No abstract

No abstract

The aim of this study was to evaluate the feasibility and toxicity of a novel hyperthermic chemotherapy approach for patients with locally recurrent adenocarcinoma of the rectum. All patients were pre-irradiated (> or = 45 Gy) and had histologically proven pelvic recurrence. Hyperthermic chemotherapy was applied according to a modified 'OFF'-schedule with weekly infusions of 43 mg/m2 of oxaliplatin (i.v., 120 min), 500 mg/m2 of folinic acid (i.v., 120 min) and 2.6 g/m2 of continuous infusional 5-fluorouracil (24 h) for 6 consecutive weeks. Oxaliplatin was started in parallel to pelvic radiofrequency hyperthermia that was provided by the BSD 2000-system. A total of 67 applications were administered to nine patients and were well tolerated. A total of 55/67 (82%) chemotherapy courses were applied without dose-reduction. In 62/67 (93%) hyperthermia sessions, a treatment time of > 60 min was maintained. Tolerated power levels were on average 600 W and, thus, slightly lower than those described in curative pelvic hyperthermia schedules. Eight out of 10 episodes of severe (WHO III degrees) toxicity represented typical side-effects of the chemotherapy given (nausea n = 4, diarrhoea n = 3, neuropathy n = 1). Two severe adverse events were firstly attributable to hyperthermia (haematuria, n = 1; deterioration of a decubital ulcer, n = 1). No patient suffered WHO-disease progression during the treatment period. Two patients achieved a partial remission. It is concluded that hyperthermic chemotherapy with oxaliplatin, folinic acid and 5-FU is feasible on an outpatient basis. Overall toxicity was moderate, although hyperthermia may add side-effects to this approach. Results, moreover, suggest a relevant palliative effect in patients with pre-irradiated pelvic recurrence of rectal cancer.

Assessment of perfusion with 15O-labelled water (H215O) requires measurement of the arterial input function (AIF). The arterial time activity curve (TAC) measured using the peripheral sampling scheme requires corrections for delay and dispersion. In this study, parametrizations with and without arterial spillover correction for fitting of the tissue curve are evaluated. Additionally, a completely noninvasive method for generation of the AIF from a dynamic positron emission tomography (PET) acquisition is applied to assess perfusion of pelvic tumours. This method uses a volume of interest (VOI) to extract the TAC from the femoral artery. The VOI TAC is corrected for spillover using a separate tissue TAC and for recovery by determining the recovery coefficient on a coregistered CT data set. The techniques were applied in five patients with pelvic tumours who underwent a total of 11 examinations. Delay and dispersion correction of the blood TAC without arterial spillover correction yielded in seven examinations solutions inconsistent with physiology. Correction of arterial spillover increased the fitting accuracy and yielded consistent results in all patients. Generation of an AIF from PET image data was investigated as an alternative to arterial blood sampling and was shown to have an intrinsic potential to determine the AIF noninvasively and reproducibly. The AIF extracted from a VOI in a dynamic PET scan was similar in shape to the blood AIF but yielded significantly higher tissue perfusion values (mean of 104.0 +/- 52.0%) and lower partition coefficients (-31.6 +/- 24.2%). The perfusion values and partition coefficients determined with the VOI technique have to be corrected in order to compare the results with those of studies using a blood AIF.

No abstract

The increase in partition coefficient reflects an increased diffusion distance of radio-labeled water. Therefore water diffusion is increased due to hyperthermia. Analogous to water diffusion, the diffusion of inert gases is also facilitated, improving the oxygenation of hypoxic tumor cells. Our results suggest that tumor oxygenation can probably be enhanced by regional hyperthermia for a period of more than 1 h after heating, provided hyperthermia is applied for at least 60 min. The effect was observed to be reversible within one week.

Background: Dose escalated three-dimensional conformal radiotherapy with 70 Gy against glioblastomas was compared retrospectively with the standard scheme of 60 Gy using 2-D-planning. Patients and Methods: In the period from 1994 to 1998, a series of 135 patients with glioblastomas was treated by surgery and postoperative radiotherapy. A conversion from 2-D into 3-D-planning was carried out in 4/1996. The prescribed total dose for the first 65 patients was 60 Gy (group 60). A boost up to 70 Gy was added for the remaining 70 patients (group 70). Results: The median survival time was 8.0 months for group 60 and 8.3 months for group 70. A dependency on the applied dose range was found. The median survival time was 3 months for patients who received a radiation dose of 55 Gy or less, 8.6 months for doses between 56 and 65 Gy, and 9.6 months for patients with a dose between 66 and 75 Gy (p < 0.01). In a multivariate analysis only the performance status maintained significance (p = 0.02) as a prognostic factor, while the dose range reached borderline significance (p = 0.09). Conclusion: No statistically significant survival prolongation was reached despite a dose escalation to 70 Gy.

Temperature measurement during hyperthermia may allow only determination of intermediate perfusion values.