ESTRO 2024 - Abstract Book

S1397

Clinical - Head & neck

ESTRO 2024

Between December 2008 and December 2022, 107 patients with GO received RT. After excluding 33 patients who underwent surgery before RT, didn’t have a sufficient follow -up period, or received RT on one eye, a total of 74 patients were analyzed. RT was applied to both orbits with the dose of 20 Gy in 10 fractions and 51 patients were treated with steroid concurrently. 65 patients (87.8%) had used steroids before RT, and 53 patients (81.5%) had not shown a response. Symptoms were evaluated with a modified clinical activity score (CAS) and responder was defined as patients who had CAS decreased by two or more points. The most common symptoms were eyelid swelling (81.1%), conjunctival edema (81.1%), and redness of conjunctiva (66.2%). Diplopia was shown in 48 patients (64.9%).

Results:

With the median follow-up of 44.5 months (range 4.8 ~ 169.6), CAS at the beginning of RT was significantly higher compared to those at the end of RT, 1 month, 4 months, and 6 months after RT (p<0.001) (Table 1). However, diplopia significantly improved at the 4 months after RT (p=0.039). Symptom duration before RT (p=0.048) and the initial CAS (p=0.002) were predictive factors of response to RT after 1 month. 63 patients who initiated RT within 12 months of symptoms showed a shorter duration of steroid use after RT compared to 11 patients who showed symptoms more than 12 months (p=0.011). Even though it is not significant, their intravenous and per oral amount of steroid usage also showed differences between those who started RT within 12 months and after 12 months (p=0.375 and p=0.320, respectively) (Figure 1).

Table 1. Response to radiotherapy

At the beginning of RT

4 months after RT

6

months

At the end of RT 1 month after RT

p value

after RT

n

%

n

%

n

%

n

%

n

%

0.049 a

Diplopia

None

26

35.1

27

36.5

32

43.2

35

47.3

39 55.7

Intermittent

29

39.2

29

39.2

24

32.4

25

33.8

25 35.7

Inconstant

or

19

25.7

18

24.3

18

24.3

14

18.9

6

8.6

constant

<0.001 b

CAS

CAS (mean± SD)

3.55±1.23

2.65±1.34

1.96±1.16

1.63±1.18

1.27±1.09

Inactive GO (CAS<3) 14

18.9

35

47.3

49

66.2

55

74.3

53 71.6

Active GO (CAS≥3)

60

81.1

39

52.7

25

33.8

15

20.3

7

9.5

a Kruskal-Wallis test, b Analysis of Variance (ANOVA) test

Figure 1. Comparison of Steroid therapy according to Symptom Duration before RT