To begin, we need to define oligometastatic disease in PCa. Initially described as an intermediate state between localized disease and widespread systematic metastases, the definition now can be somewhat variable. In this talk, he defines it as intermediate state of tumor spread with limited metastatic potential, better prognosis than systemic spread, low volume metastatic disease, and in which metastasis directed therapy may be beneficial.
The APCCC Conference 2017 completed a survey of members that addressed their opinions on oligometastatic disease – key take-away points: Most thought it was bone & LN mets that could be treated with local therapy and limited to <= 3 mets. However, opinions on treatment was all over the map.
What is the goal of treatment of oligometastatic disease?
1) Improve cancer-specific survival
2) Improve overall survival
3) Delay progression to systemic therapy
Prerequisites for long-term success:
1) Accurate imaging to detect early metastases
2) Complete eradication of all oligometastatic sites
3) Acceptable toxicity
With regards to imaging, we are still trying to optimize imaging that can pick up early low-volume metastases.
- PSMA PET superior to Choline PET scan
- However, in a study correlating Choline PET to salvage LN dissection – 84% had positive nodes in areas other than the single positive PET imaging.
- In a paper by Tilki et al (2015, J Urol), the German group assessed the efficacy of salvage LND in 58 patients over a 7 year period
o Choline PET identified 39.7% accurately, but 60% were false negative!
- Therefore, if panning on salvage LND, do a wide excision beyond what the imaging shows
- Multiple single institution series have demonstrated PSA-progression free survival with sLND
- Key predictors of clinical relapse:
o PSA < 4 pre-treatment
o Positive LNs at RP
- However, it is unclear if these patients have survival benefit due to the shorter follow-up
- Degree of biochemical response / PSA decline is predictive of response
- Complications following sLND for PCa
Predicting optimal response to sLND: In a paper published by the speaker, the following identified:
Pre-operative parameters: PSA < 4, PSA-DT > 1 year, Gleason score < 8, Positive PET scan in true pelvis alone
Post-postoperative parameter: Complete biochemical response, < 3 positive LNs prior to RP, absence of extranodal extension.
Presented by: Axel Heidenreich
Written by: Thenappan Chandrasekar, MD, Clinical Fellow, University of Toronto, Twitter: @tchandra_uromd at the 37th Congress of Société Internationale d’Urologie - October 19-22, 2017- Lisbon, Portugal