Side-effects of local hyperthermia: results of a prospectively randomized clinical study

A Review of the Current Clinical Evidence for Loco-Regional Moderate Hyperthermia in the Adjunct Management of Cancers

Regional hyperthermia therapy (RHT) is a treatment that applies moderate heat to tumours in an attempt to potentiate the effects of oncological treatments and improve responses. Although it has been used for many years, the mechanisms of action are not fully understood. Heterogenous practices, poor quality assurance, conflicting clinical evidence and lack of familiarity have hindered its use. Despite this, several centres recognise its potential and have adopted it in their standard treatment protocols. In recent times, significant technical improvements have been made and there is an increasing pool of evidence that could revolutionise its use. Our narrative review aims to summarise the recently published prospective trial evidence and present the clinical effects of RHT when added to standard cancer treatments. In total, 31 studies with higher-quality evidence across various subsites are discussed herein. Although not all of these studies are level 1 evidence, benefits of moderate RHT in improving local tumour control, survival outcomes and quality of life scores were observed across the different cancer subsites with minimal increase in toxicities. This paper may serve as a reference when considering this technique for specific indications.

Efficacy and Safety Evaluation of the Various Therapeutic Options in Locally Advanced Cervix Cancer: A Systematic Review and Network Meta-Analysis of Randomized Clinical Trials

Treatment options in locally advanced cervix cancer (LACC) have evolved around radiation therapy (RT) and/or chemotherapy (CT), hypoxic cell sensitizers, immunomodulators (Imm), and locoregional moderate hyperthermia (HT). A systematic review and network meta-analysis was conducted to synthesize the evidence for efficacy and safety in terms of long-term locoregional control (LRC), overall survival (OS), and grade ≥3 acute morbidity (AM) and late morbidity (LM). Five databases were searched, and 6285 articles (1974-2018) were screened per the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. Fifty-nine randomized trials in untreated LACC without surgical intervention were shortlisted. These used 13 different interventions: RT alone and/or neoadjuvant CT (NACT), adjuvant CT (ACT), concurrent chemoradiation therapy (CTRT) (weekly cisplatin [CDDP]/3-weekly CDDP/combination CT with CDDP/non-CDDP-based CT), hypoxic cell sensitizers, Imm, or HT. Odds ratios (ORs) using random effects network meta-analysis were estimated. Interventions for each endpoint were ranked according to their corresponding surface under cumulative ranking curve values. Of the 9894 patients evaluated, the total events reported for LRC, OS, AM, and LM were 5431 of 8197, 4482 of 7958, 1710 of 7183, and 441 of 6333, respectively. ORs and 95% credible intervals (CrIs) for the 2 best strategies were HT + RT versus CTRT + ACT (OR, 1.23; 95% CrI, 0.49-3.19) for LRC, CTRT (3-weekly CDDP) versus HTCTRT (OR, 1.14; 95% CrI, 0.35-3.65) for OS, RT + ACT versus RT (OR, 0.01; 95% CrI, 0.00-1.04) for AM, and NACT + RT + ACT versus RT + Imm (OR, 0.42; 95% CrI, 0.02-7.39) for LM. The 3 interventions with the highest cumulative surface under cumulative ranking curve values for all 4 endpoints were HTRT, HTCTRT, and CTRT (3-weekly CDDP). Articles with low risk of bias and those published during 2004 to 2018 also retained these interventions as the best. Two-step cluster analysis grouped these 3 modalities in a single distinctive cluster. HTRT, HTCTRT, and CTRT with 3-weekly CDDP were identified as therapeutic modalities with the best comprehensive impact on key clinical endpoints in LACC. This warrants a phase 3 randomized trial among these strategies for a head-to-head comparison and additional validation.

Hyperthermia and radiotherapy with or without chemotherapy in locally advanced cervical cancer: a systematic review with conventional and network meta-analyses

PURPOSE

A systematic review with conventional and network meta-analyses (NMA) was conducted to examine the outcomes of loco-regional hyperthermia (HT) with radiotherapy (RT) and/or chemotherapy (CT) in locally advanced cervix cancer, IIB-IVA (LACC).

METHODS AND MATERIALS

A total of 217 abstracts were screened from five databases and reported as per PRISMA guidelines. Only randomised trials with HT and RT ± CT were considered. The outcomes evaluated were complete response (CR), long-term loco-regional control (LRC), patients alive, acute and late grade III/IV toxicities.

RESULTS

Eight articles were finally retained. Six randomised trials with HTRT (n = 215) vs. RT (n = 212) were subjected to meta-analysis. The risk difference for achieving CR and LRC was greater by 22% (p < .001) and 23% (p < .001), respectively, with HTRT compared to RT. A non-significant survival advantage of 8.4% with HTRT was noted with no differences in acute or late toxicities. The only HTCTRT vs. RT trial documented a CR of 83.3% vs. 46.7% (risk difference: 36.7%, p = .001). No other end points were reported. Bayesian NMA, incorporating 13 studies (n = 1000 patients) for CR and 12 studies for patients alive (n = 807 patients), comparing HTCTRT, HTRT, CTRT and RT alone, was conducted. The pairwise comparison of various groups showed that HTRTCT was the best option for both CR and patient survival. This was also evident on ranking treatment modalities based on the "surface under cumulative ranking" values.

CONCLUSIONS

In LACC, HTRT demonstrates a therapeutic advantage over RT without significant acute or late morbidities. On NMA, HTCTRT appears promising, but needs further confirmation through prospective randomised trials.

Tumor-specific nano-entities for optical detection and hyperthermic treatment of breast cancer

The ultimate goal of this study is to develop a tumor-specific multi-functional, nano-entity that can be used for both cancer detection and treatment. Low heat (42 approximately 45 degrees C) hyperthermia is an effective cancer treatment method with little side effect. Magnetic nanoparticles, such as Fe3O4, can be heated by alternating electromagnetic (AEM) fields at well selected frequencies, without heating normal tissue. Nanogold particles (NGPs) are effective optical absorbers and also excellent fluorescent enhancers. Therefore, coating gold on Fe3O4 particles can enhance the optical contrast as well as keeping the particle property for hyperthermia. Indocyanine green (ICG), a FDA approved fluorophore, has a very low quantum yield, and its fluorescence can be enhanced by linking ICG to gold-coated Fe3O4 nanoparticles. Luteinizing hormone releasing hormone (LHRH), which has high affinity to breast cancer, can be used for tumor-specific targeting. Our study results showed: Fe3O4 particles at a size range of 10 approximately 30 nm can be heated well by an AEM field at a rate of 18 degrees C/wt%-minute; the fluorescence of ICG was extensively enhanced by NGPs; LHRH-coated gold nanoparticles provided as much cancer specificity as LHRH alone. Combining these properties in one entity, i.e., LHRH/ICG linked, gold-coated Fe3O4 nanoparticles, can be a tumor-specific nano-agent for optical detection and electro-magnetically induced hyperthermia for breast cancer.

Fever-range whole body hyperthermia increases the number of perfused tumor blood vessels and therapeutic efficacy of liposomally encapsulated doxorubicin

PURPOSE

Two major questions were addressed: (1) Can fever-range whole body hyperthermia (FR-WBH) affect the number of perfused tumor blood vessels? (2) Can pre-treatment with FR-WBH improve accumulation or anti-tumor efficacy of doxorubicin or DOXIL (liposomal doxorubicin)?

MATERIALS AND METHODS

Perfused blood vessels were visualized by intravenous injection of the fluorescent dye (DiOC7(3)) and the number of labeled vessels in tumors and normal organs of unheated mice and those previously heated to 39.5 degrees C for 6 hours were compared. Using three animal tumor models (one syngeneic murine model and two human tumor xenografts in SCID mice) we also compared tumor growth and amount of intratumoral doxorubicin (given as free drug or as DOXIL) in control mice or those given pre-treatment with FR-WBH.

RESULTS

FR-WBH had no effect on the number of CD-31 labeled blood vessels. However, in tumors, but not in normal organs of the same animals, FR-WBH resulted in a significant increase in those blood vessels which could take up dye over a prolonged period of time after heating. There was also an increase in DOXIL uptake in the tumors of mice given FR-WBH prior to drug injection as well as enhanced therapeutic efficacy in all three tumor models.

CONCLUSIONS

FR-WBH increases the number of perfused blood vessels in tumors over a prolonged period following FR-WBH and thus may be useful for improving tumor targeting of cancer therapeutics. We discuss these data in relation to long-conserved thermoregulatory features in normal vasculature, which may be deficient in tumor vasculature.

Prospective thermal dosimetry: the key to hyperthermia's future

PURPOSE

This review summarizes recent results from two randomized trials testing the complete response rate and local control benefits for the addition of hyperthermia to external beam radiation.

METHODS

In both series, there was a statistically significant benefit to adjuvant hyperthermia.

RESULTS

The establishment of a standardized nomenclature for clinical hyperthermia prescription will help to facilitate the broader usage of hyperthermia.

CONCLUSIONS

Carefully conducted phase III trials with rigorous quality assurance must employ prospective thermal dosimetry to validate the role of hyperthermia in multi-modality therapy.

Radiation Modifiers: Treatment Overview and Future Investigations

Many radiosensitizers are in current clinical use. In addition, a myriad of potential new targeted therapies, which may also interact with radiation, are in clinical development. The clinical utility of new targeted therapies, in combination with existing radiation sensitizers (chemotherapies) requires further evaluation, as does the understanding of their acute and late radiation effects. Free radical scavengers appear to show promise as radioprotectors, but data for mucoprotection are less convincing.

Randomized trial of hyperthermia and radiation for superficial tumors

PURPOSE

Randomized clinical trials have demonstrated hyperthermia (HT) enhances radiation response. These trials, however, generally lacked rigorous thermal dose prescription and administration. We report the final results of a prospective randomized trial of superficial tumors (</= 3 cm depth) comparing radiotherapy versus HT combined with radiotherapy, using the parameter describing the number of cumulative equivalent minutes at 43 degrees C exceeded by 90% of monitored points within the tumor (CEM 43 degrees C T(90)) as a measure of thermal dose.

METHODS

This trial was designed to test whether a thermal dose of more than 10 CEM 43 degrees C T(90) results in improved complete response and duration of local control compared with a thermal dose of </= 1 CEM 43 degrees C T(90). Patients received a test dose of HT </= 1 CEM 43 degrees C T(90) and tumors deemed heatable were randomly assigned to additional HT versus no additional HT. HT was given using microwave spiral strip applicators operating at 433 MHz.

RESULTS

One hundred twenty-two patients were enrolled; 109 (89%) were deemed heatable and were randomly assigned. The complete response rate was 66.1% in the HT arm and 42.3% in the no-HT arm. The odds ratio for complete response was 2.7 (95% CI, 1.2 to 5.8; P = .02). Previously irradiated patients had the greatest incremental gain in complete response: 23.5% in the no-HT arm versus 68.2% in the HT arm. No overall survival benefit was seen.

CONCLUSION

Adjuvant hyperthermia with a thermal dose more than 10 CEM 43 degrees C T(90) confers a significant local control benefit in patients with superficial tumors receiving radiation therapy.

Combined treatment of inoperable carcinomas of the uterine cervix with radiotherapy and regional hyperthermia. Results of a phase II trial

AIM

The disappointing results for inoperable, advanced tumors of the uterine cervix after conventional radiotherapy alone necessitates improving of radiation therapy. Simultaneous chemotherapy or altered radiation fractionation, such as accelerated regimen, increase acute toxicity and treatment is often difficult to deliver in the planned manner. The purpose of this phase II study was to investigate the toxicity and effectiveness of a combined approach with radiotherapy and regional hyperthermia.

PATIENTS AND METHODS

From January 1994 to October 1995 18 patients with advanced carcinomas of the uterine cervix were treated in combination with radiotherapy and hyperthermia. The patients were treated with 6 to 20 MV photons delivered by a linear accelerator in a 4-field-box technique to a total dose of 50.4 Gy in 28 fractions. In the first and fourth week 2 regional hyperthermia treatments were each applied with the Sigma-60 applicator from a BSD-2000 unit. After this a boost to the primary tumor was given with high-dose-rate iridium-192 brachytherapy by an afterloading technique with 4 x 5 Gy at point A to a total of 20 Gy and for the involved parametrium anterioposterior-posterioanterior to 9 Gy in 5 fractions.

RESULTS

The acute toxicity was low and similar to an external radiotherapy alone treatment. No Grade III/IV acute toxicity was found. The median age was 47 years (range 34 to 67 years). In 16 of 18 patients a rapid tumor regression was observed during combined thermo-radiotherapy, which allowed the use of intracavitary high-dose-rate brachytherapy in these cases. Complete and partial remission were observed in 13 and 4 cases, respectively. One patient did not respond to the treatment. The median follow-up was 24 months (range 17 to 36 months). The local tumor control rate was 48% at 2 years. Median T20, T50 and T90 values were 41.7 degrees C (range 40.3 to 43.2 degrees C), 41.1 degrees C (range 39.2 to 42.5 degrees C) and 39.9 degrees C (range 37.7 to 41.9 degrees C), respectively. Cumulative minutes of T90 > 40 degrees C (Cum40T90) and cumulative minutes, which were isoeffective to 43 degrees C, were calculated (CEM43T90, CEM43T50, CEM43T20). CEM43T90 was found to be a significant parameter in terms of local tumor control for the 4 hyperthermia treatments (p = 0.019).

CONCLUSIONS

This treatment modality has proved to be feasible and well tolerable. The rapid tumor shrinkage in the combined approach of radiotherapy with hyperthermia before beginning brachytherapy seems to be a good prerequisite for improving of the disappointing results in cure of advanced cancer of the uterine cervix.

Identification of high-risk groups among node-positive patients with stage IB and IIA cervical carcinoma

The purpose of the present study was to identify a subset of high-risk patients among surgically treated node-positive patients with stage IB and IIA cervical carcinoma. From 1982 through 1991, 334 patients underwent radical hysterectomy for FIGO stage IB and IIA cervical carcinoma. In 68 patients pathological analysis of the surgical specimen revealed positive pelvic nodes. In this group, a Cox proportional hazard analysis was performed to examine the prognostic significance of clinicopathological variables. Only for adenocarcinoma (P = 0.002) and parametrium infiltration (P = 0.003) was evidence of an association with prognosis found. Based on these two factors, patients with positive pelvic nodes were categorized into a low-risk group (squamous cell carcinoma without parametrium infiltration, N = 33) and a high-risk group (squamous cell carcinoma with parametrium infiltration or adenocarcinoma, N = 34). The 5-year disease-specific survival in the low-risk group was 94% compared with 60% in the high-risk group (P = 0.003). For patients in the high-risk group, there is an urgent need for alternative adjuvant treatment to improve outcome.

Response of 145 spontaneous canine head and neck tumours to radiation versus radiation plus microwave hyperthermia: results of a randomized phase III clinical study

The results of a phase III, clinical trial of local microwave hyperthermia (target = 2 x 44 degrees C for 30 min) and megavoltage radiation (4 x 9 Gy fractions) in the treatment of 145 naturally occurring canine head and neck cancers are reported. Patients were re-examined at regular intervals following treatment until death. The median follow up time was 90 weeks. Tumour response, patient survival and normal tissue toxicity were analysed by treatment allocation. There was no significant difference in best tumour response nor patient survival between the two treatment groups. There was no difference in acute normal tissue toxicity but there was a suggestion that patients receiving RT and HT may suffer a higher incidence of late skin reactions. Histological type and tumour volume were of prognostic significance with smaller tumours and carcinomas showing higher response rates. There were also positive associations between minimum tumour dose and best tumour response and percentage of tumour heated and best tumour response. The results of this study must be interpreted in the knowledge of limitations on the dose and fractionation schedule for radiation therapy, the small number of hyperthermia treatments applied and the variation in tumour type and size that is inevitable in a clinical study. It is concluded that the quality of hyperthermia in terms of intra-tumour temperatures and the uniformity of heating is of paramount importance in governing response to adjuvant hyperthermia.

Persistent and/or late complications of combined radiation therapy and hyperthermia

Persistent and/or late complications were analysed in 64 patients (183 fields) that were treated with combined hyperthermia and radiation therapy for advanced, recurrent or metastatic cancer. The incidence and type of complications were evaluated over a minimum follow-up period of 2 years from the onset of treatment (mean 38.7 months; range 24-82.5 months). The primary malignancies included: breast (39), melanomas (6), adenoid cystic carcinomas of salivary glands (4), prostate (4), soft tissue sarcomas (3), squamous cell carcinoma of head and neck (3), lymphomas (3), transitional cell carcinoma of bladder (1) and basal cell carcinoma of the skin (1). The persistent complications noted included induration and fibrosis (39 hyperthermia fields, 22 patients), ulceration at the site of prior tumour (three patients, three fields), and ulceration in normal tissue (one patient, one field). Brachial plexopathy developed in one patient treated for recurrent breast cancer, but she had active disease at that time. A squamous cell carcinoma of the skin developed within the treatment field in a breast cancer patient. Radionecrosis of the mandible was seen in one patient treated for a floor of the mouth cancer, and osteomyelitis with septic arthritis developed in one patient treated for a soft tissue sarcoma of the thigh. Univariate logistic regression analyses of pretreatment and radiation-hyperthermia treatment parameters revealed that maximal tumour temperature had a borderline significant correlation with the development of complications (p = 0.07). Multivariate analyses of the pretreatment and treatment parameters revealed the best-two-covariate model to predict complications included mean maximal tumour temperature and tumour type (macroscopic tumours had greater incidence of complications than for microscopic residual disease). The rate and type of persistent and/or late complications seen following combined radiation and hyperthermia did not appear to dramatically differ from those that would be anticipated from irradiation alone in this patient population, with the exception of an increased incidence of areas of induration and tumour necrosis.