ESTRO 2024 - Abstract Book

S2628

Clinical - Urology

ESTRO 2024

considered. The collected data included information on primary tumor characteristics, any imaging modality used for staging, dates of biochemical relapse, clinical relapse, and data regarding toxicity. Descriptive and frequency analyses were performed, and the mean time to event was calculated. Time-to-event analysis considered biochemical progression, clinical progression, and distant metastasis progression after salvage RT. Univariate Cox regression was utilized, and significant covariates (p <0.05) were included in the multivariate Cox regression.

Results:

A total of 1625 pts with a median age of 64.3 years and a median follow-up of 4.2 y (IQR 2.49-6.28) were included in the analysis. IMRT/VMAT technique accounted for 96.2% of treatments and 632 (39%) underwent imaging pre-sRT. Characteristics of the population have been summarized in Table 1.

Characteristic

N = 1,625

PSA pre-surgery

8 (6, 12)

pT

1

3 (0.2%)

2

656 (41%)

3

943 (58%)

4

10 (0.6%)

pN

0

1,028 (66%)

1

518 (34%)

Surgical Margins

0

773 (50%)

1

768 (50%)

post-op ISUP grade

1

219 (14%)

2

451 (28%)

3

448 (28%)

4

271 (17%)

5

223 (14%)

PSA level first BCR

0.26 (0.19, 0.48)

Table 1 – Patient characteristics, NAs not showed

A total of 617 events (38%) of biochemical recurrence after salvage radiotherapy was recorded, with a median time of 2.89 (IQR 1.36-4.84) years (Fig. 1). At multivariate analysis for biochemical recurrence free survival (BRFS), the