[en] Functional imaging using ¹⁸F-FDG-PET provides the clinician with additional information about the tumour response during and/or after induction chemo-/chemo-radiotherapy. Semiquantitative analysis with SUV measurements allows prediction of histopathologic remission with sensitivity and specificity of 65-85%. In addition, SUV reductions by > 40-60% in relation to the baseline scan indicate better disease-free and overall survival rates. Successful response prediction has been shown in some tumour entities early during or after the first chemo-/chemo-radiotherapy cycle. This allows an early adaptation of therapeutic strategies including avoidance of invasive procedures or surgical tumour removal. Standardization of the application and performance of PET-scans is of crucial importance with respect to inter-institutional comparisons and diagnostic validity. The optimal time-point of sequential investigations during/after radiotherapy remains unclear and warrants further interventional studies. (orig.)

[en] The effects of tissue damage associated with invasive pO₂ measurements on radiation sensitivity were investigated using a xenografted squamous cell carcinoma model. For the tumour cure experiments, single dose irradiations were given following different regimens of polarographic pO₂ measurements associated with different degrees of mechanical tissue damage. With a dose of 32 Gy, 57% of animals were cured. Following 3 tracks of needle measurements, 73% of tumours were locally controlled, and 75% were cured after 8 needle tracks. The polarographic measurements gave virtually identical oxygenation data for recurrent or cured tumours (both median pO₂ 1.0 mmHg), respectively. There was thus no evidence of decreased radiosensitivity associated with tissue damage after invasive pO₂ measurements. The pre-therapeutic oxygenation status gave no evidence for a prediction of radiation response on an individual basis. (orig.)

[en] The effect of fractionated irradiation on the oxygenation status of experimental tumours was investigated using polarographic assessment of the pO₂ distribution. Since an improvement in tumour oxygenation could simply be the result of tumour shrinkage, a comparison of pO₂ readings of untreated size-matched control tumours was performed. Irradiation was carried out using 6 fractions of 6 Gy applied within 11 days. A comparison of polarographic pO₂ data with size-matched untreated tumours revealed a significant improvement in oxygenation after the irradiation. The median pO₂ was 0.9±0.1 mmHg for unirradiated tumours at a volume of 180 mm³, while the corresponding data for irradiated tumours of comparable size were 2.3±0.5 mmHg on day 21 and 4.8±0.9 mmHg on day 28 after start of irradiation. From these results it can be concluded that the improvement of oxygenation after fractionated irradiation is not solely the result of a reduced tumour volume. (orig.)

[en] The aim of the study was to evaluate dysphageal symptoms and to measure the effect of local analgesic treatment using parametric oesophageal multiple swallow scintigraphy (PES) during external beam irradiation of the mediastinal region. Fifteen patients (most with lung cancer) with dysphagia grade II underwent PES during external beam radiotherapy of the mediastinum before and after application of local analgesics. Dynamic parametric condensed images were recorded. The intensity of clinical symptoms was correlated with the emptying rate at 10 s (ER-10 s) and the mean transit time (MTT). Visual analysis of the images was performed and the results were correlated with the fields of irradiation portals. Of the 15 patients, 12 showed a correlation between irradiation portals and the region of oesophageal motility disorder. Concordant results of clinical symptoms and PES data were found. In nine patients with a decrease in dysphagia following local analgesia, an increase in mean ER-10 s and a decrease in MTT were observed. In three patients with deterioration in clinical symptoms after analgesic treatment, a similar decrease in mean ER-10 s was found, though MTT remained constant. In three patients with normal values, motility disorders were detected in the dynamic study. In conclusion, PES was found to be a sensitive tool for the validation of dysphageal symptoms in patients during external beam irradiation of mediastinal tumours and for the evaluation and quantification of the efficacy of local analgesic treatment. Additional visual analysis of the dynamic study is helpful in diagnosing minimal disorders. (orig.)

[en] Background: Pronounced oxygen deficiency in tumors which might be caused by a diminished oxygen transport capacity of the blood (e.g., in anemia) reduces the efficacy of ionizing radiation. The aim of this study was to analyze whether anemia prevention by recombinant human erythropoietin (rHuEPO) affects the radiosensitivity of human glioblastoma xenografts during fractionated irradiation. Material and Methods: Anemia was induced by total body irradiation (TBI, 2 x 4 Gy) of mice prior to tumor implantation into the subcutis of the hind leg. In one experimental group, the development of anemia was prevented by rHuEPO (750 U/kg s.c.) given three times weekly starting 10 days prior to TBI. 13 days after tumor implantation (tumor volume approx. 40 mm³), fractionated irradiation (4 x 7 Gy, one daily fraction) of the glioblastomas was performed resulting in a growth delay with subsequent regrowth of the tumors. Results: Compared to nonanemic control animals (hemoglobin concentration cHb = 14.7 g/dl), the growth delay in anemic mice (cHb = 9.9 g/dl) was significantly shorter (49 ± 5 days vs. 79 ± 4 days to reach four times the initial tumor volume) upon fractionated radiation. The prevention of anemia by rHuEPO treatment (cHb = 13.3 g/dl) resulted in a significantly prolonged growth delay (61 ± 5 days) compared to the anemia group, even though the growth inhibition found in control animals was not completely achieved. Conclusions: These data indicate that moderate anemia significantly reduces the efficacy of radiotherapy. Prevention of anemia with rHuEPO partially restores the radiosensitivity of xenografted glioblastomas to fractionated irradiation. (orig.)

[en] Purpose: To analyze the long-term results following whole brain radiotherapy (WBRT) with sequential intrathecal (i.th.) cytosine arabinoside (Ara-C) ± intravenous (i.v.) Ara-C in patients with primary central nervous system lymphoma (PCNSL). Patients and Methods: 14 patients were treated between July 1987 and August 1995. All had sporadic PCNSL with proven histology of high-grade CNS lymphoma (twelve diffuse large-cell B-lymphomas, one lymphoblastic lymphoma, one large T-cell lymphoma). Patients were treated with two to four cycles of induction chemotherapy (40 mg/m² Ara-C i.th.), four patients received additional Ara-C i.v. (150 mg/m², d1-4). WBRT was administered using 1.8-Gy fractions. Intrathecal chemotherapy was planned afterwards in 4-week intervals for 6 months. Posttreatment neurocognitive evaluations were performed in two long-term survivors. Results: Two of four patients who received i.v. and i.th. induction chemotherapy showed progressive disease, and irradiation was started immediately. Six of 14 patients received 50.4 Gy WBRT, four patients had WBRT up to 39.6 Gy followed by a 10.8-Gy boost. Five patients died early during therapy either due to a decline of the general medical condition or progressive disease. Median survival was 41 months (95% confidence interval: 6-79 months), survival at 3 and 5 years was 59% and 42%, respectively. Six patients survived for 3 years, two younger patients are still alive (> 12 years). They show only slightly impaired neurocognitive functions without clinical relevance. Conclusion: This WBRT-based protocol with i.th. meningeal prophylaxis using Ara-C ± i.v. Ara-C yields substantial long-term survival with moderate toxicity. The value of i.v. chemotherapy is currently being investigated in prospective studies. (orig.)