ESTRO 2024 - Abstract Book

S1885

Clinical - Mixed sites, palliation

ESTRO 2024

was prescribed to a median biological effective dose (BED10) of 70 Gy (IQR 48-72 Gy), delivered in 5 fractions (IQR 5 5). Median gross tumor volume (GTV) and median planning target volume (PTV) were 11.8 (IQR 8.9-23.9) and 41.7 (IQR 29.3-61.4) cc, respectively. Median estimated follow-up was 16.3 months (95% CI 7.4-18.5). Overall local control rate based on RECIST criteria was 80% (CR = 17.1%, PR = 45.7%, SD = 17.1%), with a 1- and 2-year LPFS rates of 81.2% (95% CI 62.7-91.1) and 73.1% (95% CI 48.0-87.4), respectively. A PTV BED10 dose >70 Gy was correlated with improved LRFS (2-year LPFS 83.3% BED >70 Gy vs 61.9% BED <70 Gy, p = 0.027). One- and 2-year DFS rates were 36.6% (95% CI 18.8-54.5) and 32.0% (95% CI 15.2-50.2), respectively, and the corresponding OS rates were 62.8% (95% CI 40.0-79.0) and 51.4% (95% CI 28.6-70.2), respectively. At univariate analysis, less than 3 SBRT-treated oligometastatic sites correlated with survival (HR for DFS 0.30 [95% CI 0.11-0.80], p = 0.016, and HR for OS 0.24 [95% CI 0.07-0.82], p = 0.023). No SBRT-related adverse events G>2 occurred, and no cases of adrenal insufficiency were recorded (hormonal and electrolytes testing showed only transient variation within the reference range).

Patients, n

32 35

Treated AGMs, n

Sex, n (%)

Female

12 (37.5) 20 (62.5)

Male

Age, median (IQR)

68 (62.7-74.5)

Primary tumor, n (%) *

Lung Renal Other

26 (81.2) 5 (15.6)

1 (3.1)

Histology, n (%) *

Adenocarcinoma Clear cell Small cell

20 (62.5)

Other

5 (15.6)

4 (12.5)

3 (9.4)

AGM classification, n (%) ^

De-novo

9 (28.1) 13 (40.6)

Repeat

Induced

10 (31.2)

AGM timing presentation, n (%) ^

Synchronous

8 (25.0)

Early metachronous (6-24 months)

9 (28.1)

Late metachronous (> 24 months)

15 (46.9) 15 (42.9) 20 (57.1)

AGM side, n (%) ^

Right

Left

Patients at high risk of adrenal insuffiency, n (%) °

4 (12.5)

Pre-SBRT systemic therapy, n (%) *

Chemotherapy

3 (9.4)

Immunotherapy

11 (34.4)

Target therapy

5 (15.6)

Combination

7 (21.9)