Local Ablative Radiotherapy Reverts CRPC to Earlier Disease Stage

[Balsam01]

TAKE-HOME MESSAGE

•This study evaluated the impact of local radiotherapy in men with oligometastatic prostate cancer. The authors included 15 men with PSMA-PET–detected metastatic (low-volume) castrate-resistant prostate cancer. These men underwent local ablative radiotherapy to either bone or nodal metastatic sites. A PSA response was observed in 73% of patients. Mean time to PSA progression or last follow-up was 17.9 months, as opposed to 2.9 months estimated without ablative radiotherapy.

•Based on this, the authors conclude that select men with low-volume castrate-resistant prostate cancer had a meaningful PSA response to local radiation to the lead metastatic site. A randomized trial should be performed to further study the utility of this modality in patients with advanced prostate cancer.

– Gautam Jayram, MD



Urology 

Written by Alberto Bossi MD

The treatment of patients diagnosed with prostate cancer, PCa, and presenting an (oligo-)metastatic disease (both at presentation or after a local treatment) is indeed attracting a growing interest of the scientific community. The article by Lohaus et al. reports a limited series of 15 asymptomatic patients with a progressive PSA and an oligometastatic castration resistant PCa treated with external beam radiotherapy, EBRT, on bone and/or lymph node localizations identified on Gallium PSMA –PET-CT. EBRT was able to stop the progression of the PSA calculated as PSA-doubling time. The hypothesis generated by this observation is that local EBRT may have a clinically significant impact on PSA response even in this subset of advanced PCa patients. Few “leading” metastatic sites, triggered by EBRT, may be responsible of the PSA progression in the castration resistant patient and molecular imaging such as PSMA-PET may be able to identify those sites to guide subsequent EBRT. As acknowledged by the authors themselves, more solid data are needed before confirming the interest of this observation.

abstract

This abstract is available on the publisher's site.

In prostate cancer, disease progression after primary treatment and subsequent androgen deprivation therapy is common. Intensification of systemic treatment is the standard of care. Recently, 68Ga prostate-specific membrane antigen positron emission tomography (PSMA-PET) imaging was introduced to identify oligometastatic prostate cancer patients. In this retrospective, exploratory study, we report on the efficacy of PSMA-PET-guided local ablative radiotherapy (aRT) in 15 oligometastatic castration-resistant prostate cancer (CRPC) patients, selected from our prospective institutional database and treated between 2013 and 2016. After multidisciplinary discussion, aRT was delivered with two different schedules. Androgen deprivation therapy remained unchanged. Prostate-specific antigen (PSA) response and time to PSA progression were analysed. For comparison, individual time to PSA progression without aRT was estimated by individual PSA doubling time (PSADT). PSA response was observed in 11 patients (73%). Mean time to PSA progression or last follow-up was 17.9mo, as opposed to 2.9mo estimated from the PSADT without aRT (p<0.001). A relevant subset of CRPC patients had a PSA response with aRT to PET-positive lead metastases. A prospective trial is in preparation.

PATIENT SUMMARY

In selected patients with prostate-specific antigen (PSA) increase during androgen deprivation, metastases were detected with prostate-specific membrane antigen positron emission tomography imaging. Fifteen patients with three or fewer metastases were treated with high-dose radiotherapy. Subsequently, PSA values dropped in 11 patients and in six patients no PSA progression was detected for >12mo.

European Association of Urology

Can Local Ablative Radiotherapy Revert Castration-Resistant Prostate Cancer to an Earlier Stage of Disease?

Eur Urol 2019 Apr 01;75(4)548-551, F Lohaus, K Zöphel, S Löck, M Wirth, J Kotzerke, M Krause, M Baumann, EGC Troost, T Hölscher

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

[tango65]

This is realy interesting. to me.

I am close to this situation of castration resistant and early mets. My local oncologist wants to do the same that was done in the study. I agree with his idea but to be sure about this plan, I consulted with Dr. Morris at the Sloan Kettering Cancer Center . He recommended the same. To have Ga 68 PSMA PET/CT studies done and when metastases were detected to treat them with SABRT if oligo metastatic or with Lu 177 PSMA if SABRT was not possible. He said that if I was lucky I could delay the use of the new anti androgens/chemo for 1 or 2 years. Apparently this avenue of treatment is already been used in the clinical setting by some oncologists. This study seems to support this plan of treatment.

[garythomas]

I am metastatic castrate resistant. I had a pelvic node picked up by an F18 PSMA pet scan. Then had five doses of SBRT to it. PSA fell from 1.21 to 0.46 in about six months and I have not needed second generation ADT yet.