Randomised trial of hyperthermia as adjuvant to radiotherapy for recurrent or metastatic malignant melanoma. European Society for Hyperthermic Oncology

Preoperative hyperthermia combined with radiochemotherapy in locally advanced rectal cancer: a phase II clinical trial

OBJECTIVE

A prospective phase II study was performed to determine the feasibility and efficacy in terms of response rate, resectability, and morbidity in patients with locally advanced rectal cancer who received preoperative regional hyperthermia combined with radiochemotherapy (HRCT).

SUMMARY BACKGROUND DATA

Recent studies suggest that preoperative radiochemotherapy in locally advanced rectal cancer can induce downstaging, but after resection the incidence of local recurrences remains high. Hyperthermia (HT) may add tumoricidal effects and improve the efficacy of radiochemotherapy in a trimodal approach.

PATIENTS AND METHODS

Thirty-seven patients with histologically proven rectal cancer and T3 or T4 lesions, as determined by endorectal ultrasound and computed tomography, entered the trial. 5-Fluorouracil (300-350 mg/m2) and leucovorin (50 mg) were administered on days 1 to 5 and 22 to 26. Regional HT using the SIGMA 60 applicator (BSD-2000) was given once a week before radiotherapy (45 Gy with 1.8-Gy fractions for 5 weeks). Surgery followed 4 to 6 weeks after completion of HRCT.

RESULTS

Preoperative treatment was generally well tolerated, with 16% of patients developing grade III toxicity. No grade IV complications were observed. The overall resectability rate was 32 of 36 patients (89%), and 31 resection specimens had negative margins (R0). One patient refused surgery. In 5 patients (14%), the histopathologic report confirmed no evidence of residual tumor (pCR). A partial remission (PR) was observed in 17 patients (46%). The survival rate after 38 months was 86%. In none of the patients was local recurrence detected after R0(L), but five patients developed distant metastases.

CONCLUSION

Preoperative HRCT is feasible and effective and may contribute to locoregional tumor control of advanced rectal cancer, which is to be proven in an ongoing phase III trial.

ESHO quality assurance guidelines for regional hyperthermia

The Technical Committee and the Clinical Committee of the ESHO evaluated the experience of the institutes which are active in clinical regional hyperthermia using radiative equipment. Based on this evaluation, QA guidelines have been formulated. The focus of these guidelines lies on what must be done not on how it should be done. Subjects covered are: treatment planning, treatment, treatment documentation, requirements and characterization of equipment, safety aspects, hyperthermia staff requirements and instrumentation for quality assurance.

Radiochemotherapy and hyperthermia in the treatment of rectal cancer

We evaluated the use of regional hyperthermia with radio-chemotherapy in a phase I/II study on locally advanced rectal carcinomas. Thirty-four patients with primary advanced (stage T3/T4) rectal carcinomas (24 patients) or recurring rectal carcinomas (6 patients) were treated using preoperative radiochemo-thermotherapy. Initial tumour staging was carried out clinically (degree of fixation) and using endorectal ultrasonography and CT. Radiotherapy was carried out with the patient prone (on a belly board) at 5 x 1.8 Gy per week up to 45 Gy at the reference point. 5-Fluorouracil (300-500 mg/m2) was administered with low-dose leucovorin (50 mg) on days 1-5 and 22-26. Patients were treated with regional hyperthermia each week prior to radiotherapy, using the Sigma-60 ring of the BSD-2000 system. Temperature/position curves and temperature/time curves were recorded via endocavitary catheters (tumour contact, bladder, vagina). Following endosonographic and clinical restaging, the operation was carried out 4-6 weeks after the end of preoperative therapy. In cases where tumours were unresectable, a boost of up to 60 Gy was given. Twenty-three of the 34 patients (68%) proved to be curatively resectable. Of these patients, 70% were downstaged endosonographically during preoperative therapy. The actuarial survival rates among these patients were 85% (primary rectal cancer) and 60% (recurrences) at 30 months. All in all, the preoperative multimodal therapy was well tolerated, and premature termination was necessary in only two cases. The quality of temperature distribution (T90, cum min T90 > 40.5 degrees C) depends on the power level and relative power density. The response (particularly downstaging) correlates significantly with the quality parameters of the temperature distributions. This regimen proved practical and effective, with encouraging downstaging rates and local control rates.

Dose uniformity of ferromagnetic seed implants in tissue with discrete vasculature: a numerical study on the impact of seed characteristics and implantation techniques

The results from simulations with a new three-dimensional treatment planning system for interstitial hyperthermia with ferromagnetic seeds are presented in this study. The thermal model incorporates discrete vessel structures as well as a heat sink and enhanced thermal conductivity. Both the discrete vessels and the ferroseeds are described parametrically in separate calculation spaces. This parametric description has the advantage of an arbitrary orientation of the structures within the tissue grid, easy manipulation of the structures and independence from the resolution of the tissue voxels (tissue calculation space). The power absorption of the self-regulating seeds is according to empirical data. The thermal effects of an unlimited number of thin layers surrounding the seed (coatings, catheters) can be modelled. The initial calculations have been performed for an array of 12 identical ferromagnetic seeds in a tissue volume with a computer generated artificial vessel network spanning four vessel generations in both the arterial and venous tree. The heterogeneously distributed large isolated vessels impair the temperature distribution significantly, indicating the limited accuracy of continuum models. Simulations with different types of ferromagnetic seeds have confirmed that the efforts of previous studies to optimize the self-regulating temperature control and the implantation techniques of the ferroseeds will improve the homogeneity of the temperature distribution in the target volume. Multifilament seeds implanted in brachytherapy needles and tubular seeds appear to be the most favourable configurations. The division of long seeds into shorter segments with the appropriate Curie temperature will further improve the homogeneity of the temperature distribution without increasing the average temperature in the volume of interest. Given the proper thermal tissue data, the model presented in this study will prove to be a useful tool in making choices for the implant geometry, seed spacing and Curie temperature.

A 433 MHz Lucite cone waveguide applicator for superficial hyperthermia

The effective field size (EFS, SAR > or = 50% of the maximum SAR at 1 cm depth) of a conventional 433 MHz water filled waveguide applicator (32 cm2, aperture area 100 cm2) has been increased by: (1) replacement of the two diverging brass side walls which are parallel to the direction of the electric field by Lucite walls; and (2) Placement of a heterogeneous permittivity in the centre of the aperture. SAR distributions were measured at several depths in layered fat-muscle phantoms. With Lucite side walls the SAR distribution becomes wider in the H-plane of the aperture, resulting in a circular SAR distribution. In this situation the EFS is 67 cm2. Additional insertion of a PVC cone with a top angle of 15 degrees at the centre of the aperture increases the EFS to 91 +/- 6 cm2 for a waterbolus of 18 x 18 x 1 cm3. The experiments also demonstrated that the resulting EFS is affected by the waterbolus size and shape. Calorimetric measurements showed that the efficiency of the improved applicator is comparable to the efficiency of the conventional water filled waveguide applicator, 50 and 56% respectively. The modifications reported provide a simple and inexpensive means to increase the EFS and can be easily implemented in water filled waveguide applicators.

Hyperthermia may decrease the development of telangiectasia after radiotherapy

CASE REPORT

A patient with recurrent breast cancer was reirradiated twice on adjacent fields with a time interval of 9 months. The first time she was treated with reirradiation alone, the second time with reirradiation plus hyperthermia. The reirradiation schedule for both fields was 8 x 4 Gy in 4 weeks. Both fields overlapped partly with the field of postoperative radiotherapy, which was applied 57 and 66 months earlier to a total dose of 40.5 Gy.

RESULTS

During the 52 to 61 months follow-up, a remarkable difference in telangiectasia development, between the parts of the reirradiation fields overlapping with the primary radiotherapy field, became apparent. Telangiectasia was observed 9 months after treatment with reirradiation alone and progressed to confluent in 47 months after treatment. In the reirradiation plus hyperthermia area, the maximum observed telangiectasia was slight until 52 months after treatment.

DISCUSSION

The difference in the development of telangiectasia between these fields cannot be explained by differences in any of the known radiation treatment related prognostic factors. A protective effect by hyperthermia has been suggested by Haveman and coworkers, who have shown experimentally that heat treatment leads to enhanced proliferation of endothelial cells, thereby inducing a fast repopulation and replacement of X-ray damaged cells.

CONCLUSION

This difference in telangiectasia formation is an interesting observation. Whether such a protective effect of hyperthermia is of general relevance has to become clear from more extensive clinical studies.

Principles and guidelines for surgeons: management of cutaneous malignant melanoma. European Society of Surgical Oncology Brussels

This article outlines and discusses the principles of the guidelines for the management of malignant melanoma by surgeons. The guidelines are based, in large part, on the consensus of the Dutch Melanoma Working Party that was revised in 1997. The article reflects internationally accepted treatment principles that have arisen both from critical assessment of existing evidence and data, and from the outcome of randomized studies.

Carbon dioxide laser for cutaneous melanoma metastases: indications and limitations

A total of 469 in-transit or satellite lesions were treated by carbon dioxide (CO2) laser vaporization in 15 patients. The treatment was performed mostly on an outpatient basis, under local anaesthesia. The technique was easily mastered and quickly performed. Wound healing and patient acceptance were good. A major drawback, however, proved to be the unexpected high incidence of recurrences at the lasered sites. In our opinion CO2 laser treatment may be considered as a palliative option in patients with a moderate to extensive amount of cutaneous metastases, whose lesions preferably are < 10 mm and in whom local excision is not feasible anymore. For extremity lesions this treatment may have a place after failure of isolated limb perfusion. CO2 laser treatment cannot be considered a first-line option unless the issue of local recurrences is solved.

Changes in muscle blood flow distribution during hyperthermia

Blood flow is a critical parameter for obtaining satisfactory temperature distributions during clinical hyperthermia. This study examines the changes in blood flow distribution in normal porcine skeletal muscle before, during and after a period of regional microwave hyperthermia. The baseline blood flow distribution during general anaesthesia and after the insertion of the thermal probes was established independently in order to isolate the changes due to hyperthermia. General anaesthesia alone and thermocouple insertion during anesthesia had no significant effect on the muscle blood flow distribution. Regional microwave heating generated a non-uniform blood flow distribution which was a function of the tissue temperature distribution. Blood flow was greater in those tissues samples in which higher temperatures were recorded and less in those sampled further from the applicators peak SAR (Specific Absorption Rate). The increase in blood flow appears to be primarily a local phenomenon. Although muscle blood flow may be considered to be uniform prior to heating, this does not hold during hyperthermia treatment. Therefore, the non-uniform nature of the blood distribution during heating should be incorporated into any practical bioheat transfer model.

Hyperthermia and incorporation of halogenated pyrimidines: radiosensitization in cultured rodent and human tumor cells

PURPOSE

To investigate the possible benefit of hyperthermia (HT) in combination with radiosensitization by halogenated pyrimidines (HPs) in rodent as well as in human tumor cells.

METHODS AND MATERIALS

Exponentially growing rodent cells, radiosensitive R-1 and MOS cells and radioresistant RUC-II and V79 cells, and human SW1573 cells, were exposed to 0, 1, 2, and 4 microM of chloro- (CldUrd), bromo- (BrdUrd), or iodo-deoxyuridine (IdUrd) in the culture medium. Survival after irradiation with gamma-rays from a 137Cs source and/or hyperthermic treatment (HT, 60 min at 42 degrees C) was determined by clonogenic assay. Linear-quadratic analyses of the radiation survival curves were performed to assess sensitization in the dose range 1 to 3 Gy relevant to radiotherapy.

RESULTS

The incorporation of HPs sensitized all cell lines to HT and resulted in radiosensitization dependent on the percentage of thymidine replacement. At equal levels of thymidine replacement, IdUrd was the most potent radiosensitizer. HT further increased radiation-induced lethality of cells that had incorporated HPs. Linear-quadratic analyses showed that HT further increased the linear parameter of the LQ formula while the quadratic parameter was not significantly changed.

CONCLUSION

The combination of HT and HPs act additively in increasing the radiosensitivity of rodent tumor cell lines with varying radiosensitivities as well as of a human tumor cell line. In particular, the ratio of the linear parameter to the quadratic parameter, relevant for fractionation effects in radiotherapy, was increased.

Long-duration, mild whole body hyperthermia with cisplatin: tumour response and kinetics of apoptosis and necrosis in a metastatic rat mammary adenocarcinoma

This study examines antitumour effect and induction of apoptosis and necrosis after treatment with long-duration, mild whole body hyperthermia (LL-WBH, 40.0 degrees C, for 6 h) in simultaneous combination with cisplatin (CDDP) on primary and metastatic tumour growth in a rat mammary adenocarcinoma. A significantly greater delay in primary mammary tumour growth was observed after treatment with LL-WBH + CDDP, compared to either modality alone (p < 0.05). LL-WBH alone caused a significant delay in spontaneous metastasis to the axillary lymph node (ALN) and LL-WBH + CDDP tended to further increase the delay in ALN metastasis. Survival was longest in rats receiving LL-WBH + CDDP, compared to other groups (p < 0.05). CDDP induced a peak of tumour apoptosis at 24 h after treatment beginning that was significantly greater than LL-WBH alone (p < 0.05). The peak of tumour apoptosis induced by LL-WBH + CDDP from 12 to 24 h was significantly greater than any other group (p < 0.01). These results suggest that the extent of treatment-induced apoptosis seems to correlate positively with antitumour response and the combination or LL-WBH with CDDP may lead to a promising adjuvant therapy for breast cancer.

Rationale for different approaches to combined melphalan and hyperthermia in regional isolated perfusion

The addition of hyperthermia (HT) to regional isolated perfusion (RIP) with Melphalan theoretically has two advantages. Firstly, heat can selectively kill cells in poorly vascularised areas that are usually not reached by the drug. Secondly, in vitro data have revealed that the effect of Melphalan is enhanced at temperatures 39-45 degrees C. However, for the simultaneous application of Melphalan and HT, as it is given in most institutes, both normal and tumour tissues within the volume are treated with both modalities. It is unclear whether--for the same heat dose--the cytotoxicity of Melphalan is enhanced more in tumour tissue than in normal tissues. As the applied dose of Melphalan in RIP is selected on maximum acceptable toxicity, any enhancement of toxicity is undesired. Indeed, Melphalan application at temperatures > 41 degrees C has resulted in unacceptable toxicity. In most institutes, the hyperthermia dose is reduced in comparison to application as a single-modality treatment, to allow simultaneous combination without unacceptable toxicity. In this review, the rationale for two different approaches is summarised which may make it possible to improve the benefit from the theoretical advantage of the use of HT in RIP. It is meant to stimulate discussion as a possible first step in the design of new treatment protocols.

Relationship between thermal dose and outcome in thermoradiotherapy treatments for superficial recurrences of breast cancer: data from a phase III trial

PURPOSE

The objective of this study was to determine whether the thermal dose delivered during hyperthermia treatments and other thermal factors correlate with outcome after combined radiation and hyperthermia of breast carcinoma recurrences. Data were from the combined hyperthermia and radiation treatment arms of four Phase III trials, which when pooled together, demonstrated a positive effect of hyperthermia.

METHODS AND MATERIALS

Four Phase III trials addressing the question of whether hyperthermia could improve the local response of superficial recurrent breast cancer to radiation therapy were combined into a single analysis. Thermal dosimetry data were collected from 120 of the 148 breast cancer recurrence patients who received hyperthermia. The data were analyzed for correlations between thermal parameters as well as important clinical parameters and outcome (complete response rate, local disease free survival, time to local failure, and overall survival).

RESULTS

Five thermal parameters were tested, all associated with the low regions of the measured temperature distributions. Max(TDmin) and Sum(TDmin) were associated with complete response where TDmin is the minimum thermal dose measured by any of the tumor temperature sensors during a treatment: Max(TDmin) is the maximum of TDmin over a series of treatments. Using a categorical relationship with a cutoff of 10 min for Sum(TDmin), the complete response rate was 77% for Sum(TDmin) > 10 min and 43% for Sum(TDmin) < or = 10 min (p = 0.022, adjusted for study center and significant clinical factors). The overall complete response rate for hyperthermia and radiation was 61% compared to 41% for radiation alone. Either Max(TDmin) or Sum(TDmin) were also associated with local disease free survival, time to local failure and overall survival.

CONCLUSIONS

An earlier report of this trial demonstrated a significant benefit when hyperthermia was added to radiation in the treatment of breast cancer recurrences. The analysis of thermal factors demonstrates that parameters representative of the low end of the measured temperature distributions are associated with initial complete response rate, local disease-free survival, time to local failure and overall survival.

Augmentation in chemosensitivity of intratumor quiescent cells by combined treatment with nicotinamide and mild hyperthermia

C3H/He and Balb/c mice bearing SCC VII and EMT6/KU tumors, respectively, received continuous administration of 5-bromo-2'-deoxyuridine (BrdU) for 5 days using implanted mini-osmotic pumps to label all proliferating (P) cells. Nicotinamide was administered intraperitoneally before cisplatin injection and/or tumors were locally heated at 40 degrees C for 60 min immediately after cisplatin injection. The tumors were then excised, minced and trypsinized. The tumor cell suspensions were incubated with cytochalasin-B (a cytokinesis-blocker), and the micronucleus (MN) frequency in cells without BrdU labeling (quiescent (Q) cells) was determined using immunofluorescence staining for BrdU. The MN frequency in total (P+Q) tumor cells was determined from tumors that had not been pretreated with BrdU labeling. The sensitivity to cisplatin was evaluated in terms of the frequency of induced micronuclei in binuclear tumor cells (MN frequency). In both tumor systems, the MN frequency in Q cells was lower than that in the total cell population. Nicotinamide treatment elevated the MN frequency in total SCC VII cells. Mild heating raised the MN frequency more markedly in Q cells than in total cells. The combination of nicotinamide and mild heat treatment increased the MN frequency more markedly than either treatment alone. In total SCC VII cells, nicotinamide increased 195mPt-cisplatin uptake. Mild heating elevated 195mPt-cisplatin uptake in total EMT6/KU cells. Cisplatin-sensitivity of Q cells was lower than that of total cells in both tumor systems. Nicotinamide sensitized tumor cells including a large acutely hypoxic fraction, such as those of SCC VII tumors, through inhibition of the fluctuations in tumor blood flow. Tumor cells including a large chronically hypoxic fraction such as Q cells were thought to be sensitized by mild heating through an increase in tumor blood flow.

Effects of 42 degrees C hyperthermia on intracellular pH in ovarian carcinoma cells during acute or chronic exposure to low extracellular pH

PURPOSE

To determine whether intracellular pH (pHi) is affected during hyperthermia in substrate-attached cells and whether acute extracellular acidification potentiates the cytotoxicity of hyperthermia via an effect on pHi.

METHODS AND MATERIALS

The pHi was determined in cells attached to extracellular matrix proteins loaded with the fluorescent indicator dye BCECF at 37 degrees C and during 42 degrees C hyperthermia at an extracellular pH (pHe) of 6.7 or 7.3 in cells. Effects on pHi during hyperthermia are compared to effects on clonogenic survival after hyperthermia at pHe 7.3 and 6.7 of cells grown at pHe 7.3, or of cells grown and monitored at pHe 6.7.

RESULTS

The results show that pHi values are affected by substrate attachments. Cells attached to extracellular matrix proteins had better signal stability, low dye leakage and evidence of homeostatic regulation of pHi during heating. The net decrease in pHi in cells grown and assayed at pHe = 7.3 during 42 degrees C hyperthermia was 0.28 units and the decrease in low pH adapted cells heated at pHe = 6.7 was 0.14 units. Acute acidification from pHe = 7.3 to pHe = 6.7 at 37 degrees C caused an initial reduction of 0.5-0.8 unit in pHi, but a partial recovery followed during the next 60-90 min. Concurrent 42 degrees C hyperthermia caused the same initial reduction in pHi in acutely acidified cells, but inhibited the partial recovery that occurred during the next 60-90 min at 37 degrees C. After 4 h at 37 degrees C, the net change in pHi in acutely acidified cells was 0.30 pH unit, but at 42 degrees C is 0.63 pH units. The net change in pHi correlated inversely with clonogenic survival.

CONCLUSIONS

Hyperthermia causes a pHi reduction in cells which was smaller in magnitude by 50% in low pH adapted cells. Hyperthermia inhibited the partial recovery from acute acidification that was observed at 37 degrees C in substrate attached cells, in parallel with a lower subsequent clonogenic survival.

Analysis of thermal parameters obtained during phase III trials of hyperthermia as an adjunct to radiotherapy in the treatment of breast carcinoma

An analysis of 351 HT treatment sessions administered to 101 patients receiving radiotherapy and hyperthermia (RT + HT) who were entered into Phase III concurrent randomized trials for recurrent (BrR) and intact (BrI) breast tumours is presented. A complete response (CR) was recorded in 50 of 84 (59.5%) fields in the case of recurrent breast patients and in 10 of 17 (59%) fields in the case of the intact breast patients. In comparison, 15 of 60 (25%) patients entered into BrR who received RT alone and 8 of 12 (66.7%) patients receiving RT alone entered into BrI trial achieved CR. A set of thermal parameters is defined and evaluated on a treatment by treatment basis. Patient and tumour characteristics influential on CR are identified and thermal parameters which have additional prognostic value are investigated. Multivariate logistic analysis of the non-thermal data showed that maximum depth of tumour, presence or history of disease outside the treated area and RT regimen were most influential on CR. Tumour volume (cm3) (OR = 0.996, 95% CI = 0.993-1.004, p = 0.08) was not a strong prognostic covariate; tumour area and linear dimensions were even less significant (p = 0.41). The cumulative minimum thermal isoeffect dose (equivalent minutes at 43 degrees C) accrued over the 1st, 1st and 2nd, and 1st, 2nd and 3rd treatment sessions was the only thermal parameter to exhibit an association with CR consistently, Other thermal parameters found to contribute to the predictive models were MINTIME > 42 degrees C calculated for the first treatment session and %sensors > 43 degrees C (peak) calculated for the 2nd treatment session.

Alteration in the hypoxic fraction of quiescent cell populations by hyperthermia at mild temperatures

We investigated oxygenation of quiescent (Q) tumour cells in vivo by mild heat treatment. C3H/He mice bearing SCC VII tumours received BrdU continuously for 5 days via implanted mini-osmotic pumps, to label all proliferating (P) cells. The tumours were then irradiated after treatment, and were excised, minced and trypsinized. The tumour cell suspension thus obtained were incubated with cytochalasin-B (a cytokinesis blocker), and the micronucleus (MN) frequency in cells without BrdU labelling was determined using immunofluorescence staining for BrdU. This MN frequency was then used to calculate the surviving fraction of unlabelled cells from the regression line for the relationship between the MN frequency and the surviving fraction of total (P + Q) tumour cells. Thus, a cell survival curve could be determined for the cells not labelled with BrdU, which can be regarded as the Q cells in a tumour for all practical purposes. The MN frequency in total tumour cell population was determined from the irradiated tumours that were not pretreated with BrdU. Assays performed immediately after irradiation of both normally aerated and hypoxic tumours showed that Q cells contained higher hypoxic fractions than the total tumour cell population. Mild heat treatment (40.0 degrees C, 60 min) before irradiation decreased the hypoxic fraction, even when is was combined with nicotinamide administration. In contrast, mild heating did not decrease the hypoxic fraction when the mice were placed in a circulating carbogen (95% O2/5% CO2) chamber. Therefore, mild heat treatment was thought to preferentially oxygenate the chronically hypoxic fraction.

The influence of vasculature on temperature distributions in MECS interstitial hyperthermia: importance of longitudinal control

The quality of temperature distributions that can be generated with the Multi Electrode Current Source (MECS) interstitial hyperthermia (IHT) system, which allows 3D control of the temperature distribution, has been investigated. For the investigations, computer models of idealised anatomies containing discrete vessels, were used. A 7-catheter hexagonal implant geometry with a nearest neighbour distance of 15 mm was used. In each interstitial catheter with a diameter of 2.1 mm a number of 1 up to 4 electrodes were placed along an 'active section' with a length of 50 mm. The electrode segments had lengths of 50, 20, 12 and 9 mm respectively. Both single vessel and vessel network situations were analysed. This study shows that even in situations with discrete vasculature and perfusion heterogeneity it remains possible to obtain satisfactory temperature distributions with the MECS IHT system. Due to its 3D spatial control the temperature homogeneity in the implant can be made quite satisfactory.

Adenocarcinoma of the prostate: innovations in management

Adenocarcinoma of the prostate (CaP) in the Western world has become the most common noncutaneous human tumor. CaP is also the second most important cause of cancer deaths among the male population in the United States. Major progress was made in the past decade in better understanding this disease process, as well as in improved diagnostic accuracy. This improved diagnostic accuracy was due to wide application of prostate-specific antigen (PSA), use of transrectal ultrasound (TRUS), and greater awareness among clinicians of CaP. The use of PSA in clinical practice has resulted in a sharp increase in the number of patients diagnosed with capsule-confined tumors. The optimal treatment for capsule-confined CaP is in the process of being defined. Radical prostatectomy in the United States is currently the most commonly applied treatment for younger patients. Excellent treatment results with a 10-year actuarial survival > 80% are readily obtainable in properly selected patients. Nerve-sparing procedures helped reduce the high incidence of impotence that occurs in patients after radical retropubic prostatectomy. Radiotherapy remains the other curative treatment method in the management of CaP patients, with long-term survival rates similar to those reported in surgical series. Due to the problem of frequent preoperative tumor understaging, a routine use of postoperative irradiation to the prostatic fossa produces an excellent (> 95%) incidence of local tumor control. Management of patients with metastatic disease has undergone a considerable evolution with the development of modern hormonal management and treatment with strontium-89 to control intractable bone pain. Newer treatment methods such as hyperthermia are currently being investigated. Major efforts are directed toward the reduction of short- and long-term treatment toxicity associated with surgery, radiotherapy, and hormonal management, thus improving patient quality of life.

Combined external beam irradiation and external regional hyperthermia for locally advanced adenocarcinoma of the prostate

PURPOSE

To determine the safety and efficacy of combined external beam irradiation and external regional hyperthermia in the treatment of adenocarcinoma of the prostate.

METHODS AND MATERIALS

From 1987 to 1994, 30 patients received combined external beam irradiation and external regional hyperthermia for locally advanced prostate cancer. The results of the 21 patients with newly diagnosed (n = 18) or locally recurrent (n = 3) adenocarcinoma are reported herein. No patient had evidence of distant metastases. Total radiotherapy doses of 65-70 Gy to the prostate were planned using a four-field box technique. Hyperthermia treatments were delivered using an annular phased array microwave device. The treatment goal was to achieve temperatures > or = 42 degrees C in all measured points within the prostate.

RESULTS

Of the newly diagnosed patients, 16 out of 18 (89%) had T3 or T4 tumors, 11 out of 18 (61%) had Gleason scores of 7-9, and the mean pretreatment Prostate Specific Antigen (PSA) was 69 ng/ml. The median follow-up of all 21 patients was 36 months. None of the patients achieved the treatment goal of all intratumoral temperatures > or = 42 degrees C. The mean CEM 43 T90 was 2.34 min. The disease-free survival at 36 months is 25%; 12 out of 18 (67%) of the patients have relapsed. The only significant predictor of relapse was pretreatment PSA. There were no complications > Grade 3.

CONCLUSIONS

In spite of the inability to achieve high tumor temperatures, the relapse-free survival rate in this population of patients with very advanced localized prostate cancer treated with radiation therapy plus hyperthermia compares favorably with most series using radiation therapy alone. Further studies aimed at improving the ability to deliver hyperthermia to the prostate are warranted.

Hyperthermia enhances the cytotoxicity and platinum-DNA adduct formation of lobaplatin and oxaliplatin in cultured SW 1573 cells

The cytotoxicity of cisplatin and cisplatin-DNA adduct formation in vitro and in vivo is clearly enhanced by hyperthermia. We investigated whether cytotoxicity and platinum-DNA adduct formation of two promising new third-generation platinum derivatives, lobaplatin [1,2-diamminomethylcyclobutane platinum(II) lactate] and oxaliplatin [oxalato-1,2-diaminocyclohexane platinum(II)], are also enhanced by hyperthermia. Cisplatin was used for comparison. SW 1573 cells were incubated with cisplatin, lobaplatin or oxaliplatin at different concentrations for 1 h at 37 degrees, 41 degrees and 43 degrees C. The reproductive capacity of cells was determined by cloning experiments. Immunocytochemical detection of platinum-DNA adducts was performed with the rabbit antiserum NKI-A59. At 37 degrees C, cisplatin was the most cytotoxic, followed by oxaliplatin and lobaplatin. Hyperthermia clearly enhanced the cytotoxicity of cisplatin, lobaplatin and oxaliplatin. There was no further increase in cytotoxicity at 43 degrees C compared to 41 degrees C for cisplatin and oxaliplatin. A further increase in cytotoxicity at 43 degrees C was observed for lobaplatin. At 43 degrees C thermal enhancement was higher for lobaplatin than for oxaliplatin, with the reverse pattern at 41 degrees C. For both drugs, thermal enhancement of cytotoxicity was lower than observed for cisplatin. Immunocytochemical detection of platinum-DNA adducts was feasible for all the drugs. Adduct formation was enhanced at 43 degrees C for cisplatin, lobaplatin and oxaliplatin with a relative increase of 410%, 170% and 180%. These results seem to confirm that an increase in platinum-DNA adduct formation is involved in the in vitro thermal enhancement of cytotoxicity. The observed thermal enhancement of cytotoxicity of lobaplatin and oxaliplatin in vitro warrants further in vivo investigations.

Long duration-mild whole body hyperthermia of up to 12 hours in rats: feasibility, and efficacy on primary tumour and axillary lymph node metastases of a mammary adenocarcinoma: implications for adjuvant therapy

The feasibility and efficacy of low temperature (40 degrees C) long duration whole body hyperthermia (LL-WBH) was investigated in rats bearing a highly metastatic mammary adenocarcinoma (MTLn3). We compared the treatment effects of various durations of LL-WBH (40 degrees C for 2-12 h) to that of conventional short duration-high temperature WBH (SH-WBH, 41.5 degrees C for 2 h). SH-WBH, 2 h LL-WBH, and 4 h LL-WBH resulted in only modest primary tumour growth delays (TGDs) of 0.9, 1.1 and 1.8 d (days) respectively. In contrast, significantly increased TGDs of 2.8, 3.2, 2.6, and 3.1 d were achieved with 6, 8, 10 and 12 h LL-WBH, respectively (p < 0.05 compared to SH-WBH, 2 h-LL-WBH, and 4 h-LL-WBH). Notably, LL-WBH reduced the incidence of axillary lymph node metastasis at 14 days post-treatment, from 100% in normothermic controls and 92% after SH-WBH, to 33, 40, 50, and 60% following 4, 6, 8 and 10 h LL-WBH respectively. When the duration of LL-WBH was extended to 12 h, no reduction in axillary lymph node metastasis was observed. Normal tissue toxicity of LL-WBH appeared to be minimal and LL-WBH durations of up to 12 h were well tolerated. These data show that LL-WBH for durations of from 4 to 10 h has greater antitumour activity than SH-WBH, against mammary adenocarcinoma, suggesting that LL-WBH may have therapeutic potential in the treatment of malignant disease.

Reduction of hypoxic cells in solid tumours induced by mild hyperthermia: special reference to differences in changes in the hypoxic fraction between total and quiescent cell populations

C3H/He mice bearing SCC VII tumours received 5-bromo-2'-deoxyuridine (BrdU) continuously for 5 days via implanted mini-osmotic pumps in order to label all proliferating (P) cells. The tumours were then heated at 40 degrees C for 60 min. At various time points after heating, tumour-bearing mice were irradiated while alive or after being killed. Immediately after irradiation, the tumours were excised, minced and trypsinized. The tumour cell suspensions obtained were incubated with cytochalasin-B (a cytokinesis blocker), and the micronucleus (MN) frequency in cells without BrdU labelling, which could be regarded as quiescent (Q) cells, was determined using immunofluorescence staining for BrdU. The MN frequency in the total (P+Q) tumour cell population was determined from the irradiated tumours that were not pretreated with BrdU. The MN frequency of BrdU unlabelled cells was then used to calculate the surviving fraction of the unlabelled cells from the regression line for the relationship between the MN frequency and the surviving fraction of total (P+Q) tumour cells. In general, Q cells contained a greater hypoxic fraction (HF) than the total tumour cell population. Mild heating decreased the HF of Q cells more markedly than in the total cell population, and the minimum values of HFs of both total and Q cell populations were obtained 6 h after heating. Two days after heating, the HF of total tumour cells returned to almost that of unheated tumours. In contrast, the HF of Q cells did not return to the HF level of unheated tumours until 1 week after heating. It was thought that irradiation within 12 h after mild heating might be a potentially promising therapeutic modality for controlling radioresistant Q tumour cells.

Radiation therapy for malignant melanoma

Sufficient biologic and clinical evidence now exists to refute the longstanding dogma that melanomas are uniformly radiation resistant and hence radiation therapy has little role in the management of this disease. Although surgery remains the treatment of choice for the vast majority of localized melanomas, available data indicate that radiation therapy is a viable alternative for a few subsets of patients in whom surgery would result in cosmetic or functional deformity, such as patients with large facial lentigo maligna melanomas or small or intermediate-sized uveal melanomas. Retrospective and Phase II prospective studies have revealed that elective/adjunctive radiation therapy improves the local-regional control rate in patients with thick primary lesions, nodal involvement, or mucosal melanomas. However, the impact of elective/adjunctive radiation therapy on the survival rate has yet to be determined. Radiation therapy has been established as a simple and cost-effective treatment modality for palliation of patients with symptomatic metastatic spread. The response of metastatic deposits to radiation varies with the tumor volume, total dose, and dose per fraction. The choice of optimal fractionation depends on tumor site and the patient's survival expectation. New data indicate that hyperthermia enhances the response of metastatic lesions to radiation. Ongoing research with a variety of experimental strategies may offer the possibility of further increasing the utility of radiation therapy in the management of this disease.

Potential for power deposition conformability using reflected-scanned planar ultrasound

Specialized heating devices for the simultaneous delivery of hyperthermia and ionizing radiation are being developed by several investigators in an effort to increase thermal radiosensitization in clinical treatment. One particular device is the SURLAS (Scanning Ultrasound Refléctor-Linear Array System), which was designed specifically to operate concomitantly with medical linear accelerators. The technical feasibility of the SURLAS has been demonstrated, and a design optimization study has been performed. The main objective of this paper is to demonstrate the potential for power deposition conformability of the SURLAS. This has been done using a thermographic technique which provides qualitative, high spatial-resolution measurements of power deposition distributions. The technique consists of normally insonating one surface of a 1 cm layer of a Polyurethane phantom while the temperature field on the opposite air-exposed surface is recorded using an infrared camera during the first few minutes after power insult. The thermal fields measured in this way are good qualitative estimates of relative power deposition. To demonstrate conformability, a region of 10 cm (the length of the array) by 12 cm (the scanning distance) on the air-exposed phantom surface was divided into 24 sectors (24 subregions with independent power control). Each sector was 2.5 x 2 cm across and long the scanning direction respectively. Several sector insonation patterns were synthesized in an open-loop fashion by properly adjusting power levels to each of the elements of an array as a function of reflector position as the reflector was scanned continuously in a reciprocating fashion at a constant speed. The array was made of a single piezoelectric crystal with resonant frequency of 2.2 MHz and electrically segmented into four 2.5 x 2.5 cm elements. The reflector was made of a 0.5 mm thick Brass plate. Sufficient power was supplied to the array to induce peak temperature elevations of about 10 degrees C in 60s at a scanning speed of 2.4 cm/s. The results show that measured relative power deposition patterns agreed well with programmed insonation patterns demonstrating that the SURLAS possesses great potential for power conformability, and thus, for temperature feedback power deposition control.

Role of radiotherapy and hyperthermia in the management of malignant melanoma

The overall response rates of malignant melanoma (MM) to ionizing radiation are similar to those of other malignant neoplasms. This is based on recent radiobiological data on MM cell lines and radiobiological analyses of large clinical experiences, using a spectrum of fractionation schedules on diverse MM lesions. In contrast to other carcinomas, MM exhibits an unusual spectrum of radiobiological responses characteristic for early- and late-response tissues implying that there is a wide range of sensitivities to radiation fraction sizes. This is confirmed by clinical response and tumor control data from prospective trials in which different fractionation schedules produced control rates between 40 and > 90%. These experiences suggest that primary MM lesions as well as skin and lymph node metastases may be more responsive to larger fraction sizes than parenchymal metastases. The same holds true when irradiation is used as an adjuvant for locoregional treatment of the primary MM and draining lymphatics. Total doses for maximum tumor control rates remain to be established for the different fractionation schemes of proven effectiveness. Hyperthermia in combination with regionally applied cytotoxic agents or irradiation has produced encouraging enhancements in MM cytotoxicity. However, due to contradicting results, these data need to be validated by additional clinical investigation.

Cytokine production after whole body and localized hyperthermia

The levels of TNF, IL-1 and IL-6 in circulating blood female WAG/Ry rats were assessed in relation to treatment with localized hyperthermia of the right hind leg or with whole-body hyperthermia (WBH). After a localized treatment for 30 min at 43 or 44 degrees C no detectable increase in levels of IL-6 or TNF was obtained. Hyperthermia for 30 min at 45 degrees C led to an elevated level of IL-6 of 19.4 +/- 5.2 U/ml above the control level of 24 h after treatment. Levels of IL-1 were never higher than those in control animals that received only anaesthesia. Anaesthesia induced a peak level of approximately 131 U/ml IL-1 6 h after treatment. Serum levels of IL-1 and IL-6 are enhanced after WBH. IL-1 reaches a peak level already during WBH about 15 after reaching 41.5 degrees C. IL-6 levels were not enhanced during WBH but 1 h after WBH a clear peak was observed. Anaesthesia with sham WBH did not lead to enhanced IL-6 levels but enhanced IL-1 levels were clearly detected. We did not detect TNF in any sample after WBH. It is concluded from the present results that IL-6 is not induced by a 'standard' treatment of localized hyperthermia as used in oncotherapy (i.e. 60 min at 43 degrees C) to such a high level locally that this is reflected in increased levels in circulating blood. WBH at clinically relevant temperatures leads to enhanced levels of IL-1 and IL-6. The difference in IL-6 response after WBH or localized hyperthermia probably is related to the fact that in WBH also the bone marrow is treated. This may lead to stimulation of this important stem cell compartment of the peripheral blood. The sequence of appearance of IL-1 and IL-6 after hyperthermia is akin to the sequence in an inflammatory response. However, the experiments with sham treatment show that IL-1 may appear in the circulating blood not followed by IL-6. These results indicate that enhanced IL-1 levels may reflect a stress reaction of the animal related to the (sham) treatment. Enhanced levels of IL-1 after WBH correlate with enhanced levels of ACTH in the circulating blood.

Thirty-five years of isolated limb perfusion for melanoma: indications and results

Isolated limb perfusion (ILP) for limb melanoma remains controversial despite its frequent use for over 35 years. To determine whether it has proven benefits, reported results have been reviewed. The value of adjuvant ILP cannot be determined from the multitude of retrospective studies on this subject. Preliminary results of the large European Organization for Research and Treatment of Cancer-World Health Organization-North American Perfusion Group trial suggest that patients with melanomas of 1.5-3.0 mm in thickness who do not undergo elective lymph node dissection may have a locoregional control benefit from ILP. However, as long as a definite survival advantage for ILP has not been demonstrated, such treatment does not seem justified for these patients. The value of prophylactic ILP after resection of recurrent limb melanoma is also scientifically unproven. The potential prevention of further limb recurrence for only a limited period of time, as demonstrated in a rather small Swedish trial, probably does not justify routine use of ILP in these patients; a large international trial will be needed to assess whether ILP provides a survival advantage. For those with locally inoperable limb melanoma, ILP appears to be the treatment of choice since it results in complete disappearance of all macroscopic disease in a substantial proportion of patients, removing the need for amputation and providing palliation of symptoms. However, high limb recurrence rates and short duration of response need improvement. Results of alternative treatments should be compared prospectively with those of ILP in this clinical situation.

Adjuvant VHF therapy in locally recurrent and primary unresectable rectal cancer

In a prospective randomized study, 434 mHz microwave therapy combined with external beam radiotherapy (VHF + RT) was compared with standard external beam radiotherapy (RT) in controlling locally recurrent or unresectable primary adenocarcinoma of the rectum. Independent assessors documented quality of life scores, performance status, toxicities, local response to treatment, and systemic disease progression before treatment and after treatment and every 8 weeks thereafter. Of 75 patients randomized, 73 were eligible for inclusion in the study. Forty-three of these patients had local pelvic tumour recurrence only and 21 also had distant metastases. In addition, nine patients had primary inoperable carcinomas, two of whom also had metastases. Thirty-seven patients were randomized to RT and 36 to VHF + RT. The median dose of radiation in the VHF+RT arm was 4275 cGy with a median fraction size of 150 cGy and median duration of therapy of 48.5 days versus 4500 cGy in the RT-only arm with a median fraction size of 180 cGy and median duration of therapy of 38 days. These doses are unlikely to be significantly different in biological effect. No significant difference between the two groups was observed in extent and duration of local control, measures of toxicity or quality of life scores. Additionally, survival and cumulative incidence of pelvic site of first progression did not differ significantly between the groups. We conclude that VHF microwave therapy in conjunction with radiotherapy produces no therapeutic advantage over conventional radiation therapy alone in the treatment of locally recurrent rectal carcinoma.

A phase I/II study to evaluate radiation therapy and hyperthermia for deep-seated tumours: a report of RTOG 89-08

The purpose of this paper is to evaluate the safety and efficacy of deep hyperthermia in conjunction with radiation therapy. This study employed 'second generation' electromagnetic devices which were felt to be better able to confine heating and spare normal tissue than the devices evaluated in a previous study (RTOG 84-01). Sixty six patients at six institutions were enrolled on a prospective Phase I/II study. Eligible deep seated tumours were treated with a combination of external hyperthermia and radiation therapy. Radiation consisted of 1.7-2 Gy per fraction, 4-5 fractions per week, to > 20 Gy (previously irradiated lesions) or > 50 Gy (no previous radiation). Deep hyperthermia was delivered with electromagnetic devices: BSD 2000 for 92% of cases, Thermotron for 5% of cases, other low frequency electromagnetic for 4% of cases. Hyperthermia was delivered < or = twice weekly. Overall complete and partial response rates were 34% and 16% respectively. Response was not correlated with maximum tumour temperature or disease site. There was, however, a strong association with radiation dose: 54% CR with > or = 45 Gy versus 7% with < 45 Gy (p < 0.0001). The achieved temperatures were less than ideal. Although the average maximum tumor temperature was 41.9 degrees C (range 35.7 degrees C-46.7 degrees C), the minimum tumour temperatures were low. The average minimum tumour temperature was 38.5 degrees C and was never > 41.8 degrees C. Treatment was well tolerated with no fatalities. There were four acute grade 3 or 4 toxicities (6% of patients). Patient discomfort resulted in interruption or discontinuation of sessions in 30% of the sessions. In 12 cases (18% of patients) the planned course of hyperthermia was discontinued due to acute discomfort. The devices used in this study were better tolerated than the devices used in the previous Phase I/II deep hyperthermia trial (RTOG 84-01) with less patient discomfort and no problems with severe systemic cardiovascular stress. In the previous study 68% of the hyperthermia courses were prematurely terminated primarily due to patient discomfort and toxicity; in the present study 18% were prematurely terminated. However, as indicated by the low minimum tumour temperature, fundamental problems with achieving acceptable temperature distributions remain.

Hyperthermia, radiation carcinogenesis and the protective potential of vitamin A and N-acetylcysteine

The in vivo carcinogenic risk of hyperthermia, alone or in combination with irradiation, and the anti-carcinogenic potential of vitamin A and N-acetylcysteine (AcCys) were investigated. Starting 1 month before treatment, 160 rats were divided into four diet groups: no additives, vitamin A-enriched diet, AcCys and the combination vitamin A + AcCys. In 10 animals per diet group, the hind leg was treated with either X-irradiation alone (16 Gy), hyperthermia alone (60 min at 43 degrees C), hyperthermia 5 h prior to irradiation or hyperthermia 5 h after irradiation. Animals were observed for 2 years after treatment with regard to the development of tumours either inside or outside the treated volume. After 16 Gy alone 12 +/- 5% of the animals developed a tumour. Tumour incidence increased to 37 +/- 9% (borderline significance P = 0.07 versus treatment with X-rays alone) when hyperthermia was applied prior to X-rays, and to 24 +/- 8% (NS) with hyperthermia after irradiation. The relative risk ratio (RRR) for tumour induction was increased to 2.4 by hyperthermia if combined with X-irradiation. Pathological characterization of induced tumours showed that these were of the fibrosarcoma, osteosarcoma and carcinoma type. Vitamin A alone or in combination with AcCys slightly protected against the induction of tumours by X-rays without or with hyperthermia (RRR of 0.4). However, morphological changes such as lipid accumulation in hepatocytes and damage to the parenchyma were noticed in livers from all animals that were given a vitamin-A-enriched diet (P < 0.0001). Data from the present and past reports show that hyperthermia alone is not carcinogenic, but that it may increase radiation carcinogenesis. Treatment temperature and time of exposure to heat in addition to the radiation dose applied are important factors in the carcinogenic process. The enhancement of radiation carcinogenesis seems to occur independently of the sequence and time interval between irradiation and hyperthermia. However, not all data are consistent with this interpretation.

Tumour oxygenation is increased by hyperthermia at mild temperatures

The effects of hyperthermia on the oxygenation status in R3230 AC tumours of Fischer rats were measured using a polarographic oxygen electrode system. The median pO2 in about 10 mm diameter tumours grown s.c. in the leg of rats was 3.7 +/- 0.3 mm Hg and it significantly increased upon heating at modest temperatures. For example, the tumour pO(2) measured within 10-15 min after heating for 30 min at 42.5 degrees C was about three-fold greater than that in the control tumours. About 62% of PO(2) values measured in control tumours were < 5 mm Hg. After heating at 42.5 degrees C for 30 min, 37% of PO(2) values were < 5 mm Hg. Such an increase in tumour oxygenation or reoxygenation of hypoxic cells appeared to result from an increase in tumour blood flow caused by the mild temperature hyperthermia. The presence of hypoxic cells in tumours is believed to be a major factor in limiting the effectiveness of radiotherapy, certain chemotherapy drugs and phototherapy. Hyperthermia at mild temperatures easily achievable with the use of presently available clinical hyperthermia devices may be an effective means to overcome the hypoxic protection in the treatment of human tumours.

The effect of heat on Na+/H+ antiport function and survival in mammalian cells

PURPOSE

Because intracellular pH (pHi) is a determinate of thermosensitivity, it is important to understand the relationship between heat cytotoxicity and the mechanisms responsible for pHi regulation, such as the Na+/H+ antiport. The objective of this study is to elucidate the relationship between heat damage and Na+/H+ antiport activity.

METHODS AND MATERIALS

Various cell lines, EMT6, RIF-1, and its thermoresistant variant TR-4, and CCL39, and its variant that lacks the Na+/H+ antiport (PS120), were all heated using a water bath. Parallel assessments of antiport function and pHi were made using the fluorescent dye 2,7-biscarboxyethyl-5(6)-carboxyfluorescein (BCECF).

RESULTS

Exposure of EMT6 cells to 43-46 degrees C for 30-60 min caused progressive decline in antiport activity, in parallel with cytotoxicity. When the same degree of cytotoxicity was induced by ionizing radiation, no alteration in Na+/H+ antiport function was observed. Despite a 10-fold lower survival in RIF-1 compared to TR-4 cells after heating, there was no difference in the thermosensitivity of their antiports. Antiport activity in the TR-4 cells, however, was higher than that of RIF-1 cells both before and during heating. Intracellular pH for TR-4 cells decreased minimally during heating, in contrast to a decline of 1 pH unit in RIF-1 cells despite similar relative levels of antiport activity, suggesting that in this pair of cell lines, antiport activity does not play a major pHi regulatory role. PS120 and CCL39 cells and similar survival levels when heated at pHe 7.2 in the presence of NaHCO3, which allows function of the other major regulator of pHi, the Na+ -dependent HCO3-/Cl- exchanger. This occurred despite a drop in pHi in the PS120 cells during heating. A reduced survival was observed, however, in PS120 cells after 43 degrees C for 30-60 min at either pHe 6.5 or pHe 7.2 in the absence of NaHCO3. Intracellular pH was consistently greater for PS120 than CCL39 cells.

CONCLUSION

We demonstrated that damage to the Na+/H+ antiport likely reflects early heat-induced change in membrane function, but is not a primary target for heat cytotoxicity. Although there is an association between survival, antiport function, and pHi level under most treatment conditions, the precise role of the Na+/H+ antiport in mediating thermal cytotoxicity remains uncertain.

Hyperthermia as an adjuvant to radiation therapy of recurrent or metastatic malignant melanoma. A multicentre randomized trial by the European Society for Hyperthermic Oncology

The ESHO protocol 3-85 is a multicentre randomized trial investigating the value of hyperthermia as an adjuvant to radiotherapy in treatment of malignant melanoma. A total of 134 metastatic of recurrent malignant melanoma lesions in 70 patients were randomized to receive radiotherapy alone (3 fractions in 8 days) or each fraction followed by hyperthermia (aimed for 43 degrees C for 60 min). Radiation was given with high voltage photons or electrons. Tumours were stratified according to institution and size (above or below 4 cm) and randomly assigned to a total radiation dose of either 24 or 27 Gy to be given with or without hyperthermia. The endpoint was persistent complete response in the treated area. A number of 128 tumours in 68 patients were evaluable, with an observation time between 3 and 72 months. Sixty-five tumours were randomized to radiation alone and 63 to radiation + heat. Sixty received 24 Gy and 68 tumours received 27 Gy, respectively. Size was < or = 4 cm in 81 and > 4 cm in 47 tumours. Overall the 2-year actuarial local tumour control was 37%. Univariate analysis showed prognostic influence of hyperthermia (rad alone 28% versus rad + heat 46%, p = 0.008) and radiation dose (24 Gy 25% versus 27 Gy 56%, p = 0.02), but not of tumour size (small 42% versus large 29%, p = 0.21). A Cox multivariate regression analysis showed the most important prognostic parameters to be: hyperthermia (odds ratio: 1.73 (1.07-2.78), p = 0.02), tumour size (odds ratio: 0.91 (0.85-0.99), p = 0.05) and radiation dose (odds ratio: 1.17 (1.01-1.36), p = 0.05). Analysis of the heating quality showed a significant relationship between the extent of heating and local tumour response. Addition of heat did not significantly increase the acute or late radiation reactions. The overall 5-year survival rate of the patients was 19%, but 38% in patients if all known disease was controlled, compared to 8% in the patients with persistent active disease.

A century with hyperthermic oncology in Scandinavia

The hyperthermic research during the last 100 years is reviewed with the aim to describe a research activity which has been performed in parallel to and associated with the development of radiation oncology. Basic and clinical research in several Scandinavian centres has made major international contributions to the establishment of a rationale for and implementation of hyperthermia as a combined modality treatment with chemotherapy or radiation in oncology. At the same time it has been demonstrated that collaboration and integration easily could be performed within the Scandinavian centres. Hyperthermic oncology is therefore a typical example of how research involving both biological, physical/engineering, and clinical skills in a proper environment can create valuable results.