ESTRO 2024 - Abstract Book

S2491

Clinical - Urology

ESTRO 2024

commonly to a prescription dose of 2300 cGy in three fractions (n = 11, 73.33%) and with a mean MIB dose of 2407 cGy (IQR: 2363- 2420 cGy) to a mean nodule volume of 2.34 cc (IQR: 0.87 – 7.00 cc). Overall, three grade 3 toxicities were observed, both in the non-MIB cohort (i.e. grade 3 diarrhea, and two grade 3 urinary tract obstructions). We observed no significant difference in toxicity in those who underwent an MIB versus those that did not for grade 2+ GU (p = 0.206) or GI toxicity (p = 0.286), respectively. Moreover, no significant difference was observed across time in EPIC urinary (p = 0.316) or bowel summary (p = 0.593) scores in those patients that did and did not receive an MIB. In fact, the non-MIB cohort demonstrated more time points with a decline below the MID. Similarly, no significant difference was observed in any urinary or bowel subscale scores between the two cohorts.

Conclusion:

Intraprostatic lesional microboost during a 3-fraction SBRT prostate boost in concert with pelvic nodal irradiation is a feasible method of dose escalation in aggressive prostate cancer. With early follow-up, we observed no significant difference in CTCAE toxicity nor any appreciable difference in patient reported quality of life outcomes based on EPIC questionnaires for those who underwent an MIB. Future research should explore long-term side effects and oncologic outcomes of this novel method of dose escalation.

Keywords: SBRT, radiation, high-risk prostate cancer

2016

Digital Poster

Impact of dose escalation on positive nodes in prostate cancer patients with pelvic nodal disease.

Arantxa Mera Errasti 1 , Ana Maria Soto-Cambres 1 , Saba Jiries Rabi Mitre 1 , Laura Montezuma Niño 1 , Gemma Calvet 1 , Hector Perez-Montero 2 , Gemma Sancho Pardo 1 1 Hospital de la Santa Creu i Sant Pau, Radiation Oncology, Barcelona, Spain. 2 Institut Catala d'Oncologia. Hospital Duran i Reynals, Radiation Oncology, Barcelona, Spain

Purpose/Objective:

Patients with prostate tumors with pelvic lymph node disease are a very heterogeneous cohort and a therapeutic challenge today.

STAMPEDE study (1) showed higher metastasis free survival (MFS) and overall survival (OS) when adding abiraterone to androgen deprivation therapy (ADT) and local radiotherapy in high risk prostate cancer patients. These results settled this treatment as the new standard of care. However, the grade of evidence when intensifying radiation treatment remains low.

The aim of our study is to analyze the results of patients with N1 prostate cancer treated with ADT and whole pelvic irradiation and the impact of dose escalation over the positive lymph nodes.