Table 2.

Circulating tumor cells as prognostic marker and potential candidate for surrogate of survival in clinical trials

Clinical trial	Drug(s)	Method	Results	References
Phase III	Abiraterone	CellSearch®	CTCs <5 at 12 weeks associated with better 2-year   survival	Scher et al. [84]
Phase III	Enzalutamide	CellSearch®	CTC status at 12 weeks predicted time to   radiographic response	Anand et al. [82]
Phase III	Docetaxel	CellSearch®	CTCs >5 at baseline associated with better median   and 2-year OS	Goldkorn et al. [80]
Phase II	Satraplatin + bevacizumab	CellSearch®	CTCs >5 associated with worse OS	Vaishampayan et al. [76]
Phase II	Temsirolimus	CellSearch®	Lack of CTC conversion to favorable counts during   tx matched lack of clinical activity	Armstrong et al. [77]
Phase I	Cabozantinib	CellSearch®	Higher response rate in pts with favorable CTC   count conversion	Lee et al. [78]
Phase I	Melphalan	CellSearch®	CTCs <5 after tx associated with longer OS	Shamash et al. [79]

CTC circulating tumor cells, OS overall survival, pts patients, tx treatment