ESTRO 2024 - Abstract Book

S2389

Clinical - Urology

ESTRO 2024

Material/Methods:

We prospectively enrolled 721 PCa patients who had undergone RP during the EASY-1 trial (Early Salvage radiotherapy-1). Inclusion criteria encompassed PCa treated with RP, including those with pT2 with positive surgical margins (R1), pT3a irrespective of surgical margin status, or pT3b with negative surgical margins (R0), with a postoperative undetectable PSA level (<0.01 ng/ml) within 40 days after surgery. Patients with nodal metastases were excluded. The surveillance protocol involved regular PSA assessments every 2 months during the first year, followed by assessments every 3 months during the second and third years. Subsequently, PSA assessments were performed every 4 months up to the fifth year and then every 6 months until the tenth year after surgery. esRT was initiated upon biochemical relapse (BCR), defined as two consecutive PSA values ≥0.2 ng/ml. A multivariate Cox regression model was employed to identify independent predictors of BCR.

Results:

Among the patients, 262 (38%), 251 (36.4%), 121 (17.6%), and 53 (7.7%) had pT2R1, pT3aR0, pT3aR1, and pT3bR0 PCa, respectively. In R1 patients, 59% had positive surgical margins ≥3 mm. Gleason Grades at the margin were 3, 4, and 5 in 178 (46.1%), 139 (36%), and 5 (0.3%) patients, respectively. Overall, 64 (9.3%) patients experienced BCR (median follow-up: 39 months). The median time to BCR was 15 months (IQR 8-21), with a median PSA at BCR of 0.21 ng/mL (IQR 0.18-0.32). Out of the 64 patients with BCR, 60 (90%) received esRT. The 5-year BCR-FS rate was 85.5%. Patients with pT2R1/ISUP 4-5 and those with pT3/ISUP 4-5, regardless of margin status, had significantly lower BCR-FS compared to men with pT2R1/ISUP 1-3 and pT3/ISUP 1- 3 (p≤0.01). In the multivariate analysis, pathologic ISUP 4- 5 (HR 2.2) and pT3R1 (HR 2.56) were identified as independent predictors of BCR (all p≤0.003).

Conclusion:

Intensive surveillance with PSA monitoring following RP and early detection of BCR, coupled with esRT, demonstrates the potential for achieving high BCR-FS rates in patients with intermediate-high risk PCa. Pathologic ISUP 4-5 and pT3aR1 status emerge as independent predictors of BCR.

Keywords: Early salvage radiotherapy, prostate cancer, PSA

1098

Proffered Paper

Phase II trial of hypofractionated postoperative radiotherapy in prostate cancer: NCT04484038

Asunción Hervás 1 , Almudena Zapatero 2 , Ana María Carballo 3 , Aurora Rodríguez 4 , Marta Barrado 5 , Antonio Salinas 6 , Clara Eito 7 , Mariana Peñas 8 , Fernando López-Campos 1 , Felipe Couñago 9 , Carmen Martín de Vidales 2 , Ana Otero 10 , Pilar Samper 11 , Paula Peleteiro 3 , Marina S Depiaggio 12 , Leonardo Guerrero 13 , Mariano Porras 14 , Antonio J Lozano 15 , Rocío Pérez 16 , Ignacio Rodríguez-Melcón 17 , Begoña Caballero 18 , Walter A Vasquez 19 , Ana Alvárez 20 , Gemma Sancho 21 , Jorge Lázaro 22