$428 Posters

lpts had respectively well differentiated, dedifferentiated and myxoid RLPS weighting from 0.4 to 10.6 Kg. At a median follow up of 15 months (3 - 45) one pts has developed a local relapse while another developed distant metastasis.

Conclusion: This strategy of pre-op EBRT for RLPS with a CTV limited to the posterior abdominal wall is feasible, well tolerated and may allow a better sparing of dose to critical organs: a longer follow-up is needed to evaluate the long term results both in terms of toxicity and local control.

1017 poster

Intraoperative electrons + external irradiation in resected extremity soft tissue sarcomas: recurrence patterns and patients outcome

J.A. Blanco Rodriguez, F.A. Calvo, M. Ferrer, M.A. Lozano, R. Garcia, A. Calin, F.J. Serrano, A. Fondevilla, R. Herranz Gregorio Maranon University Hospital, Oncology, Madrid, Spain Purpose: To analyze sarcoma control (initial extremity involvement) and patient evolution after intensified post- resection radiotherapy (RT) using an intraoperative irradiation boost component (IOERT).

Patients and methods: From 1995 to 2003, 51 patients with extremity sarcoma received and IOERT boost (10-15 Gy) to the tumor bed area at the time of surgical resection. Dominant histology was liposarcoma (33%). Median sarcoma size was 8 cm (largest dimension; range 1 to 23 cm). 18% had positive margins. Recurrent disease was present in 12 (24%; 5 previous RT). Postoperative RT (45-50Gy) was added when feasible (78%). Adyuvant chemotherapy was given to high grade histologies (16%). All the stages were represented (30% stage III or superior). Disease recurrence was actively treated for rescue (curative intent) in 70%.

Results: Median follow-up time is 51 months, with an overall survival of 86%. Total recurrence rate 33%: 6% local, 19% systemic and 8% mixed. Prognostic features related to local control in univariant and multivariate analysis were positive surgical margins (p=0,019) and recurrent disease (p=0,039). Survival was significantly influenced by adyuvant external beam RT: 92% vs 72% (p=0,018).

Conclusions: IOERT is a valuable treatment component in the management of extremity sarcoma patients, able to promote local sarcoma control. Prognostic features with influence in outcome are emerging in mature clinical experiences, which should be incorporated to clinical research strategies.

1018 poster

Local treatment of osteogenic sarcoma (OS) with hypofractionated-accelerated radiotherapy (HA-RT) L. Gandola ~, N. Bedinf, E. Pignoli 2, G. Cefalo 3, M. Casan--~'~ova , R. Bertulll 4, F. Spreafico 3, M. Terenziam ~, M. Massimino ~, R. Luksch 3 ~ lstituto Nazionale Tumori, Radiotherapy, Milan, Italy 21stituto Nazionale Tumori, Health Physics, Milan, Italy 31stituto Nazionale Tumori, Pediatric Oncology, Milan, Italy 41stituto Nazionale Tumori, Medical Oncology, Milan, Italy Purpose: To evaluate efficacy of HA-RT in controlling bone lesions from OS.

Patients and methods: From 1994 to 2004, 27 pts (median age 17 yrs) with OS were irradiated to 28 skeletal sites with a non conventional fractionation modality: 48 Gy devided in 3 Gy bi-daily fraction, 5 treatment days~week for a total of 8 treatment days. 10 pts (Group I) were irradiated for palliation

of progressive OS (3 primary tumors, 7 bone metastases). 18 primary tumor sites were irradiated, in combination with CT, as an alternative to immediate surgery in presence of synchronous metastases (3 pts Group II), as the only local treatment when surgery was unfeasible because of site and size of disease or refused by the patient (5 pts Group Ill), or as complementary treatment after intralesional surgery (10 pts Group IV).

Results: HA-RT was always completed as planned and all pts showed a good compliance to treatment schedule. In the 10 Group I pts, a clinical and/or radiological response was achieved in 9/10 irradiated sites (90%) for a median time of 6 mos corresponding to median time of survival. Except for 1 non-responder, tumor progression never occurred in the irradiated bone. In the 3 Group II pts, no local relapse occurred before surgery (1 pt, +12 mos) or death due to progressive OS elsewhere (2 pts, + 26 and 28 mos). In the 5 Group III pts (4 pelvis, 1 vertebra), only 1 local progression occurred (+35 mos from HA-RT), while local control was obtained in the remaining 4 until death (+10, 13, 72 mos from HA-RT) or last f-u (+ 72 mos). In the 10 Group IV pts, 1 local relapse occurred 46 mos after RT, 4 pts remained progression free after a median time of 28 mos, and 5 pts died of metastatic spread after a median time of 24 mos. Severe sequalea developed in 6/18 evaluable pts with a minimum f-u of 7 mos: 3 small bowel obstructions requiring surgery, 2 osteoradionecrosis, 1 soft tissue fibrosis.

Conclusions: HA-RT was highly effective in providing durable clinical and/or radiological response in 17/18 pts (94%) with evaluable bone lesions from OS. Furthermore, only in 1/17 responders (6%) OS relapsed in the irradiated bone. Significant complications of HA-RT developed in 33% of evaluable pts but, considering the high rate of local control in this subset of pts with a severe prognosis, the therapeutic index of this radiotherapeutic modality, remained remarkable.

Stereotactic radiotherapy 1019 poster

Hypofractionated stereotactic radiotherapy in the thoracic region

J. Van de Steene 1, S. Van Acker 2, V. Vinh-Hung ~, G. Soete ~, N. Linthout 2, M. Voordeckers ~, D. Verellen 2, J. De Mey 3, M. Noppen 4, G. Storme ~ ~ Oncologic Center, AZ-VUB, Radiotherapy, Brussels, Belgium 20ncologic Center, AZ-VUB, Radiophysics, Brussels, Belgium 3AZ-VUB, Medical Imaging, Brussels, Belgium 4AZ-VUB, Pneumology, Brussels, Belgium Introduction:We started a feasibility study in June 2001 on conformal, hypofractionated radiotherapy (RT) with on-line image guided set-up correction, in patients with pulmonary primary tumours or metastasis.

Methods: During accrual 101 patients fitted inclusion criteria, of which 81 are included in this analysis (24 primary medically inoperable lung cancers, 20 locally advanced lung cancers, 33 patients with pulmonary metastasis from other tumours, 4 others). RT -delivered with a 6 MV linac with micromultileaf collimator - was hypofractionated in most cases. Patient set-up was on-line verified and corrected with stereoscopic X-ray imaging using either automated fusion (between radioscopic images and DRR's) on anatomy or implanted markers. Patients with locally advanced lung cancer received a mediastinal RT (APPA fields) and stereotactic boost. Doses ranged from 30 to 82 Gy, given in fractions from 2 to 20 Gy, for a total of 128 isocenters. All RT