The effect of various chemotherapeutic agents given with mild hyperthermia on different types of tumours

Update on chemotherapeutic agents utilized for perioperative intraperitoneal chemotherapy

A new strategy currently under evaluation in patients with peritoneal carcinomatosis from gastrointestinal and gynecologic cancers is perioperative intraperitoneal chemotherapy. Although results to date show benefit to carefully selected groups of patients, continued local-regional failure is seen in many treated patients. Continued clinical and laboratory research efforts to improve local-regional effects are desired. The chemotherapeutic agents that have been used in the past or are currently being tested were reviewed. Their pharmacologic properties and clinical features were collected from the medical literature and are reviewed in the text. An organized presentation of available data concerning the drugs available for perioperative intraperitoneal chemotherapy for peritoneal surface malignancy was made. From this review, new possibilities for improved doses, schedules, and drug combinations for perioperative intraperitoneal chemotherapy may become important in future clinical studies. Continued optimal utilization of intraperitoneal chemotherapy treatments in the operating room with hyperthermia or normothermic treatment in the early postoperative period is desirable. Innovative treatment strategies can improve the outcome of patients with peritoneal surface malignancy.

The role of hyperthermia in regional alkylating agent chemotherapy

The role of hyperthermia during regional alkylating agent chemotherapy is controversial. The aim of this study was to determine the exact contribution of hyperthermia to tumor response during isolated limb infusion with l-phenylalanine mustard. Rats bearing rodent fibrosarcoma on the hindlimb underwent isolated limb infusion with saline, saline plus heat, l-phenylalanine mustard, l-phenylalanine mustard under conditions of normothermia, or l-phenylalanine mustard plus hyperthermia. Heat was administered locally using an in-line hot water circulation loop. Treatment with l-phenylalanine mustard at a concentration of 15 or 50 micrograms/mL was ineffective at producing tumor growth delay (P = 0.24 and 0.41, respectively). Furthermore, thermal enhancement of l-phenylalanine mustard activity was not seen at 15 micrograms/mL. However, administration of high-dose l-phenylalanine mustard, 50 micrograms/mL, with increasing amounts of heat yielded increasing tumor growth delay, increased regressions, and decreased proliferative index. Although l-phenylalanine mustard infusion under normothermia yielded a tumor growth delay of 7.1 days, combination l-phenylalanine mustard + hyperthermia treatment produced tumor growth delay of 27.0 days (P < 0.01; with two of five animals showing a complete response). Four hours after isolated limb infusion, 50.9% of cells in tumor treated with l-phenylalanine mustard + hyperthermia experienced apoptosis, whereas only 18.1, 16, and 4.4% of cells underwent apoptosis after treatment with l-phenylalanine mustard, saline + hyperthermia, or saline. The mean concentration of l-phenylalanine mustard within tumor relative to perfusate following isolated limb infusion was found to be similar among all groups at 0.023, 0.025, and 0.032 in animals undergoing isolated limb infusion with l-phenylalanine mustard, l-phenylalanine mustard + normothermia, and l-phenylalanine mustard + hyperthermia, respectively. These data indicate a synergistic cytotoxic effect of l-phenylalanine mustard + hyperthermia in isolated limb infusion, which is not attributable to enhanced tumor drug uptake.

Docetaxel and hyperthermia: factors that modify thermal enhancement

BACKGROUND

Hyperthermia enhances the cytotoxicity of some chemotherapeutic agents and recent studies suggest that docetaxel may show improved response at elevated temperatures. Factors that may modify the thermal enhancement of docetaxel were studied to optimize its clinical use with hyperthermia.

METHODS

The tumor studied was an early-generation isotransplant of a spontaneous C3Hf/Sed mouse fibrosarcoma, Fsa-II. All studies were approved by the Animal Care and Use Committee. Docetaxel was given as a single intraperitoneal injection. Hyperthermia was achieved by immersing the tumor-bearing foot into a constant temperature water bath. Four factors were studied: duration of hyperthermia, sequencing of hyperthermia with docetaxel, intensity of hyperthermia, and tumor size. To study duration of hyperthermia tumors were treated at 41.5 degrees C for 30 or 90 min immediately after intraperitoneal administration of docetaxel. For sequencing of hyperthermia and docetaxel, animals received hyperthermia treatment of tumors for 30 min at 41.5 degrees C immediately after drug administration, hyperthermia both immediately and 3 hr after docetaxel administration and hyperthermia given only at 3 hr after administration of docetaxel. Intensity of hyperthermia was studied using heat treatment of tumors for 30 min at 41.5 or 43.5 degrees C immediately following docetaxel administration. Effect of tumor size was studied by delaying experiments until three times the tumor volume (113 mm(3)) was observed. Treatment of tumors lasted for 30 min at 41.5 degrees C immediately following drug administration. Tumor response was studied using the mean tumor growth time.

RESULTS

Hyperthermia in the absence of docetaxel had a small but significant effect on tumor growth time at 43.5 degrees C but not at 41.5 degrees C. Hyperthermia at 41.5 degrees C for 90 min immediately after docetaxel administration significantly increased mean tumor growth time (P = 0.0435) when compared to tumors treated with docetaxel at room temperature. Treatment for 30 min had no effect. Application of hyperthermia immediately and immediately plus 3 hr following docetaxel was effective in delaying tumor growth. Treatment at 3 hr only had no effect. No significant difference in mean tumor growth time was observed with docetaxel and one half hour of hyperthermia at 41.5 or 43.5 degrees C. For larger tumors, hyperthermia alone caused a significant delay in tumor growth time. Docetaxel at 41.5 degrees C for 30 min did not significantly increase mean tumor growth time compared to large tumors treated with docetaxel at room temperature.

CONCLUSIONS

Docetaxel shows a moderate increase in anti-tumor activity with hyperthermia. At 41.5 degrees C the thermal enhancement of docetaxel is time dependent if hyperthermia is applied immediately following drug administration. With large tumors docetaxel alone or docetaxel plus hyperthemia showed the greatest delays in tumor growth time in the experiments.

Hypothermia reduces sulphur mustard toxicity

The effect of temperature on the development of sulphur mustard (HD)-induced toxicity was investigated in first passage cultures of human skin keratinocytes and on hairless guinea pig skin. When cells exposed to HD were incubated at 37 degrees C, a concentration-dependent decline in viability was observed that was maximal by 2 days. In contrast, no significant HD-induced toxicity was evident up to 4 days posttreatment when the cells were incubated at 25 degrees C. However, these protective effects were lost by 24 h when the cells were switched back to 37 degrees C. The protective effects of hypothermia were also demonstrated when apoptotic endpoints were examined. The HD concentration-dependent induction of fragmented DNA (as quantitated using soluble DNA and the TUNEL reaction), morphology, and p53 expression were all significantly depressed when cell cultures were incubated at 25 degrees C compared to 37 degrees C. When animals were exposed to HD vapour for 2, 4, and 6 min and left at room temperature, lesions were produced whose severity was dependent on exposure time and that were maximal by 72 h posttreatment. Moderate cooling (5-10 degrees C) of HD exposure sites posttreatment (4-6 h) significantly reduced the severity of the resultant lesions. However, in contrast to the in vitro results, these effects were permanent. It appears that the early and noninvasive act of cooling HD-exposed skin may provide a facile means of reducing the severity of HD-induced cutaneous lesions.