TY - JOUR
T1 - Tumour control probability after Ruthenium-106 brachytherapy for choroidal melanomas
AU - Espensen, Charlotte A
AU - Appelt, Ane L
AU - Fog, Lotte S
AU - Thariat, Juliette
AU - Gothelf, Anita B
AU - Aznar, Marianne C
AU - Kiilgaard, Jens F
PY - 2020/8
Y1 - 2020/8
N2 - Purpose: Ruthenium-106 (Ru-106) brachytherapy is a common eye-preserving treatment for choroidal melanomas. However, a dose-response model describing the relationship between the actual delivered tumour dose and tumour control has, to the best of our knowledge, not previously been quantified for Ru-106 brachytherapy; we aimed to rectify this. Material and methods: We considered consecutive patients with primary choroidal melanomas, treated with Ru-106 brachytherapy (2005–2014). Dosimetric plans were retrospectively recreated using 3D image-guided planning software. Pre-treatment fundus photographies were used to contour the tumour; post-treatment photographies to determine the accurate plaque position. Patient and tumour characteristics, treatment details, dose volume histograms, and clinical outcomes were extracted. Median follow-up was 5.0 years. The relationship between tumour dose and risk of local recurrence was examined using multivariate Cox regression modelling, with minimum physical tumour dose (D
99%) as primary dose metric. Results: We included 227 patients with median tumour height and largest base dimension of 4 mm (range 1–12, IQR 3–6) and 11 mm (range 4–23, IQR 9–13). The estimated 3 year local control was 82% (95% CI 77–88). Median D
99% was 105 Gy (range 6–783, IQR 65–138); this was the most significant factor associated with recurrence (p <.0001), although tumour height, combined TTT and Ru-106 brachytherapy, and sex were also significant. The hazard ratio (HR) for a 10 Gy increase in D
99% was 0.87 (95% CI 0.82–0.93). Using biological effective dose in the model resulted in no substantial difference in dose dependence estimates. Robustness cheques with D
1–99% showed D
99% to be the most significant dose metric for local recurrence. Conclusion: The minimum tumour dose correlated strongly with risk of tumour recurrence, with 100 Gy needed to ensure at least 84% local control at 3 years.
AB - Purpose: Ruthenium-106 (Ru-106) brachytherapy is a common eye-preserving treatment for choroidal melanomas. However, a dose-response model describing the relationship between the actual delivered tumour dose and tumour control has, to the best of our knowledge, not previously been quantified for Ru-106 brachytherapy; we aimed to rectify this. Material and methods: We considered consecutive patients with primary choroidal melanomas, treated with Ru-106 brachytherapy (2005–2014). Dosimetric plans were retrospectively recreated using 3D image-guided planning software. Pre-treatment fundus photographies were used to contour the tumour; post-treatment photographies to determine the accurate plaque position. Patient and tumour characteristics, treatment details, dose volume histograms, and clinical outcomes were extracted. Median follow-up was 5.0 years. The relationship between tumour dose and risk of local recurrence was examined using multivariate Cox regression modelling, with minimum physical tumour dose (D
99%) as primary dose metric. Results: We included 227 patients with median tumour height and largest base dimension of 4 mm (range 1–12, IQR 3–6) and 11 mm (range 4–23, IQR 9–13). The estimated 3 year local control was 82% (95% CI 77–88). Median D
99% was 105 Gy (range 6–783, IQR 65–138); this was the most significant factor associated with recurrence (p <.0001), although tumour height, combined TTT and Ru-106 brachytherapy, and sex were also significant. The hazard ratio (HR) for a 10 Gy increase in D
99% was 0.87 (95% CI 0.82–0.93). Using biological effective dose in the model resulted in no substantial difference in dose dependence estimates. Robustness cheques with D
1–99% showed D
99% to be the most significant dose metric for local recurrence. Conclusion: The minimum tumour dose correlated strongly with risk of tumour recurrence, with 100 Gy needed to ensure at least 84% local control at 3 years.
UR - http://www.scopus.com/inward/record.url?scp=85085396788&partnerID=8YFLogxK
U2 - 10.1080/0284186X.2020.1762925
DO - 10.1080/0284186X.2020.1762925
M3 - Journal article
C2 - 32412331
SN - 0284-186X
VL - 59
SP - 918
EP - 925
JO - Acta Oncologica
JF - Acta Oncologica
IS - 8
ER -