San Antonio, Texas USA (UroToday.com) There has been recent interest in the use of definite treatment of the primary tumor in patients with metastatic prostate cancer. The rationale comes from several retrospective trials suggesting an improvement in overall survival, along with benefits in reduction of symptoms related to local progression of the disease. Furthermore, there is evidence of molecularly lethal prostate cancer hidden in primary tumors along with emerging evidence that tumor biology may be affected by extirpation of the primary site.
In this session, Dr. Chapin (MD Anderson) discussed the role of local therapy in patients with oligometastatic disease. It appears that surgical extirpation of the prostate gland following systemic therapy is feasible with comparable complication rates to patients with localized disease. The speaker then presents preliminary observations of the phase 2 multicenter randomized trial comparing best systemic therapy (BST) vs. BST plus definitive therapy in patients with metastatic prostate cancer. His first observation was the stage migration seen in patient with high risk disease towards low volume M1 disease due to the improvements in in imaging (sodium fluoride bone scans and PSMA PET scans). There is paucity data on the natural history of these patients with low volume metastatic disease thus treatment options should be explored within the confines of clinical trials.
Oligometastatic patients tend to have favorable outcomes regardless of therapy elected which may impact the effect of definite treatment in this patient population in regards to OS. Finally there is evidence that the metastatic tumor burden response to systemic therapy maybe un-linked to the primary tumor response, creating a subgroup of patients in which local treatment maybe the most efficacious.
Given the favorable outcomes seen in the patient with oligometastatic disease the speaker cautions in the broad application of local therapy before prospective data becomes available. Local therapy may not be beneficial in everyone, which may place patients at unnecessary risk of peri-operative complications and side effects. Current phase 2 and future phase 3 trials will focus on response to systemic therapy rather than the presence of metastatic disease which targets the tumor biology rather than the imaging findings.
The speaker concludes that local treatment of patients with metastatic prostate cancer is feasible and safe when compared to patients with localized disease. Local excision may improve oncological and quality of life outcomes; however, this needs to be validated in randomized control trials. Before broad acceptance of local treatment in patients with metastatic disease there needs to be a clear understanding of the underlying biology of the prostate cancer treated to intelligently integrate multimodal therapies and personalize care in this cohort of patients.
Presented By: Brian Chapin, MD, MD Anderson
Written By: Andres F. Correa MD, Society of Urologic Oncology Fellow, Fox Chase Cancer Center
17th Annual Meeting of the Society of Urologic Oncology - November 30 -December 2, 2016 – San Antonio, Texas USA