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Salvage brachytherapy for locally-recurrent prostate cancer after radiation therapy: A comparison of efficacy and toxicity outcomes with high-dose rate and low-dose rate brachytherapy - PDF Version
Henríquez López I, González-San Segundo C, Vegas JO, Gutierrez C, Hervas A, Cabeza Rodriguez MÁ, Valero Albarrán J, Rodríguez Villalba S, Álvarez Gonzalez A, Sancho Pardo G, Zapatero A, Álvaro PC.
Radiother Oncol. 2019 Sep 27. pii: S0167-8140(19)33090-7. doi: 10.1016/j.radonc.2019.09.006. [Epub ahead of print]
What was your motivation for initiating this study?
In Spain, as in many other countries, prostate cancer patients are treated with external beam radiotherapy. After biochemical relapse, a majority receive palliative hormonal treatment.
On the other hand, only 10% of patients are treated with any form of local salvage therapy (brachytherapy (BT), prostatectomy, cryotherapy or high-intensity focused ultrasound (HIFU)). Interestingly, biochemical control with any of these local salvage techniques is around 50% at five years.
The main motivation for this study was to find out whether the centres in Spain were carrying out salvage BT. Mainly we wanted to know which technique was used, and whether the results were consistent with those published in the literature. This investigation followed our first experience in Spain with salvage brachytherapy [1].
What were the main challenges during the work?
We were interested to discover whether there was any difference in terms of effectiveness or toxicity between low-dose rate (LDR) and high-dose rate (HDR) BT. The challenge was, in the absence of guidelines, to define the optimal candidate profile for BT, because we started from a wide variation of criteria (no defined inclusion criteria, different treatment schemes, two brachytherapy techniques, etc.). We acknowledged the limitations of a retrospective study to reach a meaningful conclusion.
In other words, we investigated whether there were differences concerning clinical, biological and technical characteristics between the two forms of BT.
What were the most important findings of your study?
I would emphasise that the most important finding of this study was that salvage brachytherapy either with HDR or LDR was an effective and well-tolerated treatment technique, when it was offered to well-selected patients for whom radiotherapy had failed. Another important observation was that there were no significant differences between the techniques and either could be used. The importance of this finding must be highlighted, because there are centres that have only one technique available.
Finally, it should be noted that salvage brachytherapy results in prolongation of the patients’ drug-free survival, and delays the use of androgen deprivation therapy. Although we are aware that the level of genito-urinary toxicity was high (around 23%), it is important to highlight that patients had been treated initially with radiotherapy. Brachytherapy makes it possible to re-treat without the production of unacceptable toxicity rates.
What are the implications of this research?
Given the results of this study, we now discuss the possibility of salvage brachytherapy before proposing androgen deprivation therapy.. A large percentage of patients have now the possibility to choose salvage curative treatment before starting palliative therapy.
Selection of patients for local salvage brachytherapy is important for optimal results. For this selection, clinical, biological and radiological characteristics are considered. Brachytherapy can be offered safely through use of optimal imaging techniques, such as pelvic magnetic resonance imaging (MRI), choline PET-CT, choice of the optimal dose and treatment with both HDR and LDR.
References
1. Henríquez I, Sancho G, Hervás A, Guix B, Pera J, Gutierrez C, et al. Salvage brachytherapy in prostate local recurrence after radiation therapy: predicting factors for control and toxicity. Radiat Oncol 2014;30:102. https://doi.org/10.1186/1748-717X-9-102.
2. Henríquez López I, González-San Segundo C, Vegas JO, Gutierrez C, Hervas A, Cabeza Rodriguez MÁ, Valero Albarrán J, Rodríguez Villalba S, Álvarez Gonzalez A, Sancho Pardo G, Zapatero A, Álvaro PC. Salvage brachytherapy for locally-recurrent prostate cancer after radiation therapy: A comparison of efficacy and toxicity outcomes with high-dose rate and low-dose rate brachytherapy.
Radiother Oncol. 2019 Sep 27. pii: S0167-8140(19)33090-7. doi: 10.1016/j.radonc.2019.09.006.
Fig. 2 Prostate-specific antigen relapse-free survival (PSA-RFS) for high-dose-rate (HDR) and low-dose-rate (LDR) salvage brachytherapy
Henríquez López
Hospital Universitario Sant Joan,
Reus, Spain