Combination hyperthermia and radiation therapy for cutaneous malignant melanoma

miR-182 Enhanced the Proliferation, Migration and Invasion of Malignant Melanoma Cells by Modulating Zinc Finger Protein 36, C3H Type-Like 1 (ZFP36L1)

Background and Objectives: Malignant melanoma (MM) is the most aggressive skin cancer based on the enhanced proliferative and metastatic ability of melanocytes. Recently, some studies have revealed that higher levels of ZFP36L1 suppressed the proliferation, migration and invasion of multiple types of cancer cells. By searching the database, it was found that miR-182 has the potential to target ZFP36L1 and reduce ZFP36L1 expression. However, whether the possible effects of miR-182 on the development of malignant melanoma and the underlying mechanism remains largely unclear. Materials and Methods: ZFP36L1 and miR-182 expression levels in malignant melanoma cell lines were examined by performing western blotting and RT-qPCR. Then, CCK-8, wound healing and transwell assays were exploited to determine the potential roles of ZFP36L1 and miR-182in MM cells, respectively. Results: In this study, aberrant downregulation of ZFP36L1 was observed in MM cell lines (WM-115, A375). ZFP36L1 overexpression repressed the proliferation, migration and invasion of MM cells. Besides, bioinformatics analysis and luciferase reporter assay confirmed that miR-182 directly target ZFP36L1 and suppressed ZFP36L1 expression. What’s more, miR-182 weakened the inhibitory efficacy of ZFP36L1 on the proliferation, migration and invasion of these two cells. Conclusions: The study validated that miR-182 promoted the proliferation, migration and invasion of malignant melanoma cells through the repression of ZFP36L1.

lncRNA TINCR attenuates the proliferation and invasion, and enhances the apoptosis of cutaneous malignant melanoma cells by regulating the miR‑424‑5p/LATS1 axis

Cutaneous malignant melanoma (CMM) is responsible for ≥1/2 of skin cancer‑related mortalities. The aberrant expression of long non‑coding RNAs (lncRNAs) has been associated with the development of CMM. However, to the best of our knowledge, the role of the lncRNA TINCR ubiquitin domain containing (TINCR) in CMM has not been previously investigated, and thus, the current study aimed to evaluate this in vitro and in vivo. Reverse transcription‑quantitative PCR (RT‑qPCR) was used to analyze microRNA (miR)‑424‑5p expression, and RT‑qPCR and western blotting were used to measure TINCR, large tumor suppressor kinase 1 (LATS1), cellular communication network factor 2 (CTGF), cellular communication network factor 1 (CCN1) and AXL receptor tyrosine kinase (AXL) mRNA and protein expression levels, respectively. Cell Counting Kit‑8, flow cytometry and Transwell assays were used to detect the proliferation, apoptosis and invasion of CMM cell lines, respectively. The binding sites between TINCR and miR‑424‑5p were predicted using the miRDB database. A dual luciferase reporter assay and RT‑qPCR were used to identify the relationship between TINCR and miR‑424‑5p in CMM cell lines. The bioinformatics analysis revealed that TINCR was one of the most significantly downregulated lncRNAs in CMM, and advanced stage CMM tissues showed the greatest decrease in TINCR expression. Moreover, in the collected CMM tissues and tested cell lines of the current study, TINCR expression was found to be downregulated compared with the respective controls. Notably, TINCR overexpression inhibited the expression levels of CTGF, CCN1 and AXL, decreased the proliferation and invasion, and induced the apoptosis of CMM cell lines. In addition, a mutual binding association was identified between miR‑424‑5p and TINCR in CMM cells. LATS1, a target of miR‑424‑5p, was found to be positively regulated by TINCR. TINCR activated Hippo signaling and repressed the activity of Yes 1 associated transcriptional regulator by regulating LATS1 expression, while LATS1 knockdown reversed the effect of TINCR overexpression on CMM cells. Collectively, the findings of the present study suggested that TINCR may attenuate the progression of CMM by regulating the miR‑424‑5p/LATS1 signaling axis. These results indicated that TINCR may play a tumor suppressive role in CMM.

Quo Vadis Oncological Hyperthermia (2020)?

Heating as a medical intervention in cancer treatment is an ancient approach, but effective deep heating techniques are lacking in modern practice. The use of electromagnetic interactions has enabled the development of more reliable local-regional hyperthermia (LRHT) techniques whole-body hyperthermia (WBH) techniques. Contrary to the relatively simple physical-physiological concepts behind hyperthermia, its development was not steady, and it has gone through periods of failures and renewals with mixed views on the benefits of heating seen in the medical community over the decades. In this review we study in detail the various techniques currently available and describe challenges and trends of oncological hyperthermia from a new perspective. Our aim is to describe what we believe to be a new and effective approach to oncologic hyperthermia, and a change in the paradigm of dosing. Physiological limits restrict the application of WBH which has moved toward the mild temperature range, targeting immune support. LRHT does not have a temperature limit in the tumor (which can be burned out in extreme conditions) but a trend has started toward milder temperatures with immune-oriented goals, developing toward immune modulation, and especially toward tumor-specific immune reactions by which LRHT seeks to target the malignancy systemically. The emerging research of bystander and abscopal effects, in both laboratory investigations and clinical applications, has been intensified. Our present review summarizes the methods and results, and discusses the trends of hyperthermia in oncology.

LncRNA FOXD3-AS1 promotes proliferation, invasion and migration of cutaneous malignant melanoma via regulating miR-325/MAP3K2

PURPOSE

The aim was to study the mechanism of LncRNA FOXD3-AS1 in cutaneous melanoma.

METHODS

FOXD3-AS1 levels in 47 pairs of melanoma samples were detected. We used qRT-PCR to detect FOXD3-AS1, miR-325 and MAP3K2 expression in different staging samples and cutaneous melanoma cell lines. We used Kaplan-Meier curve to analyze survival rate in patients with FOXD3-AS1 high and low expression. Sh-FOXD3-AS1, miR-325, miR-325 inhibitor and oeMAP3K2 were transfected. The proliferation of A375 and SK-MEL-1 was detected by CCK8 and EdU labeling assay and cell clone formation assay. Dual luciferase reporter assay and pull down assay was used to confirm the binding site of FOXD3-AS1, miR-325 and MAP3K2. Flow cytometry was applied to detect the effect of lncRNA on cell cycle. The migration and invasion ability were detected by transwell assay.

RESULTS

LncRNA FOXD3-AS1 highly expressed in cutaneous melanoma cells and tissues. Patients with highly expressed LncRNA FOXD3-AS1 were always with shorter overall survival time. When LncRNA FOXD3-AS1 was knockdown, proliferation, invasion and migration of cutaneous malignant melanoma, and tumor weight was inhibited, and cell cycle was arrested. LncRNA FOXD3-AS1 negatively regulated the expression of miR-325, and then improved the level of MAP3K2. MiR-325 was with similarly effects on above biological process, and MAP3K2 overexpression could rescue the influence of sh-FOXD3-AS1. Tumor volume and weight were measured to confirm the effect of sh-FOXD3-AS1 in vivo.

CONCLUSION

LncRNA FOXD3-AS1 could promote proliferation, invasion and migration of cutaneous malignant melanoma via regulating miR-325/MAP3K2 axis.

Evaluation of nonlinear optical behavior of mouse colon cancer cell line CT26 in hyperthermia treatment

Hyperthermia treatment can induce component changes on cell. This study explored the potential of Z-scan to improve accuracy in the identification of subtle differences in mouse colon cancer cell line CT26 during hyperthermia treatment. Twenty-one samples were subjected individually to treatment of hyperthermia at 41, 43, and 45 °C. Each hyperthermia treatment was done in six different time (15, 30, 45, 60, 75, and 90 min). Two optical setups were used to investigate the linear and nonlinear optical behavior of samples. Prior to the Z-scan technique, all samples were fixed with 1 mL of 5% paraformaldehyde. The linear optical setup indicated that extinction coefficient cannot monitor cell changes at different treatment regimes. But the nonlinear behavior of CT26 in all hyperthermia treatment regimens was different. By increasing the time and/or temperature of hyperthermia treatments, change in the sign of nonlinear refractive index from negative to positive occurred in earlier time intervals. This phenomenon was seen for 41, 43, and 45 °C in 75, 60, and 45 min, respectively. The results showed that the Z-scan technique is a reliable method with the potential to characterize cell changes during hyperthermia treatment regimes. Nonlinear refractive index can be used as a new index for evaluation of cell damage.

Radio-Hyperthermia in Post-Surgical Recurrence of Melanoma

Aims and background

Malignant melanoma is one of the most radioresistant tumors. It can be treated with combinated hyperthermia and radiation therapy.

Methods

From January 1991 through June 1992, 7 patients, 1 male and 6 female, aged 40-88 years (mean 75), with skin and nodal postsurgical recurrences of melanoma, were treated with a combination of radiation therapy and hyperthermia. Two patients presented systemic disease when they reached our observation, but all of them were without symptoms. None of them underwent surgical excision of the recurrence before or during thermoradiotherapy. None received chemotherapy for these recurrences or had received radiotherapy in the past. They were irradiated with electron beams, with electron energies selected according to the depth of the lesions. The total dose was 40 Gy in 10 fractions in 5 weeks. Hyperthermia was administered for 10 minutes to 1 hour after irradiation. An inductive method of radiofrequency heating at 434 of 915 MHz was used depending on the depth of the lesions. In all of these treatments a ionized water bolus was used. The prescribed hyperthermic dose was 42 °C for half a hour. The treatments were carried out twice a week for 5 weeks. A fiberoptic multichannel thermometer was used for thermometry.

Results

Four patients (57 %) achieved a complete response, 2 patients (29 %) a partial response, and 1 patient (14 %) stabilization. We found no correlation between tumor volume and response rate. Site effects and complications of the treatment were minimal (moderate erythema).

Conclusions

Our results are in the wide range of values reported in the literature.

Multipronged Design of Light-Triggered Nanoparticles To Overcome Cisplatin Resistance for Efficient Ablation of Resistant Tumor

Chemotherapeutic drugs frequently encounter multiple drug resistance in the field of cancer therapy. The strategy has been explored with limited success for the ablation of drug-resistant tumor via intravenous administration. In this work, the rationally designed light-triggered nanoparticles with multipronged physicochemical and biological features are developed to overcome cisplatin resistance via the assembly of Pt(IV) prodrug and cyanine dye (Cypate) within the copolymer for efficient ablation of cisplatin-resistant tumor. The micelles exhibit good photostability, sustained release, preferable tumor accumulation, and enhanced cellular uptake with reduced efflux on both A549 cells and resistant A549R cells. Moreover, near-infrared light not only triggers the photothermal effect of the micelles for remarkable photothermal cytotoxicity, but also leads to the intracellular translocation of the micelles and reduction-activable Pt(IV) prodrug into cytoplasm through the lysosomal disruption, as well as the remarkable inhibition on the expression of a drug-efflux transporter, multidrug resistance-associated protein 1 (MRP1) for further reversal of drug resistance of A549R cells. Consequently, the multipronged effects of light-triggered micelles cause synergistic cytotoxicity against both A549 cells and A549R cells, and thus efficient ablation of cisplatin-resistant tumor without regrowth. The multipronged features of light-triggered micelles represent a versatile synergistic approach for the ablation of resistant tumor in the field of cancer therapy.

Efficacy of superficial and deep regional hyperthermia combined with systemic chemotherapy and radiotherapy in metastatic melanoma

BACKGROUND AND OBJECTIVE

Response rates of cutaneous-subcutaneous or lymph node metastases of melanoma to systemic chemotherapy are rather low. We report our clinical experience with superficial and deep regional hyperthermia in combination with radiotherapy and/or chemotherapy with carboplatin.

PATIENTS/METHODS

We treated 15 patients with metastatic melanoma (6 men, 9 women; age 39-84 years, mean age 60 years) by using superficial or deep regional hyperthermia produced by electromagnetic energy. Superficial hyperthermia was delivered to skin or lymph node metastases in combination with radiochemotherapy in 12 patients, while deep regional hyperthermia was administered with an annular array applicator to lymph node metastases either in combination with radiochemotherapy (1 patient) or with carboplatin alone (2 patients). The clinical response was assessed by clinical evaluation and/or computer tomography and/or ultrasonography at monthly intervals.

RESULTS

Both superficial and deep regional hyperthermia was well tolerated. We observed 5 complete local remissions (34%), 6 partial local remissions (40%) and 2 patients with stable disease (13%). The best results were obtained in cutaneous or retroperitoneal metastases.

CONCLUSIONS

Local response can be achieved in inoperable metastatic melanoma using superficial or deep regional hyperthermia in combination with radiochemotherapy or chemotherapy.

Regulators of homologous recombination repair as novel targets for cancer treatment

To cope with DNA damage, cells possess a complex signaling network called the ‘DNA damage response’, which coordinates cell cycle control with DNA repair. The importance of this network is underscored by the cancer predisposition that frequently goes along with hereditary mutations in DNA repair genes. One especially important DNA repair pathway in this respect is homologous recombination (HR) repair. Defects in HR repair are observed in various cancers, including hereditary breast, and ovarian cancer. Intriguingly, tumor cells with defective HR repair show increased sensitivity to chemotherapeutic reagents, including platinum-containing agents. These observations suggest that HR-proficient tumor cells might be sensitized to chemotherapeutics if HR repair could be therapeutically inactivated. HR repair is an extensively regulated process, which depends strongly on the activity of various other pathways, including cell cycle pathways, protein-control pathways, and growth factor-activated receptor signaling pathways. In this review, we discuss how the mechanistic wiring of HR is controlled by cell-intrinsic or extracellular pathways. Furthermore, we have performed a meta-analysis on available genome-wide RNA interference studies to identify additional pathways that control HR repair. Finally, we discuss how these HR-regulatory pathways may provide therapeutic targets in the context of radio/chemosensitization.

Gold nanoshelled liquid perfluorocarbon nanocapsules for combined dual modal ultrasound/CT imaging and photothermal therapy of cancer

The integration of multimodal contrast-enhanced diagnostic imaging and therapeutic capabilities could utilize imaging guided therapy to plan the treatment strategy based on the diagnostic results and to guide/monitor the therapeutic procedures. Herein, gold nanoshelled perfluorooctylbromide (PFOB) nanocapsules with PEGylation (PGsP NCs) are constructed by oil-in-water emulsion method to form polymeric PFOB nanocapsules, followed by the formation of PEGylated gold nanoshell on the surface. PGsP NCs could not only provide excellent contrast enhancement for dual modal ultrasound and CT imaging in vitro and in vivo, but also serve as efficient photoabsorbers for photothermal ablation of tumors on xenografted nude mouse model. To our best knowledge, this is the first report of gold nanoshell serving as both CT contrast agents and photoabsorbers for photothermal therapy. The novel multifunctional nanomedicine would be of great value to offer more comprehensive diagnostic information to guide more accurate and effective cancer therapy.

Cost-effectiveness analysis of electrochemotherapy with the Cliniporatortrade mark vs other methods for the control and treatment of cutaneous and subcutaneous tumors

INTRODUCTION

Tumors of any histological origin can give rise to cutaneous and subcutaneous metastases during follow-up. This study aims to evaluate the costs and benefits of electrochemotherapy (ECT) with the Cliniporatortrade mark vs other currently used methods in the control and treatment of cutaneous and subcutaneous advanced neoplasms.

MATERIALS AND METHODS

A cost-effectiveness analysis was carried out on ECT using the Cliniporator vs other techniques (radiotherapy, hyperthermia associated with radiotherapy and chemotherapy, interferon-alpha, and isolated limb perfusion) for the control and treatment of cutaneous and subcutaneous neoplasms. The direct health costs were attributed a value according to the Italian National Healthcare System. Resource consumption and clinical outcomes were derived from cost survey data collection and literature review.

RESULTS

ECT is cost-effective with an incremental cost effectiveness ratio (ICER) of euro1,571.53 to achieve a further additional response. Radiotherapy and interferon-alpha are the least effective strategies. A combination of hyperthermia, chemotherapy, radiotherapy, and interferon-alpha treatment are dominated by ECT (more costly and less effective). Isolated limb perfusion is the most effective treatment, but is very costly (euro18,530.47) because of the use of antiblastic drugs (TNFalpha), with an ICER of euro92,717.29.

CONCLUSIONS

After sensitivity analysis, the study results confirm the favorable cost-effectiveness ratio of ECT with the Cliniporator and justify its wider use.

Transpupillary thermotherapy of occult subfoveal choroidal neovascularization in patients with age-related macular degeneration

OBJECTIVE

To evaluate the efficacy of transpupillary thermotherapy for the treatment of occult subfoveal choroidal neovascularization (CNV) in patients with age-related macular degeneration.

DESIGN

A retrospective, noncomparative case series.

PARTICIPANTS

Sixteen eyes of 15 consecutive patients who presented with occult subfoveal choroidal neovascularization secondary to age-related macular degeneration.

INTERVENTION

After informed consent was obtained, 16 eyes of 15 patients were treated with transpupillary thermotherapy. All patients underwent pretreatment fluorescein angiography and were deemed untreatable by the Macular Photocoagulation Study standard. Transpupillary thermotherapy was delivered using a diode laser at 810 nm. A variable spot size of 1.2 mm, 2.0 mm, or 3.0 mm was used depending on the size of CNV. The diode laser was delivered through a contact lens, and treatment was initiated in one spot for 60 seconds' duration at a power range between 360 and 1000 mW. The end point was an area of no visible color change to a light-gray appearance.

MAIN OUTCOME MEASURES

In all eyes, outcome was assessed by Snellen chart visual acuity and clinical examination. In 10 of 16 eyes, preoperative and postoperative fluorescein angiography and optical coherence tomography were available. In the remaining 6 of 16 eyes, exudation was measured by postoperative clinical examination alone.

RESULTS

Three eyes (19%) showed a two-or-more-line improvement in visual acuity over a period of 6 to 25 months. Mean follow-up was 13 months. Visual acuity remained stable (no change or one-line improvement) in nine treated eyes (56%). The remaining four eyes (25%) showed a decline (equal to one-line worsening or greater) in visual acuity. Fifteen eyes (94%) demonstrated decreased exudation on fluorescein angiography, optical coherence tomography, and/or clinical examination.

CONCLUSIONS

Transpupillary thermotherapy shows no deleterious side effects in treating occult subfoveal choroidal neovascularization. A randomized, prospective study is necessary to evaluate treatment efficacy.

Transpupillary thermotherapy

Hyperthermia has long been recognized as potentially useful in the treatment of human neoplasms. Only recently has technology allowed hyperthermic treatment to be delivered to ocular structures in the form of ultrasound, microwave, or ferromagnetic energy. A novel technique, transpupillary thermotherapy, allows the direct application of hyperthermic energy to posterior segment ocular structures. The treatment of two posterior segment diseases, choroidal melanoma and choroidal neovascularization attributable to age related macular degeneration, are reviewed in this article.

Histopathological findings in human choroidal melanomas after transpupillary thermotherapy

AIMS

The effect of transpupillary thermotherapy (TTT) on human choroidal melanomas was investigated by means of histopathology.

METHODS

Before enucleation TTT was performed in 11 eyes with a xenon are photocoagulator with a red filter or a diode laser at 810 nm. The exposure time was 1 minute; the estimated temperature at the top of the tumour was about 65 degrees C.

RESULTS

Seven of 11 tumours developed necrosis to a maximum depth of 3.9 mm with a sharp demarcation between the necrotic and the viable part of the tumour. The depth correlated with penetration of heat into the tumour. Scattered small haemorrhages in the transitional zone between the necrotic and the viable part of the tumour were observed in three eyes but large haemorrhages were absent. Ocular media were not affected owing to the low rate of absorption of radiation at 810 nm. TTT did not cause significant scleral damage. Intrascleral tumour cells with a viable appearance were observed in one eye, where the tumour was almost totally necrotic.

CONCLUSION

Results show that TTT has potential as a conservative therapeutic treatment for choroidal melanomas.

Clinical experience using 8 MHz radiofrequency capacitive hyperthermia in combination with radiotherapy: results of a phase I/II study

PURPOSE

Since 1985, the University of Minnesota Hospital and Clinic has investigated the efficacy and safety of 8 MHz radiofrequency (RF) capacitive hyperthermia using the Thermotron RF-8. This study reports the thermometric and clinical results of 119 patients treated with RF hyperthermia in combination with radiotherapy (RT).

METHODS AND MATERIALS

Of 119 patients, 69 received high-dose RT and 50 patients received low-dose RT because of previous irradiation to the treatment site. The most common anatomic sites treated were within the pelvic cavity or head and neck area. Thirty-three percent and 24% of tumors treated were > 7 cm and > 10 cm in largest diameter, respectively. Forty percent of the patients had deep-seated tumors (depth > 6 cm). Hyperthermia was given as soon as possible after RT twice weekly, allowing at least 72 h between treatments. The objective was to raise intratumoral temperatures to 42-43 degrees C or above for 30-50 min while keeping normal tissue temperatures below 40-41 degrees C.

RESULTS

Of 119 patients, 40% achieved a Tmax tumor temperature of > 42 degrees C and 40% achieved 40-42 degrees C Tmax. Higher Tmax) tumor temperatures were observed as tumor size increased. Tumors > 10 cm in largest diameter had a Tmax of 42.2 degrees C. Tumor depth was not a significant factor for the tumor temperatures achieved. Of 119 patients, 11% achieved complete response and 38% achieved partial response. Of the no-response patients, 34% had symptomatic palliation and 15% had stable disease for at least 12 months after treatment. We were able to treat tumors of patients with subcutaneous fat as thick as 3 cm by precooling the fat for 20 min with 10-15 degrees C saline-filled boluses prior to the initiation of heating. During treatment, 60% of patients complained of varying degrees of pain and 19% had pain that was a factor in limiting treatment. Vital signs were relatively stable and not a factor in limiting treatment.

CONCLUSION

The Thermotron RF-8 is a useful hyperthermia device that can raise tumor temperatures to a therapeutic level (i.e., 42 degrees C) in a significant proportion of patients with superficial, subsurface, and deep-seated tumors, with minimal adverse effects, complications, and systemic stress. Further clinical studies using improved thermometry systems are warranted.

Prognostic factors in metastatic malignant melanoma treated with combined radiation therapy and hyperthermia

From May 1981 to September 1991, 38 patients with metastatic malignant melanoma were treated with combined radiation therapy and hyperthermia to a total of 97 hyperthermia treatment fields. Prior treatments to these sites included surgery (31 patients, 76 fields), chemotherapy (18 patients, 54 fields), immunotherapy (14 patients, 42 fields) and radiation therapy (7 patients, 13 hyperthermia fields). Hyperthermia was given to fields located in the head and neck region, trunk and extremities in 30, 45 and 22 cases, respectively. Nodular-diffuse tumours were present in 86 fields while 11 fields were treated for microscopic residual tumour deposits. Concurrent radiation therapy was given in 180-400 cGy per fraction, 2-5 times per week for a mean total dose of 4098 cGy per field. Hyperthermia treatments were delivered using either microwave or ultrasound devices (286 and 48 treatments, respectively) with a mean (range) of 3.4 (1-14) hyperthermia treatments per field for a mean (range) of 43 (10-70) min per field. Patients (n = 34; 84 fields) were available for follow-up for a mean (range) of 14.6 (0.4-82.5) months. At 3 weeks post-treatment, 34 fields had complete, ongoing, or partial responses; 39 fields had no response; and there were no recurrences in the 11 fields treated for microscopic residual disease. Local control was maintained in 31% (26/84) fields with a mean follow-up of 14.6 months. At 36 months, five patients remained alive with complete control of their treated local disease. Statistical analyses revealed that patients with soft tissue metastases only, who were older at the time of hyperthermia, had a longer time between initial diagnosis and hyperthermia treatment, received a higher dose of radiation, had no previous chemotherapy, and had small tumour volumes, had a higher initial response. Multivariate analyses revealed that the three-covariate model including time interval between initial diagnosis and hyperthermia treatment, previous chemotherapy, and metastases to soft tissue only, best predicted response. The results of the investigation support the continued study of combined radiation therapy and hyperthermia treatments for selected patients with metastatic melanoma, and indicate that long-term survival can occasionally be obtained with this approach.

Role of brachytherapy in malignant melanoma: a preliminary report

From August 1979 to May 1986, various brachytherapy techniques were applied at Memorial Sloan Kettering Cancer Center (MSKCC) in an adjuvant setting with/without surgery and external radiation therapy in the management of advanced malignant melanoma. Thirty-three patients underwent brachytherapy procedures. The patients' ages ranged from 35 to 82 years, with a median age of 56 years. Fourteen patients had disease localized to the implant site, whereas 19 patients also had disseminated disease elsewhere. The indications for implant were residual gross disease (21), microscopically positive margins (3), and histologically negative but clinically close margins of resection (9). Local control at the implant site was noted in 80% of patients at 6 months and 42% of patients at 1 year; two patients had reached 54 months and 72 months with no evidence of disease. Local control was 100% (9/9) in patients with histologically negative but clinically close margins of resection, and 48% (11/23) with microscopically positive margins and/or gross residual disease. Complications were seen as follows: delay in wound healing (1), wound infections (4), radiation enteritis (1), small bowel obstruction (1). The present study suggests that brachytherapy combined with surgery can achieve a good local control in patients with negative but clinically close margins of resection. In patients with gross residual disease who are at a high risk for local recurrence, approximately one-half can be locally controlled with this approach. These preliminary results should be tested in a prospective controlled study.

The current and potential role of hyperthermia in radiotherapy

Current clinical experience strongly suggests that hyperthermia will become an important modality as an adjuvant to radiotherapy in the treatment of locally advanced solid tumors. Hyperthermia must therefore be considered a topic of general interest. Biologically, hyperthermia has two different types of interactions with radiation. Firstly, heat has a radiosensitizing effect. This is most prominent with simultaneous application, but is of the same magnitude in both tumor and normal tissue and will not improve the therapeutic ratio unless the tumor is heated to a higher temperature than the normal tissue. Secondly, hyperthermia exhibits a direct cytotoxic effect, and a moderate heat treatment alone can almost selectively destroy tumor cells in a nutritionally deprived chronically hypoxic and acidic environment. Because such cells are the most radioresistant, a smaller radiation dose is needed to control the remaining more radiosensitive cells. If critical, irradiated normal tissues are also heated, the cytotoxicity is best utilised if heat is given at least 3-4 hours after irradiation. The magnitude of both the sensitizing and the cytotoxic effect depends on temperature and heating time. Clinically, heating of superficial tumors (e.g. breast, neck nodes and malignant melanoma) has confirmed the biological rationale for using hyperthermia as an adjuvant to radiotherapy. An overview of available data gives thermal enhancement ratios of approximately 1.5 in several superficial tumor sites after external heating. From a practical point of view, true simultaneous treatment is almost impossible using external heating, and the major effect of the combined treatment will have to rely on hyperthermic cytotoxicity. This makes the design of clinical schedules less complicated since only a few heat fractions may be needed to achieve an optimal effect. On this basis, several randomized clinical trials have been activated with the aim to evaluate the role of adjuvant hyperthermia in the primary treatment of advanced (superficial) tumors. In addition, studies are underway to specifically elucidate the clinical relevance of thermotolerance and other biological issues. So far, the clinical evaluation has almost solely been limited to superficial tumors, or to situations where interstitial heating is feasible. External heating of "deep" seated tumors is still preliminary, and most studies are in Phase I-II, with emphasis on toxicity and feasibility. The initial results are promising with regard to improved tumor control and acceptable toxicity.

Hyperthermia in combination with definitive radiation therapy: results of a Phase I/II RTOG Study

Between August 1981 and April 1986, 133 patients with superficial malignant tumors not previously treated with radiotherapy were entered on a Phase I/II RTOG study evaluating hyperthermia plus definitive radiotherapy. Eligible patients included those with superficial epithelial or mesenchymal tumors less than 4 cm in depth. Protocol radiotherapy specified a tumor dose of 60 Gy delivered in 1.8-2.0 Gy fractions 5 times/week with a boost of 5-10 Gy through reduced portals to residual tumor. Protocol hyperthermia, delivered twice weekly, was to start within 15 minutes following irradiation and to consist of 60 minutes of heat to a tumor temperature of 43 degrees C. Sixteen patients were excluded. Of the 117 eligible patients, the treated lesions had site/histologies which were 35% head & neck/squamous, 46% breast/adenocarcinoma, and 19% other site/histologies. Lesions were 3 cm or larger for 77% of patients. Of the 41 patients with head & neck/squamous lesions, skin or subcutaneous necrosis occurred within 6 months for 2% of the patients; 12% experienced thermal blisters. Fourteen patients were followed for 6 months or more following start of treatment; none of these experienced late toxicities more severe than telangiectasis. Complete responses were observed in 51% of these patients. Of the 54 patients with breast/adenocarcinoma lesions, skin or subcutaneous necrosis occurred within 6 months for 13% of the patients; 17% experienced thermal blisters. Thirty-seven patients were followed for 6 months or more following start of treatment; complications observed during this period included 13% with ulceration and one case of skin necrosis. Complete responses were observed in 85% of these patients. Local control was maintained at nearly this level for at least 2 years. Logistic regression analyses showed site/histology, greatest tumor diameter and average tumor temperature to be significantly related to response. Based on these promising findings, the RTOG has instituted a randomized Phase III study evaluating radiation therapy with or without hyperthermia in this patient population.

Thermoradiotherapy of malignant melanoma

From 1978 through February 1986, 49 measurable lesions in 18 patients with recurrent primary or metastatic malignant melanomas were treated with a combination of radiation therapy and hyperthermia. The primary sites were head and neck (eight), chest wall (two), pelvis (one), upper extremities (three), and lower extremities (35). Because of the length of the study, the dose and fractionation of radiation therapy varied (dose per fraction from less than 400 cGy to 800 cGy and a total dose of 2000 cGy to 6000 cGy). This variation was mostly dependent on the prior course of radiation therapy of these lesions. The hyperthermia technique used in these patients was superficial local microwave hyperthermia; a minority of patients were treated with ultrasound. Complete response was achieved in 29 lesions (59.2 per cent) and partial response in six lesions (12 per cent). In a separate analysis of 67 lesions with superficial malignant melanoma who were treated by radiation therapy alone, a 24 per cent complete response and a 34 per cent partial response were achieved. Detailed analyses are presented in regard to dose per fraction, total radiation dose, and the size of lesions.

Regional hyperthermia for deep-seated malignancies using the BSD annular array

Forty-four patients were treated using the BSD-1000 Annular Phased Array between April 1983 and December 1986. There were 32 pelvic, nine abdominal, two extremity, and one thoracic sites treated. Mean tumour volume was 646 cc. Thirty-nine patients had concurrent radiation therapy, receiving a mean dose of 38 Gy. Mean average temperature was 41.0 +/- 1.4 degrees C. Most patients experienced local or systemic toxicity, requiring temporary treatment interruption in 33 patients, and termination of treatment in eight. Chronic complications were seen in four, but these were in patients receiving high total radiation doses as well. There were six complete and five partial responses. Among the 32 patients with pelvic tumours, mean tumour volume was 317 cc, mean radiation dose was 42 Gy, and mean average temperature was 41.3 +/- 1.2 degrees C. There were five complete and four partial responses. Achieving tumour temperatures greater than or equal to 42 degrees C with the annular array is difficult, due to both systemic and local toxicity. To improve clinical hyperthermia for thoracic, abdominal, and pelvic tumours, new technologies such as steerable phased array microwave systems; scanned, focused ultrasound; and permanently implantable thermoregulating ferromagnetic seeds, or new approaches such as using drugs to alter blood flow, or combining hyperthermia with antineoplastic drugs or biological agents, will be necessary.

Hyperthermia as an adjuvant to radiotherapy in the treatment of malignant melanoma

One hundred and fifteen cutaneous or lymph node metastases from malignant melanoma were treated with three fractions of irradiation alone in 8 days (62 tumours) or followed by heat either immediately (simultaneous treatment, 26 tumours) or after an interval of 3-4 h (sequential therapy, 27 tumours). In addition, three tumours were treated unsuccessfully with heat alone. The total doses of radiation varied between 15 and 30 Gy, allowing a dose-response analysis. For irradiation alone the isoeffective dose to obtain 50 per cent complete response (TCD50) was 26.3 Gy. Addition of heat reduced the TCD50 significantly (p less than 0.05) with a thermal enhancement ratio (TER) of 1.43 for simultaneous treatment and 1.24 for sequential therapy. Also the persistent local control at 18 months was improved by hyperthermia (56 per cent versus 86 per cent, p less than 0.05). However, simultaneous treatment also enhanced the acute skin response to the same extent as the tumour (TER 1.42 for severe erythema). This schedule thus gave no therapeutic gain. In contrast, no normal tissue enhancement was found after sequential treatment (TER 1.02). Such a treatment schedule resulted in a significantly improved therapeutic ratio of 1.22. This effect was especially prominent in larger tumours (if sufficiently heated) and an analysis corrected for volume showed a TER of 1.51. A special analysis was performed in patients with multiple lesions. 15 pairs of tumours were given the same radiation dose, with or without hyperthermia. Out of these, 11 showed a better response, three showed the same response, and only in one pair was the best response in the tumour obtained by radiation alone.

The role of radiotherapy in recurrent and metastatic malignant melanoma: a clinical radiobiological study

A review of the literature and our data has been completed to analyze the clinical radiobiology of malignant melanoma. Six hundred eighteen radiotherapy-treated malignant melanoma lesions were analyzed with regard to radiobiological parameters such as total dose, dose per fraction, treatment time, tumor volume, and various fractionation models. Forty-eight per cent of the treated tumors achieved complete response, which was persistent in 87% after 5 years. Neither total dose, treatment time, nor various modifications of the NSD concept showed any well-defined correlation with response. There was, however, a significant relationship between dose per fraction and response, and a high dose per fraction yielded a significantly better response (59% CR for doses greater than 4 Gy versus 33% CR for doses per fraction less than or equal to 4 Gy). The lack of treatment time influence allowed analysis of the data according to the linear-quadratic model, resulting in an alpha/beta ratio of 2.5 Gy. Using this ratio, an iso-effect for different fractionation schedules could be estimated by the extrapolated total-dose (ETD). The ratio was further improved when corrected for the tumor volume. Thus, an iso-effect formula for malignant melanoma could be calculated as: ETDvol (Gy) = D X [d + 2.5)/2.5) X M-.33, where D and d are total dose and dose per fraction in Gy, respectively, and M is the mean tumor diameter in cm. Based on a logit analysis, a complete response level of 50% appeared at an ETDvol value of 83 Gy. The formula is currently the best way to determine an optimal radiation schedule for an effective radiation treatment of malignant melanoma. The tumor response was further improved in 134 additional cases receiving adjuvant hyperthermia. Here, a thermal enhancement ratio (TER) of 2.0 was observed. In a group of 131 patients with only local or regional disease, a 5 year survival rate of 49% was observed in 77 patients with persistent local tumor control, but only 3% survived among the 54 patients in whom local therapy failed. It is therefore, highly important to the probability of survival in recurrent melanoma that proper local treatment be performed.

Ethanol. A heat sensitizer on neuroblastoma cells in culture

The presence of 1% ethanol in culture medium during heat treatment (40 degrees C for 8 hours and 43 degrees C for 15 minutes) was sufficient to enhance the effect of hyperthermia on murine neuroblastoma cells (NBP2) in culture, on the criteria of growth (number of viable cells per dish) and survival (colony formation). However, the metabolites of ethanol, acetaldehyde, and sodium acetate at concentrations of 0.003% and 0.125% in culture medium, respectively, under the same experimental conditions did not modify the effect of heat (40 degrees C) on these cells. The presence of same concentration of ethanol, acetaldehyde, or sodium acetate for 15 minutes or 8 hours at 37 degrees C did not affect the growth or the survival of NB cells in culture. These results suggest that ethanol itself rather than its metabolites is responsible for the enhancement of heat effect on NB cells. When ethanol and its metabolites were allowed to remain in the culture medium for the entire periods of heat treatment and observation, they also enhanced the effects of heat on NB cells; however, acetaldehyde was more effective.

Improved response of a murine fibrosarcoma (Meth-A) to interstitial radiation when combined with hyperthermia

Removable Iridium-192 implants provided a dose of 10 Gy/day or 41.5 cGy/hr at 0.5 cm from the center of 1.0 cm diameter tumors. The total radiation (x) alone was 20, 40 or 60 Gy, representing 2, 4, or 6 days of continuous radiation. The doses used for the combined treatments at elevated temperatures were 10, 20 or 30 Gy. The local tumor hyperthermia (LTH) treatment (43.6 for 35 min, water bath) was administered once for each 10 Gy of dose. The combined radiation + LTH was clearly superior to that achieved with radiation or LTH alone and yielded Thermal Enhancement Ratios (TER) of 3.4-3.9. Local tumor control rate was 67% and 89% for the 20 and 30 Gy x + LTH groups, respectively. A comparison of the results obtained in this study with those of earlier studies on the same tumor system indicate that the effects of Iridium-192 alone on this rapidly proliferating tumor were comparable to similar total doses of fractionated external beam radiation. Iridium + LTH produced a tumor response comparable to that achieved with external fractionated radiation + LTH. Combined treatment effect of elevated temperature appears to be less dose rate dependent in the range of 40 cGy/hr to 100 cGy/min and more dependent upon total dose accumulation.

Local hyperthermia in combination with definitive radiotherapy: increased tumor clearance, reduced recurrence rate in extended follow-up

Fifty-nine patients with superficial malignancies appropriate for treatment with definitive radiotherapy and technically suitable for application of local microwave hyperthermia were available for at least 6 months follow-up. Thirty-one of these patients presented with two lesions, only one of which was heated, the other serving as internal control. The responses of the lesions which were heated were compared with those receiving only radiation. The heated lesions responded more quickly, reconfirming observations previously made. However, at subsequent 6 months, 1 year, 18 months and 2 years follow-ups, tumor clearance was shown to be significantly more complete as compared with the internal controls. At 6 months follow-up complete response with combined therapy was observed in 27 of 31 lesions (87%) in contrast to complete response in 12 of 31 (39%) lesions treated with radiotherapy alone. At one year combined modality treatment produced complete response in 19 of 19 lesions (100%) while radiotherapy alone yielded complete response in 10 of 19 lesions (53%). At 18 months, 8 of 9 lesions (89%) treated with combined therapy remained controlled, 1 having recurred. Seven of 9 (78%) treated by radiotherapy alone were controlled, 2 having recurred. At 2 years, 6 patients were available for follow-up and 6 of 6 (100%) of lesions treated with combined modality remained controlled. Among those treated by radiotherapy alone, 5 of 6 (83%) remained controlled, while 1 recurred. The rate of tumor recurrence among the heated lesions was significantly lower than was found among the controls. The recurrence rate among the controls was similar to that expected in a similar group of patients treated with definitive radiotherapy. Therefore, in addition to its established capability to shrink tumors, hyperthermia in combination with radiotherapy has been shown to increase the rate of overall tumor clearance and reduce recurrences compared with that obtained from radiotherapy alone.

Tumour growth delay, cell inactivation and vascular damage following hyperthermic treatment of a human melanoma xenograft

The effect of hyperthermia at 42.5 degrees C on a human melanoma xenograft in athymic mice was studied. The tumours were heated in vivo in a water-bath. Tumour growth delay and single-cell survival in vitro were used as endpoints. Qualitative information regarding heat-induced vascular damage was obtained from microangiographic analysis. Tumour growth delay after a given treatment was considerably longer than that expected from the cell survival measured in vitro immediately after treatment. Experiments in which removal of the tumours was delayed revealed that tumour cells were continuously dying for at least 24 hr after heat treatment. The volume of the tumour vasculature was considerably reduced after treatment, suggesting that the delayed cell death was attributed to vascular occlusion which resulted in an insufficient supply of oxygen and nutrients and an increased tumour acidity. The present work indicates that at least two mechanisms may be involved in heat-induced cell inactivation in our xenograft: firstly, direct cytotoxic effect of heat; secondly, indirect effect following heat-induced vascular damage.

Ultrasonic comparison of two morphologically distinct melanosomes in malignant melanomas

Ultrasonic measurement (0.333-200 MHz) of melanosomes isolated from B16 and Harding Passey (HP) mouse melanomas indicates that the partial wave resonance and principal relaxation of the 2 kinds of melanosomes are similar, but that their stochastic resonance is markedly different. The structure of the melanosomes appears basically amorphous, but linearly ordered and copolymeric in the molecular dimension of a segment composed of 5-6 zigzag units, which are packed closely in B16 and more openly in HP.

Differential responses to radiation and hyperthermia of cloned cell lines derived from a single human melanoma xenograft

One uncloned and five cloned cell lines were derived from a single human melanoma xenograft. Cells from passages 7-12 were exposed to either radiation or hyperthermia (42.5 degrees C, pH = 7.4) under aerobic conditions and the colony forming ability of the cells was assayed in soft agar. The five cloned lines showed individual and characteristic responses to radiation as well as to hyperthermia. The variation in the response to radiation was mainly reflected in the size of the shoulders of the survival curves rather than in the D0-values. The variation in the response to hyperthermia was mainly reflected in the terminal slopes of the survival curves. The survival curve of cells from the uncloned line, both when exposed to radiation and hyperthermia, was positioned in the midst of those of the cloned lines. The response of the cloned lines to radiation did not correlate with the response to hyperthermia, indicating that tumor cell subpopulations which are resistant to radiation may respond well to hyperthermia.

Effect of hyperthermia in combination with vitamin E and cyclic AMP on neuroblastoma cells in culture

The effect of heat in combination with DL-alpha-tocopheryl (vitamin E) succinate and adenosine 3', 5'-cyclic monophosphate (cAMP) stimulating agents on mouse neuroblastoma cells ( NBP2 ) in culture on the criterion of growth inhibition (due to cell death and inhibition of cell division) was studied. Heat (41 degrees-40 degrees) alone inhibited growth; however, the extent of growth inhibition was dependent upon the temperature and the time of heat treatment. Heat (41 degrees-40 degrees) in combination with vitamin E succinate (5 micrograms/ml) produced an additive effect on the criterion of growth inhibition. Vitamin C (100 micrograms/ml) failed to modify the effect of heat. Prostaglandin A2, a stimulator of adenylate cyclase, and 4 - (3-butoxy-4-methoxybenzyl)-2-imidazolidinone ( R020 -1724), an inhibitor of cyclic nucleotide phosphodiesterase, are known to induce irreversible differentiation in mouse neuroblastoma cells in culture. These agents, in combination with heat (40 degrees) produced a synergistic effect on the criterion of growth inhibition. These data suggest that the addition of vitamin E and cAMP stimulating agents may increase the effectiveness of hyperthermia protocol.

The pharmacologic manipulation of blood flow in hyperthermia therapy

Many human tumors treated by hyperthermia do not reach therapeutic temperatures (42 degrees C). The explanation for this difference may be that some tumors react to thermal stress in a manner similar to normal tissues; ie, they increase blood flow during hyperthermia in order to dissipate the heat. Higher temperatures might be achieved in these heat-resistant tumors by administering vasoconstrictive agents in an effort to reduce blood flow. In this preliminary study, we determined the extent to which pharmacologic inhibition of local blood flow might allow higher temperatures to develop in normal muscles exposed to localized radiofrequency hyperthermia. We found that the local muscle temperature rise could be increased by at least 90% in two dogs and six rabbits with the use of a local vasoconstrictive drug.

Combined continuous ultra low dose rate irradiation and radiofrequency hyperthermia in the C3H mouse

Intradermally inoculated RIF tumors and normal skin of male C3H mice were implanted with variable activities of Iodine 125 seeds or dummy seeds enclosed in Vicryl sutures, and subjected to 0, 1, 2 or 3 local radiofrequency heat treatments for 30 minutes. Each treatment raised the tumor volume to 44 degrees C. Gastrointestinal toxicity (assessed by weight change), skin reaction, tumor growth delay, and tumor cure were assessed. Neither radiofrequency treatment alone or continuous ultra low dose rate irradiation up to 16,000 rad over 180 days alone was successful in curing these tumors; however, combined modality treatments employing doses as low as 8,000 rad over 180 days plus two radiofrequency treatments did effect cures. Gastrointestinal toxicity was best correlated with hyperthermia treatments, while skin reactions secondary to hyperthermia were prolonged by continuous ultra low dose rate irradiation. Implications for clinical usage are discussed.

Tumor control and therapeutic gain with different schedules of combined radiotherapy and local external hyperthermia in human cancer

Tumor control and therapeutic gain have been evaluated in a series of studies on patients with multiple lesions employing different protocols of combined radiotherapy (RT) and local external hyperthermia (HT). Tumor response has been evaluated during a follow-up ranging 6 to 18 months. Therapeutic enhancement factor (TEF) was defined as the ratio of thermal enhancement (TE) of tumors to TE of skin, where TE was clinically evaluated as the ratio of percent response (i.e., complete tumor clearance and moist desquamation, respectively) after combined modality to percent response after RT alone. Local tumor control was constantly better in lesions treated with any combined modalities in comparison with RT alone. The use of high RT dose per fraction appeared to increase tumor control only in the combined modalities groups, the immediate (so called "simultaneous") schedule (HT at 42.5 degrees C/45 min, applied immediately after each RT fraction, twice a week) being more effective than the delayed (so called "sequential") treatment (HT at 42.5 degrees C/45 min, delivered 4 h after each RT fraction, twice a week). The combination of high RT dose per fraction with high temperature HT (45 degrees C for 30 min) achieved the best tumor control. No increased radiation skin reaction was observed when a conventional fraction size of RT was used (3 daily fractions of 1.5-2 Gy, 4 h interval between fractions) in association with HT (42.5 degrees C/45 min, every other day, immediately after the second daily RT fraction). A remarkable enhancement of skin reaction was observed, however, when using high RT doses per fraction in association with 42.5 degrees C HT, especially with the immediate treatment schedule. No enhancement of skin reaction was obtained after high RT doses per fractions and 45 degrees C HT because an active skin cooling by means of circulating cold water was used in these cases. Consequently, a good TEF (1.58) was obtained when conventional RT doses per fraction were used in association with 42.5 degrees C HT. TEF values of 1.40 and 1.15 were observed when high RT doses per fraction were employed in association with the delayed and immediate 42.5 degrees C HT, respectively. HT at 45 degrees C can be safely employed only when tumors can be heated selectively or at least preferentially in comparison with normal tissue; in the lesions treated with such a schedule a TEF of 2.10 was obtained.

Blood flow in human tumors during hyperthermia therapy: demonstration of vasoregulation and an applicable physiological model

A quantitative assessment of the effect of localized magnetic-loop hyperthermia on blood flow was performed in 12 human tumors using the 133Xe clearance method. Because blood flow in these tumors changed in response to needle injection, a physiologically based, one-compartment model was developed that included both a hyperemic and a steady-state component. In six tumors, changes in blood flow induced by heat were also observed. The ability of tumor vessels to respond dynamically to stress and the degree of response may be predictive of tumor heating capacity and subsequent therapeutic response.

Basic principles in hyperthermic tumor therapy

Literature on hyperthermic tumor therapy in the past 10 years has grown exponentially. Since 1975 three international symposia on cancer therapy by hyperthermia have been held. Hyperthermia is of clinical interest in the temperature range of 40 degrees-43 degrees C. Higher temperatures of 44 degrees-46 degrees C are not clinically realizable. With local heat application a higher elevation of tissue temperature is possible. Whole-body hyperthermia in men is limited physiologically, as the rate of complications increases exponentially above 42 degrees C. The heat dose normally is defined by temperature degree and time of temperature elevation. Hyperthermia has several effects on tumor cells. It influences proliferation activity; within the mitotic cycle, preferentially the M-phase cells and S-phase cells are thermosensitive. It is possible to synchronize tumor proliferation by heat. Hyperthermia inactivates tumor cells in hypoxic condition as well. This was demonstrated in vitro with tumor cells under varying oxygenation and with spheroid experimental tumors. Experiments with solid tumors in animals had the same effect. Hyperthermia enhances the effect of radiation on tumors. In solid human tumors only 3%-5% of cells are in growth fraction; 95% of tumor cells are hypoxic or prenecrobiotic. Only well-oxygenated cells are sensitive to a sparsely ionizing radiation and can be killed. This selective radiosensitivity is the reason why other radiation qualities for radiotherapy, which are also effective on hypoxic cells, are examined. Neutrons and heavy ions are densely ionizing radiations, which inactivate hypoxic radioresistant cells. Hyperthermia in combination with sparsely ionizing radiations--e.g., X-rays or gamma rays--could be an alternative to neutrons or heavy ions. The main problem with heat application in clinical radiotherapy is the lack of heating methods which are able to heat the entire volume of a large solid tumor homogeneously. In small experimental animals there is a TER of about 1.5-2.0. The therapeutic gain of additional heat in radiotherapy is greatly dependent on localization of the tumor (skin, extremities) and on cooling of the skin. Hyperthermia enhances cytostatic drugs. Many investigations have been done on the interaction of heat and cytostatics; in vitro experiments evaluated three types. First, the activity of many drugs increases slightly with temperature; no special effects are observed above 42 degrees C. Examples of drugs of that pattern are the hypoxic sensitizer Ro-07-0582 and the alkylating agents thio-TEPA and CCNU. A second type of mechanism is seen with cytostatic drugs which exhibit greatly increased effectiveness at temperatures above 42 degrees C; adriamycin and bleomycin belong to this type.(ABSTRACT TRUNCATED AT 400 WORDS)

Normal tissue response to localized deep microwave hyperthermia in the rabbit's prostate: a preclinical study

Experiments were performed to determine the response of normal tissues of the rectal cavity and the prostate to localized 2.45 GHz microwave deep hyperthermia. Hyperthermia at 43 degrees C was delivered by means of a coaxial probe in the rectal cavity for 30 min. once or twice at an interval of 2 days. Normal tissues of the rectum, urinary bladder, and prostate were histologically examined up to three months after treatments. In almost all of the treated animals no tissue and organ injury resulted from localized deep hyperthermia at 43 degrees C. This treatment appears to be safe for the treatment of carcinoma of the prostate.

Effect of hyperthermia on human melanoma cells heated either as solid tumors in athymic nude mice or in vitro

Human melanoma cells were exposed to clinically acceptable hyperthermia (42.5 degrees C) either as solid tumors in athymic nude mice or suspended in culture medium. Single cell survival was in both cases assayed in vitro in soft agar. The response to heat varied considerably among the five melanomas studied. The D0-values ranged from 21 to 590 min when the cells were heated in vitro. The response to heat following treatment in vivo was for a given melanoma larger than that following treatment in vitro. However, cells which were resistant to heat treatment in vitro, were also resistant to treatment in vivo, and those which were sensitive in vitro were also sensitive in vivo.

Combination hyperthermia and radiation therapy for malignant melanoma

Since 1975, clinical studies have been carried out to determine whether radiation when combined with localized hyperthermia evokes improved tumor control compared to that achieved with radiation alone. Local tumor hyperthermia was achieved using radiofrequency inductive heating at 27.12 MHz. In bulky lesions (greater than 100 cm3), radiofrequency conductive heating at 13.56 MHz was also used. More than 100 lesions in 38 patients were treated with radiation alone and hyperthermia in combination with radiation. Most lesions were treated either twice a week or once a week, depending on radiation dose fractionation scheme used. The overall result of tumor control rate of the combined therapy is superior to radiation therapy alone (75% versus 46%; P less than 0.01). No enhanced normal tissue morbidity was seen following the combined therapy. The detailed analysis of the treatment results shows that the tumor control rate is dependent on dose per fraction, the total dose, and the initial tumor volume. The radiation alone, at high doses per fraction, was effective in controlling 80% of the lesions, if the tumor volume was less than 10 cm3, compared to 30% when the tumor volumes were larger. The combination therapy, on the other hand, effected 80% local tumor control regardless of the tumor volume. The importance of good thermal distribution within the tumor volume, selective heating of the tumor tissues and the sequence and time interval between the combined therapy is discussed.

Regional hyperthermia for cancer

The clinical use of regional hyperthermia combined with radiation therapy, chemotherapy, or both in 107 patients with advanced cancer is reported. Surgery was subsequently carried out in eight patients. The radiofrequency equipment used is capable of heating tumors at any depth with few adverse side effects. Complete responses to therapy occurred in 16 percent of patients, and partial responses in 52 percent. Striking pain relief was observed in both responders and nonresponders.