paediatrics Brussels 17

Ependymoma reirradiation d T. E. M ERCHANT et al .

89

Fig. 2. Example of craniospinal and metastatic site dosimetry (second course of radiotherapy [RT 2

]) for ependymoma

after prior focal radiation therapy (RT 1

). The central isodose on the RT 1

plan (white) represents the prescription dose of

59.4 Gy.

resection (GTR) in 26, near-total resection (NTR; # 5 mm thickness residual) in 6, and subtotal resection (STR) in 5 pa- tients. Seventeen patients had anaplastic tumor grade, 6 were found to have focal anaplasia, and the remainder had differ- entiated EP. : initial irradiation A variety of dose, volume, and fractionated regimens were used for the initial treatment. Thirty-six patients were treated by using conventional fractionation (1.6–2.0 Gy/d) to 60.4 ( n = 1), 59.4 ( n = 22), 55.8 ( n = 2), 54 ( n = 5), 50.4 ( n = 2), 50 ( n = 1), 48 ( n = 1), 40 ( n = 1), and 37.8 Gy ( n = 1). Two patients were treated by using hyperfractionated irradi- ation (1.2 Gy/d) to 69.6 Gy. Three patients were treated with supplemental radiosurgery as part of their initial manage- ment: 1 with 8 Gy after fractionated 40 Gy, 1 with 9 Gy after fractionated 54 Gy, and 1 with 15 Gy after fractionated 59.4 Gy. One patient received CSI to 30.4 Gy followed by focal fractionated irradiation to 48 Gy as a part of initial manage- ment. All patients were treated with 4- or 6-MV photons. RT 1

3–62 months), and combined local and metastatic failure ( n = 4) occurred with a median time of 10 months (range, 7–26 months; Fig. 3 ). At the time of RT 1 relapse, 2 patients were treated briefly with chemotherapy (ifosfamide, carbo- platin, and etoposide for two cycles) and 35 of 38 patients were treated with additional surgery. All 4 patients with com- bined local and metastatic failure underwent attempted resec- tion of local and metastatic disease (one to four metastatic sites/patient), and GTR was achieved in 2 patients. Twelve of 13 patients with metastatic failure underwent metastasec- tomy (one to three metastatic sites/patient). The extent of re- section was characterized as GTR in 7, NTR in 3, and STR in 2 patients. Nineteen of 21 patients with local failure un- derwent GTR ( n = 12), NTR ( n = 4), or STR ( n = 3). : radiosurgery Six lesions in 6 patients were treated by means of radiosur- gery using a median dose of 18 Gy (range, 15–20 Gy). Le- sions in 5 patients were entirely within the high-dose volume of previous treatment; the lesion in the sixth patient was an isolated metastasis to the lateral ventricle. Median time from initiation of RT 1 to RT 2 was 21.9 months (range, 7.5–67.7 months), and from RT 1 failure to RT 2 , 1.4 months (range, 0.4–2.3 months). Four patients underwent surgery be- fore RT 2 , resulting in GTR ( n = 2) or STR ( n = 2). Two pa- tients experienced progression with local failure at 6.3 and RT 2

and treatment before RT 2

Failure after RT 1

Median time to failure after RT 1 was 19 months (range, 3–73 months). Local failure ( n = 21) occurred with a median time of 20 months (range, 9–73 months), metastatic failure ( n = 13) occurred with a median time of 22 months (range,