-treated patients with advanced pancreatic ductal adenocarcinoma. We conducted a randomised clinical trial to investigate RHT with cisplatin added to gemcitabine (GPH) compared with gemcitabine (G) in the adjuvant setting of resected pancreatic ductal adenocarcinoma. METHODS: This randomised, multicentre, open-label trial randomly assigned patients to either GPH (gemcitabine 1000 mg/m2 on day 1, 15 and cisplatin 25 mg/m2 with RHT on day 2, 3 and 15,16) or to G (gemcitabine 1000 mg/m2 on day 1,8,15), four-weekly over six cycles. Disease-free survival (DFS) was the primary end-point. Secondary end-points included overall survival (OS) and safety. RESULTS: A total of 117 eligible patients (median age, 63 years) were randomly allocated to treatment (57 GPH; 60 G). With a follow-up time of 56.6 months, the median DFS was 12.7 compared to 11.2 months for GPH and G, respectively (p = 0.394). Median post-recurrence survival was significantly prolonged in the GPH-group (15.3 versus 9.8 months; p = 0.031). Median OS reached 33.2 versus 25.2 months (p = 0.099) with 5-year survival rates of 28.4% versus 18.7%. Excluding eight patients who received additional capecitabine in the G-arm (investigators choice), median OS favoured GPH (p = 0.052). Adverse events CTCAE (Common Terminology Criteria for Adverse Events) grade ≥3 occurred in 61.5% (GPH) versus 63.6% (G) of patients. Two patients in the G-group died because of treatment-related toxic effects. CONCLUSIONS: The randomised controlled Hyperthermia European Adjuvant Trial study failed to demonstrate a significant difference in DFS. However, it suggests a difference in post-recurrence survival and a trend for improved OS. CLINICALTRIALS: gov, number NCT01077427.

VISTA in Soft Tissue Sarcomas: A Perspective for Immunotherapy?

(1) Background: V domain immunoglobulin suppressor of T cell activation (VISTA) plays a critical role in antitumor immunity and may be a valuable target in cancer immunotherapy. To date, it has never been studied in a large and well-characterised cohort of soft tissue sarcomas (STS). (2) Methods: Using immunohistochemistry, we examined VISTA expression in tumour tissues of 213 high-risk STS. We then analysed whether VISTA was associated with other clinicopathological parameters, including tumour-infiltrating lymphocyte (TIL) counts, programmed death receptor-1 (PD1), programmed death ligand-1 (PDL1), CD3, grading, and long-term survival. (3) Results: We observed VISTA expression in 96 (45%) of 213 specimens with distinct patterns ranging from 26 to 63% for histological subtypes. VISTA was associated with higher grade (G3 vs. G2, p = 0.019), higher TIL counts (p = 0.033), expression of PD1 (p = 0.046), PDL1 (p = 0.031), and CD3+ (p = 0.023). In patients without CD3+ TILs, 10-year survival was higher when VISTA was expressed compared to when there was no VISTA expression (p = 0.013). In a multivariate analysis, VISTA expression was independently associated with prolonged survival (p = 0.043). (4) Conclusions: VISTA is expressed in different STS subtypes and is associated with increased TILs, PD-1, PD-L1, and CD3 expression. Patients with VISTA+ tumours show improved survival. These results may help define future immunotherapeutic approaches in STS.

Immune infiltrates in patients with localised high-risk soft tissue sarcoma treated with neoadjuvant chemotherapy without or with regional hyperthermia: A translational research program of the EORTC 62961-ESHO 95 randomised clinical trial.

BACKGROUND: The EORTC 62961-ESHO 95 randomised trial showed improved long-term survival of patients with high-risk soft-tissue sarcoma by adding regional hyperthermia to neoadjuvant chemotherapy. We hypothesised that immune infiltrate of patients treated with neoadjuvant therapy associate with clinical outcome. METHODS: Tumour infiltrating lymphocytes (TILs) and CD8, FOXP3, PD-1, and PD-L1 were evaluated in sequential biopsies of patients after four cycles of therapy. RESULTS: From a subgroup of 109 patients who had been randomised between July 1997 and November 2006 to neoadjuvant chemotherapy (53 patients) or neoadjuvant chemotherapy with regional hyperthermia (56 patients), 137 biopsies were obtained. TILs increased in paired second biopsies independent of treatment allocation (p < 0.001). FOXP3 regulatory T cells decreased (p = 0.002), and PD-L1 expression of tumours became undetectable. In the multivariate analysis, post-treatment high TILs correlated to LPFS (HR: 0.34; 95% CI 0.15-0.75; p = 0.008) and DFS (HR: 0.38; 95% CI 0.17-0.82; p = 0.015). In comparing post-treatment immune infiltrate between treatment arms, tumour response was associated with neoadjuvant chemotherapy with regional hyperthermia (p = 0.013) and high TILs (p = 0.064). High CD8 cell infiltration was associated with improved LPFS (HR: 0.27; 95% CI 0.09-0.79; Log-rank p = 0.011) and DFS (HR: 0.25; 95% CI 0.09-0.73; Log-rank p = 0.006). Improved survival at 10 years was associated with immune infiltrate after neoadjuvant chemotherapy with regional hyperthermia. CONCLUSION: Preoperative therapy re-programs a non-inflamed tumour at baseline into an inflamed tumour. The post-treatment immune infiltrate became predictive for clinical outcomes. The combination with regional hyperthermia primes the tumour microenvironment, enabling enhanced anti-tumour immune activity in high-risk soft tissue sarcomas. TRIAL REGISTRATION: ClinicalTrials.gov, NCT00003052.

Neoadjuvant Chemoradiation Combined with Regional Hyperthermia in Locally Advanced or Recurrent Rectal Cancer.

BACKGROUND: To prospectively analyze feasibility and pathological complete response (pCR) rates of neoadjuvant chemoradiotherapy combined with regional hyperthermia (RHT) in patients with locally advanced (LARC) or recurrent (LRRC) rectal cancer. METHODS: between 2012 and 2018, 111 patients with UICC stage IIB-IV or any locally recurrent rectal cancer were included (HyRec-Trial, ClinicalTrials.gov Identifier: NCT01716949). Patients received radiotherapy with concurrent 5-Fluororuracil (5-FU)/Capecitabine and Oxaliplatin, and RHT. Stage 1 feasibility analysis evaluated dose-limiting toxicities (DLT) after 19 patients, stage 2 after 59 evaluable patients. Analysis of the pCR rate was based on histopathological reports. RESULTS: the feasibility rates for stages 1 and 2 were 90% (17/19) and 73% (43/59), respectively. In the intention-to-treat population the pCR rate was 19% (20/105; 90% confidence interval (CI) 13.0-26.5). In the per-protocol-analysis, complete tumor regression was seen in 28% (18/64) and 38% (3/8) of the patients with LARC and LRRC, respectively. Complete resection rates (R0) among patients with LARC and LRRC who received surgery were 99% (78/84) and 67% (8/12). CONCLUSIONS: the intensified neoadjuvant and multimodality treatment schedule was feasible and led to comparable early toxicity rates as described by other trials that used the similar chemoradiation protocol. The presented treatment regimen resulted in a very high pCR rate and appears as a promising option for patients with LRRC.

Perioperative chemotherapy and regional hyperthermia for high-risk adult-type soft tissue sarcomas.

A group of patients with adult-type soft tissue sarcoma is at high risk of local recurrence and distant metastases. Age, tumour site, histological subtype, tumour size and grade have been identified as the most important independent adverse prognostic factors. Macroscopically complete tumour resection is considered as the mainstay of treatment with the addition of preoperative or postoperative radiotherapy for extremity or trunk localisation. Retroperitoneal localisation requires compartmental resection and is associated with a worse prognosis. Here, radiotherapy is of no proven value. Perioperative chemotherapy is considered to treat micrometastatic disease not detectable at the time of diagnosis. The neoadjuvant application gives the risk of distant metastasis the greatest importance as therapy is carried out at the earliest possible time, whereas adjuvant chemotherapy is delayed by surgery and the necessary wound healing. With reported response rates up to 30%, both the operability may be improved and the risk of intraoperative tumour cell dissemination may be reduced, resulting also in reduced local relapse rates. However, the potential risk of early tumour progression may counteract this benefit. Optimised strategies with multimodality approaches including chemotherapy, regional hyperthermia (RHT) and immunotherapeutic agents have been shown to improve survival in high-risk patients. Here, we focus on the data from available randomised studies investigating the use of perioperative chemotherapy in patients with high-risk adult-type soft tissue sarcoma, including the use of RHT for local enhancement of chemotherapy effect and immune induction.

Cancer Testis Antigens and Immunotherapy: Expression of PRAME Is Associated with Prognosis in Soft Tissue Sarcoma.

(1) Background: PRAME, NY-ESO-1, and SSX2 are cancer testis antigens (CTAs), which are expressed in testicular germ cells with re-expression in numerous cancer types. Their ability to elicit humoral and cellular immune responses have rendered them promising targets for cancer immunotherapy, but they have never been studied in a large and well-characterised cohort of soft tissue sarcomas (STS). (2) Methods: On a protein level, we examined PRAME, NY-ESO-1, and SSX2 expression in tumour tissues of 249 high-risk STS using immunohistochemistry. We correlated expression levels with clinicopathological parameters including tumour-infiltrating lymphocyte (TIL) counts, grading, and long-term survival. (3) Results: Expression of PRAME, NY-ESO-1, and SSX2 was observed in 25 (10%), 19 (8%), and 11 (4%) of 249 specimens with distinct patterns for histo-subtypes. Expression of PRAME was associated with shorter patient survival (p = 0.005) and higher grade (G2 vs. G3, p = 0.001), while NY-ESO-1 expression was correlated with more favourable survival (p = 0.037) and lower grade (G2 vs. G3, p = 0.029). Both PRAME and NY-ESO-1 expression were more frequent in STS with low TIL counts. In multivariate analysis, high PRAME and low SSX2 expression levels as well as metastatic disease and non-radical resections were independent predictors of shorter overall survival. (4) Conclusions: CTAs PRAME, NY-ESO-1, and SSX2 show distinct expression patterns in different STS subtypes. These results demonstrate their prognostic relevance and may guide future immunotherapeutic approaches in STS.

Systemic antitumor effect by regional hyperthermia combined with low-dose chemotherapy and immunologic correlates in an adolescent patient with rhabdomyosarcoma - a case report.

Introduction: An abscopal effect is a clinical observation whereby a local treatment is associated with regression of metastatic cancer at a site distant from the primary location of treatment. Here, we describe the clinical systemic effect induced by regional hyperthermia combined with low-dose chemotherapy and provide immunologic correlates.Case presentation: A 15-year-old patient had been diagnosed with alveolar rhabdomyosarcoma (ARMS). All previous treatment options failed in the patient including haploidentical stem cell transplantation and donor lymphocyte infusion. The patient presented with local and metastatic disease, and upon admission, underwent regional hyperthermia combined with low-dose chemotherapy. Immediately following therapy severe skin reactions were observed. Skin biopsies revealed an intraepithelial lymphocytic infiltration dominated by CD3+/CD8+ T cells with a regular network of dendritic cells. Clinical images compared before and during sequential treatment cycles showed complete metabolic response of the local tumor for more than 10 months of therapy. In addition, metastases completely regressed although they were not direct targets of regional hyperthermia. The systemic effect was associated with enhanced frequency of NK cells and T cells expressing the lectin-like natural-killer group 2 D activating receptor (NKG2D), an increase of the CD56bright subset of NK cells, as well as an increase of effector/memory and effector CD8+ and CD4+ T cells in the blood while the percentage of CD25+FOXP3+ regulatory T cells declined.Conclusions: Regional hyperthermia combined with low-dose chemotherapy had the potential to create a systemic effect which was associated with activation of NK cells and T cells.

Effect of Neoadjuvant Chemotherapy Plus Regional Hyperthermia on Long-term Outcomes Among Patients With Localized High-Risk Soft Tissue Sarcoma: The EORTC 62961-ESHO 95 Randomized Clinical Trial.

IMPORTANCE: Patients with soft tissue sarcoma are at risk for local recurrence and distant metastases despite optimal local treatment. Preoperative anthracycline plus ifosfamide chemotherapy improves outcome in common histological subtypes. OBJECTIVE: To analyze whether the previously reported improvement in local progression-free survival by adding regional hyperthermia to neoadjuvant chemotherapy translates into improved survival. DESIGN, SETTING, AND PARTICIPANTS: Open-label, phase 3 randomized clinical trial to evaluate the efficacy and toxic effects of neoadjuvant chemotherapy plus regional hyperthermia. Adult patients (age ≥18 years) with localized soft tissue sarcoma (tumor ≥5 cm, French Federation Nationale des Centers de Lutte Contre le Cancer [FNCLCC] grade 2 or 3, deep) were accrued across 9 centers (6, Germany; 1, Norway; 1, Austria; 1, United States) from July 1997 to November 2006. Follow-up ended December 2014. INTERVENTIONS: After stratification for tumor presentation and site, patients were randomly assigned to either neoadjuvant chemotherapy consisting of doxorubicin, ifosfamide, and etoposide alone, or combined with regional hyperthermia. MAIN OUTCOMES AND MEASURES: The primary end point was local progression-free survival. Secondary end points included treatment safety and survival, with survival defined from date of randomization to death due to disease or treatment. Patients lost to follow-up were censored at the date of their last follow-up. RESULTS: A total of 341 patients were randomized, and 329 (median [range] age, 51 [18-70] years; 147 women, 182 men) were eligible for the intention-to-treat analysis. By December 2014, 220 patients (67%; 95% CI, 62%-72%) had experienced disease relapse, and 188 (57%; 95% CI, 52%-62%) had died. Median follow-up was 11.3 years. Compared with neoadjuvant chemotherapy alone, adding regional hyperthermia improved local progression-free survival (hazard ratio [HR], 0.65; 95% CI, 0.49-0.86; P = .002). Patients randomized to chemotherapy plus hyperthermia had prolonged survival rates compared with those randomized to neoadjuvant chemotherapy alone (HR, 0.73; 95% CI, 0.54-0.98; P = .04) with 5-year survival of 62.7% (95% CI, 55.2%-70.1%) vs 51.3% (95% CI, 43.7%-59.0%), respectively, and 10-year survival of 52.6% (95% CI, 44.7%-60.6%) vs 42.7% (95% CI, 35.0%-50.4%). CONCLUSIONS AND RELEVANCE: Among patients with localized high-risk soft tissue sarcoma the addition of regional hyperthermia to neoadjuvant chemotherapy resulted in increased survival, as well as local progression-free survival. For patients who are candidates for neoadjuvant treatment, adding regional hyperthermia may be warranted. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00003052.

Hyperthermia adds to trabectedin effectiveness and thermal enhancement is associated with BRCA2 degradation and impairment of DNA homologous recombination repair.

The tetrahydroisoquinoline trabectedin is a marine compound with approved activity against human soft-tissue sarcoma. It exerts antiproliferative activity mainly by specific binding to the DNA and inducing DNA double-strand breaks (DSB). As homologous recombination repair (HRR)-deficient tumors are more susceptible to trabectedin, hyperthermia-mediated on-demand induction of HRR deficiency represents a novel and promising strategy to boost trabectedin treatment. For the first time, we demonstrate enhancement of trabectedin effectiveness in human sarcoma cell lines by heat and characterize cellular events and molecular mechanisms related to heat-induced effects. Hyperthermic temperatures (41.8 or 43°C) enhanced significantly trabectedin-related clonogenic cell death and G2/M cell cycle arrest followed by cell type-dependent induction of apoptosis or senescence. Heat combination increased accumulation of γH2AX foci as key marker of DSBs. Expression of BRCA2 protein, an integral protein of the HRR machinery, was significantly decreased by heat. Consequently, recruitment of downstream RAD51 to γH2AX-positive repair foci was almost abolished indicating relevant impairment of HRR by heat. Accordingly, enhancement of trabectedin effectiveness was significantly augmented in BRCA2-proficient cells by hyperthermia and alleviated in BRCA2 knockout or siRNA-transfected BRCA2 knockdown cells. In peripheral blood mononuclear cells isolated from sarcoma patients, increased numbers of nuclear γH2AX foci were detected after systemic treatment with trabectedin and hyperthermia of the tumor region. The findings establish BRCA2 degradation by heat as a key factor for a novel treatment strategy that allows targeted chemosensitization to trabectedin and other DNA damaging antitumor drugs by on-demand induction of HRR deficiency.

Concomitant trimodality therapy of re-irradiation, chemotherapy and regional hyperthermia for a pretreated inoperable sarcoma recurrence.

We hereby present a case of pre-treated unresectable sarcoma recurrence of the trunk which showed an excellent response to concomitant tri-modal therapy, consisting of re-irradiation, chemotherapy and regional hyperthermia even with a strong compromised re-irradiation dose. No significant toxicity of the combined therapy and fast achievement of the pain and neurological symptoms relief are reported. The case shows that concurrent tri-modality treatment can be considered as a therapeutic option for the management of pre-treated unresectable recurrence even in there-irradiation setting.

Evaluation of several FDG PET parameters for prediction of soft tissue tumour grade at primary diagnosis and recurrence.

OBJECTIVES: This study evaluates the diagnostic accuracy of SUV-based parameters derived from [(18) F]-2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) in order to optimize non-invasive prediction of soft tissue tumour (STT) grade. METHODS: One hundred and twenty-nine lesions from 123 patients who underwent FDG-PET for primary staging (n = 79) or assessment of recurrence (n = 44) of STT were analyzed retrospectively. Histopathology was the reference standard for tumour grading. Absolute values and tumour-to-liver ratios of several standardized uptake value (SUV) parameters were correlated with tumour grading. RESULTS: At primary diagnosis SUVmax, SUVpeak, SUVmax/SUVliver and SUVpeak/SUVliver showed good correlation with tumour grade. SUVpeak (area under the receiver-operating-characteristic, AUC-ROC: 0.82) and SUVpeak/SUVliver (AUC-ROC: 0.82) separated best between low grade (WHO intermediate, grade 1 sarcoma, and low risk gastrointestinal stromal tumours, GISTs) and high grade (grade 2/3 sarcoma and intermediate/high risk GISTs) lesions: optimal threshold for SUVpeak/SUVliver was 2.4, which resulted in a sensitivity of 79 % and a specificity of 81 %. At disease recurrence, the AUC-ROC was <0.75 for each parameter. CONCLUSIONS: A tumour SUVpeak of at least 2.4 fold mean liver uptake predicts high grade histopathology with good diagnostic accuracy at primary staging. At disease recurrence, FDG-PET does not reliably separate high and low grade lesions. KEY POINTS: • Several SUV parameters accurately predict soft tissue sarcoma grade at primary diagnosis. • Tumour-to-liver ratios are of comparable value to absolute SUV parameters. • SUV peak /SUV liver >2.4 had 79 % sensitivity and 81 % specificity for high grade lesions. • At recurrence, FDG PET does not reliably indicate high grade sarcomas.

Effectiveness of regional hyperthermia with chemotherapy for high-risk retroperitoneal and abdominal soft-tissue sarcoma after complete surgical resection: a subgroup analysis of a randomized phase-III multicenter study.

OBJECTIVE: To determine whether regional hyperthermia (RHT) in addition to chemotherapy improves local tumor control after macroscopically complete resection of abdominal or retroperitoneal high-risk sarcomas. BACKGROUND: Within the prospectively randomized EORTC 62961 phase-III trial, RHT and systemic chemotherapy significantly improved local progression-free survival (LPFS) and disease-free survival (DFS) in patients with abdominal and extremity sarcomas. That trial included macroscopically complete and R2 resections. METHODS: A subgroup analysis of the EORTC trial was performed and long-term survival determined. From 341 patients, 149 (median age 52 years, 18-69) were identified with macroscopic complete resection (R0, R1) of abdominal and retroperitoneal soft-tissue sarcomas (median diameter 10 cm, G2 48.3%, G3 51.7%). Seventy-six patients were treated with EIA (etoposide, ifosfamide, doxorubicin)+RHT (≥5 cycles: 69.7%) versus 73 patients receiving EIA alone (≥5 cycles: 52.1%, P=0.027). LPFS and DFS as well as overall survival were determined. RESULTS: RHT and systemic chemotherapy significantly improved LPFS (56% vs 45% after 5 years, P=0.044) and DFS (34% vs 27% after 5 years, P=0.040). Overall survival was not significantly improved in the RHT group (57% vs 55% after 5 years, P=0.82). Perioperative morbidity and mortality were not significantly different between groups. CONCLUSIONS: In patients with macroscopically complete tumor resection, RHT in addition to chemotherapy resulted in significantly improved local tumor control and DFS without increasing surgical complications. Within a multimodal therapeutic concept for abdominal and retroperitoneal high-risk sarcomas, RHT is a treatment option beside radical surgery and should be further evaluated in future trials.

Gemcitabine treatment of rat soft tissue sarcoma with phosphatidyldiglycerol-based thermosensitive liposomes.

PURPOSE: The pyrimidine analogue gemcitabine (dFdC) is frequently used in the treatment of patients with solid tumors. However, after i.v. application dFdC is rapidly inactivated by metabolization. Here, the potential of thermosensitive liposomes based on 1,2-dipalmitoyl-sn-glycero-3-phosphodiglycerol (DPPG2-TSL) were investigated as carrier and targeting system for delivery of dFdC in combination with local hyperthermia (HT). METHODS: DPPG2-TSL were prepared by the lipid film hydration and extrusion method and characterized by dynamic light scattering, thin layer chromatography, phosphate assay and HPLC. In vivo experiments were performed in Brown Norway rats with a syngeneic soft tissue sarcoma. Local HT treatment was performed by light exposure. RESULTS: DPPG2-TSL were stable at 37°C in serum and showed a temperature dependent dFdC release >40°C. Plasma half-life of dFdC was strongly increased from 0.07 h (non-liposomal) to 0.53 h (liposomal, vesicle size 105 nm) or 2.59 h (liposomal, 129 nm). Therapy of BN175 tumors with dFdC encapsulated in DPPG2-TSL + HT showed significant improvement in tumor growth delay compared to non-liposomal dFdC without HT (p < 0.05), non-liposomal dFdC with HT (p < 0.01), and liposomal dFdC without HT (p < 0.05), respectively. CONCLUSIONS: Gemcitabine encapsulated in DPPG2-TSL in combination with local HT is a promising tool for the treatment of solid tumors. Therefore, these encouraging results ask for further investigation and evaluation.

Non-ionic Gd-based MRI contrast agents are optimal for encapsulation into phosphatidyldiglycerol-based thermosensitive liposomes.

Thermosensitive liposomes (TSL) with encapsulated magnetic resonance imaging (MRI) longitudinal relaxation time (T(1)) contrast agents (CAs) have been proposed for MRI assisted interventional thermotherapy in solid tumors. Here the feasibility of 6 clinically approved CAs (Gd-DTPA, Gd-BOPTA, Gd-DOTA, Gd-BT-DO3A, Gd-DTPA-BMA, and Gd-HP-DO3A) for formulation into TSL was investigated. CAs were passively encapsulated with 323 mOs kg(-1) into 1,2-dipalmitoyl-sn-glycero-3-phosphocholine/1,2-distearoyl-sn-glycero-3-phosphocholine/1,2-dipalmitoyl-sn-glycero-3-phosphodiglycerol 50/20/30 (mol/mol) TSL (DPPG(2)-TSL) to obtain stable formulations. T(1) relaxivity (r(1)) and diffusive permeability to water (P(d)) across the membrane were determined. Shelf life at 4°C was investigated by determining lysolipid content up to 10 weeks after preparation. All preparations were monodispersed with comparable small vesicle sizes (~135 nm). Neither zeta potential nor phase transition temperature (T(m)) was affected by the CA. The formulations showed an increase in r(1) in the temperature range between 38 and 44°C. This correlated with the phase transition. Change in r(1) (Δr(1)=r(1)(45.3°C)-r(1)(37.6°C)) and r(1) (T

Proteins and cholesterol lipid vesicles are mediators of drug release from thermosensitive liposomes.

Thermosensitive liposomes (TSL) are a promising tool for triggered drug delivery in combination with local hyperthermia. Objective of this study was to investigate the influence of serum on TSL in more detail and to identify serum components which are responsible for increasing drug release. Four different formulations were investigated: DPPC/DSPC/1,2-dipalmitoyl-sn-glycero-3-phosphodiglycerol (DPPG(2)) 50/20/30 (mol/mol) (DPPG(2)-TSL); DPPC/DSPC/DPPG(2)/DSPE-PEG2000 50/15/30/5 (mol/mol) (DPPG(2)/PEG-TSL), DPPC/P-Lyso-PC/DSPE-PEG2000 90/10/4 (mol/mol) (PEG/Lyso-TSL), and DPPC/DSPC/DSPE-PEG2000 80/15/5 (mol/mol) (PEG-TSL). DPPG(2)-TSL was the only formulation which was unaffected by osmotic stress. All formulations tested were influenced by serum components but the susceptibility was depended on the lipid composition of the vesicle. Presence of albumin (HSA) or cholesterol-containing lipid vesicles (DPPC/Chol-LLV) increased the membrane permeability for all tested formulations at temperatures around and above T(m) in a concentration based manner. PEGylation was not able to prevent the observed effect. PEG-TSL and PEG/Lyso-TSL were more susceptible to DPPC/Chol-LLV than DPPG(2)-containing TSL. In contrast, immunoglobulin type G (IgG) affected only anionic formulations. The membrane of DPPG(2)-TSL and DPPG(2)/PEG-TSL was more susceptible toward IgG as compared to HSA. DPPG(2)-TSL and PEG/Lyso-TSL were differentially influenced by fetal calf serum (FCS). As DPPG(2)-TSL was stabilized by pre-incubation with FCS at 37°C, this was the opposite for PEG/Lyso-TSL which were destabilized under these conditions. Individual serum components were unable to mimic the complex situation in full serum. Hence, the use of plasma or serum is still inevitable to investigate stability and release properties of novel TSL formulations until all serum components have been identified that alter TSL integrity.

Hsp70, a messenger from hyperthermia for the immune system.

Heat shock proteins (Hsps) hold a dual role depending on their location. Inside cells, they fulfill essential survival functions as molecular chaperones forming complexes with intracellular polypeptides (self or foreign) to help in protein folding, the resolution of protein aggregates and intracellular protein transport. Released from the cell, they act as messengers communicating the cells' interior protein composition to the immune system for initiation of immune responses against intracellular proteins. Here we describe the mechanisms by which Hsp70, the heat-inducible Hsp70 family member, crosstalks with the immune system. Further, we discuss that clinical hyperthermia could be a way to initiate the immunologic activity of Hsp70 by upregulating its expression and facilitating release through local necrosis.

Hyperthermia in soft tissue sarcoma.

Patients with high-risk soft tissue sarcomas (STS)-FNCLCC grade 2-3, size >5 cm, deep to the fascia-are at risk for developing local recurrence and distant metastasis despite surgical tumor resection. Therefore, the management of high-risk STS requires a multidisciplinary approach. Besides surgery, radiotherapy, and chemotherapy, regional hyperthermia (RHT) has the potential to become the fourth standard treatment modality for the treatment of these patients. RHT means non-invasive selective heating of the tumor area to temperatures within the range of 40-43°C for 60 min by the use of an electromagnetic heating device. Thereby RHT is always applied in addition to radiotherapy or chemotherapy or both but is not effective as a single treatment. Beside direct cytotoxicity, RHT in combination with chemotherapy enhances the drug cytotoxicity mainly by increased chemical reaction and intratumoral drug accumulation. For the neoadjuvant setting, RHT in combination with a doxorubicin- and ifosfamide-based chemotherapy has been shown to dramatically improve the tumor response rate but also prevents from early disease progression as compared to chemotherapy alone. The addition of RHT to a multimodal treatment of high-risk STS consisting of surgery, radiotherapy, and chemotherapy either in the neoadjuvant setting but also after incomplete or marginal tumor resection has been shown to significantly improve local recurrence- and disease-free survival. Based on these results and in conjunction with the low RHT-related toxicity, RHT combined with preoperative or postoperative chemotherapy should be considered as an additional standard treatment option for the multidisciplinary treatment of locally advanced high-grade STS.

Size of thermosensitive liposomes influences content release.

Thermosensitive liposomes (TSL) in combination with regional hyperthermia represent a powerful tool for tumor specific drug delivery. The objective of this study was to investigate the influence of vesicle size on the biophysical properties of TSL. TSL were composed of DPPC/DSPC/1,2-dipalmitoyl-sn-glycero-3-phosphoglyceroglycerol (DPPG(2)) 50:20:30 (mol/mol) (DPPG(2)-TSL) and DPPC/P-Lyso-PC/DSPE-PEG2000 90:10:4 (mol/mol) (PEG/Lyso-TSL) with encapsulated fluorescent dye carboxyfluorescein, anticancer drug doxorubicin or magnetic resonance contrast agent gadodiamide. Extrusion was performed with polycarbonate filters of distinct pore size to obtain TSL with different diameters (50 to 200nm). Phase transition temperature (T(m)) of the bilayer forming phospholipids was not influenced by vesicle size in the tested range. However, vesicle size had a major impact on in vitro content release properties of TSL in the investigated temperature range between 30 and 45°C. Generally, vesicle size was inversely related to content release properties with increased content release rates for decreased vesicle sizes. Size dependency of content release properties varied between all tested formulations and DPPG(2)-TSL were generally less affected by size changes in the range of 100 to 150nm as compared to PEG/Lyso-TSL. Independent from gadodiamide release, vesicle size influenced the signal intensity of DPPG(2)-TSL also at temperatures below T(m) due to improved water exchange for smaller vesicles. Liposomes around 100nm in size are routinely used in vivo, hence a quality control for TSL preparations is required prior to use. Even small changes in size or a wider size distribution might affect stability and release properties and thus yield in decreased efficacy or unwanted side effects of drug loaded TSL during in vivo applications.