DNA double-strand breaks in mammalian cells exposed to gamma-rays and very heavy ions. Fragment-size distributions determined by pulsed-field gel electrophoresis

The spatial distribution of DNA double-strand breaks (DSB) was assessed after treatment of mammalian cells (V79) with densely ionizing radiation. Cells were exposed to beams of heavy charged particles (calcium ions: 6.9 MeV/u, 2.1.10(3) keV/microm; uranium ions: 9.0 MeV/u, 1.4.10(4) keV/microm) at the linear accelerator UNILAC of GSI, Darmstadt. DNA was isolated in agarose plugs and subjected to pulsed-field gel electrophoresis under conditions that separated DNA fragments of size 50 kbp to 5 Mbp. The measured fragment distributions were compared to those obtained after gamma-irradiation and were analyzed by means of a convolution and a deconvolution technique. In contrast to the finding for gamma-radiation, the distributions produced by heavy ions do not correspond to the random breakage model. Their marked overdispersion and the observed excess of short fragments reflect spatial clustering of DSB that extends over large regions of the DNA, up to several mega base pairs (Mbp). At fluences of 0.75 and 1.5/microm2, calcium ions produce nearly the same shape of fragment spectrum, merely with a difference in the amount of DNA entering the gel; this suggests that the DNA is fragmented by individual calcium ions. At a fluence of 0.8/microm2 uranium ions produce a profile that is shifted to smaller fragment sizes in comparison to the profile obtained at a fluence of 0.4/microm2; this suggests cumulative action of two separate ions in the formation of fragments. These observations are not consistent with the expectation that the uranium ions, with their much larger LET, should be more likely to produce single particle action than the calcium ions. However, a consideration of the greater lateral extension of the tracks of the faster uranium ions explains the observed differences; it suggests that the DNA is closely coiled so that even DNA locations several Mbp apart are usually not separated by less than 0. 1 or 0.2 microm.

Lethal pulmonary toxicity after autologous bone marrow transplantation/peripheral blood stem cell transplantation for hematological malignancies

BACKGROUND AND PURPOSE

Retrospective evaluation of the incidence of lethal pulmonary complications (LPC) with special emphasis on interstitial pneumonia (IP) in a large group of patients homogeneously treated with hyperfractionated total body irradiation (HTBI) before autologous bone marrow transplantation (ABMT) or peripheral blood stem cell transplantation (PBSCT) for hematological malignancy. The factors influencing IP are discussed.

MATERIALS AND METHODS

Of 260 patients (maximum follow-up 137 months) that were treated with ABMT or PBSCT for hematological neoplasms between 1982 and 1994, 209 patients received HTBI and could be evaluated with respect to lethal pulmonary complications and especially lethal interstitial pneumonia. For most patients (n = 155), the HTBI dose was 14.4 Gy (lung dose 9-9.5 Gy) given in 12 fractions over 4 days. Twenty-one patients received a total dose of > or =15 Gy with pulmonary doses of 9-10.5 Gy.

RESULTS

The actuarial overall 5-year survival for all 209 patients evaluated was 44 +/- 4%, enabling valid evaluation with respect to lethal pulmonary toxicity. The actuarial incidence of all LPC during the first year was calculated as being 8 +/- 2%. The actuarial incidence of lethal IP is certainly lower and was estimated to be between 3 and 5% for all patients. The overall treatment-related mortality was 12% in 188 patients that received a total dose of <15 Gy and 24% among the patients treated with a total dose of > or =15 Gy.

CONCLUSION

ABMT/PBSCT, like other transplant modalities without significant graft versus host disease (GvHD), has a low transplant-related mortality, a very small rate of overall LPC and a low incidence of lethal IP after HTBI. Doses up to 14.4 Gy with lung doses of 9-9.5 Gy can be administered safely. For total doses of > or =15 Gy with lung doses of 9-10.5 Gy, the risk of serious transplant-related complications cannot yet be finally assessed but such higher doses should be considered with caution because of the possibility of increasing toxicity in organs other than the lung.

[Cosmetic results of breast conserving therapy for breast carcinoma. Treatment results from the Heidelberg Radiation Clinic in the years 1984 to 1992]

PURPOSE

In this study we retrospectively analyzed local control, survival rate and late cosmetic results of women with early breast cancer receiving breast conserving therapy.

PATIENTS AND METHODS

All patients (1984 through 1992) of the Department of Radio-Oncology (University of Heidelberg), who received breast conserving therapy consisting of conservative surgery followed by radiotherapy, were interviewed and asked to come. Subjective estimation of the cosmetic results of therapy was evaluated by means of a questionnaire. Cosmesis, circumferences and temperatures of different mammary regions were assessed and measured. Side effects and late sequelae were valued by the EORTC/RTOG-score.

RESULTS

Mean follow-up time of 192 women (pT1: 71.9%, pT2: 28.1%) was 4.5 years (median: 4.0 years). 26.6% of them were nodal positive. Positive nodal status correlated with high tumor grading (p = 0.0001). Ten patients developed distant metastases; one of them subsequent to having suffered a loco-regional failure. Eight loco-regional failures occurred, 3 of them before radiotherapy (salvage). Following radiotherapy altogether 5 loco-regional failures (= 2.6%) were found; 3 women concerning were pre-, 2 postmenopausal. Three of these patients died, in 1 case occurred distant metastasis. Seventeen patients died, 3 of them presenting loco-regional failure, 8 of them showing distant metastasis. Sixty-four women were examined for cosmesis with the following result: a poor result was observed twice, a fair result 13 times, a good result 34 and an excellent result 15 times. Self-assessment was significantly better than observer's assessment. Third-degree late sequelae were found once, second-degree was seen 11 times, first-degree 38 times and no visible late sequelae were observed 14 times. The use of wedges was followed with borderline significance (p = 0.06) either by a better cosmesis and fewer late sequelae. Neither the type of surgery nor the width of the fields nor the quality of radiation (Co60 or 6 MVX) nor boost-application influenced the cosmetic result. Measured circumferences and distances showed no significant differences in the groups of the patients with poor or fair and good or excellent cosmesis. The temperature of the seized and contralateral breast showed no significant difference as well. With increasing distance from primary therapy the cosmetic results deteriorated.

CONCLUSION

Breast conserving therapy consisting of conservative surgery followed by radiotherapy causes predominantly excellent to good cosmetic results combined with an acceptable amount of late side effects. The decreased rate of good and excellent cosmetic long-term results is biological interesting and requires further studies.

Radiation-induced micronucleus formation in human skin fibroblasts of patients showing severe and normal tissue damage after radiotherapy

PURPOSE

Treatment schedule and total dosage in radiation therapy is based on the tumoricidal doses and the tolerance dose of the perifocal normal tissue. Since large-scale variations occur between the patients concerning the side effects, one of the major goals of radiation research recently has been the development of a predictive in vitro assay. This paper is a contribution to that effort.

MATERIALS AND METHODS

Skin fibroblasts of patients with normal-tissue reactions or acute and/or late increased side effects and cell lines of four individuals carrying the heritable disease ataxia telangiectasia were irradiated in vitro. The formation of micronuclei was chosen as biological endpoint and the results were compared with the clinically observed side effects.

RESULTS

In general, a radiation dose-dependent increase in micronucleus frequency was found. The cells of the majority of the sensitive patients, as well as those of homozygous and heterozygous ataxia telangiectasia individuals, showed a higher micronucleus induction than the average of the donors with normal sensitivity.

CONCLUSIONS

The micronucleus test seems to be a very promising tool in the evaluation of radiation sensitivity prior to therapy. However, larger studies are needed to confirm these findings and to optimize the methodology, and it is presumed that a final predictive assay will consist of a combination with other test systems.

Combined effects of ionizing radiation and 4-hydroperoxyfosfamide in vitro

BACKGROUND AND PURPOSE

Combined radiochemotherapy has gained increasing interest in clinical applications. The effects of combined exposure of ionizing radiation and 4-hydroperoxyifosfamide (4HOOIF) on cell survival were investigated in vitro.

MATERIALS AND METHODS

Clonogenic survival of log phase V79, Caski (squamous carcinoma), Widr (colon carcinoma) and MRI-221 cells (human melanoma) was determined after combined exposure to 4HOOIF and radiation. Measurement of cell survival for different cell cycle phases was performed after mitotic shake-off (V79) or appropriate intervals after serum stimulation of plateau phase cells (Widr). Control of cell cycle distribution was performed using flow cytometry.

RESULTS

In all cell lines tested, a combined exposure resulted in cell killing that was greater than for independent action. While this type of radiosensitization was of minor magnitude for log-phase cells or cells in G1 substantial radiosensitization was detected for S-phase cells with enhancement ratios (calculated from the respective mean inactivation doses) of up to 1.5.

CONCLUSIONS

The results demonstrate the interaction of 4HOOIF and radiation-induced cell damage with marked cell cycle specificity. Since the largest combination effect was observed for the most radioresistant S-phase cells, damage interaction could be mediated by an interference of 4HOOIF with the repair/fixation pathway of radiation-induced potentially lethal damage.

[3D-Ct-planned interstitial HDR brachytherapy + percutaneous irradiation and chemotherapy in inoperable pancreatic carcinoma. Methods and clinical outcome]

PURPOSE

Clinical experiences in interstitial 192-iridium HDR brachytherapy for the treatment of unresectable pancreatic carcinoma are presented. Brachytherapy has been used as boost irradiation in a multimodality treatment concept together with external radiotherapy and simultaneous chemotherapy. Practicability during clinical routine, tolerability and toxicity of treatment are investigated.

PATIENTS AND METHODS

Nineteen patients (9 female, 10 male, median age 67 years) with unresectable carcinoma of the pancreas have been treated with interstitial brachytherapy. Distribution according to UICC stages showed 4, 10 and 5 patients in stage II to IV respectively. In all cases afterloading technique with 192-iridium in HDR-modus was used. A total dose of 10 to 34 Gy to the reference isodose was delivered (single dose 1.88 to 5 Gy, median 2.5 Gy). Brachytherapy was followed by external radiotherapy, delivering an additional dose of 40 to 58 Gy. Nine patients received simultaneous chemotherapy (5-fluorouracil, leucovorin). Treatment planning was performed based on CT scans, allowing spatial correlation of isodose curves to the patient's anatomy.

RESULTS

Median survival time was 6 months. A trend of lower survival rates with advanced stage of disease (median survival stage IV 4 months, stage II and III 6.5 months) was seen. Local control rate was 70%. Brachytherapy treatment was well tolerated, severe acute side effects were not observed. One patient developed pancreatic fistulae 4 months and 1 patient a gastric ulcer 7 months after treatment. Pain release was achieved in all patients.

CONCLUSIONS

192-iridium HDR-brachytherapy is an effective tool in the treatment of unresectable pancreatic carcinoma with a high rate of local control and a low rate of side effects and is comparable IORT or seed implantation.

Abdominal irradiation in unilateral nephroblastoma and its impact on local control and survival

PURPOSE

The influence of abdominal radiotherapy was analyzed in 122 patients with unilateral Wilms tumor eligible for local irradiation according to postoperative SIOP-stage.

MATERIAL & METHODS

122 of 454 children with Wilms tumor diagnosed between January 1989 and March 1994 in Germany were eligible for abdominal irradiation after preoperative chemotherapy and tumor resection according to SIOP9/GPOH protocol. There were 88 children with standard histology (SH; local Stage IIN+ and III) and 34 children with unfavorable histology (UH; anaplastic, clear cell and rhabdoid, local Stages II and III). Local irradiation was given postoperatively parallel to polychemotherapy according to protocol with appropriate dose reductions of Actinomycin D (dactinomycin) during the course of radiotherapy. Fifteen Gy to the tumor bed were prescribed in standard histology, with 30 Gy to regional lymph nodes, if histologically positive. Thirty Gy were given in unfavorable histology. Boost doses up to 15 Gy were possible for macroscopic residuals. Ages ranged between 6 months and 21 years (median 4.2 years).

RESULTS

Only 98 of 122 eligible children were irradiated. Reasons for ommission of radiotherapy were: Stage III only due to intraoperative biopsy (n = 6), due to resected cava thrombus (n = 5); young age (n = 2); undergrading/understaging (n = 7); other reasons (n = 4). There were 19 abdominal recurrences (4 of 88 with SH; 15 of 34 UH). In 5 patients, local recurrence was the only site of failure. There were 6 local failures in 24 nonirradiated but eligible children (25%) vs. 13 of 98 in irradiated children (13%); p = 0.15. In SH 0 of 15 nonirradiated vs. 4 of 73 treated children (p = NS) and in UH 6 of 8 nonirradiated vs. 9 of 26 irradiated children developed local recurrence (p < 0.05). Of 19 children with local recurrence as one site of failure, 18 have died. This comprises 67% of 27/122 children with fatal outcome in the observation period. In the patients eligible for abdominal radiotherapy, projected 3-year relapse-free survival is 85% for the group of children with standard histology and 41% for the children with unfavorable histology.

CONCLUSION

Despite impressive overall results for this multicenter trial in unilateral nephroblastoma, local recurrence remains a grave prognostic parameter. Evaluation of irradiated vs. eligible but not irradiated children suggests that radiotherapy to the tumor bed is of considerable impact for local control in the risk groups eligible for abdominal irradiation as defined in the SIOP9/GPOH protocol.

Randomized trial comparing early postoperative irradiation vs. the use of nonsteroidal antiinflammatory drugs for prevention of heterotopic ossification following prosthetic total hip replacement

PURPOSE

A randomized trial was undertaken to assess the comparative efficacy of early postoperative irradiation with either 5 or 7 Gy vs. the use of nonsteroidal antiinflammatory drug (NSAID) for prevention of heterotopic ossification (HO) following prosthetic total hip replacement (THP).

METHODS AND MATERIALS

Between 1993 and 1994, 301 patients were randomized to receive postoperative irradiation (5 or 7 Gy) or NSAID. One hundred and thirteen patients were treated with NSAID (indomethacin 2 x 50 mg/day for 1 week), 93 patients were irradiated with a single 7 Gy fraction, 95 patients with a single 5 Gy fraction. The treatment volume included the soft tissues between the periacetabular region of pelvis and the intertrochanteric portion of the femur. X-rays of treated hips were obtained immediately and 6 months after surgery. Heterotopic ossification was scored according to the Brooker Grading system. One hundred patients receiving no prophylactic therapy after total hip arthroplasty between 1988 and 1992, were analyzed and defined as historical control group.

RESULTS

Incidence of heterotopic ossification was 16.0% in NSAID-group (Brooker Score I: 8.0%; II: 6.2%; III: 1.8%; IV: 0%), 30.1% in 5 Gy group (Brooker Score I: 24.7%; II: 4.3%; III: 1.1%; IV: 0%), and 11.1% in 7 Gy group (Brooker Score I: 11.6%; II: 0%; III: 0%; IV: 0%). Regarding overall heterotopic ossification there was a significant difference between the NSAID group and the 5 Gy group (p < .015), respectively, between the 7 Gy group and the 5 Gy group (p < .0001). No significant difference was noted in the influence of overall HO between the NSAID and the 7 Gy group (p > 0.3). Analyzing the clinically significant HO (Brooker Score III and IV) patients irradiated with 7 Gy developed less HO than those treated with NSAID (p = 0.003). Incidence of HO was greater in the untreated historical control group (Brooker Score I: 26%; II: 15%; III: 19%; IV: 5%) than in all three prophylacticly treated groups.

CONCLUSION

Prophylactic irradiation of the operative site after hip replacement with single a 7 Gy fraction is the most effective postoperative treatment schedule in prevention of clinically significant heterotopic ossification. This therapy modality is more effective than irradiation with a single 5 Gy fraction or use of NSAID.

[Prospective study on the prevention of heterotopic ossification after total hip replacement. Non-steroidal anti-inflammatory agents versus radiation therapy]

PURPOSE

Two prospective trials were undertaken to assess the comparative efficacy of early postoperative irradiation with different radiation doses versus the postoperative use of nonsteroidal antiinflammatory drugs (NSAID) for prevention of heterotopic ossification (HO) following prothetic total hip replacement (THP).

PATIENTS AND METHOD

Between 1992 and 1994 585 patients received THP. These patients were randomed in two longitudinal studies each with 3 treatment arms comparing postoperative irradiation with 4 x 3 Gy (101 patients), 1 x 5 Gy (93 patients), 1 x 7 Gy (95 patients) and the postoperative use of the NSAID indometacin for 7 days (113 patients) respectively for 14 days (90 patients) und acetyl salicyl acid (ASS) for 14 days (93 patients). Heterotopic ossification was scored according to the Brooker grading system. One hundred patients receiving no prophylactic therapy after total hip arthroplasty between 1988 and 1992 were analysed and defined as historical control group.

RESULTS

Incidence of heterotopic ossification was 5% in the 4 x 3 Gy group (Brooker grade I 5%, grade II 0%, grade III 0%), 30.5% in the 1 x 5 Gy group (Brooker grade I 24.7%, grade II 4.1%, grade III 1.0%) and 10.5% in the 1 x 7 Gy group (Brooker grade I 10.5%, grade II 0%, grade III 0%). 15.9% of the indometacin-7 days-group developed heterotopic ossification (Brooker grade I 8%, grade II 6.2%, grade III 1.7%, grade IV 0%), 12.2% of the indometacin-14 days-group (Brooker grade I 8.9%, grade II 2.2%, grade III 1.1%) and 37.5% of the ASS-group (Brooker grade I 27.9%, grade II 4.3%, grade III 5.3%). The lowest incidence of heterotopic ossification was found for the 4 xx 3 Gy and the 1 x 7 Gy group, but no significant difference between these two different treatments was observed.

CONCLUSION

Prophylactic irradiation of the operative site after hip replacement is more effective than the use of NSAID. Because no significant difference between the fractionated ingle dose irradiation was found and the latter is more comfortable for patients and more economical, irradiation with single 7 Gy fraction should be preferred.

[Intracavitary afterloading therapy as a new technique of boost irradiation in anal canal carcinoma]

PURPOSE

There are different techniques of boost irradiation in the treatment of patients with anal carcinoma. A new system of applicators is presented, which can be used for an intracavitary afterloading therapy.

MATERIAL AND METHODS

Three different applicators are available, the first with a central catheter (K1), a second with 5 semicircular fixed catheters (K2) and an eccentric shield, a third with 8 circular fixed catheters and a central shield (K3).

RESULTS

The adequate choice of applicator and catheters takes into consideration the individual localisation and extension of anal carcinoma in planning therapy. Thus, in circular growing tumors, an irradiation of the whole circumference of the anal canal is possible. In non-circular growing tumors, the dose applied in the non-affected part of the anal canal can be reduced to a quarter of the dose applied at the tumor.

CONCLUSION

The new system of intracavitary afterloading therapy is a good alternative to previous techniques of boost irradiation in the treatment of anal carcinoma. By means of this technique, irradiation can be highly individualized, the tumor better included and non-affected sections of the anal canal saved.

PDR brachytherapy with flexible implants for interstitial boost after breast-conserving surgery and external beam radiation therapy

BACKGROUND AND PURPOSE

For radiobiological reasons the new concept of pulsed dose rate (PDR) brachytherapy seems to be suitable to replace traditional CLDR brachytherapy with line sources. PDR brachytherapy using a stepping source seems to be particularly suitable for the interstitial boost of breast carcinoma after breast-conserving surgery and external beam irradiation since in these cases the exact adjustment of the active lengths is essential in order to prevent unwanted skin dose and consequential unfavorable cosmetic results. The purpose of this study was to assess the feasibility and morbidity of a PDR boost with flexible breast implants.

MATERIALS AND METHODS

Sixty-five high risk patients were treated with an interstitial PDR boost. The criteria for an interstitial boost were positive margin or close margin, extensive intraductal component (EIC), intralymphatic extension, lobular carcinoma, T2 tumors and high nuclear grade (GIII). Dose calculation and specification were performed following the rules of the Paris system. The dose per pulse was 1 Gy. The pulse pauses were kept constant at 1 h. A geometrically optimized dose distribution was used for all patients. The treatment schedule was 50 Gy external beam to the whole breast and 20 Gy boost. PDR irradiations were carried out with a nominal 37 GBq 192-Ir source.

RESULTS

The median follow-up was 30 months (minimum 12 months, maximum 54 months). Sixty percent of the patients judged their cosmetic result as excellent, 27% judged it as good, 11% judged it as fair and 2% judged it as poor. Eighty-six percent of the patients had no radiogenous skin changes in the boost area. In 11% of patients minimal punctiform telangiectasia appeared at single puncture sites. In 3% (2/65) of patients planar telangiectasia appeared on the medial side of the implant. The rate of isolated local recurrence was 1.5%. In most cases geometrical volume optimization (GVO) yields improved dose distributions with respect to homogeneity and compensation of underdosage at the margins of the implant. Only in 9% of patients was the dose distribution impaired by GVO. However, GVO causes a number of substantial changes of the dose distribution which have consequences for its application.

CONCLUSIONS

The interstitial CLDR boost of the breast can be replaced by the PDR technique without severe acute and late complications and without deterioration of the cosmetic results.

CT simulation in stereotactic brain radiotherapy--analysis of isocenter reproducibility with mask fixation

BACKGROUND AND PURPOSE

CT verification and measurement of isocenter deviation using repeated mask fixation in linac-based stereotactic high dose radiotherapy of brain metastases were performed in this study.

MATERIALS AND METHODS

For stereotactic radiotherapy of brain metastases a commercial head mask fixation device based on thermoplastic materials (BrainLAB) was used. A two-step planning-treatment procedure was performed. Immediately before treatment the patient was relocated in the mask and a verification CT scan of the radiopaque marked isocenter was performed and if necessary its position was corrected. The verification procedure is described in detail. Twenty-two CT verifications in 16 patients were analyzed. Deviations were measured separately for each direction. A 3D-deviation vector was calculated. Additionally the average amount of deviation in each of the three dimensions was calculated.

RESULTS

The mean deviation and standard deviation (SD) of the isocenter was 0.4 mm (SD 1.5 mm) in the longitudinal direction, -0.1 mm (SD 1.8 mm) in the lateral direction and 0.1 mm (SD 1.2 mm) in the anterior-posterior direction. The mean three-dimensional distance (3D-vector) between the verified and the corrected isocenter was 2.4 mm (SD 1.3 mm). The average deviation (without consideration of direction) was 1.1 mm (SD 1.1 mm), 1.3 mm (SD 1.3 mm) and 0.8 mm (SD 0.9 mm) in the longitudinal, lateral and sagittal directions, respectively. No correlation was found between 3D-deviation and the distance of the isocenter from the reference plane nor between deviation and the position of metastases in the brain (central versus peripheral or between different lobes), or the date of treatment.

CONCLUSION

Reproducibility of the isocenter using the presented mask fixation is in the range of positioning reproducibility reported for other non-invasive fixation devices for stereotactic brain treatment. Our results underline the importance of CT verification as a quality assurance method in stereotactic radiotherapy. Under the condition of a preceding CT verification the mask can be used for single dose stereotactic radiotherapy. For fractionated stereotactic irradiation of small target volumes we recommend repeated CT verifications to assure reproducibility.

Invasive thymoma: treatment with postoperative radiation therapy

PURPOSE

To assess radiation therapy and chemotherapy in the treatment of invasive thymoma and thymic carcinoma.

MATERIALS AND METHODS

In 1981-1995, 43 patients received irradiation after total (n = 23) or subtotal (n = 20) resection. Tumors were thymic carcinoma (n = 10) or invasive thymoma (n = 33). Masaoka stage was II in 10 patients, III in 14, and IV in 19. Median total dose applied was 50 Gy (range, 10-72 Gy). Seventeen patients (five with stage III and 12 with stage IV) also received chemotherapy.

RESULTS

Patients with thymic carcinoma had a median survival of 9.5 months, compared with 50 months for patients with invasive thymoma (P = .008). Patients' median survival and 5-year survival rates were 97 months and 90% for stage II, 65 months and 67% for stage III, and 32.5 months and 30% for stage IV tumors (P = .024). Overall control rate within the radiation field was 81% (35 patients) and overall local control rate within the thorax was 74% (32 patients). Of the 17 patients who received chemotherapy and radiation therapy, nine had thymic carcinoma and a median survival of 12 months (range, 1.4-23.0 months).

CONCLUSION

With total doses of 45-50 Gy, local control is achievable after radical resection. Whether patients with completely resected stage II thymomas should receive radiation after surgery remains uncertain, as does the role of chemotherapy in the treatment of thymoma.

[Pneumonitis after radiotherapy of bronchial carcinoma: incidence and influencing factors]

BACKGROUND

The most important side effect in radiotherapy of lung cancer is pneumonitis. The incidence of pneumonitis was evaluated in a retrospective study in the patient collective of the University of Heidelberg. Therapy related and therapy independent factors have been evaluated.

PATIENTS AND METHODS

In 348 of 392 cases with lung cancer who were treated by local irradiation between January 1989 and January 1992 the patient's records were evaluable for response and toxicity. All patients were treated by megavolt equipment with a conventional fractionation in most cases. Standard target volumes were irradiated including the lymphatic drainage. From a dose of above 30 Gy a technique sparing the spinal cord was chosen. Retrospectively pneumonitis was classified into 4 grades starting from slight symptoms to respiratory insufficiency requiring O2. Grade I and II were summarized to slight, grade III and IV to severe pneumonitis.

RESULTS

Regarding the treatment prior to irradiation patients with primary irradiation were affected in 26.5% (17% slight, 9.5% severe), with postoperative irradiation in 14% (9.3% slight, 4.7% severe), with radiochemotherapy of small cell lung cancer (SCLC) in 15.4% (12% slight, 3.4% severe) by this side effect. These differences were not significant (p = 0.32). The median onset of pneumonitis was 31 days after end of irradiation (severe 23 days, slight 44 days, p = 0.026). By a univariate analysis the total dose at the prescription point was the most important factor (30 to 50.5 Gy 11%, 52 to 59 Gy 15%, 60 to 74 Gy 26%, p = 0.007). High single doses (2.5 Gy) were only applied within a study of radiochemotherapy with a randomised sequential and alternating schedule. So that the increased rate of pneumonitis (42%) is not clearly separable from other influencing variables. A correlation between the applied techniques and the irradiated volume (measured by planimetric methods) was not demonstrable. Regarding the independent factors a high age, female sex and a low FeV1 were unfavourable. However, age and sex corrected FeV1 was not predictive.

CONCLUSIONS

The observed incidence is within the range of literature. By a clinical point of view the total dose is an obvious factor. Also single doses above 2 Gy have to be seen critically (a total dose of 50 Gy). The results confirm the fact that patients with a low FeV1 are not suitable to a high dose irradiation of the chest. In this connection old patients and women also should be seen as patients at risk.

Three dimensional variability in patient positioning using bite block immobilization in 3D-conformal radiation treatment for ENT-tumors

BACKGROUND AND PURPOSE

The aim of this prospective study was to analyze the three-dimensional (3D) reproducibility of the isocenter position and of patient positioning with the use of bite block immobilization by means of a simple verification procedure for a complex beam arrangement applied for ENT-tumors.

MATERIALS AND METHODS

We analyzed the positioning data of 29 consecutive patients treated for ENT-tumors at the Department of Radiotherapy and Oncology of the University of Wurzburg. A total of 136 treatment sessions were analyzed. Patients were positioned and immobilized using an individualized bite block system and a head and neck support. A complex beam arrangement was applied combining two offset rotational and two oblique wedge fields on a 5 MV linear accelerator. Orthogonal verification films were taken once weekly. Four to six film pairs per patient were obtained (during 4-6 weeks) with a mean number of 4.7 film pairs per patient. These were compared to the corresponding orthogonal simulator films taken during primary simulation. Deviations of the verified isocenter from the isocenter on the simulator film were measured and analyzed in three dimensions in terms of overall, systematic and random categories. A 3D-deviation vector was calculated from these 3D data as well as a 2D-deviation vector (for comparison with literature data) from the lateral verification films.

RESULTS

The overall setup deviation showed standard deviations (SD) of 2.5, 2.7 and 3.1 mm along the cranio-caudal, anterior-posterior and medio-lateral axes, respectively. The random component ranged from SD 1.9 to 2.1 mm and the systematic component ranged from SD 1.8 to 2.2 mm. The mean length of the 3D-vector was 3.1 mm for the systematic as well as the random component. Ninety percent of 3D systematic and random deviations were less than 5 mm. The mean length of the 2D-vector was 2.4 mm for the random component and 2.2 mm for the systematic component. Ninety percent of 2D-random and systematic variations were less than 4 mm.

CONCLUSIONS

The presented individualized bite block immobilization device provides an accurate and reproducible patient positioning for 3D-conformal radiation therapy in the head and neck. Random and systematic deviations in each of the three directions are in the range of +/-4 mm (2 SD, comprising 95% of the deviations) and are within the range or even less than deviations described for most thermoplastic or PVC-mask fixation devices. These deviations should be taken into account during definition of planning target volume in head and neck tumors.

In vitro radiosensitivity of primary human fibroblasts. Lack of correlation with acute radiation toxicity in patients with head and neck cancer

BACKGROUND AND PURPOSE

There is a considerable hope among clinicians and radiobiologists to detect genetically radiosensitive patients prior to radiotherapy. A predictive assay would enable adjustment of the total irradiation dose to the individual at a constant risk of normal tissue complications. In this prospective study, the clonogenic survival assay for primary human fibroblasts to determine radiosensitivity in vitro was evaluated and then correlated with clinically observed acute radiation reactions.

MATERIALS AND METHODS

One hundred twenty-five independent survival experiments with primary fibroblasts derived from 63 biopsies from 55 cancer and non-cancer patients were performed.

RESULTS

A wide variation of cell survival between biopsies was detected. Statistical analysis revealed a highly significantly larger interindividual than intraindividual variation of SF2 values. However, a considerable scatter of SF2 values in repeated experiments was observed in individual cases. Age, gender, disease status (cancer patient, non-cancer patient) and origin of fibroblasts (skin, periodontal tissue) were demonstrated not to be statistically significant confounding factors on the intrinsic radiosensitivity in vitro. In a prospective study, no correlation of the SF2 and acute reactions in 25 patients with head and neck cancer treated with a primary accelerated radiochemotherapy was detected.

CONCLUSION

Our data show that the clonogenic assay is able to distinguish between intrinsic radiosensitivities of primary human fibroblasts if a statistical approach is used but does not predict acute radiation toxicity.

Predictive value of the flow cytometric PCNA assay (proliferating cell nuclear antigen) in head and neck tumors after accelerated-hyperfractionated radiochemotherapy

PURPOSE

Proliferation of tumor cells during radiotherapy may limit tumor control, especially in rapidly proliferating tumors such as head and neck carcinomas. We present a flow cytometric method for detection of PCNA in solid head and neck tumors and how these data correlate with outcome.

METHODS AND MATERIALS

Pretherapeutic biopsies of 20 inoperable patients with Stage IV squamous cell carcinoma were examined. Biparametric flow cytometry was done after anti-PCNA (PC10) and propidium iodine staining were performed. PCNA index (percentage PCNA positive cells), DNA index, and S phase fraction (SPF, euploid tumors only) were determined. The therapy consisted of an accelerated-hyperfractionated radiochemotherapy (66 Gy/5 weeks, concomitant boost of 1.6 Gy/day in weeks 4+5, Carboplatin 5 x 70 mg/m2 in weeks 1+5). The median follow-up time was 30 months.

RESULTS

Fourteen patients suffered from disease progession and 12 died. Median actuarial, cause-specific survival, and disease-free survival (DFS) times were 17 and 9 months, respectively. PCNA indices ranged from 4 to 70% (median 9%); there were 7 aneuploid and 13 euploid tumors. SPF ranged from 4 to 14.5% (median 10.5%). Neither SPF nor ploidy had a significant influence on outcome. Patients were divided according to PCNA index in higher (n = 10) and lower (n = 10) than the median. Survival and DFS were 13 and 6 months for the group >9% and 20 and 15 months for the group <9%. The difference in DFS was significant (p = 0.03, log rank test).

CONCLUSION

These results fall in line with other studies showing the influence of pretherapeutic proliferation on outcome after radiotherapy. Although the moderately accelerated therapy regimen certainly reduces the influence of proliferation on outcome, patients with faster proliferating tumors still have a worse outcome. DFS is the more relevant endpoint in this study because of effective salvage therapies, which influence survival.

CT planning of boost irradiation in radiotherapy of breast cancer after conservative surgery

BACKGROUND AND PURPOSE

A study was performed to compare the accuracy of clinical treatment set-up and CT planning of boost irradiation in radiotherapy of breast cancer.

MATERIAL AND METHODS

Between September 1993 and October 1994, 45 women who underwent breast conserving surgery and irradiation containing a boost to the tumour bed were investigated. Prospective evaluation of CT planning of the boost was carried out. The target volume/boost field, electron energy and treatment set-up had been defined on the basis of clinical examination, initial and postsurgical mammograms by one radiotherapist. Next, a planning CT was performed in treatment position and a CT-based treatment plan was calculated according to a target volume defined by another radiotherapist. The clinical treatment set-up was imported into our computer planning system and the resulting isodose plots were compared with those from CT planning and reviewed critically.

RESULTS

The clinically defined treatment set-up had to be modified in 80% of the patients. Most discrepancies observed were related to the size of the boost field itself and the chosen electron energy. Minor changes had to be made with respect to angle of table and gantry.

CONCLUSIONS

Critical review of the isodose plots from both methods showed clear advantages for CT planning. Guidelines for target definition in CT planning of boost irradiation and subgroups of patients benefiting from this technique are described.

[The locoregional recurrence of rectal carcinoma. A computed tomographic analysis and a target volume concept for adjuvant radiotherapy]

BACKGROUND

In the adjuvant postoperative radiotherapy of rectal carcinoma the knowledge of the predominant areas of recurrences is of major importance for the definition of the target volume. We analysed the pattern and locations of tumor recurrences in the CT scans of 155 patients and correlated the findings with the primary tumor location (above and below the peritoneal duplication) and the operating method (abdominoperineal extirpation, anterior resection. Hartmann procedure).

PATIENTS AND METHOD

Hundred and fifty-five patients with the diagnosis of rectal carcinoma recurrences were treated in our institution between 1980 and 1995. To determine the extension of the recurrent tumor within the pelvic levels (presacral levels S1-S5, precoccygeal, pelvic floor level and perineal level) and the tumor infiltration of pelvic organs and muscles we analysed the pretherapeutic CT images. The lymph node recurrences were classified as: pararectal, presacral, iliac internal, iliac external, iliac communis and para-aortal recurrences.

RESULTS

Sixty-one percent of the patients with rectum extirpation and 66% with anterior resection showed a combined local and nodal recurrence. Isolated lymph node recurrences were rare (4% and 5%) (Tables 2 and 3). The local recurrence was mostly situated in the presacral pelvis, predominantly there was an infiltration of the presacral space at the level of S4, S5 and os coccygis regardless of the operating method and the primary tumor location (Figure 1). The anastomosis was involved in the tumor recurrence in 93% of the anteriorly resected patients (Table 3). In 9 out of 96 patients after rectum extirpation the pelvic region caudal of the tip of the coccyx was the origin of the recurrent tumor (Table 2, Figure 2). Primarily all 9 patients had a deep-seated carcinoma (< 6 cm ab ano). Only 2 patients showed an isolated perineal recurrence after rectum extirpation (Table 2. Figure 2). Two thirds of the deep-seated tumors showed a vaginal involvement (Figures 3 and 4). The incidence of iliac internal and presacral nodal recurrence was 47 to 59% (Figures 3 and 4). The incidence of iliac external lymph node recurrences was 7% after rectum extirpation and 2% after anterior resection/Hartmann procedure.

CONCLUSION

Our data demonstrate that 2/3 of the patients with tumor-bed recurrences also show lymph node recurrences predominantly in the iliac internal and presacral groups. This has to be considered in the definition of the boost target volume. The target volume must also include the dorsal wall of the urogenital organs. A ventral extension of target volume up to iliac external lymph nodes is not necessary.

[The conformal radiotherapy of localized prostatic carcinoma: acute tolerance and early efficacy]

AIM

In a prospective trial early effectiveness and acute toxicity of conformal 3D-planned radiotherapy for localized prostate cancer was quantified using dose-volume-histogramms and evaluated with respect of treatment technique.

PATIENTS AND METHOD

Thirty-two men (44 to 80 years old) with locally advanced carcinoma of the prostate (stage B2 or C) have been treated by 3D-planned conformal radiotherapy using high energy photons. In 28/32 men treatment technique was a monoaxial bisegmental rotation with irregular fields. With single doses of 2.0 Gy a mean total dose of 63.9 +/- 4.9 Gy according to ICRU was applied within 46 +/- 4 days. Maximum dose was in the mean 105.1% +/- 3.8%. 3D treatment volume was 274.1 +/- 113.4 cm3. Median follow-up is 1.8 years (15 to 34 months). Toxicity was evaluated according to RTOG-EORTC by patient interview and physical examination on a weekly basis during radiotherapy and by regular follow-up.

RESULTS

Eleven patients had none, 15 mild (RTOG grade 1) and 6 moderate symptoms (RTOG grade 2, mainly diarrhoea, dysuria and polyuria). Acute complications leading to treatment interruption did not occur. In 16 patients symptoms disappeared within 6 weeks after radiotherapy. Only 2 men had symptoms which lasted longer than 3 months and were endoscopically examined. Up to now no late complications were detected. Incidence and severity of toxicity was significantly (p < 0.05) related to the size of treatment volume. Acute toxicity was found to depend statistically significant (p < 0.05) on the proportional volume of bladder and rectum, irradiated with more than 35 Gy. In 81% of the patients with pretherapeutic elevated PSA levels normalisation of PSA was observed. Overall mean PSA levels of 15.7 +/- 22.6 micrograms/l at the beginning of radiotherapy fell to 2.1 +/- 3.7 micrograms/l 6 weeks after irradiation. Only 1 Patient relapsed locally 22 months after radiation therapy.

CONCLUSION

We conclude that due to modern 3D-planned conformal techniques with optimization of treatment dose and improved protection of critical organs such as urinary bladder and rectum, radiotherapy allows an effective and well tolerated therapy of localized prostatic carcinoma.

[Bone metastasis in breast carcinoma]

113278891978 and 1988 278 patients with metastatic disease of breast cancer were treated at the Clinic of Radiotherapy of the University of Würzburg. 192 of these patients developed skeletal metastases. Particularly the skeletal axis was affected. In 58.3 percent (162 patients) skeletal metastasis was the first metastasis. The median age of the patients was 62.5 years at time of diagnosis of skeletal metastasis. Median interval between primary diagnosis of breast cancer and diagnosis of skeletal metastasis was 2.9 years. Median survival of patients with skeletal metastasis was 1.7 years. Skeletal metastases could not worse survival time, if other metastases already existed. Because of the relatively good prognosis we have to improve and combine the local and systemic therapy.

Migration patterns in pulsed-field electrophoresis of DNA restriction fragments from log-phase mammalian cells after irradiation and incubation for repair

An assay system was developed to detect changes of restriction fragment profiles obtained after pulsed-field gel electrophoresis (PFGE) for DNA from mammalian cells that were irradiated and incubated for repair. DNA was prepared from irradiated log-phase human melanoma cells (MRI 221) after incubation for repair (6 h) and was digested with the rare-cutting restriction enzyme NotI (RE) prior to PFGE separation. DNA-fragment size distributions were compared to the respective PFGE profiles from unirradiated controls. After doses of 5 and 10 Gy (plus a 6-h incubation for repair), the relative amount of DNA retained in the plug during PFGE was increased. For higher doses (30 and 60 Gy), this phenomenon was superimposed by the residual fragmentation (25-30% of the initial breakage of 0.42 dsb/100 Mbp/Gy). Since irradiated cells accumulated in S phase during incubation for repair, a correction for the reduced electrophoretic migration of DNA from S-phase cells was necessary, and a 0.5% increase in DNA retention per 1% S-phase increment was found. However, the % retention for the 5 Gy plus repair sample was significantly higher than for the S-phase adjusted control (p < 0.01). Radiation induced DNA-protein crosslinks cannot account for the observed phenomenon because of the extensive proteolysis in DNA preparation, and also a loss of restriction enzyme recognition sites appear to be an unlikely explanation from simple quantitative considerations. Based on the recent observation of misrejoining during dsb repair, it is proposed that the incorrect joining of DNA ends also causes a more random distribution of replicating DNA in restriction fragments derived from cells in S phase after incubation for repair. This process would necessarily increase the proportion of DNA unable to migrate in PFGE.

[Accelerated hyperfractionated simultaneous radiochemotherapy in advanced head-neck carcinomas in comparison: split course and concomitant boost concept]

PATIENTS

Between 1989 and 1992, 38 patients with advanced squamous cell carcinomas of the head and neck were treated by an accelerated hyperfractionated split-course radiochemotherapy (SCRC). This therapy was carried out at the ENT department and department of radiooncology of the University of Heidelberg. Within 51 days, 70.2 Gy were applied in three courses. In every course, simultaneous chemotherapy with cisplatin (60 mg/m2/week)/5 Fu (bolus: 350 mg/m2/d)/Leucovorin (bolus: 50 mg/m2 + 100 mg/m2/24 h) was carried out. Between 1992 and 1994, 50 patients suffering from advanced head and neck cancer (stage III, V) were also treated with an accelerated hyperfractionated concomitant-boost radiochemotherapy (CBRC) at the same departments. A total dose of 66 Gy, was applied within 33 days. The patients were also treated with simultaneous chemotherapy with carboplatin (70 mg/m2/24 h) in the first and fifth week.

RESULTS

In about 50% of the patients treated with SCRC, the therapy was more than 10 days longer than the scheduled period. The lack of compliance due to toxicity was considered as one of the main reasons for this delay. After the first course of SCRC, eight of 38 patients showed mucositis of the upper aerodigestive tract (WHO grade > 3); after the second course, 11 of 38 patients; and after the third course, 15 of 38 patients. Fifty-two percent of the patients developed emesis, 10% leucopenia < 1 nl, 10% nephrotoxicity, 3% pancreatitis, 3% thrombosis, 3% gastritis, and 3% auditory threshold shifts of about more than 10 dB. In about 7.5% of the patients treated with CBRC, the therapy was more than 10 days longer than the scheduled period. The mucositis of the upper aerodigestive tract (50% of the patients showed WHO-grade > 3) was considered to be the main reason for this. In four patients a neutropenia < 1 nl was detected, in one patient anemia < 7 g/dl and n 33 patients thrombocytopenia < 100/nl.

CONCLUSIONS

In conclusion, the concomitant boost radiochemotherapy showed a lower toxicity and higher acceptance than the split-course radiochemotherapy. This is documented in lower protocol delays and better results in the two-years survival time in case of concomitant boost radiotherapy.

Fotemustine given simultaneously with total brain irradiation in multiple brain metastases of malignant melanoma: report on a pilot study

Melanoma patients with multiple brain metastases not amenable to surgery or stereotactic radiotherapy were treated with total brain irradiation in fractions of 2.5 Gy four times weekly, up to 40 Gy. At days 1, 8, and 25100 mg/m2 fotemustine was infused 4 h before irradiation. Of 12 evaluable patients, four showed partial remission and three stabilization in the brain. The median survival in these two groups of patients was 6 months; the survival of the other patients was 2 months. Severe haematological side effects were observed in 6/13 patients. In conclusion, the combination of fotemustine and total brain irradiation seems to be more effective than either treatment alone, but bears the risk of additional bone-marrow toxicity.