Abstract
Background Thermal dose in clinical hyperthermia reported as cumulative equivalent minutes (CEM) at 43 °C (CEM43) and its variants are based on direct thermal cytotoxicity assuming Arrhenius ‘break’ at 43 °C. An alternative method centered on the actual time–temperature plot during each hyperthermia session and its prognostic feasibility is explored. Methods and materials Patients with bladder cancer treated with weekly deep hyperthermia followed by radiotherapy were evaluated. From intravesical temperature (T) recordings obtained every 10 secs, the area under the curve (AUC) was computed for each session for T > 37 °C (AUC > 37 °C) and T ≥ 39 °C (AUC ≥ 39 °C). These along with CEM43, CEM43(>37 °C), CEM43(≥39 °C), T mean, T min and T max were evaluated for bladder tumor control. Results Seventy-four hyperthermia sessions were delivered in 18 patients (median: 4 sessions/patient). Two patients failed in the bladder. For both individual and summated hyperthermia sessions, the T mean, CEM43, CEM43(>37 °C), CEM43(≥39 °C), AUC > 37 °C and AUC ≥ 39 °C were significantly lower in patients who had a local relapse. Individual AUC ≥ 39 °C for patients with/without local bladder failure were 105.9 ± 58.3 °C-min and 177.9 ± 58.0 °C-min, respectively (p = 0.01). Corresponding summated AUC ≥ 39 °C were 423.7 ± 27.8 °C-min vs. 734.1 ± 194.6 °C-min (p < 0.001), respectively. The median AUC ≥ 39 °C for each hyperthermia session in patients with bladder tumor control was 190 °C-min. Conclusion AUC ≥ 39 °C for each hyperthermia session represents the cumulative time–temperature distribution at clinically defined moderate hyperthermia in the range of 39 °C to 45 °C. It is a simple, mathematically computable parameter without any prior assumptions and appears to predict treatment outcome as evident from this study. However, its predictive ability as a thermal dose parameter merits further evaluation in a larger patient cohort.
Highlights
Reporting hyperthermia (HT) treatments in clinical practice using a common denominator is a matter of active deliberation
The thermal dose is expressed as CEM43 or its variants were in the temperatures (T), T90, T50, T10 or a suitable index temperature have been integrated with CEM43 [2,3,4,5]
Between December 2012 and December 2019, 21 consecutive patients with muscleinvasive bladder cancers (MIBC) with associated comorbidities that rendered them unfit for radical surgery or intensive chemoradiotherapy (CTRT) or those who refused these interventions were considered for bladder preservation treatment with HT and RT (HTRT) following transurethral resection of bladder tumor (TURBT)
Summary
Reporting hyperthermia (HT) treatments in clinical practice using a common denominator is a matter of active deliberation. Thermal dose, first proposed in 1984 by Sapareto and Dewey, is based on the concept of the cumulative equivalent of minutes at 43 C (CEM43) [1]. The thermal dose is expressed as CEM43 or its variants were in the temperatures (T), T90, T50, T10 or a suitable index temperature have been integrated with CEM43 [2,3,4,5]. Thermal dose in clinical hyperthermia reported as cumulative equivalent minutes (CEM) at 43 C (CEM43) and its variants are based on direct thermal cytotoxicity assuming Arrhenius ‘break’ at 43 C. An alternative method centered on the actual time–temperature plot during each hyperthermia session and its prognostic feasibility is explored
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
