EAU PCa 2018: Local Treatment in M+ PCa
There are several reasons for administering local treatment in metastatic patients. These include the reduction of tumor burden (cytoreductive), reduction of the shedding of metastatic cells and circulating tumor cells, decrease of the paraneoplastic effects, and lowering the immunosuppressive effect of the tumor. There is a precedent for this approach in other cancers such as renal cell carcinoma, where cytoreductive nephrectomy is performed, and ovarian cancer.
In a systematic review assessing 16 retrospective studies mainly taken form population-based databases, metastatic patients who underwent local treatment were analyzed, and a benefit for this treatment was observed. This translated to improved overall survival and cancer specific mortality.
Which metastatic patients need to be considered for local treatment is an important question. A study aiming to answer this question was published in 2015 based on the US SEER population-based database. (1) Overall, 8197 metastatic patients were assessed, with 628 of them receiving local therapy. The study demonstrated that if the predicted cancer specific mortality risk at 3 years was more than 50%, there was no point in pursuing local treatment. If the risk was lower, the cancer specific mortality of patients undergoing local treatment was better. A multi-institutional study analyzing perioperative outcomes in 106 men who underwent radical prostatectomy for distant-metastatic prostate cancer at presentation showed the safety of such a procedure (2). To date, the EAU guidelines state local therapy in metastatic patients should only be offered to patients as part of a trial. This is due to the lack of level 1 evidence on this topic.
The speakers moved on to discuss the role of metastasis-directed therapy (MDT) in patients who relapsed after local treatment. The aim of MDT is to delay the initiation of systemic treatment. The EAU guidelines currently state that MDT should be regarded as an experimental approach, due to the fact that the evidence supporting this approach is poor. However, there are many level 1 evidence studies that are currently underway, which will hopefully help us understand the role of MDT. The studies include the STAMPEDE , PEACE-1, and HORRAD which will examine the role of radiotherapy in metastatic patients, and additional studies examining the role of radical prostatectomy in addition to hormonal therapy.
In summary, local treatment might have a possible role in metastatic patients, but to-date no high-level evidence exists to support this approach. Side effects of this therapy are most probably acceptable but need further study. Randomized controlled trials are needed to properly assess oncological, functional and quality of life results.
Speaker: P. Sooriakumaran, Oxford (UK) N. Fossati, Milan (IT)
Written by: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre, Twitter:@GoldbergHanan at the 2nd EAU Update on Prostate Cancer (PCa18)– September 14-15, 2018 – Milan, Italy
References:
1. Fossati N et al. Eur Urol 2015
2. P. Sooriakumaran et al. Eur Urol 62 (2012) 1-15