ESTRO 2024 - Abstract Book

S820

Clinical - CNS

ESTRO 2024

The median follow up was 18 months (range - 6-24 months). The complete obliteration rate for patients followed up for 2 years was 66.6%. The obliteration rates at the end of 6, 12 and 24 months were 63.3 % (19), 83.3% (25) and 100% (30) respectively. The obliteration rate at 6 months was significantly better in patients who received dose in single fraction and had low PTV (5.7 cc) with (p - 0.008) and (p - 0.005) respectively. At 1 year, patients with younger age (< 30 years), dose in single fraction and low PTV (5.7 cc) had significantly higher obliteration rate with (p - 0.03), (p - <0.001) and (p - 0.001) respectively. The obliteration rate was significantly better at 2 years also in younger age group (< 30 years), dose in single fraction and low PTV (5.7 cc) with (p - 0.03), (p - <0.0001) and (<0.0001) respectively. The obliteration rates at 6 months, 1 year and 2 years were higher in patients with low modified radiosurgery based AVM grading score (<1.46) with (p - 0.004), (p - 0.001) and (p - 0.001) respectively. Three patients had hemorrhage from the AVM and 1 patient had developed radiation induced necrosis after irradiation. None of the patients in our study had developed any neurological deficits and no fatalities were reported.

Table 1 - Association of modified radiosurgery based AVM grading score with obliteration

Association of AVM score with obliteration

Median score

p-value

At

6

months

partial stable

1.18

(1.05,

1.46)

0.004

2.42 (1.86, 3.96)

At

1

year

Complete Partial Stable

1.18

(1.05,

1.29)

<0.001

1.94

(1.46,

2.5)

3.96 (2.42, 3.96)

At

2

years

Complete Partial

1.18

(1.03,

1.46)

<0.001

3.14 (2.42, 3.96)

Table 2 - showing rates of obliteration with various predictive factors

p

-

value

Obliteration at 6 months -

0.008

Fraction size (1 vs 3) PTV - 5.7 cc (4.1, 11)

0.005

Obliteration at 1 year

0.03

Age

<0.001

Fraction size (1 vs 3) PTV - 5.7 cc (4.1, 8.5)

0.001

Obliteration at 2 years