Focal Therapy

Introduction

With focal therapy the treatment of prostate cancer is focussed only on the cancer region within the prostate. Thereby the aim is to spare healthy prostate tissue and surrounding nerves in order to preserve urinary continence and erectile function while still treating the cancerous region.

This new treatment paradigm was developed as a response to complications seen after whole-gland treatment (treating the entire prostate) like surgery or radiotherapy. In order to be a candidate for a focal treatment, prostate cancer needs to be confined to one localized region within the prostate and be of intermediate aggressiveness.

Different techniques can be used to focally ‘ablate’ (treat) prostate cancer (freezing, laser, focussed ultrasound (heating) or electricity. We used irreversible electroporation as ablative modality, in which the tumour is killed by high-voltage electrical shocks between needles that surround the tumour. Our research line contains multiple projects on selection the appropriate patient for focal therapy, evaluation the outcomes of focal therapy and is looking to improve the outcomes and selection for this new modality.

What we’ve done so far

First of all we looked at how to select the appropriate patient and found that a combination of the use of MRI and template biopsies (that is to take multiple prostate biopsies out of every region within the prostate) was able to selection patients accurately (Tran et al., 2016). This was followed by our first trials on the use of irreversible electroporation in prostate cancer (Blazevski, Scheltema, et al., 2020; Blazevski, Scheltema, Yuen, & Masand, 2019; Ting et al., 2016; Valerio et al., 2014; van den Bos et al., 2017). Our latest publication showed that we are able to clear the prostate cancer in roughly 95% whilst still being able to treat the other 5% with surgery or radiotherapy. 99% of patients preserved their urinary continence and 76% preserved their erectile function (Blazevski et al., 2019). Other studies showed that it’s safe to treat anywhere within the prostate (Blazevski, Amin, et al., 2020; Scheltema et al., 2018) and that surgery after focal therapy is still a good treatment option (Blazevski et al, 2022).

Ongoing projects

As we found that the MRI after focal therapy is less reliable as normal (Scheltema, Chang, et al., 2017), we are looking to improve the diagnostic options after focal therapy. This may be done with PET CT scanning (PSMA) or by looking more closely to changes in the tissue on biopsies after focal therapy (an area that’s called (epi)genetics). We are also still treating patients with irreversible electroporation and are monitoring them to get a more mature insight in the outcomes of this new treatment. Moreso, we expanded the treatment to patients that have a localized recurrence after radiotherapy within their prostate (without the presence of metastasis) (Scheltema, van den Bos, et al., 2017).

Future directions

Our aim is to establish this new treatment option as a valid treatment option for men with localized prostate cancer due to the low risk of side effects and the effectiveness we see. In order to succeed we must improve our patient selection (truly finding those with only one region of prostate cancer within their prostate) and be able to rule out any remaining cancer after the treatment. One other area that may be explored is the evolving world of immunology. In other types of cancer is has been shown that the immune system is able to recognise cancer better after is has been ablated. Potentially the combination between an ablation and immunotherapy could be the way forward for certain types of prostate cancer.