ESTRO 2024 - Abstract Book

S1104

Clinical - Gynaecology

ESTRO 2024

EBRT + Brachytherapy = 52

Primary Radiotherapy Modality

EBRT only = 18 Brachytherapy only = 3

Cervix = 33

Uterus = 27

Primary Gynaecological Malignancy

Ovary = 6

Vagina = 4 Vulva = 3

Time from Primary Radiotherapy to Reirradiation

Median 28 months (Range 4 months to 30 years)

Primary EBRT dose fractionation

Median 45Gy/25# (Range 24Gy/12# to 54Gy/28#)

Prescribed SBRT dose

Median 30Gy/5# (Range 24Gy to 33Gy in 3 to 5 fractions)

Cyberknife = 53

Delivery platform

C-arm linac = 22 MR-linac = 6

Soft tissue = 49

Treatment site

Lymph node = 20 Positive surgical margin = 12

Median 18.7cm 3 (range 2.1 to 91.8cm 3 )

GTV/CTV volume

Table 1 . Treatment data for patient cohort

Median OS was 43.5 months (95% CI 33.8 to 69.9 months) ( Figure 1 ). Median PFS was 12.9 months (95% CI 7.9 to 19.5 months) ( Figure 2 ) and median time to local failure of treated lesion was 35.7 months (95% CI 24.7 months to not reached). For cervix versus uterine cancer relapse the median OS was 36.6 months (95% CI 19.7 months to not reached) versus 69.9 months (95% CI 38.6 months to not reached), median PFS was 7.4 months (95% CI 3.6 – 35.7 months) versus 16.1 months (95% CI 10.7 to 30.2 months). Time from primary radiotherapy (r = 0.74) but not GTV/CTV volume (r = 0.25) correlated with longer time to treatment failure. SBRT reirradiation was well tolerated with acute G3 toxicity reported in 2 patients (1x diarrhoea, 1x fatigue). Late G3 toxicity was documented in 2 patients (1x Nausea, 1x Vaginal Stricture), occurring >2 years after treatment.