Fractionated stereotactic radiotherapy in the treatment of pituitary adenomas.

PURPOSE: The purpose of this work was to evaluate tumor control and side effects associated with fractionated stereotactic radiotherapy (FSRT) in the management of residual or recurrent pituitary adenomas. PATIENTS AND METHODS: We report on 37 consecutive patients with pituitary adenomas treated with FSRT at our department. All patients had previously undergone surgery. Twenty-nine patients had nonfunctioning, 8 had hormone-producing adenoma. The mean total dose delivered by a linear accelerator was 49.4 Gy (range 45-52.2 Gy), 5 × 1.8 Gy weekly. The mean PTV was 22.8 ccm (range 2.0-78.3 ccm). Evaluation included serial imaging tests, endocrinologic and ophthalmologic examination. RESULTS: Tumor control was 91.9 % for a median follow-up time of 57 months (range 2-111 months). Before FSRT partial hypopituitarism was present in 41 % of patients, while 35 % had anterior panhypopituitarism. After FSRT pituitary function remained normal in 22 %, 43 % had partial pituitary dysfunction, and 35 % had anterior panhypopituitarism. Visual acuity was stable in 76 % of patients, improved in 19 %, and deteriorated in 5 %. Visual fields remained stable in 35 patients (95 %), improved in one and worsened in 1 patient (2.7 %). CONCLUSION: FSRT is an effective and safe treatment for recurrent or residual pituitary adenoma. Good local tumor control and preservation of adjacent structures can be reached, even for large tumors.

Positron-emission tomography CT to identify local recurrence in stage I lung cancer patients 1 year after stereotactic body radiation therapy.

PURPOSE: To evaluate the diagnostic value of positron-emission tomography/computed tomography (PET/CT) in stage I lung cancer patients treated with stereotactic body radiation therapy (SBRT), who have suspicious or unclear local recurrence findings in CT 1 year after treatment. PATIENTS AND METHODS: A group of 29 patients with unclear or suspicious CT findings 1 year after SBRT were examined with PET/CT. The ability of standard uptake values (SUVmax, SUVmean and posttherapeutic reduction in SUV) to detect local failure and identify patients at a high risk of disease-specific death was evaluated using logrank statistics. Histology and clinical follow-up were the gold standards for local recurrence. RESULTS: SUVmean greater than 3.44 (p = 0.001); SUVmax greater than 5.48 (p = 0.009) or a relative reduction in SUVmean or SUVmax of less than 43 (p = 0.030) or 52 % (p = 0.025), respectively, was indicative of local recurrence. These parameters also correlated with an increased risk of disease-specific death: SUVmean greater than 2.81 (p = 0.023); SUVmax greater than 3.45 (p = 0.007) or a relative reduction in SUVmean or SUVmax of less than 32 (p = 0.015) or 52 % (p = 0.013), respectively, was indicative of an increased risk of disease-specific death. CONCLUSION: PET/CT performed 1 year after SBRT can reliably identify local recurrence and therefore help to clarify unclear CT findings. As posttherapeutic glucose metabolism also correlates with disease-specific survival, PET/CT may help to stratify lung cancer patients for additional treatment 1 year after SBRT.

Respiratory gated [18F]FDG PET/CT for target volume delineation in stereotactic radiation treatment of liver metastases.

PURPOSE: The use of 4D-[(18)F]fluorodeoxyglucose (FDG) PET/CT in combination with respiratory gated magnet resonance imaging (MRI) in target volume definition for stereotactic radiation of liver metastases was investigated. METHODS AND MATERIALS: A total of 18 patients received respiration gated FDG-PET/CT and MRI. Data were fused using a rigid co-registration algorithm. The quality of the co-registration was rated on a scale from 1 (excellent) to 5 (poor) for co-registration of MRI with gated PET and ungated PET. Gross tumor volume (GTV) was delineated in CT (GTV (CT)), MRI (GTV(MRI)), and PET (GTV(PET)). MRI- and PET-based GTVs were defined by three observers each. Interobserver variability was calculated for all patients as well as for subgroups with and without previous treatment of liver metastases. All GTVs were compared for all patients and separately for patients with previous local therapy. In addition, a semiautomatic segmentation algorithm was applied on the PET images. RESULTS: Co-registration between MR and PET images was rated with 3.3 in average when non-gated PET was used and improved significantly (p < 0.01) to 2.1 using gated PET. The average GTV(CT) was 51.5 ml, GTV(MRI) 51.8 ml, and the average GTV(PET) 48.1 ml. Volumes delineated in MRI were 9.9% larger compared to those delineated in CT. Volumes delineated in PET were 13.8% larger than in MRI. The differences between the GTVs were more pronounced in patients with previous treatment. The GTVs defined in MRI showed an interobserver variability of 47.9% (84.1% with previous treatment and 26.2% without previous treatment). The PET-defined GTVs showed an interobserver variability of 21% regardless of previous treatment. Semiautomatic segmentation did not provide satisfying results. CONCLUSION: FDG-PET can distinguish vital tumor tissue and scar tissue, and therefore alters the GTV especially in patients with previous local treatment. In addition, it reduces the interobserver variability significantly compared to MRI. However, respiratory gated PET is necessary for good co-registration of PET and MRI.

Dose-escalated simultaneous integrated-boost treatment of prostate cancer patients via helical tomotherapy.

PURPOSE: The goal of this work was to assess the feasibility of moderately hypofractionated simultaneous integrated-boost intensity-modulated radiotherapy (SIB-IMRT) with helical tomotherapy in patients with localized prostate cancer regarding acute side effects and dose-volume histogram data (DVH data). METHODS: Acute side effects and DVH data were evaluated of the first 40 intermediate risk prostate cancer patients treated with a definitive daily image-guided SIB-IMRT protocol via helical tomotherapy in our department. The planning target volume including the prostate and the base of the seminal vesicles with safety margins was treated with 70 Gy in 35 fractions. The boost volume containing the prostate and 3 mm safety margins (5 mm craniocaudal) was treated as SIB to a total dose of 76 Gy (2.17 Gy per fraction). Planning constraints for the anterior rectal wall were set in order not to exceed the dose of 76 Gy prescribed to the boost volume. Acute toxicity was evaluated prospectively using a modified CTCAE (Common Terminology Criteria for Adverse Events) score. RESULTS: SIB-IMRT allowed good rectal sparing, although the full boost dose was permitted to the anterior rectal wall. Median rectum dose was 38 Gy in all patients and the median volumes receiving at least 65 Gy (V65), 70 Gy (V70), and 75 Gy (V75) were 13.5%, 9%, and 3%, respectively. No grade 4 toxicity was observed. Acute grade 3 toxicity was observed in 20% of patients involving nocturia only. Grade 2 acute intestinal and urological side effects occurred in 25% and 57.5%, respectively. No correlation was found between acute toxicity and the DVH data. CONCLUSION: This institutional SIB-IMRT protocol using daily image guidance as a precondition for smaller safety margins allows dose escalation to the prostate without increasing acute toxicity.

Imaging of tumor physiology: impacts on clinical radiation oncology.

As the metabolic microenvironment markedly influences the therapeutic response of malignant tumors, imaging of the microenvironment is one of the goals researcher have been aiming at for years. Several methods such as positron emission tomography, functional magnetic resonance imaging (MRI) or contrast enhanced MRI/CT are now available. For radiation oncology, tumor oxygenation and perfusion are the most important (patho-) physiological parameters that might be included in radiotherapy regimens and treatment planning. In order to overcome resistance of tumor cells resulting from hypoxia, positron emission tomography (PET) using nitroimidazole tracers is the most advanced technique at this time. Since reproducibility of the PET signal/tracer distribution, thresholding and exact quantification are not thoroughly understood and further investigation is needed before including it into radiotherapy regimens. To image tumor perfusion, dynamic contrast enhanced computed tomography (DCE-CT) or dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) are the most suitable techniques. Co-investigation of tumor oxygenation and perfusion should be performed in order to investigate their interaction and consequences for radiooncology.

Prediction of very short survival in patients with brain metastases from breast cancer.

AIMS: Current prognostic models are not accurate enough to identify brain metastases patients with very short survival, i.e. <2 months, who are unlikely to derive major benefit from whole brain radiotherapy. Our aim was to develop a more reliable model. MATERIALS AND METHODS: This was a retrospective analysis of a German database, which was used to develop a score, and an additional database from Norway, which was used for validation purposes. RESULTS: The groups included 67 and 32 patients, respectively. An analysis of prognostic factors resulted in a risk score based on performance status, extra-cranial metastases, the interval from breast cancer to brain metastases and a need for corticosteroid treatment, which classified 63 of 67 test patients correctly. However, the validation failed and unfortunately the risk score that performed best in the Norwegian patients (31 of 32 correctly predicted) was not applicable to the German patients. CONCLUSIONS: The prediction of short survival is associated with several caveats and seems to result in an unacceptable risk of withholding radiotherapy in patients who actually survive for longer than 2 months.

Ten-year data on 138 patients with endometrial carcinoma and postoperative vaginal brachytherapy alone: no need for external-beam radiotherapy in low and intermediate risk patients.

OBJECTIVE: To evaluate long-term outcome, risk factors, and causes of death in stage I-IIIA endometrial carcinoma (EC) patients treated only with adjuvant vaginal brachytherapy (VB) and to clarify for which subgroups of patients it is safe to omit external-beam radiotherapy (EBRT). METHODS: Out of 224 EC patients receiving postoperative radiotherapy between 1990 and 2002, 138 had VB alone in curative intent (FIGO [2002]: 85%I, 12%II, 3%IIIA; 18 low risk [IA G1-2, IB G1], 103 intermediate risk [IB G2-3, IC G1-2, IIA-B G1-2], 17 high risk [IC G3, IIIA]). After surgery+/-lymphadenectomy, HDR-brachytherapy prescription (in 95.7% of patients) was 3x10 Gy to the surface or 3x5 Gy at 5 mm tissue depths. RESULTS: Median follow-up was 107 months (range 3-185). Three intermediate and 7 high risk-patients relapsed. The 10-year vaginal control was 99.2%, locoregional control was 95.2% (low/intermediate/high risk: 100%/98.9%/68.8%), and disease-free survival (DFS) was 91.7% (100%/96.8%/55.2%). Risk factors for poor DFS were lymphovascular space invasion, > or = 50% myometrial invasion (univariate, p<0.05), pathological FIGO-stage, and grade 3 (uni-/multivariate, p<0.05). Leading causes of deaths (n=41) were cardiovascular disease (29%) and other malignancies (24%) ahead of EC (19.5%). The 10-year overall survival was 68.5% and the disease-specific survival was 92.4%. Thirty-five secondary tumors in 31 patients led to a higher actuarial death rate (10-year 9.9%, 15-year 17.7%) than EC (7.6%). CONCLUSIONS: Restricting adjuvant therapy to VB alone seems to be safe in low and intermediate risk EC and can be recommended. As death rarely relates to early-stage EC, value of adjuvant therapy is probably better reflected by DFS rather than by overall survival.

Identification of thyroxine-binding globulin-San Diego in a family from Houston and its characterization by in vitro expression using Xenopus oocytes.

T4-binding globulin (TBG) is a liver glycoprotein that transports iodothyronines in serum. Several TBG variants with reduced T4 binding affinity have been described, all of which are also characterized by reduced serum TBG concentrations and reduced heat stability. Their loss of binding thus appears to be due to a general defect of the molecule. We now report the occurrence of a variant TBG, detected in a family from Houston, TX, with half the normal T4 binding affinity and heat stability but normal serum concentration and isoelectric focussing pattern. The propositus was identified by reduced total T4 and T3 serum levels. All family members were euthyroid, and inheritance followed an X-linked pattern. Sequence analysis of the TBG gene of the propositus and his heterozygous mother revealed two amino acid substitutions: serine 23 with threonine (S23T), and the known polymorphism leucine 283 with phenylalanine (L283F). These substitutions are identical to those of TBG-San Diego (TBG-SD), a variant with similar properties except for a reduced serum concentration. Expression of recombinant TBG-SD/H with the S23T substitution in Xenopus oocytes reproduced the binding defect and heat lability. The amount of TBG-SD/H synthesized and secreted by the oocytes was not different from that of normal TBG. The difference in serum TBG concentrations in affected members of the San Diego and Houston families thus does not appear to be due to an error in the measurement of TBG, but may be related to differences in the rates of degradation.

Three-dimensional in vitro cocultivation of lung carcinoma cells with human bronchial organ culture as a model for bronchial carcinoma.

We describe the development of a three-dimensional in vitro organ culture model for bronchial carcinoma using bronchial mucosa organ cultures and three different human non-small cell lung cancer cell lines. During precultivation, bronchial fragments obtained as biopsies during routine bronchoscopy had regenerated a complete epithelial covering with a well-preserved organotypic architecture around a nucleus consisting of connective tissue. To create cocultures, different types of confrontation between tumor cells and organ cultures were applied. Histologic light microscopy and scanning electron microscopy were used in analysis. When tumor cells were confronted with completely epithelialized organ cultures, they showed a low incidence of attachment. When organ cultures were wounded before confrontation, tumor cells always attached to the wounded side and showed a progressive invasion into the stromal tissue. Measurements of the penetration depth of tumor cells into the organ cultures after different incubation times permitted the quantitative evaluation of invasion. Histologic studies revealed well-differentiated normal epithelium in spite of long culture periods. Histologic features of the tumors were those of an invasive undifferentiated carcinoma and showed marked similarities to the situation in vivo. The coculture model permits internal controls because it contains both normal human epithelium and human tumor cells in the same organotypic culture. Therefore it offers opportunities for various in vitro investigations on therapeutic and diagnostic modalities of lung cancer, as indicated in this paper by an example of photodynamic procedures with 5-aminolevulinic acid.

[Increased incidence of bronchial carcinomas. What is new in therapy and diagnosis?]. / Immer mehr Bronchialkarzinome. Was gibt es Neues bei Therapie und Diagnostik?

The increasing incidence and continuing poor prognosis of lung cancer make new therapeutic concepts necessary. For stage I and stage II disease, surgery remains the treatment of choice. In the case of inoperable patients, radiotherapy, used alone, may be a curative alternative. To improve the prognosis of stages II and III of non-small-cell lung cancer, multi-modal treatments such as neoadjuvant chemotherapy, combined chemo-/radiotherapy and post-operative irradiation are still being researched. Although present results indicate higher survival rates, these approaches have not yet become standard. The palliative options for stages III and IV have also clearly been expanded in recent years, so that late-stage lung cancer may yet respond to treatment. Such options are, in particular, invasive bronchoscopic procedures, such as treatment with the Nd-YAG laser, cryotherapy, dilatation and the implantation of stents, or intraluminal irradiation. The major and decisive measure, however, is still prevention which, for 85% of all lung cancer consists in the rejection of nicotine abuse. In the meantime, sensitive methods of early diagnosis have also become available. However, they are invasive and thus not suitable for large-scale screening, but are reserved for high-risk patients. Non-invasive methods are currently under development.