903 poster A STUDY OF OUTCOMES OF LOCAL RADIOTHERAPY FOR PRIMARY CUTANEOUS LYMPHOMAS.

brain. Optional staging: F-18 FDG PET/CT of the lung in breath hold technique in radiation treatment position. Restaging after SBRT was done by CT or F-18 FDG PET/CT. Maximal time for follow-up: 21 months, range 3 to 21 months. Median time for follow-up: 9 months. Results: Eighteen patients were evaluated. Nine out of 18 patients (50%) received an additional breath hold acquisition of the lung. In 2 out of 9 patients (22%) additional lesions were detected (hilar lymph nodes, mediastinal lymph nodes, pulmonary lesions) excluding them from SBRT. Due to a reduced lung function and health condition these PET positive lesions of these two patients were not histologically proven, however follow-up studies by CT or F-18 FDG PET/CT show, that these lesions were correctly staged and not false positive lesions. So far, no in-field recurrences were detected by PET/CT or CT during follow-up after SBRT. One out-field recurrence occured in hilar and mediastinal lymph nodes 12 months after SBRT, and one patient developed a singular bone metastasis 18 months after SBRT; both patients did not receive the breath hold acquisition.