ESTRO 2023 - Abstract Book

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ESTRO 2023

Results Fifteen patients, 5 patients each from three institutions were included in this study (Table 1). Definitive RT and postoperative RT was performed for 10 and 5 patients. Surgical excision was performed with a 0-2 cm margin. Besides 1 patient, all patients were treated with VMAT; 2-4 arcs with 4 MV or 6 MV photons. One patient was treated with VMAT and electron boost. The frequent dose and fractions were 70Gy in 35 fractions. The clinical target volume (CTV) was whole scalp for 11 patients, whole scalp plus prophylactic lymph node for 3 patients, and extended primary site for 1 patient. The planning target volume (PTV) was CTV with a margin of 3-5 mm in all directions. Induction, concurrent, and maintenance systematic therapy was administered for 9, 14, and 12 patients. The most frequent regimen of systematic therapy was weekly paclitaxel. The median follow-up time was 15.7 months and 8 patients were alive at analysis. The one year LC was 86% (Figure 1). The one-year OS and PFS were 66.7% and 53.3% (Figure 2). Recurrence was observed in 9 patients; 5 patients had local recurrence, and 7 patients had distant metastasis. For acute non-hematologic toxicity, grade 3 dermatitis, mucositis, and hyponatremia occurred for 12, 1, and 1 patients. For late toxicity, grade 3 and 5 skin ulceration was observed in 4 and 1 patients. The patient with grade 5 skin ulceration died because of infection by Pseudomonas aeruginosa from ulceration. Any other grade 3 or higher non-hematologic toxicities were not observed. Table 1 Patient and tumor characteristics

Characteristics

no. % median (range)

Age (years)

74 (66-90)

Sex

10

66.7

Male Female

5

33.3

Tumor diameter (cm)

9.5 (1.7-33.0)

Tumor location Scalp

14

93.3

Face

1

6.7

Skip lesions Yes

8 7

53.3 46.7

No

With ulcerative lesions Yes No With nodule lesions Yes No With muscle invasion Yes No Lymph node metastasis Yes No 2 13 5 10 11 4 2 13

33.3 66.7

73.3 26.7

13.3 86.7

13.3 86.7