Feasibility, SAR Distribution, and Clinical Outcome upon Reirradiation and Deep Hyperthermia Using the Hypercollar3D in Head and Neck Cancer Patients

(1) Background: Head and neck cancer (HNC) patients with recurrent or second primary (SP) tumors in previously irradiated areas represent a clinical challenge. Definitive or postoperative reirradiation with or without sensitizing therapy, like chemotherapy, should be considered. As an alternative to chemotherapy, hyperthermia has shown to be a potent sensitizer of radiotherapy in clinical studies in the primary treatment of HNC. At our institution, we developed the Hypercollar3D, as the successor to the Hypercollar, to enable improved application of hyperthermia for deeply located HNC. In this study, we report on the feasibility and clinical outcome of patients treated with the Hypercollar3D as an adjuvant to reirradiation in recurrent or SP HNC patients; (2) Methods: We retrospectively analyzed all patients with a recurrent or SP HNC treated with reirradiation combined with hyperthermia using the Hypercollar3D between 2014 and 2018. Data on patients, tumors, and treatments were collected. Follow-up data on disease specific outcomes as well as acute and late toxicity were collected. Data were analyzed using Kaplan Meier analyses; (3) Results: Twenty-two patients with recurrent or SP HNC were included. The average mean estimated applied cfSAR to the tumor volume for the last 17 patients was 80.5 W/kg. Therefore, the novel Hypercollar3D deposits 55% more energy at the target than our previous Hypercollar applicator. In patients treated with definitive thermoradiotherapy a complete response rate of 81.8% (9/11) was observed at 12 weeks following radiotherapy. Two-year local control (LC) and overall survival (OS) were 36.4% (95% CI 17.4–55.7%) and 54.6% (95% CI 32.1–72.4%), respectively. Patients with an interval longer than 24 months from their previous radiotherapy course had an LC of 66.7% (95% CI 37.5–84.6%), whereas patients with a time interval shorter than 24 months had an LC of 14.3% (95% CI 0.7–46.5%) at 18 months (p = 0.01). Cumulative grade 3 or higher toxicity was 39.2% (95% CI 16.0–61.9%); (4) Conclusions: Reirradiation combined with deep hyperthermia in HNC patients using the novel Hypercollar3D is feasible and deposits an average cfSAR of 80.5 W/kg in the tumor volume. The treatment results in high complete response rates at 12 weeks post-treatment. Local control and local toxicity rates were comparable to those reported for recurrent or SP HNC. To further optimize the hyperthermia treatment in the future, temperature feedback is warranted to apply heat at the maximum tolerable dose without toxicity. These data support further research in hyperthermia as an adjuvant to radiotherapy, both in the recurrent as well as in the primary treatment of HNC patients.

Effectiveness of Deep Hyperthermia Combined with Dynamic Traction in the Treatment of Knee Osteoarthritis

Background: Different treatments with varying clinical efficacies have been applied to treat knee osteoarthritis (KOA). This study observes the effectiveness of deep hyperthermia combined with dynamic traction in KOA treatment. Methods: Deep hyperthermia and dynamic traction was administered to 60 patients with KOA. The pretreatment and 20- and 40-day post-treatment visual analog scale (VAS) and Lysholm score, knee joint cavity effusion, synovium thickness, and synovial blood flow signal (by high-frequency ultrasound) of the patients were recorded. The pretreatment and 20- and 40-day post-treatment Lysholm scores were 47.17 ± 5.07, 63.22 ± 3.44, and 81.98 ± 3.30 (P < 0.001), respectively. Results: The pretreatment and 20- and 40-day post-treatment VAS scores were 5.67 ± 0.91, 2.92 ± 0.81, and 0.60 ± 0.72 (P < 0.001), respectively. The pretreatment and 20- and 40-day post-treatment articular effusion was 5.41 ± 0.46 mm, 4.34 ± 0.34 mm, and 2.32 ± 0.32 mm (P < 0.001), respectively. The pretreatment and 20- and 40-day post-treatment synovial thickness was 3.44 ± 0.31 mm, 2.79 ± 0.15 mm, and 2.32 ± 0.32 mm (P < 0.001), respectively. The pretreatment and 20- and 40-day post-treatment grades of synovial blood flow signal exhibited a significant difference (P < 0.001). Conclusion: Deep hyperthermia combined with dynamic traction can significantly improve the clinical symptoms and pain degree in KOA, reduce joint cavity effusion, synovium thickness, and internal blood flow, and the effect improves with time. The changes in soft tissues observed by high-frequency ultrasound are reliable and consistent with clinical signs.

Thermal Characterization of Phantoms Used for Quality Assurance of Deep Hyperthermia Systems

Tissue mimicking phantoms are frequently used in hyperthermia applications for device and protocol optimization. Unfortunately, a commonly experienced limitation is that their precise thermal properties are not available. Therefore, in this study, the thermal properties of three currently used QA phantoms for deep hyperthermia are measured with an “off-shelf” commercial thermal property analyzer. We have measured averaged values of thermal conductivity (k = 0.59 ± 0.07 Wm−1K−1), volumetric heat capacity (C = 3.85 ± 0.45 MJm−3K−1) and thermal diffusivity (D = 0.16 ± 0.02 mm2s−1). These values are comparable with reported values of internal organs, such as liver, kidney and muscle. In addition, a sensitivity study of the performance of the commercial sensor is conducted. To ensure correct thermal measurements, the sample under test should entirely cover the length of the sensor, and a minimum of 4 mm of material parallel to the sensor in all directions should be guaranteed.

Plasmonic photothermal microneedle arrays and single needles for minimally-invasive deep in-skin hyperthermia

We report, for the first time, crosslinked polymeric microneedle (MN) arrays and single needles (2 mm and 4.5 mm length) coated with gold nanorods (GnRs) to induce deep hyperthermia in a 3 mm-thickness skin model upon near infrared (NIR) laser irradiation.