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Head & neck
•
Risk of late damage
is higher in retreated
patients…
•
But cumulative total
dose for 20%
complication rate at 5 y
is higher than predicted
from single course
treatment
(EQD2
3
= 86 vs 67 Gy)
indicating
partial
recovery!
27
Complication free survival (%)
0
2
4
6
8
10
0
20
40
60
80
100
Time from (re)irradiation (years)
Reirradiation
N = 487
Single course
N = 3635
Lee AWM et al. Int J Radiat Oncol Biol Phys 20000
Head & neck
•
Summary studies by Lee AWM et al
•
Local control: T1>T2>T3
•
Local control: EB+IRT >IRT or EBRT only
•
Initial dose (calculated as EQD2) correlated significantly
with late complications (α/β = 2–3 Gy)
No correlation with retreatment LC (α/β = 10 Gy)
•
Retreatment dose (calculated as EQD2) correlated
significantly with LC (α/β = 10 Gy)
Borderline correlation with late complications
(p = 0.54 to 0.86 for α/β = 2–3 Gy)
28