Posters S389

Material and methods: From 10/1999 to 06/2002 a total of 52 Patients (28 female and 24 mate; median age: 56 years, range: 38-78 years) with radiographically documented painful lytic bone metastases of different primary tumors (histology: 23x breast cancer, 12x renal cell carcinoma, 6x bronchial cancer, 6x rectal cancer, 4x prostate cancer, l x gastric cancer) were included in this study, ECOG-PS <2 and estimated life expectancy >12 month.

A total dose of 36 to 40 Gy (single dose 2 Gy) was locally applied on painful bone metastases with 6 to 15 MeV photons (Linac) depending on localization and tumor depth. Treatment group A received Ibandronate 4mg i.v. on the first day of irradiation plus 3 mg i.v. every 28 days for one year. Group B received Ibandronate 1 mg i.v. on day 1, 8, 15, and 22 of radiotherapy, and an additional 3 mg i.v. every 28 days for one year.

The patients were randomly assigned to treatment groups A (n = 26) and B (n = 26), stratification was done according to histology. Pain intensity was measured using a visual analogue scale (VAS). The need for analgesics was documented according to the WHO-analgesic-score. Recalcification was analyzed semiquantitatively using conventional radiographs and/or CT. The minimum follow-up period was 12 months.

A retrospective matched-pair analysis with a historic control group was also conducted.

Results: The median baseline VAS score for all patients in the study was 8 (range 10-4) [group A: 8 (range 9-4); group B: 7 (range 10-4)]. Eight weeks after the treatment initiation, the median VAS-score was 1 (range 5-0) [group A: 0 (range 5-0); group B: 1 (range 5-0)]. At the time of final data analysis (minimum follow-up period 12 months), the median VAS score was 0 (range 5-0) [group A: 0 (range 5-0); groupB: 0 (range 3-0).

The m~dian WHO analgesic score before treatment was 3 (range 5-1 ) [group A: 3 (range 4-1 ); group B: 3 (range 5-1 )]. After 8 weeks of treatment the median analgesic score was 1 (range 4-0) [group A: 1 (range 4-1); group B: 1 (range 3-0)]. At the time of final data analysis, the median analgesic score was 1 (range 3-0) [group A: 1 (range 3-0); group B: 0 (range 3-0)].

In group A, 7/26 patients demonstrated complete recalcification, 13/26 patients had a partial recalcification, and recalcification had begun in 6/26 patients. In group B, the numbers for complete, partial and initiation of recalcification were 9, 11 and 6 (out of 26) patients, respectively. The total recalcification rate (complete and partial recalcif ication)was 40/52 (77 %). Median survival analyzed by Kaplan Meier method was in both groups 11 months. There were no statistically significant differences between treatment groups in pain scores, analgesic scores, or recalcification rates. No side effects due to infusion of Ibandronate were observed.Compared to the historic control group with matched patients characteristics (n = 50) there were significant better results in terms of pain relief and recalcification (77 % vs. 42 %; p < 0.5 McNemar test).

Conclusions: The combination of local radiotherapy and intravenously applied Ibandronate leads to a fast and substantial pain relief, which is maintained in the long-term (median: 11 months). A high rate of recalcification was observed with this treatment concept. Compared to the historic control group a significant improvement of treatment results could be achieved.

Patient immobilisation/positioning 918 poster

Implementation of fixed couch height together with an off- l ine correction protocol: results of co-work between radiation technologist (RT) and radiation oncologist (Re) W. Weyt/ens 1, ~ 1 , C. Cuyckens 1, M. Kuylen 1, A. Strubbe , I. Benoy ~, P. Huget 1 ~ St.-Augustinus Hospital, Oncology Center, Wilrijk, Belgium 2St.-Augustinus Hospital and UZA, Translational Cancer Research group, Wilrijk, Belgium Purpose: To describe the change in attitude in patient set-up and in work flow that resulted from the analysis of 1510 EPI match results brought together with the information of RT who daily treated these 53 prostate cancer patients.

Methods and materials: From March to October 2003, set up of 53 consecutive prostate cancer patients, treated with EBRT was evaluated with EPI. In total 1510 EPI's were taken and reviewed by the Re. No correction protocol was used.

Patients, not immobilized, were positioned, according to the lasers and fuchsine lines, drawn on simulator. Only the vertical couch parameter was verified with a tolerance level of 1 cm. After analysis of the results, a correction protocol was introduced and 3 RT were trained to review images with semi-automatic matching software.

After the first 3 fractions, RT analyses mean mismatch for every direction. Mean mismatches of > 3 mm are corrected for, in consultation with the Re.

Results: standard deviations of random and systematic errors were acceptable, compared to literature (<_ 3mm). But: a systematic shift towards anterior (2.8 mm) was detected for the lateral fields. This is statistically significant and clinically important but at first sight unexplained: laser misalignment and mismatch simulation-fluoro with DRR were excluded. Couches were exact the same for simulator and accelerator. Radiation technologists mentioned that, reentering the treatment room after a session, laser lines often projected anterior from fuchsine lines. Skin movement due to muscle tension could be the explanation of the systematic shift.

Conclusions: It is feasible to check set-up variability for a specific treatment. Interpretation of results should be done in co-operation with all involved parties.

Introduction of fixed couch height in stead of only laser alignment and introduction of an off line correction protocol is feasible. First results of image mismatches after the change in attitude seem to be slightly better.

919 poster

Prone breast irradiation for pendulous breasts: a comparative study

J. Bui/sen, J. Bovendeerd, R. Voncken, J.J. Jager, J.H. Berger, L.J. Boersma, M. Kunze, P. Lambin University Hospital Maastricht/Maastro Clinic, Radiotherapy, Heerlen, The Netherlands Introduction: Adjuvant radiotherapy in women with pendulous breasts may encounter technical difficulties. In the literature increased skin toxicity and worse cosmetic outcome has been described. Moreover, lung and cardiac toxicity may increase due to larger irradiated volumes. Various techniques have been described to improve treatment outcome in women with large breasts. One of these is irradiation in prone position, using a breast board. We hypothesized that for large, pendulous breasts, irradiation in prone in supine and prone position are equivalent with regard to coverage of the