The role of hyperthermia in optimizing tumor response to regional therapy

Advancing Pancreatic Cancer Surgical Treatments and Proposal of New Approaches

Pancreatic cancer is a significant challenge in oncology due to its aggressive nature and complex management, leading to high mortality rates and a dismally low 5-year survival rate. Approximately 85% of cases manifest as adenocarcinoma, while endocrine tumors constitute less than 5%. Borderline resectable and locally advanced pancreatic cancers are particularly difficult to treat due to vascular involvement, which complicates complete resections and increases morbidity. Various therapeutic modalities aim to overcome these challenges and improve patient outcomes. Traditionally, upfront surgery was the standard for resectable tumors, with multimodal chemotherapy being central to treatment. Understanding surgical anatomy is pivotal in enhancing surgical outcomes and patient survival. Resectability challenges are several when seeking to achieve R0 resections, particularly for borderline resectable tumors. Various classification systems-the MD Anderson criteria, the NCCN criteria, the AHPA/SSAT/SSO consensus statement, and the Alliance definition-assess tumor involvement with major blood vessels, with the first of these systems being broadly accepted. Vascular staging integration is also important, with the Ishikawa staging system using preoperative imaging to assess venous involvement. Furthermore, neoadjuvant therapy enhances treatment effectiveness by addressing micro-metastatic disease early, increasing R0 resection chances, and downstaging tumors for optimal surgery. Insights from the Fox Chase Cancer Center's neoadjuvant treatment approach highlight the importance of a multidisciplinary strategy when advancing therapy and improving patient prognosis. This commentary, inspired by Dr. Sanjay S. Reddy's Keynote Conference during MedNews week, highlights current advancements and ongoing challenges in the treatment of pancreatic cancer, emphasizing the need for a comprehensive, multidisciplinary approach to improve outcomes.

Nuclear import carrier Hikeshi cooperates with HSP70 to promote murine oligodendrocyte differentiation and CNS myelination

Dysregulation of factors in nucleocytoplasmic transport is closely linked to neural developmental diseases. Mutation in Hikeshi, encoding a nonconventional nuclear import carrier of heat shock protein 70 family (HSP70s), leads to inherited leukodystrophy; however, the pathological mechanisms remain elusive. Here, we showed that Hikeshi is essential for central nervous system (CNS) myelination. Deficiency of Hikeshi, which is observed in inherited leukodystrophy patients, resulted in murine oligodendrocyte maturation arrest. Hikeshi is required for nuclear translocation of HSP70s upon differentiation. Nuclear-localized HSP70 promotes murine oligodendrocyte differentiation and remyelination after white matter injury. Mechanistically, HSP70s interacted with SOX10 in the nucleus and protected it from E3 ligase FBXW7-mediated ubiquitination degradation. Importantly, we discovered that Hikeshi-dependent hyperthermia therapy, which induces nuclear import of HSP70s, promoted oligodendrocyte differentiation and remyelination following in vivo demyelinating injury. Overall, these findings demonstrate that Hikeshi-mediated nuclear translocation of HSP70s is essential for myelinogenesis and provide insights into pathological mechanisms of Hikeshi-related leukodystrophy.

Combined Therapy with Dacarbazine and Hyperthermia Induces Cytotoxicity in A375 and MNT-1 Melanoma Cells

Melanoma is a drug-resistant cancer, representing a serious challenge in cancer treatment. Dacarbazine (DTIC) is the standard drug in metastatic melanoma treatment, despite the poor results. Hyperthermia has been proven to potentiate chemotherapy. Hence, this work analyzed the combined action of hyperthermia and DTIC on A375 and MNT-1 cell lines. First, temperatures between 40 °C and 45 °C were tested. The effect of DTIC on cell viability was also investigated after exposures of 24, 48, and 72 h. Then, cells were exposed to 43 °C and to the respective DTIC IC10 or IC20 of each time exposure. Overall, hyperthermia reduced cell viability, however, 45 °C caused an excessive cell death (>90%). Combinational treatment revealed that hyperthermia potentiates DTIC’s effect, but it is dependent on the concentration and temperature used. Also, it has different mechanisms from the treatments alone, delaying A375 cells at the G2/M phase and MNT-1 cells at the S and G2/M phases. Intracellular reactive oxygen species (ROS) levels increased after treatment with hyperthermia, but the combined treatment showed no additional differences. Also, hyperthermia highly increased the number of A375 early apoptotic cells. These results suggest that combining hyperthermia and DTIC should be more explored to improve melanoma treatment.

Multifunctional Gold Nanoparticles for Improved Diagnostic and Therapeutic Applications: A Review

The medical properties of metals have been explored for centuries in traditional medicine for the treatment of infections and diseases and still practiced to date. Platinum-based drugs are the first class of metal-based drugs to be clinically used as anticancer agents following the approval of cisplatin by the United States Food and Drug Administration (FDA) over 40 years ago. Since then, more metals with health benefits have been approved for clinical trials. Interestingly, when these metals are reduced to metallic nanoparticles, they displayed unique and novel properties that were superior to their bulk counterparts. Gold nanoparticles (AuNPs) are among the FDA-approved metallic nanoparticles and have shown great promise in a variety of roles in medicine. They were used as drug delivery, photothermal (PT), contrast, therapeutic, radiosensitizing, and gene transfection agents. Their biomedical applications are reviewed herein, covering their potential use in disease diagnosis and therapy. Some of the AuNP-based systems that are approved for clinical trials are also discussed, as well as the potential health threats of AuNPs and some strategies that can be used to improve their biocompatibility. The reviewed studies offer proof of principle that AuNP-based systems could potentially be used alone or in combination with the conventional systems to improve their efficacy.

Long-Term Survival Outcomes of Metabolically Supported Chemotherapy with Gemcitabine-Based or FOLFIRINOX Regimen Combined with Ketogenic Diet, Hyperthermia, and Hyperbaric Oxygen Therapy in Metastatic Pancreatic Cancer

BACKGROUND

Despite introduction of new chemotherapeutic agents, outcomes of patients with metastatic pancreatic cancer are still poor. Metabolically supported chemotherapy (MSCT) is a novel approach targeting dysregulated energy mechanism of the tumor cell.

OBJECTIVES

This study aimed to examine the efficacy of metabolically supported administration of chemotherapy combined with ketogenic diet, hyperthermia, and hyperbaric oxygen therapy (HBOT) in patients with metastatic pancreatic cancer.

METHOD

This retrospective observational study included 25 patients with metastatic pancreatic ductal carcinoma (stage IV) who received MSCT (either gemcitabine-based or FOLFIRINOX regimen administered concomitantly with induced hypoglycemia) plus ketogenic diet, hyperthermia, and HBOT combination. Survival outcomes were evaluated.

RESULTS

During the mean follow-up duration of 25.4 ± 19.3 months, median overall survival and median progression-free survival were 15.8 months (95% CI, 10.5-21.1) and 12.9 months (95% CI, 11.2-14.6), respectively. Age and gender did not have any effect on overall survival (p > 0.05 for all).

CONCLUSIONS

MSCT administered together with ketogenic diet, hyperthermia, and HBOT appears to be a viable option with the potential to improve survival outcomes in patients diagnosed with metastatic pancreatic cancer. Further research, particularly with larger comparative clinical trials, is warranted.

Whole-body hyperthermia in combination with systemic therapy in advanced solid malignancies

Whole-body hyperthermia (WBH) might be beneficial for patients with metastasized solid malignancies when combined with systemic therapy. This review identified and summarized the phase I/II studies (n = 13/14) conducted using this combination of therapies. Most of the phase II studies used radiant heating methods in a thermal dose of 41.8 °C (1 h). All studies used classic chemotherapy. Great inter-study heterogeneity was observed regarding treatment regimes, included patients and reported response rates (12-89%). Ovarian cancer, colorectal adenocarcinoma, lung cancer and sarcoma have been studied most. Most reported toxicity (grade 3/4) was myelosuppression. Treatment related mortality was present (4 patients) in three out 14 phase II studies (350 evaluable patients, over 966 cycles of WBH with chemotherapy). Absence of phase III trials makes the additive value of WBH highly speculative. As modern oncology offers many less invasive treatments options, it is unlikely WBH will ever find its way in routine clinical care.

Gold Nanoparticles for Photothermal Cancer Therapy

Gold is a multifunctional material that has been utilized in medicinal applications for centuries because it has been recognized for its bacteriostatic, anticorrosive, and antioxidative properties. Modern medicine makes routine, conventional use of gold and has even developed more advanced applications by taking advantage of its ability to be manufactured at the nanoscale and functionalized because of the presence of thiol and amine groups, allowing for the conjugation of various functional groups such as targeted antibodies or drug products. It has been shown that colloidal gold exhibits localized plasmon surface resonance (LPSR), meaning that gold nanoparticles can absorb light at specific wavelengths, resulting in photoacoustic and photothermal properties, making them potentially useful for hyperthermic cancer treatments and medical imaging applications. Modifying gold nanoparticle shape and size can change their LPSR photochemical activities, thereby also altering their photothermal and photoacoustic properties, allowing for the utilization of different wavelengths of light, such as light in the near-infrared spectrum. By manufacturing gold in a nanoscale format, it is possible to passively distribute the material through the body, where it can localize in tumors (which are characterized by leaky blood vessels) and be safely excreted through the urinary system. In this paper, we give a quick review of the structure, applications, recent advancements, and potential future directions for the utilization of gold nanoparticles in cancer therapeutics.

Role of CTGF in Sensitivity to Hyperthermia in Ovarian and Uterine Cancers

Even though hyperthermia is a promising treatment for cancer, the relationship between specific temperatures and clinical benefits and predictors of sensitivity of cancer to hyperthermia is poorly understood. Ovarian and uterine tumors have diverse hyperthermia sensitivities. Integrative analyses of the specific gene signatures and the differences in response to hyperthermia between hyperthermia-sensitive and -resistant cancer cells identified CTGF as a key regulator of sensitivity. CTGF silencing sensitized resistant cells to hyperthermia. CTGF small interfering RNA (siRNA) treatment also sensitized resistant cancers to localized hyperthermia induced by copper sulfide nanoparticles and near-infrared laser in orthotopic ovarian cancer models. CTGF silencing aggravated energy stress induced by hyperthermia and enhanced apoptosis of hyperthermia-resistant cancers.

Hyperthermia and radiotherapy combination for locoregional recurrences of breast cancer: a review

Breast cancer is a second common form of malignancy and is one of the leading causes of mortality among cancer patients across the world. Locoregional recurrence occurs in 5–20% of patients despite upfront treatment. Local therapy (surgery plus minus re-irradiation) with or without systemic therapy is generally recommended for management. Local control rates vary; months to years, but a significant percentage lives 5 years. Therefore, treatment strategies to increase response rates are significant. Hyperthermia is one of the most potent radiosensitizers and data from meta-analysis and randomized trials support its use with radiotherapy. This study reviews the biologic rationale and clinical evidence about concomitant use of hyperthermia and radiotherapy in locally-recurrent breast cancer patients.

Chemoradiation combined with regional hyperthermia for advanced oesophageal cancer: a systematic review and meta-analysis

WHAT IS KNOWN AND OBJECTIVE

Hyperthermia is an effective treatment modality that augments the anticancer effects of radiotherapy and chemotherapy. Hyperthermia-chemo-radiotherapy (HCRT) is a combination therapy that can strengthen anticancer effects through a synergistic interaction between heat, chemotherapy and radiation. Here, we carried out a systematic review and meta-analysis to evaluate the clinical efficacy and safety of chemoradiation combined with regional hyperthermia (HCRT) for oesophageal carcinoma.

METHODS

We conducted computer searches of foreign databases, including Cochrane Library, PubMed, EMBASE, Web of Science and Chinese databases, including CBM, CNKI and WanFang; we also retrieved other sources as supplement. All relevant randomized controlled trials (RCTs) were collected to compare HCRT and other therapies, including chemotherapy combined with radiotherapy (CRT) and radiotherapy alone (RT). After literature screening, data extraction and quality evaluation performed by appropriate criteria, the meta-analyses were conducted using RevMan 5.1 software (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, Denmark).

RESULTS AND DISCUSSION

Nineteen RCTs were included, comprising 1519 patients. Meta-analysis showed that the 1-, 3-, 5- and 7-year survival, complete response and total effective rates of the HCRT group were higher than those of the CRT group; the rates of gastrointestinal reaction, leucocytopenia and radiation oesophagitis in the HCRT group were lower than those of the CRT group, indicating significant differences (P < 0·05). The 1-, 2-, 3- and 5-year survival, complete response and total effective rates of the HCRT group were higher than those of the RT group, the recurrence and distant metastasis rates of the HCRT group were lower than those of the RT group, and there were significant differences in all of the indicators (P < 0·05).

WHAT IS NEW AND CONCLUSIONS

This is the first systematic review and meta-analysis to evaluate HCRT for oesophageal carcinoma. Compared with CRT or RT, HCRT can improve long-term and short-term curative effects; it is also safe and feasible. Additional high-quality and large sample size RCTs will be necessary to further demonstrate the long-term survival benefits and comprehensive safety profile of HCRT.

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.

Rationale of hyperthermia for radio(chemo)therapy and immune responses in patients with bladder cancer: Biological concepts, clinical data, interdisciplinary treatment decisions and biological tumour imaging

Bladder cancer, the most common tumour of the urinary tract, ranks fifth among all tumour entities. While local treatment or intravesical instillation of bacillus Calmette-Guerin (BCG) provides a treatment option for non-muscle invasive bladder cancer of low grade, surgery or radio(chemo)therapy (RT) are frequently applied in high grade tumours. It remains a matter of debate whether surgery or RT is superior with respect to clinical outcome and quality of life. Surgical resection of bladder cancer can be limited by acute side effects, whereas, RT, which offers a non-invasive treatment option with organ- and functional conservation, can cause long-term side effects. Bladder toxicity by RT mainly depends on the total irradiation dose, fraction size and tumour volume. Therefore, novel approaches are needed to improve clinical outcome. Local tumour hyperthermia is currently used either as an ablation therapy or in combination with RT to enhance anti-tumour effects. In combination with RT an increase of the temperature in the bladder stimulates the local blood flow and as a result can improve the oxygenation state of the tumour, which in turn enhances radiation-induced DNA damage and drug toxicity. Hyperthermia at high temperatures can also directly kill cells, particularly in tumour areas which are poorly perfused, hypoxic or have a low tissue pH. This review summarises current knowledge relating to the role of hyperthermia in RT to treat bladder cancer, the induction and manifestation of immunological responses induced by hyperthermia, and the utilisation of the stress proteins as tumour-specific targets for tumour detection and monitoring of therapeutic outcome.

Enhancing cell kill in vitro from hyperthermia through pre-sensitizing with ultrasound-stimulated microbubbles

Ultrasound-stimulated microbubbles (MBs) were demonstrated to enhance cell kill from hyperthermia. Definity MBs were injected into wells containing 4T1 cells in culture media and scanned with 1-MHz ultrasound, an exposure duration of 30 s and a negative pressure of 0.5 or 1.3 MPa. Some cell samples were placed in a water bath heated to 42 °C for 5 min. Cell death was quantified. When combining MBs, ultrasound at 1.3 MPa and hyperthermia, more than 58.8% ± 7.21% of cells were nonviable. When exposed to hyperthermia alone or exposure to MBs and ultrasound but no hyperthermia, cell death was less than 10.1% ± 6.96% and 30.1% ± 10.8%, respectively.

Efficacy of hyperbaric oxygen therapy combined with mild hyperthermia for improving the anti-tumour effects of carboplatin

PURPOSE

The aim of this study was to evaluate the effects of hyperbaric oxygen therapy (HBO) on the enhancement of hyperthermic chemosensitisation to carboplatin at mild temperatures in experimental tumours.

METHODS

SCCVII carcinoma in C3H/He mice was used to assess tumour growth delay. The mice received intraperitoneal injections of carboplatin. For HBO treatment, the mice were exposed to HBO at 2.0 atmospheres of absolute oxygen for 60 min. For mild hyperthermia (HT), treatment at 41.5 °C for 30 min was performed. The tumour tissue pO2 levels were measured with a digital pO2 monitor during and immediately after treatment.

RESULTS

The average time taken to reach a threefold relative tumour size was significantly longer after treatment with carboplatin combined with mild HT and HBO than after treatment with carboplatin and mild HT. The relative sizes of the tumours after the combined treatment were smallest when the treatment sequence was carboplatin, mild HT, and HBO. The tumour tissue pO2 values were significantly higher immediately after mild HT followed by HBO than immediately after HBO followed by mild HT. The tumour tissue pO2 levels during mild HT and HBO generally increased, although the patterns of the increases varied.

CONCLUSION

The administration of HBO increased the effects of hyperthermic chemosensitisation to carboplatin at mild temperatures on experimental tumours, particularly when given in the sequence of carboplatin, mild HT, and HBO, a finding that supports previous clinical outcomes for a novel combined therapy using carboplatin plus HT and HBO.

The predicting value of postoperative body temperature on long-term survival in patients with rectal cancer

This study aimed to assess the association between postoperative body temperature and prognosis in patients with rectal cancer. Five hundred and seven patients with stage I to III rectal cancers were enrolled in the current study. Basal body temperature (BBT, measured at 6 am) and maximal body temperature (MBT) on each day after surgery were analyzed retrospectively. Patients were divided into two equal groups according to the median of BBT and MBT at each day. The primary end points were disease-free survival (DFS) and overall survival (OS). The univariate and multivariate analyses showed that patients with low D0-MBT (<37.4 °C) had lower 3-year DFS [adjusted hazard ratio (HR) 1.56 (95 % CI 1.08-2.24, P = 0.017)] as well as OS [adjusted HR 1.72 (95 % CI 1.05-2.82, P = 0.032)] rate as compared to those with high D0-MBT (>37.4 °C). In the subset of 318 patients with T3 stage tumor and the subgroup of 458 patients without blood transfusion as well, low D0-MBT continues to be an independent predictor of DFS/OS with an adjusted HR equal to 1.48 (95 % CI 1.02-2.24, P = 0.046)/1.68 (95 % CI 1.04-2.99, P = 0.048) and 1.45 (95 % CI 1.02-2.13, P = 0.048)/1.59 (95 % CI 1.01-2.74, P = 0.049), respectively. In addition, we found that patients have higher risk of 1-year recurrence if those were exhibiting low preoperative BBT (<36.6 °C) (17 vs. 10 %, P = 0.034). Low body temperature (D0-MBT < 37.4 °C) after surgery was an independent predictor of poor survival outcomes in patients with rectal cancer.

Radiosensitization and nanoparticles

Nanomaterials have been shown to have physical and chemical properties that have opened new avenues for cancer diagnosis and therapy. Nanoconstructs that enhance existing treatments for cancer, such as radiation therapy, are being explored in several different ways. Two general paths toward nanomaterial-enabled radiosensitization have been explored: (1) improving the effectiveness of ionizing radiation and (2) modulating cellular pathways leading to a disturbance of cellular homeostasis, thus rendering the cells more susceptible to radiation-induced damage. A variety of different agents that work via one of these two approaches have been explored, many of which modulate direct and indirect DNA damage (gold), radiosensitivity through hyperthermia (Fe), and different cellular pathways. There have been many in vitro successes with the use of nanomaterials for radiosensitization, but in vivo testing has been less efficacious, predominantly because of difficulty in targeting the nanoparticles. As improved methods for tumor targeting become available, it is anticipated that nanomaterials can become clinically useful radiosensitizers for radiation therapy.

Magnetic nanoparticle-based therapeutic agents for thermo-chemotherapy treatment of cancer

Magnetic nanoparticles have been widely investigated for their great potential as mediators of heat for localised hyperthermia therapy. Nanocarriers have also attracted increasing attention due to the possibility of delivering drugs at specific locations, therefore limiting systematic effects. The enhancement of the anti-cancer effect of chemotherapy with application of concurrent hyperthermia was noticed more than thirty years ago. However, combining magnetic nanoparticles with molecules of drugs in the same nanoformulation has only recently emerged as a promising tool for the application of hyperthermia with combined chemotherapy in the treatment of cancer. The main feature of this review is to present the recent advances in the development of multifunctional therapeutic nanosystems incorporating both magnetic nanoparticles and drugs, and their superior efficacy in treating cancer compared to either hyperthermia or chemotherapy as standalone therapies. The principle of magnetic fluid hyperthermia is also presented.

A meshless point collocation treatment of transient bioheat problems

A meshless numerical method is proposed for the solution of the transient bioheat equation in two and three dimensions. The Pennes bioheat equation is extended in order to incorporate water evaporation, tissue damage, and temperature-dependent tissue properties during tumor ablation. The conductivity of the tissue is not assumed constant but is treated as a local function to simulate local variability due to the existence of usually unclear interfacing of healthy and pathological segments. In this way, one avoids the need for accurate identification of the boundaries between pathological and healthy regions, which is a typical problem in medical practice, and sidesteps, evidently, the corresponding mathematical treatment of such boundaries, which is usually a tedious procedure with some inevitable degree of approximation. The numerical results of the new method for test applications of the bioheat transfer equation are validated against analytical predictions and predictions of other numerical methods. 3D simulations are presented that involve the modeling of tumor ablation and account for metabolic heat generation, blood perfusion, and heat ablation using realistic values for the various parameters. An evaluation of the effective medium approximation to homogenize conductivity fields for use with the bioheat equation is also provided.

Impact of hyperthermia on pharmacokinetics of intraperitoneal mitomycin C in rats investigated by microdialysis

BACKGROUND AND OBJECTIVES

Patients with peritoneal surface malignancies are treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy, commonly using mitomycin C (MMC). The purpose of this study was to investigate impact of hyperthermia on pharmacokinetics of intraperitoneal MMC.

METHODS

In 14 athymic nude male rats, microdialysis (MD) probes were implanted in jugular vein (V), hind leg muscle (M) and extraperitoneal space (XP). Probes were calibrated by retrodialysis. Intraperitonal chemotherapy perfusion (IPEC) was administered over 90 min with MMC 5 mg/kg and saline 0.9% 500 ml/kg at 35 and 41°C, defining the normothermic (NG) and hyperthermic groups (HG), respectively. MD and peritoneal perfusion fluid (PPF) samples were collected at 10 min intervals to determine MMC concentration.

RESULTS

Time-concentration curves were virtually parallel between temperature groups, with equal peak concentrations (µM) of 0.3 (V), 0.7 (XP) and 0.3 (M). The following area under time-concentration curve (AUC) ratios were calculated: AUC PPF/AUC V were 69 in NG and 79 in HG (P = 0.54); AUC XP/AUC V were 2.7 in NG and 2.6 in HG (P = 0.90).

CONCLUSIONS

IPEC provides high intraperitoneal MMC concentration and increased bioavailability in extraperitoneal tissue, combined with low systemic absorption. Hyperthermia at 41°C did not modify MMC pharmacokinetics.

Clinical experience with radio-, chemo- and hyperthermotherapy combined trimodality on locally advanced esophageal cancer

Esophageal cancer is a highly malignant and lethal disease with a low 5-year survival rate. Therefore, an effective treatment modality is required. To investigate the treatment efficacy and toxicity of radio-, chemo- and hyper-thermotherapy combined trimodality on locally advanced esophageal cancer, the medical records of 78 patients with pathologically confirmed esophageal cancer treated with chemoradiotherapy plus hyperthemia at our institution were retrospectively investigated and the 3-year outcome was carefully assessed. All 78 patients received intensity-modulated radiation therapy at a total dose of 60-66 Gy, in a conventional schedule of 1.8-2.1 Gy/fraction, 5 fractions/week. They also received 4-6 courses of chemotherapy, consisting of 450 mg/m² 5-fluorouracil for 1-5 days and 25 mg/m² cisplatin for 1-5 days, in addition to 6-12 sessions of hyperthermia, performed twice a week. Out of the 78 cases, complete remission of the primary tumor was observed in 31 (39.7%), partial remission in 44 (56.4%) and no change in 3 (3.9%) cases. The treatment response rate was 96.1%. The overall survival (OS) rate at 1, 2 and 3 years was 67.9, 41.0 and 33.3%, respectively. No significant difference in adverse effects was observed between this treatment regimen and other similar studies. Our preliminary results demonstrated that the chemo-, radio- and hyperthermotherapy combined trimodality exhibited excellent short-term clinical outcomes as regards tumor response rate and a sound long-term OS, with endurable adverse events. This trimodal treatment requires further investigation to establish its beneficial role in the treatment of patients with locally advanced esophageal cancer.

Hyperthermia versus Oncothermia: Cellular Effects in Cancer Therapy

Hyperthermia means overheating of the living object completely or partly. Hyperthermia, the procedure of raising the temperature of a part of or the whole body above the normal for a defined period of time, is applied alone or as an adjunctive with various established cancer treatment modalities such as radiotherapy and chemotherapy. The fact that is the hyperthermia is not generally accepted as conventional therapy. The problem is its controversial performance. The controversy is originated from the complications of the deep heating and the focusing of the heat effect. The idea of oncothermia solves the selective deep action on nearly cellular resolution. We would like to demonstrate the force and perspectives of oncothermia as a highly specialized hyperthermia in clinical oncology. Our aim is to prove the ability of oncothermia to be a candidate to become a widely accepted modality of the standard cancer care. We would like to show the proofs and the challenges of the hyperthermia and oncothermia applications to provide the presently available data and summarize the knowledge in the topic. Like many early-stage therapies, oncothermia lacks adequate treatment experience and long-range, comprehensive statistics that can help us optimize its use for all indications.

Tumor angiogenesis after heated lipiodol infusion via the hepatic artery in a rabbit model of VX2 liver cancer

Objectives

This study aimed to observe the changes in tumor angiogenesis after heated lipiodol (60°C) infusion via the hepatic artery in a rabbit model of VX2 liver cancer.

Materials and Methods

Twenty rabbits with VX2 hepatic tumors were randomly divided into 2 groups (10 rabbits in each group). Under anesthesia, a trans-catheter hepatic arterial infusion was performed, and lipiodol (37°C; control group) or heated lipiodol (60°C; treated group) was injected into the hepatic arteries of the animals. Then, changes in tumor angiogenesis were assessed using the following markers and methods. 1. Vascular endothelial growth factor receptor (VEGFR) and vascular endothelial growth factor (VEGF) expression levels in the tumor were assessed using western blotting and real-time quantitative polymerase chain reaction (PCR). 2. Proliferating cell nuclear antigen (PCNA) expression in the tumor was assessed through immunohistochemical staining. 3. The morphological changes in tumor vascular endothelial cells were observed using transmission electron microscopy (TEM).

Results

VEGFR and VEGF mRNA and protein expression levels were reduced in the treated group compared to the control group. PCNA protein showed reduced expression levels in the treated group compared to the control group. TEM indicated that the endothelial cell endoplasmic reticulum expanded, the chondriosome was swollen, and the endothelial cell microvilli were decreased after heated lipiodol infusion.

Conclusions

The tumor angiogenesis of rabbits with VX2 cancer was inhibited after arterial heated lipiodol infusion compared to lipiodol infusion.

Hyperthermia versus Oncothermia: Cellular Effects in Complementary Cancer Therapy

Hyperthermia means overheating of the living object completely or partly. Hyperthermia, the procedure of raising the temperature of a part of or the whole body above normal for a defined period of time, is applied alone or as an adjunctive with various established cancer treatment modalities such as radiotherapy and chemotherapy. However, hyperthermia is not generally accepted as conventional therapy. The problem is its controversial performance. The controversy is originated from the complications of the deep heating and the focusing of the heat effect. The idea of oncothermia solves the selective deep action on nearly cellular resolution. We would like to demonstrate the force and perspectives of oncothermia, as a highly specialized hyperthermia in clinical oncology. Our aim is to prove the ability of oncothermia to be a candidate to become a widely accepted modality of the standard cancer care. We would like to show the proofs and the challenges of the hyperthermia and oncothermia applications to provide the presently available data and summarize the knowledge in the topic. Like many early stage therapies, oncothermia lacks adequate treatment experience and long-range, comprehensive statistics that can help us optimize its use for all indications.

Protocol for long duration whole body hyperthermia in mice

Hyperthermia is a general term used to define the increase in core body temperature above normal. It is often used to describe the increased core body temperature that is observed during fever. The use of hyperthermia as an adjuvant has emerged as a promising procedure for tumor regression in the field of cancer biology. For this purpose, the most important requirement is to have reliable and uniform heating protocols. We have developed a protocol for hyperthermia (whole body) in mice. In this protocol, animals are exposed to cycles of hyperthermia for 90 min followed by a rest period of 15 min. During this period mice have easy access to food and water. High body temperature spikes in the mice during first few hyperthermia exposure cycles are prevented by immobilizing the animal. Additionally, normal saline is administered in first few cycles to minimize the effects of dehydration. This protocol can simulate fever like conditions in mice up to 12-24 hr. We have used 8-12 weeks old BALB/Cj female mice to demonstrate the protocol.

Changes in hepatic blood flow during transcatheter arterial infusion with heated saline in hepatic VX2 tumor

PURPOSE

This study evaluates the influence of transcatheter arterial infusion with heated saline on hepatic arterial and portal venous blood flows to tumor and normal hepatic tissues in a rabbit VX2 tumor model.

METHODS

All animal experiments were approved by the institutional animal care and use committee. Twenty rabbits with VX2 liver tumors were divided into the following two groups: (a) the treated group (n = 10), which received a 60 mL transarterial injection of 60 °C saline via the hepatic artery; (b) the control group (n = 10), which received a 60 mL injection of 37 °C saline via the hepatic artery. Using ultrasonography, the blood flows in both the portal vein and hepatic artery were measured, and the changes in the hemodynamic indices were recorded before and immediately after the injection. The changes in the tumor and normal liver tissues of the two groups were histopathologically examined by hematoxylin and eosin staining after the injection.

RESULTS

After the transcatheter arterial heated infusion, there was a decrease in the hepatic arterial blood flow to the tumor tissue, a significant decrease in the hepatic artery mean velocity (P < 0.05), and a significant increase in the resistance index (P < 0.05). On hematoxylin and eosin staining, there were no obvious signs of tissue destruction in the normal liver tissue or the tumor tissue after heated perfusion, and coagulated blood plasma was observed in the cavities of intratumoral blood vessels in the treated group.

CONCLUSIONS

The changes in tumor blood flow in the rabbit VX2 tumor model were presumably caused by microthrombi in the tumor vessels, and the portal vein likely mediated the heat loss in normal liver tissue during the transarterial heated infusion.

Combined hyperthermia and radiotherapy for the treatment of cancer

Radiotherapy is used to treat approximately 50% of all cancer patients, with varying success. Radiation therapy has become an integral part of modern treatment strategies for many types of cancer in recent decades, but is associated with a risk of long-term adverse effects. Of these side effects, cardiac complications are particularly relevant since they not only adversely affect quality of life but can also be potentially life-threatening. The dose of ionizing radiation that can be given to the tumor is determined by the sensitivity of the surrounding normal tissues. Strategies to improve radiotherapy therefore aim to increase the effect on the tumor or to decrease the effects on normal tissues, which must be achieved without sensitizing the normal tissues in the first approach and without protecting the tumor in the second approach. Hyperthermia is a potent sensitizer of cell killing by ionizing radiation (IR), which can be attributed to the fact that heat is a pleiotropic damaging agent, affecting multiple cell components to varying degrees by altering protein structures, thus influencing the DNA damage response. Hyperthermia induces heat shock protein 70 (Hsp70; HSPA1A) synthesis and enhances telomerase activity. HSPA1A expression is associated with radioresistance. Inactivation of HSPA1A and telomerase increases residual DNA DSBs post IR exposure, which correlates with increased cell killing, supporting the role of HSPA1A and telomerase in IR-induced DNA damage repair. Thus, hyperthermia influences several molecular parameters involved in sensitizing tumor cells to radiation and can enhance the potential of targeted radiotherapy. Therapy-inducible vectors are useful for conditional expression of therapeutic genes in gene therapy, which is based on the control of gene expression by conventional treatment modalities. The understanding of the molecular response of cells and tissues to ionizing radiation has lead to a new appreciation of the exploitable genetic alterations in tumors and the development of treatments combining pharmacological interventions with ionizing radiation that more specifically target either tumor or normal tissue, leading to improvements in efficacy.

Effect of transarterial pulsed perfusion with heated saline on tumor vascular permeability in a rabbit VX2 liver tumor model

PURPOSE

To evaluate the effect of transarterial pulsed perfusion with 60 °C saline on vascular permeability of tumor tissue, as well as its hepatic and renal toxicity, in a rabbit VX2 liver model.

MATERIALS AND METHODS

VX2 carcinomas were grown in rabbit livers, forty male New Zealand white tumor-bearing rabbits were randomly divided into four groups, followed by transarterial perfusion with 37 °C saline 60 ml (n=10) (control 1 group), transarterial pulsed perfusion with 37 °C saline 60 ml (n=10) (control 2 group), transarterial continuous perfusion with 60 °C saline 60 ml (n=10) (TCP group), transarterial pulsed perfusion with 60 °C saline 60 ml (n=10) (TPP group), the duration of time for tumor tissues in the range 43-45 °C of the treated groups was measured with needle thermometer during perfusion. Vascular permeability was assessed using the extravasation of Evans blue (EB) dye in the tumor or normal liver tissues of the four groups separately, the tumor or normal liver tissues of the four groups were estimated by histopathologic examination, and hepatic and renal toxicity was evaluated by means of blood biochemical analysis. The vascular endothelial cells in the tumor were observed by transmission electron microscopy (TEM).

RESULTS

The duration of time for tumor tissues in the range 43-45 °C of TPP group showed significantly longer than that of TCP group (12.3±3.3 min vs. 5.7±2.5 min) (P<0.01). After perfusion, the EB content of tumor tissue in TPP group showed significantly higher than that in TCP group (15.21±0.94 μg/100 mg vs. 10.71±0.84 μg/100 mg) (P<0.01), and also showed significantly higher than that in the two control group (3.42±0.87 μg/100 mg, 3.57±0.64 μg/100 mg) (P<0.01). Blood chemical analysis indicating there was an increase (P<0.05) in the serum ALT, AST levels in the two heated perfusion groups at 1, 2, 4, 8 h after infusion when compared to that in the two control group, but there was no significant difference in the serum ALT, AST levels among the four groups at 24 h after perfusion (P>0.05), and there was no significant difference in the serum BUN, Cr levels among the four groups at 1, 2, 4, 8, 24 h after perfusion. Observed by hematoxylin and eosin staining, there were no obvious signs of tissue destruction in liver tissue and tumor tissue. TEM indicating the endothelial cell gap was broadened and the endothelial cells' microvillus was decreased after heated perfusion.

CONCLUSIONS

The vascular permeability of the rabbit VX2 tumor was significantly increased after transarterial pulsed perfusion with 60°C saline without significant increase in hepatic and renal toxicity.

Present and future technology for simultaneous superficial thermoradiotherapy of breast cancer

This paper reviews systems and techniques to deliver simultaneous thermoradiotherapy of breast cancer. It first covers the clinical implementation of simultaneous delivery of superficial (microwave or ultrasound) hyperthermia and external photon beam radiotherapy, first using a Cobalt-60 teletherapy unit and later medical linear accelerators. The parallel development and related studies of the Scanning Ultrasound Reflector Linear Arrays System (SURLAS), an advanced system specifically designed and developed for simultaneous thermoradiotherapy, follows. The performance characteristics of the SURLAS are reviewed and power limitation problems at high acoustic frequencies (>3 MHz) are discussed along with potential solutions. Next, the feasibility of simultaneous SURLAS hyperthermia and intensity modulated radiation therapy/image-guided radiotherapy (IMRT/IGRT) is established based on published and newly presented studies. Finally, based on the encouraging clinical results thus far, it is concluded that new trials employing the latest technologies are warranted along with further developments in treatment planning.

Do liposomal apoptotic enhancers increase tumor coagulation and end-point survival in percutaneous radiofrequency ablation of tumors in a rat tumor model?

PURPOSE

To characterize effects of combining radiofrequency (RF) ablation with proapoptotic intravenous liposome-encapsulated paclitaxel and doxorubicin on tumor destruction, apoptosis and heat-shock protein (HSP) production, intratumoral drug accumulation, and end-point survival.

MATERIALS AND METHODS

R3230 mammary adenocarcinomas (n = 177) were implanted in 174 rats in this animal care committee-approved study. Tumors received (a) no treatment, (b) RF ablation, (c) paclitaxel, (d) RF ablation followed by paclitaxel (RF ablation-paclitaxel), (e) paclitaxel before RF ablation (paclitaxel-RF ablation), (f) RF ablation followed by doxorubicin (RF ablation-doxorubicin), (g) paclitaxel followed by doxorubicin without RF ablation (paclitaxel-doxorubicin), or (h) paclitaxel before RF ablation, followed by doxorubicin (paclitaxel-RF ablation-doxorubicin). Tumor coagulation area and diameter were compared at 24-96 hours after treatment. Intratumoral paclitaxel uptake with and without RF ablation were compared. Immunohistochemical staining revealed cleaved caspase-3 and 70-kDa HSP (HSP70) expression. Tumors were randomized into eight treatment arms for Kaplan-Meier analysis of defined survival end-point (3.0-cm diameter).

RESULTS

Paclitaxel-RF ablation increased tumor coagulation over RF ablation or paclitaxel (mean, 14.0 mm ± 0.9 [standard deviation], 6.7 mm ± 0.6, 2.5 mm ± 0.6, respectively; P < .001). Paclitaxel-RF ablation-doxorubicin had similar tumor coagulation (P < .05), compared with paclitaxel-RF ablation, at 24 and 96 hours. Mean intratumoral paclitaxel accumulation for paclitaxel-RF ablation (6.76 μg/g ± 0.35) and RF ablation-paclitaxel (9.28 μg/g ± 0.87) increased over that for paclitaxel (0.63 μg/g ± 0.25, P < .001). Paclitaxel substantially increased apoptosis and decreased HSP70 expression at coagulation margin. Mean end-point survival for paclitaxel-RF ablation-doxorubicin (56.8 days ± 25.3) was greater, compared with that for paclitaxel-RF ablation or RF ablation-paclitaxel (17.6 days ± 2.5), RF ablation-doxorubicin (30.3 days ± 4.9, P < .002), or paclitaxel-doxorubicin (27.9 days ± 4.1, P < .001).

CONCLUSION

Selecting adjuvant liposomal chemotherapies (paclitaxel, doxorubicin) to target cellular apoptosis and HSP production effectively increases RF ablation-induced tumor coagulation and end-point survival, and combined multidrug approach results in even better outcomes.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.10100500/-/DC1.

Effective learning strategies for real-time image-guided adaptive control of multiple-source hyperthermia applicators

PURPOSE

This paper investigates overall theoretical requirements for reducing the times required for the iterative learning of a real-time image-guided adaptive control routine for multiple-source heat applicators, as used in hyperthermia and thermal ablative therapy for cancer.

METHODS

Methods for partial reconstruction of the physical system with and without model reduction to find solutions within a clinically practical timeframe were analyzed. A mathematical analysis based on the Fredholm alternative theorem (FAT) was used to compactly analyze the existence and uniqueness of the optimal heating vector under two fundamental situations: (1) noiseless partial reconstruction and (2) noisy partial reconstruction. These results were coupled with a method for further acceleration of the solution using virtual source (VS) model reduction. The matrix approximation theorem (MAT) was used to choose the optimal vectors spanning the reduced-order subspace to reduce the time for system reconstruction and to determine the associated approximation error. Numerical simulations of the adaptive control of hyperthermia using VS were also performed to test the predictions derived from the theoretical analysis. A thigh sarcoma patient model surrounded by a ten-antenna phased-array applicator was retained for this purpose. The impacts of the convective cooling from blood flow and the presence of sudden increase of perfusion in muscle and tumor were also simulated.

RESULTS

By FAT, partial system reconstruction directly conducted in the full space of the physical variables such as phases and magnitudes of the heat sources cannot guarantee reconstructing the optimal system to determine the global optimal setting of the heat sources. A remedy for this limitation is to conduct the partial reconstruction within a reduced-order subspace spanned by the first few maximum eigenvectors of the true system matrix. By MAT, this VS subspace is the optimal one when the goal is to maximize the average tumor temperature. When more than 6 sources present, the steps required for a nonlinear learning scheme is theoretically fewer than that of a linear one, however, finite number of iterative corrections is necessary for a single learning step of a nonlinear algorithm. Thus, the actual computational workload for a nonlinear algorithm is not necessarily less than that required by a linear algorithm.

CONCLUSIONS

Based on the analysis presented herein, obtaining a unique global optimal heating vector for a multiple-source applicator within the constraints of real-time clinical hyperthermia treatments and thermal ablative therapies appears attainable using partial reconstruction with minimum norm least-squares method with supplemental equations. One way to supplement equations is the inclusion of a method of model reduction.

Continuous mild heat stress induces differentiation of mammalian myoblasts, shifting fiber type from fast to slow

Local hyperthermia has been widely used as physical therapy for a number of diseases such as inflammatory osteoarticular disorders, tendinitis, and muscle injury. Local hyperthermia is clinically applied to improve blood and lymphatic flow to decrease swelling of tissues (e.g., skeletal muscle). As for muscle repair following injury, the mechanisms underlying the beneficial effects of hyperthermia-induced muscle repair are unknown. In this study, we investigated the direct effects of continuous heat stress on the differentiation of cultured mammalian myoblasts. Compared with control cultures grown at 37 degrees C, incubation at 39 degrees C (continuous mild heat stress; CMHS) enhanced myotube diameter, whereas myotubes were poorly formed at 41 degrees C by primary human skeletal muscle culture cells, human skeletal muscle myoblasts (HSMMs), and C2C12 mouse myoblasts. In HSMMs and C2C12 cells exposed to CMHS, mRNA and protein levels of myosin heavy chain (MyHC) type I were increased compared with the control cultures. The mRNA level of MyHC IIx was unaltered in HSMMs and decreased in C2C12 cells, compared with cells that were not exposed to heat stress. These results indicated a fast-to-slow fiber-type shift in myoblasts. We also examined upstream signals that might be responsible for the fast-to-slow shift of fiber types. CMHS enhanced the mRNA and protein levels of peroxisome proliferator-activated receptor-gamma coactivator (PGC)-1alpha in HSMMS and C2C12 cells but not the activities of MAPKs (ERK1/2 and p38 MAPK) in HSMMs and C2C12 cells. These data suggest that CMHS induces a fast-to-slow fiber-type shift of mammalian myoblasts through PGC-1alpha.

Systemic chemotherapy using paclitaxel and carboplatin plus regional hyperthermia and hyperbaric oxygen treatment for non-small cell lung cancer with multiple pulmonary metastases: preliminary results

PURPOSE

The purpose of this retrospective case series was to evaluate the toxicity and efficacy of systemic chemotherapy using paclitaxel and carboplatin plus regional hyperthermia (HT) and hyperbaric oxygen treatment (HBO) for non-small-cell lung cancer (NSCLC).

MATERIALS AND METHODS

Twenty-two patients with NSCLC with multiple pulmonary metastases intravenously received paclitaxel (50 mg/m(2)), carboplatin (area under the curve of 1.0-1.5) and 10% glucose weekly for 3 out of 4 weeks. Hyperthermia (HT) of the whole thoracic region was also administered weekly during intravenous infusion of carboplatin in all patients. In addition, 16 (72%) of 22 patients received hyperbaric oxygen (HBO) treatment immediately after weekly chemotherapy. A total of 107 cycles were performed in 16 patients with HBO, and 27 cycles in 6 patients without HBO. The toxicity and efficacy of these patients were retrospectively analyzed.

RESULTS

Both the hematologic and non-hematologic toxicities were mild and leucopenia/neutropenia of > or = grade 3 was seen in one patient, while pneumonitis of > or = grade 3 occurred in one patient. Fourteen (64%) of 22 patients had an objective response. The median time to progression of disease in all patients was 8 months and in 16 patients with HBO was 9 months. Four (44%) of 9 patients with prior chemotherapy including paclitaxel and carboplatin obtained objective responses.

CONCLUSIONS

The novel combined therapy of paclitaxel and carboplatin with HT and HBO may therefore be a feasible and promising modality for treating NSCLC with multiple pulmonary metastases, and the results justify further evaluation to clarify the benefits of this treatment regimen.

Heat-responsive gene expression for gene therapy

Therapy-inducible vectors are useful for conditional expression of therapeutic genes in gene therapy, which is based on the control of gene expression by conventional treatment modalities. By this approach, combination of chemotherapy, radiation or hyperthermia with gene therapy can result in considerable, additive or synergistic improvement of therapeutic efficacy. This concept has been successfully tested in particular for gene therapy of cancer. The identification of efficient heat-responsive gene promoters provided the rationale for heat-regulated gene therapy. The objective of this review is to provide insights into the cellular mechanisms of heat-shock response, as prerequisite for therapeutic actions of hyperthermia and into the field of heat-responsive gene therapy. Furthermore, the major strategies of heat-responsive gene therapy systems in particular for cancer treatment are summarized. The developments for heat-responsive vector systems for in vitro and in vivo approaches are discussed. This review will provide an overview for this gene therapy strategy and its potential for multimodal therapeutic concepts in the clinic.

Radiochemotherapy for bladder cancer

Standard treatment for muscle-invasive bladder cancer is cystectomy. Multimodality treatment, including transurethral resection of the bladder tumour, radiation therapy, chemotherapy and deep regional hyperthermia, has been shown to produce survival rates comparable with those of cystectomy. With these programmes, cystectomy has been reserved for patients with incomplete response or local relapse. During the past two decades, organ preservation by multimodality treatment has been investigated in prospective series from single centres and co-operative groups, with more than 1000 patients included. Five-year overall survival rates in the range of 50-60% have been reported, and about three-quarters of the surviving patients maintained their bladder. Clinical criteria helpful in determining patients for bladder preservation include such variables as small tumour size (<5 cm), early tumour stage, a visibly and microscopically complete transurethral resection, absence of ureteral obstruction, and no evidence of pelvic lymph node metastases. On multivariate analysis, the completeness of transurethral resection of a bladder tumour was found to be one of the strongest prognostic factors for overall survival. Patients at greater risk of new tumour development after initial complete response are those with multifocal disease and extensive associated carcinoma in situ at presentation. Close co-ordination among all disciplines is required to achieve optimal results. Future investigations will focus on optimising radiation techniques, including all possibilities of radiosensitisation (e.g. concurrent radiochemotherapy, deep regional hyperthermia), and incorporating more effective systemic chemotherapy, and the proper selection of patients based on predictive molecular makers.

Ultrasound triggered image-guided drug delivery

The integration of therapeutic interventions with diagnostic imaging has been recognized as one of the next technological developments that will have a major impact on medical treatments. Important advances in this field are based on a combination of progress in guiding and monitoring ultrasound energy, novel drug classes becoming available, the development of smart delivery vehicles, and more in depth understanding of the mechanisms of the cellular and molecular basis of diseases. Recent research demonstrates that both pressure sensitive and temperature sensitive delivery systems hold promise for local treatment. The use of ultrasound for the delivery of drugs has been demonstrated in particular the field of cardiology and oncology for a variety of therapeutics ranging from small drug molecules to biologics and nucleic acids.

Recent insights into the biological action of heavy-ion radiation

Biological effectiveness varies with the linear energy transfer (LET) of ionizing radiation. During cancer therapy or long-term interplanetary manned explorations, humans are exposed to high-LET energetic heavy ions that inactivate cells more effectively than low-LET photons like X-rays and gamma-rays. Recent biological studies have illustrated that heavy ions overcome tumor radioresistance caused by Bcl-2 overexpression, p53 mutations and intratumor hypoxia, and possess antiangiogenic and antimetastatic potential. Compared with heavy ions alone, the combination with chemical agents (a Bcl-2 inhibitor HA14-1, an anticancer drug docetaxel, and a halogenated pyrimidine analogue 5-iodo-2'-deoxyuridine) or hyperthermia further enhances tumor cell killing. Beer, its certain constituents, or melatonin ameliorate heavy ion-induced damage to normal cells. In addition to effects in cells directly targeted with heavy ions, there is mounting evidence for nontargeted biological effects in cells that have not themselves been directly irradiated. The bystander effect of heavy ions manifests itself as the loss of clonogenic potential, a transient apoptotic response, delayed p53 phosphorylation, alterations in gene expression profiles, and the elevated frequency of gene mutations, micronuclei and chromosome aberrations, which arise in nonirradiated cells having received signals from irradiated cells. Proposed mediating mechanisms involve gap junctional intercellular communication, reactive oxygen species and nitric oxide. This paper reviews briefly the current knowledge of the biological effects of heavy-ion irradiation with a focus on recent findings regarding its potential benefits for therapeutic use as well as on the bystander effect.