Hyperthermia (HT) is a cancer treatment modality which targets malignant tissues by heating to 40–43 °C. In addition to its direct antitumor effects, HT potently sensitizes the tumor to radiotherapy (RT) and chemotherapy (CT), thereby enabling complete eradication of some tumor entities as shown in randomized clinical trials. Despite the proven efficacy of HT in combination with classic cancer treatments, there are limited international standards for the delivery of HT in the clinical setting. Consequently, there is a large variability in reported data on thermometric parameters, including the temperature obtained from multiple reference points, heating duration, thermal dose, time interval, and sequence between HT and other treatment modalities. Evidence from some clinical trials indicates that thermal dose, which correlates with heating time and temperature achieved, could be used as a predictive marker for treatment efficacy in future studies. Similarly, other thermometric parameters when chosen optimally are associated with increased antitumor efficacy. This review summarizes the existing clinical evidence for the prognostic and predictive role of the most important thermometric parameters to guide the combined treatment of RT and CT with HT. In conclusion, we call for the standardization of thermometric parameters and stress the importance for their validation in future prospective clinical studies.

Pancreatic cancer has a dismal prognosis with 5-year overall survival rate of around 5%. Although surgery is still the best option in operable cases, majority of the patients who present in locally advanced stages are deemed inoperable. Novel approaches are therefore needed for the management of around 80% of these inoperable locally advanced pancreatic cancers (LAPC). Hyperthermia (39–43 °C) is a potent radiosensitizer and further enhances the action of gemcitabine, also a known radiosensitizer. Thus through triple sensitization, a combination of hyperthermia, radiotherapy and gemcitabine could be expected to improve the therapeutic outcomes in LAPC. This phase II randomized trial, HEATPAC in unresectable LAPC, explores the feasibility and efficacy of concurrent thermochemoradiotherapy (HTCTRT) over chemoradiotherapy (CTRT) alone with pre- and post-intervention FOLFIRINOX at standard dosage and schedule. Following 4 cycles of neoadjuvant FOLFIRINOX, patients with no metastasis and absence of gross peritoneal carcinomatosis would be randomized to either (a) control arm: concurrent CTRT with gemcitabine (400 mg/m2, weekly ×6) or (b) study arm: locoregional hyperthermia (weekly ×6 during radiotherapy) with concurrent CTRT (same as in control arm). All patients would receive simultaneous-integrated boost intensity-modulated radiation therapy to doses of 56Gy and 50.4Gy to the gross and clinical target volumes respectively delivered in 28 fractions over 5.5 weeks. Deep locoregional hyperthermia would be administered weekly and monitored with real-time intraduodenal multisensor thermometry probe. A temperature of 40–43 °C for 60 min would be aimed for each hyperthermia session. On completion of CTRT/HTCTRT, patients of both groups would receive an additional 8 cycles of FOLFIRINOX. The expected 1-year baseline overall survival with CTRT alone is considered as 40%. With HTCTRT, a survival advantage of +20% is expected. Considering α = 0.05 and β = 0.80 for sample size computation, a total of 86 patients would be equally randomized into the two treatment groups. This phase II study if found to be safe and effective, would form the basis of a future phase III randomized study. The trial has been registered with the ClinicalTrials.gov ( NCT02439593 ). The study has been approved by the Ethical Commissions of Basel and Zurich and is open for patient recruitment.

Objective: Large inoperable sacral chordomas show unsatisfactory local control rates even when treated with high dose proton therapy (PT). The aim of this study is assessing feasibility and reporting early results of patients treated with PT and concomitant hyperthermia (HT). Methods: : Patients had histologically proven unresectable sacral chordomas and received 70 Gy (relative biological effectiveness) in 2.5 Gy fractions with concomitant weekly HT. Toxicity was assessed according to CTCAE_v4. A volumetric tumor response analysis was performed. Results: : Five patients were treated with the combined approach. Median baseline tumor volume was 735 cc (range, 369–1142). All patients completed PT and received a median of 5 HT sessions (range, 2–6). Median follow-up was 18 months (range, 9–26). The volumetric analysis showed an objective response of all tumors (median shrinkage 46%; range, 9–72). All patients experienced acute Grade 2–3 local pain. One patient presented with a late Grade 3 iliac fracture. Conclusion: Combining PT and HT in large inoperable sacral chordomas is feasible and causes acceptable toxicity. Volumetric analysis shows promising early results, warranting confirmation in the framework of a prospective trial. Advances in knowledge: : This is an encouraging first report of the feasibility and early results of concomitant HT and PT in treating inoperable sacral chordoma.

Background: Moderate hyperthermia is a potent and evidence-based radiosensitizer. Several indications are reimbursed for the combination of deep hyperthermia with radiotherapy (dHT+RT). We evaluated the current practice of dHT+RT in Switzerland. Methods: All indications presented to the national hyperthermia tumor board for dHT between January 2017 and June 2021 were evaluated and treatment schedules were analyzed using descriptive statistics. Results: Of 183 patients presented at the hyperthermia tumor board, 71.6% were accepted and 54.1% (99/183) finally received dHT. The most commonly reimbursed dHT indications were “local recurrence and compression” (20%), rectal (14.7%) and bladder (13.7%) cancer, respectively. For 25.3% of patients, an individual request for insurance cover was necessary. 47.4% of patients were treated with curative intent; 36.8% were in-house patients and 63.2% were referred from other hospitals. Conclusions: Approximately two thirds of patients were referred for dHT+RT from external hospitals, indicating a general demand for dHT in Switzerland. The patterns of care were diverse with respect to treatment indication. To the best of our knowledge, this study shows for the first time the pattern of care in a national cohort treated with dHT+RT. This insight will serve as the basis for a national strategy to evaluate and expand the evidence for dHT.

Purpose: The combination of hyperthermia (HT) with radio(chemo)therapy or chemotherapy (CT) is an established treatment strategy for specific indications. Its application in routine clinical practice in Europe depends on regulatory and local conditions. We conducted a survey among European clinical centers to determine current practice of HT. Methods: A questionnaire with 22 questions was sent to 24 European HT centers. The questions were divided into two main categories. The first category assessed how many patients are treated with HT in combination with radio(chemo)therapy or CT for specific indications per year. The second category addressed which hyperthermia parameters are recorded. Analysis was performed using descriptive methods. Results: The response rate was 71% (17/24) and 16 centers were included in this evaluation. Annually, these 16 centers treat approximately 637 patients using HT in combination with radio(chemo)therapy or CT. On average, 34% (range: 3–100%) of patients are treated in clinical study protocols. Temperature readings and the time interval between HT and radio(chemo)therapy or CT are recorded in 13 (81%) and 9 (56%) centers, respectively. The thermal dose quality parameter “cumulative equivalent minutes at 43 °C” (CEM43°C) is only evaluated in five (31%) centers for each HT session. With regard to treatment sequence, 8 (50%) centers administer HT before radio(chemo)therapy and the other 8 in the reverse order. Conclusion: There is a significant heterogeneity among European HT centers as to the indications treated and the recording of thermometric parameters. More evidence from clinical studies is necessary to achieve standardization of HT practice.