Hyperthermia dose-effect relationship in 420 patients with cervical cancer treated with combined radiotherapy and hyperthermia

Adding hyperthermia to standard radiotherapy (RT + HT) improves treatment outcome for patients with locally advanced cervical cancer (LACC). We investigated the effect of hyperthermia dose on treatment outcome for patients with LACC treated with RT + HT. We collected treatment and outcome data of 420 patients with LACC treated with hyperthermia at our institute from 1990 to 2005. Univariate and multivariate analyses were performed on response rate, local control, disease-specific survival and toxicity for these patients to search for a thermal dose response relationship. Besides commonly identified prognostic factors in LACC like tumour stage, performance status, radiotherapy dose and tumour size, thermal parameters involving both temperature and duration of heating emerged as significant predictors of the various end-points. The more commonly used CEM43T90 (cumulative equivalent minutes of T90 above 43 degrees C) was less influential than TRISE (based on the average T50 increase and the duration of heating, normalised to the scheduled duration of treatment). CEM43T90 and TRISE measured intraluminally correlate significantly and independently with tumour control and survival. These findings stimulate further technological development and improvement of deep hyperthermia, as they strongly suggest that it might be worthwhile to increase the thermal dose for LACC, either by treatment optimisation or by prolonging the treatment time. These results also confirm the beneficial effects from hyperthermia as demonstrated in our earlier randomised trial, and justify applying radiotherapy and hyperthermia as treatment of choice for patients with advanced cervical cancer. (c) 2009 Elsevier Ltd. All rights reserved

SAR characteristics of the Sigma-60-Ellipse applicator

Purpose: To characterize the basic performance of the Sigma-60-Ellipse applicator. Materials and methods: The E-field distributions were measured using Schottky diode sheets in a cylindrical phantom (diameter 26 cm, length 50 cm), filled with saline-water (2 g NaCl/L). The phantom was positioned symmetrically in the Sigma-60-Ellipse applicator. The stability of the SAR distribution was assessed as a function of power and frequency. Furthermore, the accuracy of target steering was evaluated at various frequencies. Finally, the SAR characteristics were compared with those of the Sigma-60 and the Sigma-Eye applicators. Results: The average 50% iso-SAR area increased from 241 to 296 cm(2) when the RF power increased from 100 to 1600 W. The SAR maximum was located in the centre of the applicator for the frequencies of 75-80 MHz and it moves towards the feet for higher frequencies (up to 3.5 cm at 120 MHz). The average 50% iso-SAR area decreased from 268 to 161 cm(2) With increasing frequency from 75 to 120 MHz. The 50% iso-SAR longitudinal length was almost stable (mean 21.3 cm) at 75-120 MHz for both power outputs of 400 and 800 W. As expected the 50% iso-SAR radial length decreased with frequency from 14.9 cm at 75 MHz to 8.4 cm at 120 MHz. There was a fair agreement between requested and measured target settings. At the lower frequencies of 75-90 MHz and at 100 MHz the SAR characteristics were almost identical to those of the Sigma-60 and Sigma-Eye applicators, respectively. Conclusion: At the frequency range of 75-90 MHz the Sigma-60 and at 100 MHz the Sigma-Eye can safely replaced by the Sigma-60-Ellipse applicator

Intra-patient comparison between two annular phased array applicators, Sigma-60 and Sigma-Eye: Applied RF powers and intraluminally measured temperatures

Purpose: To investigate whether one can replace the Sigma-60 with the Sigma-Eye applicator (or vice versa) during a deep hyperthermia treatment series without a loss in quality of the treatment. Patients and methods: Hyperthermia data of all 48 patients with locally advanced cervical cancer who were treated with both applicators were analysed. In this study no use was made of the longitudinal SAR steering option of the Sigma-Eye. Hence, the Sigma-Eye was used as a Sigma-60 with a modified shape and water bolus. Power and intraluminal temperature were analysed. Sub-group analyses were performed for six groups, categorised according to the reasons for switching between the applicators. Results: The `all patient' analysis showed a significant difference for radio frequency (RF) power indices as applied to the two applicators, but for temperatures no difference between applicators was found. Sub-group analyses showed a consistent difference for RF power indices, i.e. the RF power for the Sigma-Eye was 8-29% higher than that for Sigma-60. In contrast, in about 90% of patients the number of switch-offs was 8-62% lower when the Sigma-Eye was applied. Similarly, in 73% of patients total switch-off time was 18-150% lower for the Sigma-Eye than for the Sigma-60. For the largest sub-group (n=23), patients treated with the Sigma-Eye all had temperature indices slightly lower (Delta T=0.2-0.5 degrees C) than those for the Sigma-60 (p < 0.028). For the other five sub-groups no relevant difference was found between temperatures obtained by the two applicators. Conclusion: In the case of severe patient discomfort with the Sigma-60 or Sigma-Eye applicator, or if achieved temperatures are not satisfactory, one can freely switch between both applicators without loss of hyperthermia treatment quality

Mälestused : 1905. aasta lõppvaatus. III

http://www.ester.ee/record=b4162066*es

RF-power and temperature data analysis of 444 patients with primary cervical cancer: Deep hyperthermia using the Sigma-60 applicator is reproducible

Treatment reproducibility is important to guarantee reproducible treatment-outcome, a low-complication rate and efficient treatment procedures. This study evaluated the performance of loco-regional deep hyperthermia with four BSD-2000 configurations during 1990-2005 using the direct available parameters, i.e., temperature and power. Primary cervical cancer patients (n = 444) were all treated within the Sigma-60. Patients were grouped in three weight-groups: 70 kg. Different temperature and power indices were extensively analyzed per BSD configuration, per weight-group, and over the time-period. No substantial variations were found for temperature/power indices over the four BSD configurations or for the temperature doses in similar weight-groups. The `bare' power indices were increased with weight; however, the derivative power-related (W/kg, W/cm(2)) and temperature indices decreased. Large variations were found in the power-related parameters during 1991-1996 (1st time-period), whereas they were much smaller during 1997-2005 (2nd time-period). The most relevant change noted was the adaptation of the treatment strategy with respect to power modulation. The average frequency of switched-off was 3.4 and 8.9 times/treatment session for the 1st and 2nd time-period, respectively, while the average duration of each switched-off time was 78.2 vs. 38.3 s. The yearly average of vagina T-50 was in the range of 39.3-40.2 degrees C (1st time-period) and 40.0-40.5 degrees C (2nd time-period). In 40% of the patients, a positive correlation was found between normalized net integrated power per pelvic area and vagina T50. Good reproducible heating is achieved with the BSD-2000 Sigma-60 irrespective of the regular technological upgrades of the system and variation of trained staff-members

Weekly systemic cisplatin plus locoregional hyperthermia: An effective treatment for patients with recurrent cervical carcinoma in a previously irradiated area

Purpose: Patients with recurrent cervical carcinoma within a previously irradiated area respond poorly to chemotherapy. We have treated these patients with simultaneous cisplatin and hyperthermia ( CDDP+HT) and investigated response, toxicity, palliative effect and survival. Materials and methods: Between 1992 and 2005 47 patients received CDDP+HT. Response was evaluated by gynaecologic examination and CT-scan. The Common Toxicity Criteria ( CTC) were used for evaluation of toxicity and palliative effect. The Kaplan-Meier method was used to estimate survival, and Cox regression analysis to evaluate the influence of prognostic factors. Results: The objective response rate was 55%, palliation was achieved in 74% and operability in 19% of patients. Two patients are currently disease free at 9 years and 18+months following treatment and 2 remained disease free until death by other causes. The median survival was 8 months and was influenced by duration of disease free interval and tumour diameter. Grade 3-4 haematological toxicity was observed in 36% of patients and renal toxicity was maximum grade 2. Conclusion: CDDP+HT results in a high response rate and acceptable toxicity in patients with recurrent cervical cancer