Phase I/II trial of preoperative thermoradiotherapy in the treatment of urinary bladder cancer

Between April 1984 and September 1988, preoperative radiotherapy or thermoradiotherapy was administered to 49 patients with bladder cancer (T1-4N0M0; UICC classification, 1987). Twenty-one patients were preoperatively treated by radiotherapy alone, with 4 Gy per fraction and three fractions per week to a total dose of 24 Gy (TDF = 53, group 1). The other 28 patients were treated by the same radiotherapy regimen in combination with hyperthermia (group 2). Regional hyperthermia was administered for 35-60 min immediately after irradiation (two sessions per week to a total of four sessions) using an 8 MHz RF capacitive heating device. Group 2 was divided into group 2 (high), in which the average intravesical temperature (T(av)) was > 41.5 degrees C, which was the mean value, and group 2 (low) with a T(av) < 41 x 5 degrees C. Group 2 (high) showed a significantly higher incidence of down-staging and tumour degeneration than both group 1 and group 2 (low). In addition, the local recurrence rate was lower and survival time was longer in group 2 than in group 1, although not significantly so. In particular, the patients with T3-4 or grade 3 bladder cancer in group 2 had a longer average survival than those in group 1, although the difference was not significant. The toxicity associated with hyperthermia was pain during treatment, and complications were not serious.

Enhancement of chemosensitivity of quiescent cell populations in murine solid tumors using nicotinamide

Cis-diamminedichloroplatinum(II) (CDDP) was intraperitoneally injected into mice bearing SCC VII or EMT6/KU tumors after 10 administrations of 5-bromo-2'-deoxyuridine (BUdR) to label all the proliferating tumor cells. One hour later, the tumors were excised, minced and trypsinized. The tumor cell suspensions were incubated with cytochalasin B (a cytokinesis blocker). The micronucleus (MN) frequency was determined using immunofluorescence staining to BUdR. The cells that were not labeled with BUdR could be regarded as the quiescent cells. The MN frequency in total tumor cells was determined from the tumors that were not pretreated with BUdR. To modify the sensitivity to CDDP, nicotinamide was intraperitoneally injected before CDDP administration. In both tumor system, the MN frequency in quiescent cells was lower than in total cells. Nicotinamide pretreatment increased the MN frequency in total and quiescent cells in both tumor systems, especially in total cells of the SCC VII tumor. The nicotinamide injection increased the uptake of 195mPt-CDDP into the total cells, especially in the SCC VII tumor. Nicotinamide administration before chemotherapy using CDDP was considered to be effective for tumor control, especially in tumors including large acutely hypoxic fractions such as the SCC VII murine tumor.

Scintigraphic study on the distribution of radiolabeled cis-diamminedichloroplatinum (II) in the tumor-bearing rabbit: a comparison between intra-arterial injection with lipiodol and intravenous injection

To compare the distribution of cis-diamminedichloroplatinum (II) (CDDP) on scintigraphic images between intra-arterial injection with lipiodol and intravenous injection, we obtained serial scintigraphic images using radiolabeled CDDP (Pt-195m CDDP), which had a high specific activity (7.4 x 10(6) Bq [200 microCi]/mg-CDDP), in the rabbit VX-2 tumor system. A dose of 9.25 x 10(6) Bq (250 microCi) of Pt-195m CDDP was injected at one shot via an ear vein, while 7.4 x 10(6) Bq (200 microCi of Pt-195m CDDP mixed with 1 ml of lipiodol was injected at one shot via a saphenous artery. Mean pixel count, which was corrected for the total dose injected, in the arterially injected tumor always exceeded than that in the intravenously injected tumor. Pt-195m CDDP uptake by the rabbit tumor at 2 hr was 7.8% of the total injected dose with intravenous injection and 16.0% with intra-arterial injection. These data suggest that intra-arterial injection with lipiodol is a more useful method to increase CDDP uptake by tumors than intra-venous injection.

Radiosensitization of SCCVII tumours and normal tissues by nicotinamide and carbogen: analysis by micronucleus assay

The radiosensitizing effect on SCCVII tumours of carbogen (95% O2 + 5% CO2) combined with nicotinamide was investigated using the micronucleus assay and an in vivo/in vitro colony formation assay following single irradiation. The effects on intestinal crypt cells and bone marrow cells were also examined in mice. The frequency of micronuclei in tumours increased with an increase in the nicotinamide dose (administered 1 h before the irradiation of 5 Gy) from 0.1 to 1.0 mg/g, and showed a 1.3-fold increase at 1.0 mg/g when compared with radiation alone. The micronucleus frequency showed a more marked increase following irradiation combined with nicotinamide and carbogen inhalation starting 15 min before irradiation. The radiosensitizing effect reached a plateau at a nicotinamide dose of 0.1 mg/g in combination with carbogen, giving an enhancement ratio (ER) of 1.8 relative to radiation alone at 2 Gy. In the radiation dose range of 5-20 Gy, ERs of 1.8-1.9 and 1.5 (at a 10% cell-survival level) were obtained for the combination of 0.1 or 1.0 mg/g nicotinamide and carbogen and for carbogen alone, respectively. A slight increase in the regeneration response of the jejunum and the bone marrow was observed following irradiation combined with 0.1 mg/g nicotinamide and carbogen, yielding ERs of 1.07 for the jejunum and 1.15 for the bone marrow. Thus, the nicotinamide/carbogen combination, with its large therapeutic gain factor at low doses and proven low toxicity in humans, seems to improve the response of cancer to radiotherapy.

Distribution of radiolabeled cis-diamminedichloroplatinum (II) on scintigraphic images in the tumor-bearing rabbit

To evaluate the feasibility of using scintigraphic images to assess the distribution of cis-diamminedichloroplatinum (II) (CDDP), we obtained serial scintigraphic images using radiolabeled CDDP (Pt-195m CDDP), which had high specific activity (7.4 x 10(6) Bq [200 microCi]/mg-CDDP) in the rabbit VX-2 tumor system. Radioactivity at the heart decreased in a biexponential manner, with an initial half-time of 15.3 min and secondary phase of 4.5 days. Time-activity curves revealed that the tumor/heart ratio was greater than 1.0 (1.0-1.1) between 30 min and 4 hr after intravenous injection. The scintigraphic study clearly depicted the tumor. Pt-195m CDDP uptake by the rabbit tumor at 2 hr was 7.8% of the total injected dose. These data suggest that scintigraphic imaging using Pt-195m CDDP is a promising method for imaging tumors and evaluating their CDDP uptake.

Determination of the target volume of HeLa cells treated with platinum-195m radiolabeled trans-diaminedichloroplatinum(II): a comparison with cis-diaminedichloroplatinum(II)

HeLa S-3 cells were treated with 195mPt-radiolabeled trans-diaminedichloroplatinum(II) (TDDP) under various conditions, and the relationship between lethal effect and the number of Pt atoms binding to DNA, RNA and proteins was examined. The mean lethal concentrations for the cells treated with TDDP at 37 degrees C for 1, 2 and 3 h were 163.7, 65.8 and 24.9 microM, respectively. By using identically treated cells, the number of Pt atoms combined with DNA, RNA and protein molecules was determined after the cells were fractionated using the method of Schneider. In this way, the D0 values given as the drug concentration were substituted for the number of Pt atoms combined with each fraction, then the target volumes, expressed as the reciprocals of the D0 values, were calculated for each fraction. The results suggested that DNA and high molecular weight RNAs (except t-RNA), under some limited condition, could be the target molecules for cell killing by TDDP. The target volumes for DNA were 1.31 x 10(3), 3.01 x 10(3) and 6.26 x 10(3) nucleotides for 1, 2 and 3 h treated cells, respectively. Cell killing effects of TDDP were lower than CDDP by a factor of 39.5, 19.0 and 16.5 for 1, 2 and 3 h treatments at 37 degrees C, respectively, when viewed from the stand point of the target volume, while those from the mean lethal dose (D0) were 17.6, 9.8 and 6.7, respectively.

The number of platinum atoms binding to DNA, RNA and protein molecules of HeLa cells treated with cisplatin at its mean lethal concentration

HeLa S-3 cells were treated with 195mPt-radiolabeled cis-diamminedichloroplatinum(II) (CDDP) under various conditions, and the relationship between lethal effect and the number of Pt atoms binding to DNA, RNA and proteins was examined. The mean lethal concentrations for the cells treated with CDDP at 37 degrees C for 1, 2 and 3 h were 2.8, 2.0 and 1.1 microgram/ml, respectively. By using identically treated cells, the number of Pt atoms combined with DNA, RNA and protein molecules were determined after fractionation of the cells using the method of Schneider. In this way, the D0 values given as the drug concentration were substituted for the number of Pt atoms combined with each fraction, then the target volumes expressed as the reciprocals of D0 values were calculated for each fraction. The results provide strong support for the idea that DNA is the primary target for cell killing by CDDP, and the target volumes were 5.17 x 10(4), 5.71 x 10(4) and 1.03 x 10(5) nucleotides for 1, 2 and 3 h treated cells, respectively.

Regional hyperthermia combined with radiotherapy in the treatment of lung cancers

Twenty locally advanced lung cancers were treated by hyperthermia in combination with radiotherapy between November 1980 and January 1990. All tumors selected had invaded or were in contact with the chest wall, so that transcutaneous insertion of thermal probes into the tumor was possible. Using an 8 or 13.56 MHZ RF capacitive heating device, hyperthermia was given once or twice a week after irradiation for 30-60 min per session (1-12 sessions in total). Radiotherapy was delivered at dose of 13.6-70 Gy. The thermal parameters analyzed were a) maximum, average, and minimum intratumor temperatures (Tmax, Tav, and Tmin), which were recorded at the termination of each treatment, and b) the percentages of the intratumor points that exceeded 41 C (%T greater than or equal to 41 C). The mean +/- SD for Tmax, Tav, Tmin, and %T greater than or equal to 41 C was 42.9 +/- 1.7 C, 41.6 +/- 1.2 C, 39.7 +/- 1.1 C, and 56.2 +/- 25.8, respectively. Larger tumors showed higher thermal parameters than the smaller tumors. Of the 12 tumors treated by definitive therapy, 2 (17%) achieved CR, 7 (58%) PR, and 3 (25%) NR. Four of 10 tumors that did not achieve CR showed large intratumor low density areas on post-treatment CT, reflecting massive coagulation necrosis. Higher thermal parameters were closely related to the appearance of low-density areas but not to changes in tumor size. Four tumors treated preoperatively were successfully resected 2 weeks after thermoradiotherapy, whereas four palliatively-treated tumors showed no regression. The side effects associated with hyperthermia were pain in 12 patients (60%) and dyspnea in 3 (15%), all of which resolved after termination of treatment. A skin abscess and a pneumothorax attributed to thermal probe insertion were observed in one patient each. These results indicate that regional RF capacitive hyperthermia is clinically feasible for local treatment of selected lung cancers.

Hyperthermia combined with radiation therapy for primarily unresectable and recurrent colorectal cancer

The value of adjuvant hyperthermia to radiotherapy in the treatment of locally advanced colorectal cancers was investigated. Between 1981 and 1989, 71 primarily unresectable or recurrent colorectal tumors were treated with radiotherapy at the Department of Radiology, Kyoto University Hospital. Of the 71 tumors, 35 were treated with radiotherapy plus hyperthermia (group I), while 36 tumors (group II) were unsuitable for hyperthermia mainly because of difficulties with the insertion of temperature probes or the thickness of the patient's subcutaneous fat (greater than 2 cm). The mean total radiation dose was 58 Gy and 57 Gy for groups I and II, respectively. Thirty deep-seated pelvic tumors were treated with an 8 MHz radiofrequency capacitive heating device, and five subsurface tumors were treated with a 430 MHz microwave hyperthermia system. Hyperthermia was given following radiotherapy for 30-60 min for a total of 2-14 sessions (mean 5.7). In 32 of the 35 tumors heated, direct measurement of tumor temperature was performed. For the five tumors treated with the microwave heating device, the means of the mean maximum, average, and minimum measured intratumoral temperatures were 45.4 degrees C, 43.3 degrees C, and 40.6 degrees C, respectively. The corresponding values were 42.2 degrees C, 41.3 degrees C, and 40.3 degrees C for the 27 tumors treated with the capacitive heating device. Effective heating of deep-seated pelvic tumors was more difficult than heating of abdominal wall or perineal tumors. The local control rate at 6 months after the treatment, which was defined as absence of local progression of the tumors, was 59% (17/29) and 37% (11/30) for groups I and II, respectively. The objective tumor response rate (complete regression plus partial response) evaluated by computed tomography was 54% (19/35) in group I, whereas it was 36% (10/28) in group II. A better response rate of 67% was obtained in the 15 tumors with a mean average tumor temperature of greater than 42 degrees C. Although limitation of our current heating devices exist, the combination of hyperthermia with radiotherapy is a promising treatment modality in the treatment of locally advanced colorectal cancer.

Clinical research into hyperthermia treatment of cancer using a 430 MHz microwave heating system with a lens applicator

Tokyo Metropolitan Komagome Hospital, Kyoto University Hospital, and Aichi Cancer Center used a lens applicator microwave equipment, the HTS-100, to treat 90 patients with a total of 96 tumours. The results were analysed, and the following conclusions reached. Three clinical cases have been presented to illustrate the features of the HTS-100. (1) The results of 383 heating sessions using the HTS-100 were analysed. Even tumours larger and deeper than 5 cm could be heated above 42 degrees C. The heating area is much wider than that of the other 2450, 915, 430 MHz microwave heating equipments. (2) Hyperthermia treatment using the HTS-100 was combined with radiotherapy. The percentage effectiveness in terms of CR+PRa was 66.3% for the 89 cases which could be evaluated. Even for tumours larger than 5 cm, and deeper than 4 cm, local control was achieved in 60.7%. Thus, the indications for microwave heating have been significantly expanded. (3) Combination of microwave heating and RF heating is a new protocol which also expands the indications for hyperthermia therapy. (4) The percentage of patients experiencing the side-effects of pain, a sensation of heat, and burns was 15.6%, 6.3%, and 3.6%, respectively. Most of these side-effects were mild and temporary. The percentage of patients experiencing pain was higher than in conventional microwave heating, probably because the area of heating was wider. (5) In the future, the HTS-100 can be expected to play an important role in clinical cancer hyperthermia.

Combined effects of hepatic arterial embolization using degradable starch microspheres (DSM) in hyperthermia for liver cancer

Regional hyperthermia with a radiofrequency capacitive heating apparatus in combination with hepatic arterial embolization with degradable starch microspheres (DSM) was performed in 20 primary and six metastatic liver cancer patients. Efficacy was assessed primarily with regard to the improvement in heating efficiency. An angiocatheter was inserted into the hepatic artery in order to determine the DSM dosage adequate to arrest blood flow. The temperature rise in the tumours after heating alone and after heating combined with DSM embolization was compared. The maximum temperature and initial temperature rise within tumours were significantly improved by the combination therapy. Local tumour response could be evaluated in 10 primary and three metastatic liver cancer patients and tumour reduction over 50% was obtained in 40% and 33% respectively. Abdominal pain, nausea and vomiting, presumably due to reflux of the DSM, were experienced by several patients. In three patients heating could not be continued. However, all the symptoms were transient and responsive to symptomatic treatment, and no significant late complications were observed. Hepatic arterial embolization with DSM for liver tumours is considered effective and safe when combined with regional hyperthermia.

[Clinical assessment of thermoradiotherapy of breast cancer and cancer of the urinary bladder]

Non-randomized clinical trials of thermoradiotherapy for breast cancer and carcinoma of the urinary bladder were reported. Thermoradiotherapy was useful for breast cancer treatment in term of (1) increased local control for locally advanced tumors and (2) possibility of reducing dose of irradiation for recurrent tumors following radiotherapy. Tumor response to thermoradiotherapy was dependent on tumor volume and maximum or minimum tumor temperature. Thermoradiotherapy was also effective as a preoperative-treatment for urinary bladder cancer. The incidence of down-staging and degeneration of tumors was significantly higher in thermoradiotherapy than in radiotherapy. These effects were temperature dependent. Patients with T 3-4 NOMO or Grade 3 tumors treated with thermoradiotherapy showed a tendency of increased survival compared with those treated with radiotherapy alone.

Frequency of micronuclei in hepatocytes following X and fast-neutron irradiations--an analysis by a linear-quadratic model

The usefulness of the micronucleus assay for investigating the radiation response of hepatocytes was examined. The frequency was defined as the ratio of the total number of micronuclei to the number of hepatocytes examined. The dose-response curves were curvilinear after X rays and linear after neutrons. These dose-response curves were analyzed by a linear-quadratic model, frequency = aD + bD2 + c. The a/b ratio was 3.03 +/- 1.26 Gy following X irradiation. This value is within the range of the alpha/beta ratios reported by others using the clonogenic assay of hepatocytes. While the a/b value for neutrons was 24.3 +/- 11.7 Gy, the maximum relative biological effectiveness of neutrons was 6.30 +/- 2.53. Since the micronucleus assay is simple and rapid, it may be a good tool for evaluating the radiation response of hepatocytes in vivo.

Radiofrequency thermotherapy for malignant liver tumors

Inoperable malignant liver tumors have been treated by radiofrequency hyperthermia at Kyoto University Hospital since 1983. In this study, clinical hyperthermia for malignant liver tumor was evaluated for 67 tumors in which we could measure intratumor temperatures. Of the 67 tumors, 41 were hepatocellular carcinomas (HCC), six cholangiocarcinomas, and 20 metastatic tumors. Cholangiocarcinoma and metastatic tumors were more susceptible to this treatment than HCC. Of the three types of HCC, higher intratumor temperatures were achieved in the diffuse type than in the nodular or massive types. The minimum tumor temperature of HCC stayed below 40 degrees C in 46% of cases, especially in larger tumors. The local response rates (complete remission plus partial remission/all) were 28% and 11% for HCC and non-HCC, respectively, for thermochemotherapy; 86% and 33%, for thermoradiotherapy; and 33% and 89%, for thermotherapy with embolization. No apparent relationship was observed between the intratumor temperatures and local response rate.

Monitoring liver tumor therapy with [18F]FDG positron emission tomography

Positron emission tomography (PET) with [18F]-2-flurodeoxy-glucose (FDG) can be utilized as a functional imaging modality for monitoring liver tumor therapy. We report three cases in which PET-FDG was more useful for this purpose than other imaging methods and tumor markers.

Clinical results of thermoradiotherapy for locally advanced and/or recurrent breast cancer--comparison of results with radiotherapy alone

From August 1979 until 1988, 26 breast cancer patients with 30 tumours were treated by hyperthermia in combination with radiotherapy. Of the 30 tumours, 11 were locally advanced primary tumours (group 1), six were locally advanced recurrent tumours after operation (group 2) and 13 were locally recurrent tumours after radiotherapy (group 3). The thermal profiles showed that the capability of an RF capacitive heating device is comparatively high for large breast tumours with a volume of more than 100 cm3, and that of a 430 MHz microwave device with a single-lens applicator is excellent for localized tumours. The response rate of group 1 and 2 tumours was excellent, and superior to that of historically controlled tumours that were treated by radiotherapy alone from July 1962 until August 1979. In group 3 the tumour response to thermoradiotherapy was not different from that to radiotherapy, but the possibility of significantly reducing total irradiation dose was indicated. More than one good heating session led to a significantly high local response, and factors having a tendency to influence local response were average minimum tumour temperature, tumour volume, and number of effective heat treatments.

Radiofrequency thermotherapy for malignant liver tumors

Inoperable malignant liver tumors have been treated by radiofrequency hyperthermia at Kyoto University Hospital since 1983. In this study, clinical hyperthermia for malignant liver tumor was evaluated for 67 tumors in which we could measure intratumor temperatures. Of the 67 tumors, 41 were hepatocellular carcinomas (HCC), six cholangiocarcinomas, and 20 metastatic tumors. Cholangiocarcinoma and metastatic tumors were more susceptible to this treatment than HCC. Of the three types of HCC, higher intratumor temperatures were achieved in the diffuse type than in the nodular or massive types. The minimum tumor temperature of HCC stayed below 40 degrees C in 46% of cases, especially in larger tumors. The local response rates (complete remission plus partial remission/all) were 28% and 11% for HCC and non-HCC, respectively, for thermochemotherapy; 86% and 33%, for thermoradiotherapy; and 33% and 89%, for thermotherapy with embolization. No apparent relationship was observed between the intratumor temperatures and local response rate.

Initial clinical results of a 430 MHz microwave hyperthermia system using a lens applicator

The applicability of a 430 MHz microwave (MW) hyperthermia system using an electric field converging (lens) applicator was evaluated. Twenty-two tumors with a maximum tumor depth of less than 7 cm (10 chest wall tumors, 8 abdominal and pelvic tumors, 2 extremity tumors, and 2 neck tumors) were treated with the lens applicator heating system for a total of 72 sessions in conjunction with irradiation or chemotherapy. Of the 72 heat sessions, our treatment goal of 30 min of hyperthermia with all monitored tumor temperatures above 42 degrees C was achieved in 31 sessions (43%). The average tumor temperature was 42.5, 43.1, 42.0, and 42.0 degrees C for chest wall, abdominal and pelvic, extremity, and neck tumors, respectively; similarly 88, 83, 64 and 50% of monitored points exceeded 41 degrees C. A lens applicator heating system increased the penetration depth of MW, and tumor temperature of 41 degrees C at 5 cm from the surface was easily achieved with a four-aperture lens applicator. Of the 22 tumors, 10 tumors exhibited complete response (CR), 7 partial response (PR) and 5 no response (NR). These results suggest that the lens applicator heating system is useful for heating localized subsurface tumors with a maximum tumor depth of 5-6 cm.

[Clinical results of loco-regional hyperthermia combined with chemotherapy in the treatment of malignant tumors]

From December 1982 through January 1989, 22 patients with 25 tumors were treated by thermochemotherapy. Of the 25 tumors, 13 were locally recurrent tumors after radiotherapy, 10 distant metastases, and 2 peritoneal disseminations. Employing two types of heating devices (8MHz capacitive RF, 430MHz microwave), hyperthermia was administered once or twice weekly, for 30-60 minutes per session, up to total sessions of 2-15 (mean = 6.9). In some sessions, anticancer drugs were administered intravenously or intraarterially immediately before or simultaneously with hyperthermia. Of the 25 tumors treated, 2 (8%) showed CR, 11 (44%) PR, 7 (28%) NC, and 5 (20%) PD. The better the tumor response was, the higher local control rate was achieved. The survival rate of patients who achieved CR or PR was higher than that of patients who showed NC or PD. Tumor volume, depth of tumor, averaged maximum intratumor temperature, the number of effective heat sessions and the number of anticancer drugs used were shown to affect the tumor response by multivariate analysis. On the other hand, averaged minimum intratumor temperature and history of previous treatment did not affect the tumor response. As almost all the tumors treated were considered to be refractory to radiotherapy or chemotherapy, the tumor responses obtained with thermochemotherapy seemed very encouraging. The expanded trials are warranted to reveal the effectiveness of thermochemotherapy.

Histopathological changes of human tumors following thermoradiotherapy

Twenty human malignant tumors treated with thermoradiotherapy were examined histopathologically. Hyperthermia was administered regionally with a 13.56-MHz or 8-MHz RF heating device, once or twice a week after irradiation, 2 to 12 sessions in total. Fifteen tumors received a total radiation dose of 26 to 70 Gy in fractions of 1.8 Gy to 2.0 Gy a day, 5 days a week, whereas five tumors received a total dose of 20 to 60 Gy in fractions of 4 Gy each, twice a week. Microscopic examination of 4 of the 20 tumors revealed complete necrosis throughout the cross-section of the entire tumor. All the four tumors had received a total dose of over 60 Gy and a tumor center temperature of over 42 degrees C. In 10 tumors, more than 50% but less than 99% of the cross-section of the entire tumor had massive coagulation necrosis. The remaining six tumors showed relatively little change; the area of intratumor necrosis was less than 50%. The grade of tumor necrosis was dependent on both the temperatures of tumor center and periphery, and a total radiation dose. The small blood vessels and capillaries in the tumor parenchyma were markedly damaged in 16 of the 20 tumors, while the blood vessels in the tumor stroma were damaged in only 2 tumors. Condensation of the destroyed nucleus observed in 15 tumors was considered to be a typical change induced by thermoradiotherapy. Viable tumor cells remained in the tumor central area in only four tumors and around the blood vessels in only three tumors. However, in the tumor peripheral area, viable tumor cells were observed in 16 out of the 20 tumors. These results indicate that histopathological changes induced by thermoradiotherapy are greater in the tumor central area than in the tumor peripheral area, and provide strong rationale for utilizing full dose radiation therapy in combination with hyperthermia as opposed to lower doses for cancer therapy.

Radiofrequency (RF) capacitive hyperthermia combined with radiotherapy in the treatment of abdominal and pelvic deep-seated tumors

Thermal parameters and tumor response were determined in 33 abdominal and pelvic deep-seated tumors which were treated with hyperthermia in combination with radiation therapy. Hyperthermia was applied regionally for a total of 3-14 sessions (mean; 6.4 sessions), using an 8 MHz radiofrequency (RF) capacitive heating device. An average tumor temperature (Tav) of more than 42 degrees C was achieved in 17 (52%) tumors, and intratumor temperatures above 42 degrees C could be maintained for more than 20 min (effective heat session) in 103 (52%) of the 198 heat sessions. Of the 33 tumors, 4 tumors exhibited complete regression (CR), 7 PRa (80-99% regression), 7 PRb (50-79% regression) and 15 NR (less than 50% regression). Tumor response (CR + PRa) was apparently dependent on the thermal parameters. Tumors with Tav of more than 42 degrees C or those receiving more than three effective heat sessions showed a significantly higher response rate than those heated less effectively. This trend was also noted in minimum tumor temperature. As to radiation dose, most of the responders received a total of 60-70 Gy irradiation. The two characteristic features in tumor response in effectively heated tumors, were slow tumor regression and appearance of an intratumor low density area on post-treatment computed tomography.

Histological analysis of the effect of hyperthermia on normal rabbit hepatic vasculature

The effects of hyperthermia on rabbit hepatic vasculature were studied histologically. To investigate heat-induced vascular damage in the central veins, portal veins, and hepatic arterioles, the left lobes of rabbit liver were heated locally for 30 min in the range of 40-46 degrees C. Hyperthermia was induced by an 8-MHz radiofrequency current heating device using a needle type interstitial applicator. This device allowed application of heat to a central area of 10 x 10 mm no more than 1 degree C below the preset temperature. Within the area of 1 cm2, the percentage of damaged (ruptured or thrombosed) vessels was estimated for each type of hepatic vasculature. Vascular damage following hyperthermia continued up to 24 h after heating for the three types of hepatic vasculature. Central veins were the most thermosensitive followed by portal veins, whereas hepatic arterioles were the most thermoresistant. The temperature causing 50% vascular damage 24 h after heating was 41.5-42.5 degrees C, 42.5-43.5 degrees C, and 44-45 degrees C for central veins, portal veins, and arterioles, respectively. This differential thermal responsiveness of hepatic vasculature may be attributed to the histological structure of the vessels.

[Clinical results of thermoradiotherapy of locally advanced and recurrent breast cancers--comparison of results with radiotherapy alone]

From August 1979 through January 1988, 23 breast cancer patients with 25 tumors supposed to be refractory to conventional treatment were treated by thermoradiotherapy. Of the 25 tumors, 10 were locally advanced primary tumors [Group 1], 4 locally advanced recurrent tumors after operation more than 5 cm in maximum diameter [Group 2], and 11 locally recurrent tumors after radiotherapy [Group 3]. The present study was not a formal randomised-trial, but a historical-controlled study. The results were compared with tumors which were treated by radiation therapy alone between July 1962 and August 1979. The historical control groups comprised 11 tumors for Group 1, 17 for Group 2 and 19 for Group 3. Employing 4 types of heating devices (8, 13.56 MHz capacitive RF, 430, 2450 MHz microwave), hyperthermia was administered once or twice a week after irradiation, for 30-60 minutes per session, up to a total sessions of 2-9. Radiotherapy was delivered in fractions of 180 to 200 cGy per day, 5 days per week, up to 28-74.4 Gy in total, or in fraction of 400 cGy, two times per week, up to 28-60 Gy. Tumor temperatures were measured by inserting thermocouples into the tumors. The tumors that did not recur during follow-up of more than 3 months were regarded as locally controlled tumors, and the local control rate was calculated. The local control rate in Group 2 and the local response rate (CR + PRa) in Group 1 were higher than those of the historically controlled tumors. In Group 3, hyperthermia combined with lower total doses of irradiation showed a high local response rate similar to that by radiation therapy alone. Thus local hyperthermia in combination with radiation therapy seems to be more effective than radiotherapy alone for locally advanced and recurrent breast cancers.

Effect of misonidazole in preoperative irradiation for bladder cancer followed by total cystectomy

Between 1980 and 1984, 44 patients were treated for bladder cancer by preoperative irradiation of 40 Gy to the pelvic region followed by total cystectomy. These patients were prospectively divided into two groups at random. In 23 cases, 500 mg of misonidazole (MISO) was administered four hours prior to irradiation. Twenty-one patients were preoperatively treated by radiation alone. Most patients had histopathological grading of G3-4, and the distribution of T-factors in the two groups was comparable. Thirty-seven patients out of 44 underwent total cystectomy within three weeks after irradiation. pT-factors were carefully examined in resected specimens. Survival rates were calculated by the Kaplan-Meier method. The 5 year survival rate for T3 patients in the group treated by MISO combined with radiotherapy was 59%, while that for T3 patients in the radiation only group was 43%. A reduction in T-factors was observed in 9 of 17 T3 cases treated by MISO combined with radiation, and in one of 14 T3 cases treated by radiation alone. This finding was significant on chi-square test (p = 0.02). Since the survival rate of T3 patients with a reduction in T-factors by preoperative irradiation was superior to that of cases without reduction (70% vs. 43%), the combined use of MISO in preoperative irradiation seems to be useful for the treatment of T3 bladder cancer.