Effect of heat on the C3H mouse mammary adenocarcinoma evaluated in terms of tumor growth

Neoadjuvant Hyperthermia Combined with Hybrid Nanoarchitectures Enhances Chemoradiotherapy Efficacy in Head and Neck Carcinoma

Head and neck squamous cell carcinomas are characterized by a high incidence of recurrence, especially in patients with locally advanced disease. Standard treatment strategies can be associated with severe side effects to healthy tissues that can negatively impact the patient's quality of life. Hyperthermia (HT) is a noninvasive treatment modality that has improved the effectiveness of chemotherapy (CT) and/or radiotherapy (RT) for the management of some solid neoplasms. In this context, the association of this approach with rationally designed nanomaterials may further enhance the treatment outcome. In this study, we demonstrate the enhanced effect of neoadjuvant HT in combination with hybrid nanoarchitectures enclosing a cisplatin prodrug (NAs-CisPt) and RT. All the treatments and their combinations have been fully evaluated by employing standardized chorioallantoic membrane tumor models of HPV-negative head and neck carcinoma. An improved tumor-shrinking effect was observed by the administration of the trimodal treatment (HT/NAs-CisPt/RT), which also highlighted a significant increase in apoptosis. Our findings demonstrate that the combination of HT with nanotechnology-based CT and RT in a certain order enhances the in vivo treatment outcome. On a broader basis, this study paves the way for the next exploration of noninvasive treatment approaches for the clinical management of oral cancer based on innovative strategies.

Bovine ocular squamous cell carcinoma

Ocular squamous cell carcinoma (OSCC) in animals is a primary neoplasm of epithelial origin. OSCC or "cancer eye" is the most common malignant tumor affecting cattle in North America and is responsible for significant economic losses. In the United States, the prevalence of OSCC varies geographically and is higher in the southwestern region and in lower latitudes with higher levels of sunlight. Control of this disease would be of considerable significance to the economics and profitability of the beef and dairy cattle industries. This article reviews the characteristics of the most commonly affected animals, the factors that are believed to contribute to the development of OSCC, and the treatment options that have been proposed.

Interstitial laser hyperthermia, a new method in the management of fibroadenoma of the breast: A pilot study

BACKGROUND AND OBJECTIVE

This study attempts to evaluate the effect of interstitial laser hyperthermia in breast fibroadenomas as an outpatient procedure.

STUDY DESIGN/MATERIALS AND METHODS

In an uncontrolled prospective study, 27 patients younger than 35 years were subjected to laser phototherapy of their breast fibroadenomas. Under real-time ultrasound monitoring, Nd:YAG laser (1,064 nm wavelength) was used at 2 W for 300 sec (600 J) in a continuous wave mode to produce interstitial hyperthermia. Follow-ups were done at 2, 4, and 8 weeks. Subsequently, excision biopsy of residual lumps was performed.

RESULTS

There was significant decrease in clinical and sonographic sizes (P < 0.001). Follow-up ultrasound showed a progressive change of hyperechoic texture, from a heterogeneous to a nearly homogeneous one. There were minimal scars (2-3 mm) and no keloid or abscess formation.

CONCLUSION

Interstitial laser hyperthermia is a safe, precise, and minimally invasive outpatient procedure for in situ destruction of breast fibroadenomas.

Hyperthermia in cancer therapy

Tumor hyperthermia is a rediscovered technique of oncotherapy which has confirmed value in many studies on cell cultures, rodent and mammalian tumors as well as first investigations on patients with tumors. The biological basis for using heat in the treatment of cancer is well established. Various direct and indirect mechanisms are significant for the effect of hyperthermia on tumor tissue. Whereas there are already extensive studies on the direct effects of hyperthermia on DNA, RNA, and protein synthesis, energy metabolism, and the membrane properties of tumor cells, the indirect effects have only been investigated more closely in recent years. These are likewise important for the damage to the tumor tissue and are mediated above all via alterations in the microcirculation and the environment. The recently gained increasing significance of this new technique in combination with other treatment modalities is well documented. Technical problems of heat application must be overcome, especially in deeper tumors and problems of thermometry must be solved in order to be able to apply tumor hyperthermia not only to selected advanced or recurrent tumors, but in order to use it as the fourth pillar of tumor therapy besides surgery, radiotherapy and chemotherapy. This article considers the biological basis and important aspects of hyperthermia therapy in combination with radiotherapy and chemotherapy.

Alterations in biochemical functions during hyperthermic isolation-perfusion of the human liver

Hyperthermia (42-42.5 degrees) was applied to the liver of eight patients with cancer in the liver by a technique of isolation-perfusion. Hepatic functional integrity was assessed during perfusion through measurement of multiple perfusate constituents. Data from seven perfusions were available for analysis. During perfusion there was an increase in perfusate lactate, pyruvate, glucose, urea, potassium, alkaline phosphatase, SGOT, and LDH. All increases in these constituents were significant (P less than 0.05) except for potassium. Lactate accumulated throughout the perfusion from an initial level of 3.8 +/- 1.0 mM to 7.6 +/- 3.5 mM at 4 hr. Pyruvate increased over the first 3 hr of perfusion from 0.14 +/- 0.06 mM to 0.80 +/- 0.37 mM before declining to 0.54 +/- 0.24 mM at 4 hr. The L/P (lactate/pyruvate) ratio decreased during perfusion to less than 10 in the first 2 hr, but rose to within normal limits by the end of perfusion. The decreases in L/P ratios were significant (P less than 0.05). Initially there was a rapid rise in perfusate glucose concentrations from 4.5 +/- 0.8 mM to 20.7 +/- 5.4 mM at 2 hr with nonsignificant changes thereafter. Urea levels increased from 0.64 +/- 0.22 mM to 1.92 +/- 0.76 mM. Perfusate potassium increased from the initial level of 7.0 +/- 1.0 mM during perfusion to 8.3 +/- 1.7 mM at 2 hr before declining. SGOT, LDH, and alkaline phosphatase increased during perfusion from 21 +/- 15, 142 +/- 48, and 16 +/- 6 to 176 +/- 22, 472 +/- 53 and 52 +/- 42, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Site dependent response of tumours to combined heat and radiation

In previous experiments, large differences in thermal sensitisation were observed for tumours grown on the tails of the chest of mice. The present work reports the results of experiments to compare the response of tumours in four different sites to the radiosensitising effects of both heat and misonidazole. Factors influencing tumour response, e.g., tumour growth rate, blood flow, temperature uniformity, temperature increase during heating and drug availability, were also studied. Tumour response and most of the parameters measured varied according to the site of tumour implantation. Growth rate, blood flow and natural tumour temperature are all likely to be important. However, there appears to be no simple relationship by which tumour response could be predicted, although heat dose, the product of temperature elevation above the natural level and treatment time, may be the most relevant parameter. Clearly the choice of implant site does influence response to treatment. Tumours grown on the extremities may be poor models for human tumours, because of their low natural temperatures.

Clinical requirements for localized hyperthermia in the patient

The physical and mechanical parameters to be considered when contemplating hyperthermia as a cancer treatment modality are discussed. These parameters include heat field size, uniformity of heating, method of hyperthermic production, selection of energy, heat flow, warm-up period and thermometry.

Induced thermal resistance in the mouse ear

The mouse ear (pinna) was used to investigate the effect of two hyperthermic treatments. Heating was by immersion in hot water at 43.5 degrees C. A single treatment of about 50 minutes was required to cause necrosis in 50% of the ears heated. When heat treatment was given in two equal fractions the total heating time had to be increased if the interval between fractions was greater than four hours. By 24 hours a total treatment of about 100 minutes was required, indicating almost complete recovery from the first heating. Priming treatments at 43.5 degrees C induced thermal resistance to a second heat treatment at 43.5 degrees C. Maximum resistance was observed one day after a 20 minute priming and two days after a 40 minute priming, when the heating time had to be increased to 120 minutes, an increase by a factor of 2.4. Shorter priming treatments induced less resistance, the minimum heating time to produce an effect being two minutes. In all cases the effect decreased during the next four to five days. These results indicate that the reduced response of tissues to fractionated hyperthermia is due both to the repair of sublethal heat damage and induction of thermal resistance.

Heat-induced thermal resistance and its relationship to lysosomal response

Two separate effects of hyperthermia on mouse splenic lysosomes have been reported, dependent on the severity of the treatment. Heating to temperatures below 42.5 degrees C causes a transient increase in lysosomal acid phosphatase activity which can be correlated with the ability of moderate hyperthermia to potentiate X-ray damage. Heating to temperatures above 42.5 degrees C results in an immediate increase in lysosomal membrane permeability which may be involved in tissue necrosis. By giving a priming heat treatment at 41.8 degrees C, induced thermal resistance was demonstrated for the lysosomal membrane effect, but not for the enzyme activation. The degree of induced thermal resistance observed is similar to that reported for the cell-killing effect of heat on tissues in vivo and cells in vitro and occurs over a similar time course. The relevance of these results to the understanding of fractionated hyperthermia in cancer therapy is discussed.

Hyperthermic potentiation: biological aspects and applications to radiation therapy

Experimental studies have provided evidence that hyperthermia may be an effective agent, either alone or in combination with ionizing radiation, in the treatment of cancer. Results have shown that temperatures in the range of 42 degrees to 45 degrees C: 1) are cytotoxic, with cell lethality showing little or no dependence on levels of oxygenation; 2) inhibit the recovery of cells from sub-lethal and potentially lethal radiation damage while enhancing the levels of lethal damage; and 3) may be combined with x-irradiation in a manner to improve therapeutic ratios. The observed interaction between hyperthermia and x-rays may in part be due to differences in the Age Response Functions and reassortment of cycling cells to these two agents. Hyperthermia may also greatly change repopulation and re-oxygenation parameters in irradiated tumor and normal tissue volumes. An overall consideration of these and other factors is essential in the design of optimal schedules of combined hyperthermia and x-irradiation treatments in the management of malignant disease.

The relationship between the time of fractionated and single doses of radiation and hyperthermia on the sensitization of an in vivo mouse tumor

The present study was undertaken to explore the relationship of the time interval between application of heat and irradiation on enhanced tumor cell sensitivity. Using the Ridgway osteogenic sarcoma grown in AKD2F1/J mice, local tumor hyperthermia (42.5 +/- .5 degrees C for 15 minutes) was applied at various time intervals before or after single or fractionated doses of x irradiation. Enhancement of tumor cell sensitivity by combined treatment with radiation and heat, as measured by delay in tumor growth, cure rates, and mean survival times was inversely proportional to the time interval between application of both modalities. The interactions associated with this increased sensitivity appear to be transitory, diminishing with time between treatments. Possible mechanisms of action for thermal sensitization may involve the reduction of oxygen dependence as well as a reduced recovery capacity of tumor cells.