ESTRO 2024 - Abstract Book

S393

Brachytherapy - Urology

ESTRO 2024

355

Digital Poster

Quarter of a century iodine-seed monotherapy: a silver jubilee of clinical triumphs

Alai Goñi 1 , Belen De Paula 1 , Mikel Eguiguren 1 , Vicent Pastor 2 , Albert Bartrés 2 , Eva María Sáenz de Urturi 1 , Veronica Alba 2 , Daniel Alberto Roura 1 , María Pagola 1 , Julian Minguez 1 , Nuria Bultó 1 , Ane Mugica 1 , Leyre Gonzalez 1 , David Ignacio Ortiz de Urbina 1 , Elena Guimon 1 , Intza Uranga 1 , Usoa Iceta 1 , Amaia Sanchez 1 , Ane Otaegui 1 , Xabier Gurutzeaga 1 , Beraldo Martinez 1 , Melanie Erzilbengoa 1 , Carlos Blanco 1 , Jose María Urraca 1 , Arrate Querejeta 1 1 Onkologikoa - UGC Oncología Gipuzkoa, Radiation Oncology, San Sebastian, Spain. 2 Onkologikoa - UGC Oncología Gipuzkoa, Medical Physics, San Sebastian, Spain

Purpose/Objective:

This study presents the long-term biochemical, survival, and toxicity outcomes of patients treated with permanent low-dose-rate brachytherapy as monotherapy for prostate cancer at a single institution over a period of 25 years.

Material/Methods:

Between June 1999 and December 2016, 1302 patients diagnosed with low and intermediate risk prostate cancer underwent preloaded 144Gy iodine-seed brachytherapy monotherapy at our institution. Patients with less than a 2 year follow-up and fewer than four post brachytherapy prostate-specific antigen (PSA) tests were excluded from the analysis. Clinical outcomes and toxicity were evaluated. Toxicity was assessed using the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0.

Results:

A total of 1013 patients met the inclusion criteria and were included in the final analysis. The median age was 70 years and 22.3% of patients received 3-6 months of androgen deprivation therapy (ADT). With a median follow-up of 11.5 years, biochemical failure was observed in 163 patients (16.1%). Freedom from biochemical failure (FFBF) rates, defined by the Phoenix criterion, were 87%, 78% and 69% at 10, 15 and 20 years, respectively. Metastasis free survival (MFS) rates at 10, 15 and 20 years were 97%, 95% and 92%, respectively. Overall survival (OS) rates were 55% and 36% at 15 and 20 years, respectively. Multivariable analysis revealed that higher pre-therapeutic PSA levels and intermediate-risk prostate cancer were associated with biochemical failure. Late genitourinary (GU) grade 3 or higher toxicity rates were 9%, 14% and 18% at 10, 15 and 20 years, respectively. Gastrointestinal (GI) grade 3 or higher late toxicity rates were 2% at both 15 and 20 years.