ESTRO 2024 - Abstract Book

S405

Brachytherapy - Urology

ESTRO 2024

d'Oncologia, Radiation Oncology, Barcelona, Spain. 5 Hospital Universitario de Navarra, Medical Physics, Pamplona, Spain. 6 Universitat de Barcelona, Radiation Oncology, Barcelona, Spain

Purpose/Objective:

In 2016 we started a prospective Fase II protocol inside GICOR (Radiation Oncology Research Spanish Group) to test if focal Brachytherapy with seeds was safe and produced fewer secondary effects than total gland Brachytherapy, in patients diagnosed with uni-lobar, low-risk prostate cancer. It was a multicentric Spanish study although only 2 centers in Navarra and Catalonia included patients.

Material/Methods:

Patients diagnosed with low risk prostate cancer (PSA <10, Gleason 3+3 or 3+4, T1c-T2a) were included. In all digital exam, Biopsies and MRI showed disease to be confined to one lobe and less than 3 positive cylinders. All of them received a permanent implant of Iodine-125 seeds covering only the affected hemigland. Confirmatory biopsies at 1-2 5 years were not performed systematically. Follow-up MRI were performed 1 and 2 years after Brachytherapy to rule out early local relapse in prostate.

Results:

The study was closed in 2020 because of low recruitment. Series characteristics: Number of patients 38, Mean Age 66.5 y ( 50-78y). Laterality: 22p left, 16p right . Initial PSA: 6.58 ng/ml( 1.5-9.9). 37 patients had Gleason 3+3 and 1 Gleason 3+4. Mean follow-up: 68.63 months (44-92). Mean PSA Nadir: 1.4 ng/ml(0.17-4.24). 17 patients developed Biochemical relapse. Mean time to BQ relapse: 36,12 Months (5-82). The rate of biochemical control at 5y is only 59.6%; thus, 40.4% developed BC relapse at 5y. 14 patients had local relapse confirmed by PET or Biopsy: contralateral in 9p, ipsilateral and contralateral 4p, regional 1p. Patients were rescued with contralateral LDR-BT in 6p; HDR-BT in 2p; nodal RT+ hormonal therapy in 2p, 1 prostatectomy, 1 only hormonal treatment. After the salvage treatment, all the rescued patients are alive without disease. At this moment, 23 patients are alive without disease, 12 alive with disease, 3 died for other causes. Mean last PSA: 2.16 ng/ml (0.01-17).

Conclusion:

Hemiglandular prostate brachytherapy in our trial resulted in a negative study because we observed a very high rate of Biochemical and contralateral relapse. Biochemical and local control is much poorer that whole-gland brachytherapy. Probably the patients included in our study were not properly studied, because, although all of them had biopsies and MRI, in not all cases the MRI was prior to biopsies. The ideal situation would be to dispose of a MRI and, posterior to MRI, systematic mapped biopsies fusioned with the MRI, before Focal Brachytherapy was performed. The fact is that we are reference centers for Brachytherapy and patients are referred from different hospitals around. Another factor is that a central revision of the pathologic samples of biopsies was not performed, that would have been ideal to homogenise the series. With our results, we think that the efficacy of hemiglandular BT needs further investigation in prospective, well-designed trials.

Keywords: Focal Brachytherapy, Prostate neoplasm