Biomedical subjects

J D P Van Dijk

Publications and source records attributed to J D P Van Dijk.

3 recordsLinked to original sources

PubMed2005

High-resolution temperature-based optimization for hyperthermia treatment planning.

In regional hyperthermia, optimization techniques are valuable in order to obtain amplitude/phase settings for the applicators to achieve maximal tumour heating without toxicity to normal tissue. We implemented a temperature-based optimization technique and maximized tumour temperature with constraints on normal tissue temperature to prevent hot spots. E-field distributions are the primary input for the optimization method. Due to computer limitations we are restricted to a resolution of 1 x 1 x 1 cm3 for E-field calculations, too low for reliable treatment planning. A major problem is the fact that hot spots at low-resolution (LR) do not always correspond to hot spots at high-resolution (HR), and vice versa. Thus, HR temperature-based optimization is necessary for adequate treatment planning and satisfactory results cannot be obtained with LR strategies. To obtain HR power density (PD) distributions from LR E-field calculations, a quasi-static zooming technique has been developed earlier at the UMC Utrecht. However, quasi-static zooming does not preserve phase information and therefore it does not provide the HR E-field information required for direct HR optimization. We combined quasi-static zooming with the optimization method to obtain a millimetre resolution temperature-based optimization strategy. First we performed a LR (1 cm) optimization and used the obtained settings to calculate the HR (2 mm) PD and corresponding HR temperature distribution. Next, we performed a HR optimization using an estimation of the new HR temperature distribution based on previous calculations. This estimation is based on the assumption that the HR and LR temperature distributions, though strongly different, respond in a similar way to amplitude/phase steering. To verify the newly obtained settings, we calculate the corresponding HR temperature distribution. This method was applied to several clinical situations and found to work very well. Deviations of this estimation method for the AMC-4 system were typically smaller than 0.2 degrees C in the volume of interest, which is accurate enough for treatment planning purposes.

Body Burden↗

PubMed2004

Phase II study of carboplatin and whole body hyperthermia (WBH) in recurrent and metastatic cervical cancer.

OBJECTIVE: Hyperthermia enhances carboplatin cytotoxicity preclinically, and clinical studies have shown radiant heat Whole Body Hyperthermia (WBH) to be safe. In this study, the efficacy and toxicity of the combination of 41.8 degrees C WBH and carboplatin in recurrent and/or metastatic cervical cancer were explored. METHODS: Recurrent and/or metastatic cervical cancer patients were treated with 41.8 degrees C WBH and concurrent carboplatin, cycled every 28 days (max. 6 cycles). RESULTS: Twenty-one of 25 participants were evaluable for response: one complete remission, six partial responses, stable disease in nine patients and progression in five, leading to a response rate of 33%. Three of four evaluable chemotherapy pre-treated patients progressed, while this was seen in only 2 of 17 chemotherapy-naive patients. The median survival is 7.8 months (range 1.3 to 43+) and no patients were lost to follow up. Grades 3/4 toxicities were common: leukopenia in 35%, thrombopenia in 61% and anemia in 22% of all treatments. Excessive, partly reversible renal toxicity was seen in two patients (grades 3 and 4). CONCLUSION: The efficacy of WBH and carboplatin in recurrent and/or metastatic cervical cancer seems comparable to that of other palliative chemotherapy regimens in this disease. The considerable toxicity, though largely manageable, includes unexpected and severe unacceptable renal toxicity. This regimen seems less suitable for palliative care.

Adult↗

PubMed2003

A Systemic Hyperthermia Oncologic Working Group trial. Ifosfamide, carboplatin, and etoposide combined with 41.8 degrees C whole-body hyperthermia for metastatic soft tissue sarcoma.

BACKGROUND: Based on earlier clinical and preclinical studies, we conducted a phase II trial in metastatic sarcoma patients of the combination of 41.8 degrees C (x60 min) radiant heat (Aquatherm) whole-body hyperthermia (WBH) with 'ICE' chemotherapy. The ICE regimen consists of ifosfamide (5 g/m(2)), carboplatin (300 mg/m(2)) and etoposide (100 mg/m(2)), concurrent with WBH, with etoposide also on days 2 and 3 post-WBH. METHODS: Therapy was delivered every 4 weeks for a maximum of 4 cycles. All patients received filgrastim or lenograstim. RESULTS: Of 108 patients enrolled as of September 2001, 95 are evaluable for response. Of the evaluable patients (mean ECOG performance status approximately 1; mean age 42.3; 58% male) 33 had no prior therapy for metastatic disease, and 62 were pretreated (mean: 1.5 prior regimens). The overall response rate was 28.4% (4 complete remissions and 23 partial remissions) with stable disease (SD) in 31 patients. For no prior therapy, the response rate was 36%; in pretreated patients it was 24%. The median overall survival by Kaplan-Meier estimates was 393 days (95% CI 327, 496); the median time to treatment failure was 123 days (95% CI 77, 164). The major toxicity (287 cycles) was grade 3 or 4 neutropenia and thrombocytopenia seen in 79.7 and 60.6% of treatments respectively; there were 7 episodes of infection (grade 3/4) with 2 treatment-related deaths, bot involving disease progression and ureteral obstruction. CONCLUSION: These results are consistent with continued clinical investigation of this combined modality approach.

Adolescent↗