ESTRO 2024 - Abstract Book

S1506

Clinical - Lower GI

ESTRO 2024

Results:

A total of 50 patients (40 (80%) patients with SCC, 8 (16%) patients with BD, 2 (4%) patients with PPD) were evaluated. All patients were staged with imaging (PET-CT, MRI and UL of the groins) and a clinical examination in general anesthesia. A total of 12 (24%) patients had tumor involvement of the anal canal , while 25 (50%) and 13 (26%) patients had ≤ 10 mm. and >10 free margin to the anal verge, respectively (table 1).

Primary RT was delivered in 40 (80%) patients. The remaining 10 (20%) patients had postoperative RT after an incomplete tumour resection.

Treatment included electron beam RT with a median prescription dose of 60.0 (45.0-60.2) Gy in 28 (10-30) fractions delivered with 8 (4-18) MeV and 3-5 mm bolus. RT was delivered with a standard tube (diameter: 60 (40-120) mm) that covered the tumour with 1-1.5 cm margin. At a median follow-up of 70 (9-135) months, 7 (17.5%) local recurrences were diagnosed. The 3-year and 5-year local LC was 90.9% and 87.8% respectively. Analysis of LC according to diagnose and stage revealed and 3-year and 5-year LC of 100% for MB and PPD. For patients with SCC a 3-year and 5-year LC of 100% and 100.0% was found in T1-tumours (2 local recurrence after 64 months and 113 months follow-up in 26 patiens) compared to a 3-year and 5-year local control of 68.4% and 57.0% in T2-tumours (5 local recurrence after 20-60 months follow up in 14 patients) (p-value <0.001) (figure 1). No isolated regional or metastatic recurrences were diagnosed.