Pegylated interferon-alpha2a/ribavirin treatment of recurrent hepatitis C after liver transplantation.

Hepatitis C virus (HCV) infection invariably recurs after liver transplantation (LT), leading to significant morbidity and mortality. Although the combination of pegylated interferon-alpha (IFN-alpha)/ribavirin is the preferred treatment for these patients, the optimal schedule remains undetermined. In an uncontrolled trial, 19 patients with HCV infection recurring after LT received pegylated IFN-alpha(2a), 180 mug weekly, and ribavirin, 10 mg/kg body weight daily, for 48 weeks. The proportion of patients with undetectable HCV RNA in their serum after 12 weeks of treatment was 53%. Five patients (26%) dropped out of the study due to intolerance (in 2 cases), depression (in 1), or infectious complications (in 2). A sustained virological response (SVR), defined as undetectable serum HCV RNA 24 weeks after the end of treatment, was observed in 9/19 patients (47%). SVR was associated with an early virological response after 12 weeks of therapy (P<0.001) and a treatment duration >80% (P=0.02), but not with baseline HCV RNA level or a cumulative dose of pegylated IFN-alpha(2a) or ribavirin >80% of the scheduled dose. All 4 patients with genotype 2 or 3 reached SVR, as compared with 33% of patients with genotype 1 or 4 (P=0.03). A 48-week course of pegylated IFN-alpha(2a)/ribavirin therapy is effective in patients with recurrent HCV infection after LT.

Chemo-radiotherapy for locally advanced head and neck cancer--long-term results of a phase II trial.

The feasibility and effectiveness of a combined chemo-radiotherapy treatment modality for locally advanced head and neck cancer was tested in a phase II trial. Between 1990 and 1993, 74 patients (20 female/54 male) with head and neck cancer stage III (n = 12) and IV (n = 62) were treated with accelerated radiotherapy (72 Gy) and simultaneous chemotherapy (5-FU, folinic acid, mitomycin C). The median follow-up time was 43 months (1-72). Complete remission (CR) was absent in 76% (56/74) of patients and, after subsequent resection of residual lymph nodes, another 8 patients achieved CR. The cumulative local control rate was 72% and disease-specific survival rate was 59% at 4 years. Two patients died with treatment-related conditions (pancytopenia, larynx oedema). By multivariate analysis, only lymph node status was an independent parameter for local control (P = 0.04). This treatment was feasible and toxicity was not a treatment-limiting factor. As a consequence, a German multicentre phase III trial was initiated in 1995.

Temporary tracheobronchial stenting in malignant stenoses.

Endobronchial stent implantation has been successfully employed in malignant stenoses. The aim of this prospective study was to investigate the temporary use of tracheobronchial stents combined with tumour-specific therapy. All patients received stents for primary palliation of dyspnoea followed by radio- or chemotherapy with the aim of stent removal after reduction of the stenosis. In 22 patients suffering from severe malignant strictures, 34 endobronchial stents (29 Strecker-, 3 Dumon-, 1 Orlowski-, 1 Dynamic-Y-stents) were implanted (in 9 patients, 2 stents were necessary). Patients were treated by irradiation (n = 18) or chemotherapy (n = 4) after stent implantation. Significant improvement of dyspnoea (P < 0.001) and partial oxygen pressure (P < 0.01) was observed. In 11 out of 22 cases (50%), the stents could be removed after successful tumour-specific therapy which led to reduction of stenosis after a mean interval of 31.7 (6-104) days (temporary stenting). During the period of tumour-specific therapy, 9 patients died after a mean interval of 132 (13-347) days (definite stenting). In two cases, stents had to be removed after stent compression, stent dislocation and severe cough. The results suggest that temporary stenting, characterised by subsequent successful tumour-specific therapy, is a new valuable therapeutic strategy. It can "bridge the gap" before tumour-specific therapy can take effect. If tumour-specific therapy is ineffective, definite stenting is the palliative method of choice in severe dyspnoea in bronchial carcinoma.

Local recurrences of soft tissue sarcomas in adults: a retrospective analysis of prognostic factors in 102 cases after surgery and radiation therapy.

Between 1974 and 1990, 102 adult patients (age 18-86 years) with the diagnosis of a soft tissue sarcoma (STS) were treated with photons and/or electrons in combination with surgery. The total doses in the initial treatment volume (second order target volume) was 40-50 Gy. For the coning down volume (first order target volume) the median total dose was 59 Gy (range 45-72 Gy). A total of 18% (18/102) local failures was observed. In multivariate analysis, prognostic factors for the occurrence of a local failure were identified as follows: treatment of a primary or recurrent STS (P = 0.02), total dose (P = 0.025) and tumour grade (P = 0.05). Mode of surgery, tumour size (trunk versus extremity), pre- or postoperative radiotherapy, combined chemotherapy and tumour size (T1 versus T2) had no significant impact on the local relapse-free survival. These data give further evidence that combined surgery and radiotherapy is an effective modality in treatment of soft tissue sarcomas.

The TCD50 and regrowth delay assay in human tumor xenografts: differences and implications.

The response to irradiation of five human xenograft cell lines--a malignant paraganglioma, a neurogenic sarcoma, a malignant histiocytoma, a primary lymphoma of the brain, and a squamous cell carcinoma--were tested in nude mice. All mice underwent 5 Gy whole body irradiation prior to xenotransplantation to minimize the residual immune response. The subcutaneous tumors were irradiated at a tumor volume of 120mm3 under acutely hypoxic conditions with single doses between 8 Gy and 80 Gy depending on the expected radiation sensitivity of the tumor line. Endpoints of the study were the tumor control dose 50% (TCD50) and the regrowth delay endpoints growth delay, specific growth delay, and the tumor bed effect corrected specific growth delay. Specific growth delay and corrected specific growth delay at 76% of the TCD50 was used in order to compare the data to previously published data from spheroids. The lowest TCD50 was found in the lymphoma with 24.9 Gy, whereas the TCD50 of the soft tissue sarcomas and the squamous cell carcinoma ranged from 57.8 Gy to 65.6 Gy. The isoeffective dose levels for the induction of 30 days growth delay, a specific growth delay of 3, and a corrected specific growth delay of 3 ranged from 15.5 Gy (ECL1) to 37.1 Gy (FADU), from 7.2 Gy (ENE2) to 45.6 Gy (EPG1) and from 9.2 Gy (ENE2) to 37.6 Gy (EPG1), respectively. The corrected specific growth delay at 76% of the TCD50 was correlated with the number of tumor rescue units per 100 cells in spheroids, which was available for three tumor lines, and with the tumor doubling time in xenografts (n = 5). The TCD50 values corresponded better to the clinical experience than the regrowth delay data. There was no correlation between TCD50 and any of the regrowth delay endpoints. This missing correlation was most likely a result of large differences in the number of tumor rescue units in human xenografts of the same size.

Rationale for using invasive thermometry for regional hyperthermia of pelvic tumors.

PURPOSE: Invasive thermometry for regional hyperthermia is time-consuming, uncomfortable, and risky for the patient. We tried to estimate the benefit/cost ratio of invasive thermometry in regional hyperthermia using the radiofrequency system BSD-2000. METHODS AND MATERIALS: We evaluated 182 patients with locally advanced pelvic tumors that underwent regional hyperthermia. In every patient a tumor-related temperature measurement point was obtained either by invasive or minimally invasive catheter measurement tracks. In the earlier period for every patient an intratumoral measurement point was decided as obligatory and intratumoral catheters were implanted intraoperatively, CT guided, or under fluoroscopy. In the later period, invasive thermometry often was avoided, if a measurement point in or near the tumor was reached by an endoluminally inserted catheter (rectal, vaginal, cervical, urethral, or vesical). For every patient side effects and complications referred to thermometry were evaluated and compared with the potential benefit of the invasively achieved temperature data. The suitability of endolumimally registered temperatures is analyzed to estimate local feasibility (specific absorption rate achieved) and local effectiveness (thermal parameters correlated with response). RESULTS: In 74 of 182 patients invasive thermometry was performed, at most CT-guided for soft tissue sarcomas and rectal recurrences. In 14 of 74 (19%) side effects such as local inflammation, pain, or abscess formation occurred that enforced removal of the catheter. However, local problems were strongly correlated with the dwell time of the catheter and nearly never occurred for dwell times less than 5 days. Fortunately, no fatal complications (e.g., bleeding or perforation) occurred during or after implantation which could be attributed to the invasive thermometry procedure. Endoluminal tumor-related temperature rises per time unit (to estimate power density) were correlated with intratumoral rises at the same patients (where both measurements were available). For a subgroup of patients pooled in two Phase II studies with rectal (n = 37) and cervical (n = 18) carcinomas thermal parameters derived from endoluminal measurements were correlated with response or local control, resp. CONCLUSIONS: If a tumor-related endoluminal temperature measurement point is available, additional invasive thermometry gives no further information to improve the power deposition pattern. For primary rectal and cervical cancer, and probably as well for prostate, bladder and anal cancer, endoluminal measurements are suitable to estimate local feasibility and effectiveness. Therefore, invasive thermometry is dispensable in the majority of patients. In some selected cases, temperature measurement in the tumor center is required to estimate the maximum temperature. In those cases, dwell time of catheters should be minimized--and it should be considered to perform invasive thermometry at the beginning (one or two heat treatments).

Correlation between primary chemo- and radiation sensitivity in a panel of highly malignant human soft tissue sarcoma xenografts.

BACKGROUND AND PURPOSE: Sensitivity to radiation and sensitivity to cytotoxic drugs have been proposed to be independent properties of tumour cells. However, very few clinical or experimental studies have tested this hypothesis. Therefore, we evaluated the response to ionizing radiation and to four cytotoxic drugs in a panel of 12 human soft tissue sarcoma cell lines using the xenograft system. MATERIAL AND METHODS: NMRI-nu/nu nude mice with subcutaneous tumours received at a tumour volume of 120-200 mm3 either single dose, single agent chemotherapy with 350 mg/kg ifosfamide, 200 mg/kg dacarbazine, 10 mg/kg doxorubicin, 6.6 mg/kg cisplatin, or 24 Gy local tumour irradiation under acutely hypoxic conditions from a cobalt-60 source. Tumour response to radiotherapy and chemotherapy was measured as specific growth delay (SGD). RESULTS: A significant correlation was found between SGD after radiotherapy and SGD after decarbazine (P < 0.001) and doxorubicin (P = 0.05), whereas no correlation could be demonstrated for cisplatin. For ifosfamide, the correlation reached borderline significance. The maximal response to any of the four tested chemotherapeutic drugs correlated very well with the response to radiotherapy (P < 0.001). CONCLUSION: The results suggest that radiation sensitivity and chemosensitivity are not independent properties of soft tissue sarcoma cell lines.

High-dose rate interstitial with external beam irradiation for localized prostate cancer--results of a prospective trial.

PURPOSE: A prospective phase II trial was carried out to test the feasibility and effectiveness of a combined interstitial with external beam radiotherapy approach for localized prostate cancer. MATERIALS AND METHODS: Between October 1992 and December 1994, 82 evaluable patients were treated. T2 and T3 tumours, according to the AJCC classification system of 1992, were found in 21 and 61 cases, respectively. The median follow-up was 24 months; three patients were lost during follow-up. All of the patients were pathologically proven to be node-negative by laparoscopic node dissection of the fossa obturatoria region. A dose of 9 Gy a week was prescribed during the first and second weeks of treatment (10 Gy each week from October 1992 to December 1993) interstitially with high-dose rate Iridium-192 brachytherapy to the prostate and tumour extension beyond the capsule. External beam four-field box irradiation was then given to the prostate to a dose of 45 Gy/25 fractions (40 Gy/20 fractions from October 1992 to December 1993). RESULTS: Before starting treatment, a PSA value of > or =10 ng/ml was found in 64.6% (53/82) of patients with a median PSA of 14.0 ng/ml. The median PSA 3, 12 and 24 months after completion of therapy was 1.20, 0.78 and 0.70 ng/ml, respectively. The PSA value was < 1.0 ng/ ml in 52.9% of patients at 2 years. Negative punch biopsies 12 and 24 months after therapy were observed in 69.8% (44/63) and 73. 1% (38/ 52) of patients, respectively. A positive biopsy combined with a PSA value of > 1.0 ng/ml was considered as local failure. The local tumour control rate was 79.5% at 2 years. Acute side-effects were not increased relative to external beam irradiation alone. Severe side-effects were observed in three patients (two of the three patients had additional risk factors (colitis ulcerosa and diabetes mellitus)); they developed rectourethral fistulae requiring colostomy after biopsies from the anterior rectal wall. CONCLUSION: The described method is feasible and well tolerable. The three complications observed were not caused by irradiation alone. Biopsies from the anterior rectal wall after definitive high-dose radiotherapy for prostate cancer have to be seen as obsolete. The rate of negative prostate biopsies of 73.1% after 24 months represents an encouraging result.

Impact of the filling status of the bladder and rectum on their integral dose distribution and the movement of the uterus in the treatment planning of gynaecological cancer.

PURPOSE: Determination of the impact of the filling status of the organs at risk (bladder and rectum) on the uterus mobility and on their integral dose distribution in radiotherapy of gynaecological cancer. METHODS: In 29 women suffering from cervical or endometrial cancer two CT scans were carried out for treatment planning, one with an empty bladder and rectum, the second one with bladder and rectum filled. The volumes of the organs at risk were calculated and in 14 patients, receiving a definitive radiotherapy, the position of the uterus within the pelvis was shown using multiplanar reconstructions. After generation of a 3D treatment plan the dose volume histograms were compared for empty and filled organs at risk. RESULTS: The mobility for the corpus uteri with/without bladder and rectum filling was in median 7 mm (95%-confidence interval: 3-15 mm) in cranial/caudal direction and 4 mm (0-9 mm) in posterior/anterior direction. Likewise, cervical mobility was observed to be 4 mm (-1-6 mm) mm in cranial/caudal direction. A full bladder led to a mean reduction in organ dose in median from 94-87% calculated for 50% of the bladder volume (P < 0.05, Wilcoxon's matched-pairs signed-ranks test). For 66% of the bladder volume the dose could be reduced in median from 78 to 61% (P < 0.005) and for the whole bladder from 42 to 39% (P < 0.005), respectively. No significant contribution of the filling status of the rectum to its integral dose burden was noticed. CONCLUSIONS: Due to the mobility of the uterus increased margins between CTV and PTV superiorly, inferiorly, anteriorly and posteriorly of 15, 6 and 9 mm each, respectively, should be used. A full bladder is the prerequisite for an integral dose reduction.

Vacuum-assisted stereotactic breast biopsy: histologic underestimation of malignant lesions.

HYPOTHESIS: The histopathologic correlation between stereotactic core needle biopsy and subsequent surgical excision of mammographically detected nonpalpable breast abnormalities is improved with a larger-core (11-gauge) device. DESIGN: Retrospective medical record and histopathologic review. SETTING: University-based academic practice setting. PATIENTS: Two hundred one patients who underwent surgical excision of mammographic abnormalities that had undergone biopsy with an 11-gauge vacuum-assisted stereotactic core biopsy device. MAIN OUTCOME MEASURE: Correlation between stereotactic biopsy histologic results and the histologic results of subsequent surgical specimens. RESULTS: Results of stereotactic biopsy performed on 851 patients revealed atypical hyperplasia in 46 lesions, ductal carcinoma in situ (DCIS) in 89 lesions, and invasive cancer in 73 mammographic abnormalities. Subsequent surgical excision of the 46 atypical lesions revealed 2 cases of DCIS (4.3%) and 4 cases of invasive carcinoma (8.7%). Lesions diagnosed as DCIS on stereotactic biopsy proved to be invasive carcinoma in 10 (11.2%) of 89 patients on subsequent excision. Stereotactic biopsy completely removed 21 (23.6%) of 89 DCIS lesions and 20 (27.4%) of 73 invasive carcinomas. CONCLUSIONS: In summary, 11-gauge vacuum-assisted core breast biopsy accurately predicts the degree of disease in the majority of malignant lesions; however, understaging still occurs in 11% to 13% of lesions showing atypical hyperplasia or DCIS.

[MRI of the prostate after combined radiotherapy (afterloading and percutaneous): histopathologic correlation]. / MRT der Prostata nach kombinierter Radiotherapie (Afterloading und perkutan): Histopathologische Korrelation.

AIM: To identify the MRI changes of the prostate after combined (high-dose rate interstitial with external beam) radiotherapy for, localized prostate cancer and to correlate the findings with histology in order to determine the value of MR imaging in the follow-up of these patients. MATERIAL AND METHODS: Twenty-three patients underwent MR imaging at 1.5 T between 6 and 24 months after completion of combined radiotherapy. The prostate was imaged with axial and coronal T2-weighted sequences and axial T1-weighted sequences before and after intravenous administration of Gd-DTPA. Quadrant or sextant biopsy was performed in all cases and three patients with proven persistence of the tumor underwent salvage prostatectomy. The MRI findings were compared with the biopsy results or the large-area sections. RESULTS: On T2-weighted images the fibrotically changed peripheral zone was hypointense while persistent tumor tissue showed hyperintensity. Solid tumors were depicted when they had a diameter of 1 cm or more. Persistent tumors of the diffuse multifocal type escaped detection. Contrast-enhanced T1-weighted imaging yielded no additional information. The accuracy in detecting persistent tumor was 74%. CONCLUSIONS: Histopathologic changes seen after combined radiotherapy correlate with the findings on T2-weighted MR images. MR imaging cannot replace follow-up by routine biopsy. Its only role is assessing local operability in cases found to have increasing PSA levels during follow-up. Further studies are needed to determine the role of MR imaging in this patient population.

[Radiotherapeutic strategies for soft tissue sarcomas in adults]. / Strahlentherapeutische Strategien für Weichteilsarkome im Erwachsenenalter.

Soft tissue sarcomas account for under 1% of all cancers in adults. Most soft tissue tumours are benign, only about 1% being characterized clinically and histomorphologically as malignant neoplasms. Since these tumours are often treated by excisional biopsies without any further diagnostic imaging, precise planning of postoperative irradiation therapy is often difficult to achieve. Therefore, all soft tissue tumours with a short history should be regarded as malignant until the contrary has been proven. In general, the mode of tumour resection should be postponed until CT or MR diagnosis is complete and a biopsy of the tumour has been carried out. Whereas benign lesions need only marginal tumour resection, malignant lesions require considerable safety margins. In soft tissue sarcomas of the extremities, which account for 50-60% of all sarcomas, a wide local resection followed by postoperative irradiation with about 66 Gy can guarantee local control rates above 80% and preserve the function of the limb. Radical surgery alone can achieve the same local control, but without the high level of functional integrity. In the case of marginally resectable tumours, preoperative irradiation can induce partial tumour remission and thus allow definitive limb-sparing tumour resection. Recently, multimodal and neoadjuvant therapeutic strategies have been developed. The efficacy of these experimental strategies is not yet proven.

[Combined iridium 192 afterloading therapy of prostate carcinoma]. / Kombinierte Iridium-192-Afterloadingtherapie des Prostatakarzinoms.

The goal of radiation therapy is to deliver a high dose to the tumor while preserving normal surrounding tissue. For early-stage prostate cancer, the ultimate conformal irradiation is to place radioactive sources directly into the gland as permanent or temporary seeds. Contemporary prostate brachytherapy incorporates advances in computer analysis, imaging technology, and delivery apparatus, allowing exact and reproducible results. Accurate comparison of brachytherapy to surgery and external beam irradiation requires a randomized study. Comparisons of retrospective studies are fraught with the problems of the heterogeneous nature of early-stage prostate cancer. Pretreatment PSA and grade appear to be more sensitive variables than stage in predicting failure after irradiation. The treatment results based on biopsy are promising for the first two years. Brachytherapy may be considered as a therapeutic option: as monotherapy for early-stage disease and also as a boost following moderate doses of external beam irradiation for locally advanced disease.

[Malignant paragangliomas--the results of radiotherapy in 6 patients]. / Maligne Paragangliome--Ergebnisse der Strahlentherapie bei sechs Patienten.

Between February 1984 and May 1989, six patients (four male, two female) with malignant paragangliomas of the carotid body (n = 4) and glomus jugulare (n = 2) were irradiated in the Department of Radiation Oncology at Essen University. All patients had macroscopic (residual) tumor at the start of treatment. Five out of six paragangliomas had to be considered malignant, since histological lymph node involvement or distant metastasis was confirmed. In the sixth case extra- and intracranial tumor growth was observed. Total doses between 40 and 55 Gy using cobalt 60, 10 or 15 MeV photons were administered. Radiation therapy was canceled at 30.6 Gy in one patient because of multiple distant metastasis. Three out of four patients, who received curative treatments, were locally controlled (25 to 91 months). A local recurrence in one patient was detected 18 months after irradiation; this patient died of distant metastasis 23 months after treatment. In one out of two palliatively irradiated patients, local control could be achieved until the patient died of distant metastasis twelve months after treatment. Grade III- or grade IV-treatment toxicity was not observed. Radiation therapy of malignant paragangliomas with doses between 45 and 54 Gy in five to six weeks is an effective treatment with low toxicity and should be preferred to surgery in glomus jugulare and advanced carotid body tumors.

[Palliative culture in the stationary care for the elderly]. / Palliative Kultur in der stationären Altenhilfe.

Nursing homes are challenged by a significant change in the patient-structure. To care for dying elderly people means to enable them to live in dignity till the end. Helpful therefore is to implement Palliative Care into existing structures. This requires personal and organizational learning and development. The first step is to make central differences and contradictions visible und communicable. We describe three organizational types which leads into different core-processes. Organizational measures supporting the development of a palliative culture and indicators of successful implementation are presented.

Comparison of conventional and virtual simulation for radiation treatment planning of malignant lymphoma.

PURPOSE: The exact coverage of the lymph nodes and optimal shielding of the organs at risk are necessary for patients with Hodgkin's disease or malignant lymphoma to guarantee a high cure rate and a low rate of late effects for normal tissue. The purpose of this study was to compare conventional simulation and blocking with virtual simulation in terms of coverage of the target volume and shielding of the organs at risk in this highly curative patient group. PATIENTS AND METHODS: In 10 patients diagnosed with Hodgkin's disease and 5 patients with a Non-Hodgkin lymphoma radiation treatment planning for a mantle field or para-aortic field with inclusion of the spleen was performed in a conventional manner and with virtual simulation. With conventional technique, irradiation portals were defined during fluoroscopy and shielding of the organs at risk was drawn onto the simulation films, based on the information from previous X-ray films, CT or MRI scans. For virtual simulation, contouring of the target volumes and organs at risk (e.g. the kidneys) and the definition of the irradiation portals were performed with the AcQSim software package on a VoxelQ workstation (Picker Inc.) This was done in a beam's eye view environment on a currently driven CT scan in the treatment position. Both irradiation portals were compared in terms of coverage of the target volume and shielding of the organs at risk. RESULTS: Planning of a mantle field in the conventional way resulted in an incomplete coverage of the right hilus in 4/15 cases and of the left in 1/15 cases, respectively. The spleen and the spleen hilus were not covered completely in 5/15 and 6/15 cases, respectively. The left kidney was adequately shielded in only two thirds (10/15) of the conventionally planned fields. The planning time required for virtual simulation was reduced for the patient, but was increased for the physician because of the more time consuming contouring procedure compared to conventional simulation. CONCLUSIONS: Virtual simulation based on CT scans for radiation treatment planning of malignant lymphoma gives more information about soft tissue structures than conventional treatment planning. Therefore, it allows a more precise coverage of the target volumes and better shielding of the organs at risk. However, the time required for the whole procedure is increased. This is justified because of the often highly curative intention when treating this group of patients.

Verification of set-up deviations in patients with breast cancer using portal imaging in clinical practice.

AIM: The aim of this study was to determine set-up deviations during irradiation of patients with breast cancer using Electronic Portal Imaging (EPI). PATIENTS AND METHOD: In order to monitor the intrafractional set-up deviations multiple portal image readings were carried out on 5 patients with breast cancer. Moreover interfractional set-up deviations were determined by the acquisition of daily EPIs in a total of 20 patients. RESULTS: The results of intrafractional set-up deviation based on 130 EPIs revealed a maximum lateral and longitudinal (cranio-caudal) deviation of 2 mm (range:-10 mm to 8 mm) as well as 1 degree in rotation (range: -2 degree to 2 degrees). The interfractional set-up deviations in 20 breast cancer patients during a treatment series of 25 fractions showed mean standard deviations of 5 mm in lateral and longitudinal direction, respectively. Only in few cases deviations up to maximally 24 mm were observed. The mean standard deviation of the rotational error was 2 degrees and reached a maximum of 6.5 degrees. CONCLUSION: These results show that intrafractional set-up deviations in breast cancer patients are negligible in clinical practice. They can be attributed to random errors due to patient movement and breathing. The set-up deviations during a treatment series can be differentiated in systematic and random errors. Patient fixation and immobilization is crucial in minimizing random errors. Taking into account 10 mm safety margins as used in our department around the "clinical target volume" (CTV), set-up errors outside of this volume (PTV) were exceptional. The enlarged PTV definition of 15 mm for lateral and cranio-caudal field margins, respectively as used in this study covers 99% of the CTV in all patients.

Neutron boost irradiation of soft tissue and chondrosarcomas at the West German Tumour Centre in Essen.

In this retrospective study, the results of postoperative neutron boost therapy for 40 soft tissue- and 18 chondrosarcomas are presented. In 65.5% and 34.5% of all cases, microscopic to macroscopic tumour residual was left postoperatively. Locally advanced and moderate to highly malignant tumours were found at surgery in 81% and 69%, respectively. Except for seven patients with a whole series of neutrons to 16 Gy, the other cases were treated with initially 40 to 50 Gy photons and a subsequent neutron boost of 4 to 6 Gy. The median follow-up was 29.3 and 36.2 months for the soft tissue- and chondrosarcomas. The actuarial three-year local control and overall survival rates were 69.3% and 91% for soft tissue- vs. 55.6% and 62.9% for chondrosarcomas. With regard to the extension of surgery (microscopic or macroscopic residual), local control rates of 80% and 60% for soft tissue- vs. 62.5% and 40% for chondrosarcomas were observed. The overall local failure rate was 32.8% with a median disease-free interval of ten respectively eleven months for soft tissue and chondrosarcomas. 17 out of 19 local recurrences were due to inadequate irradiation portals for the neutron boost or to insufficient total doses in the initially treated photon target volume.