I am not sure which titles you are referring to. The title that is actually within the pivot table, which might be a variable name or label or a term like "Statistics" is important and one would rarely if ever want to hide that, so I presume that you are referring to the Title element produced by some procedures such as Frequencies.
One could hide that using a Python script, but there is an extension command that can hide all the procedure titles in the Viewer with one command. Maybe that would suffice.
Here is the syntax.
SPSSINC MODIFY OUTPUT TITLES /IF PROCESS=ALL
/VISIBILITY VISIBLE=FALSE.
This is an extension command, and it can be installed via Extensions > Extension Hub. It will appear on the menus as Utilities > Modify Output Titles.
V25 is very old - V30 was released last year, but that syntax should work.
If you really mean to hide the titles within the pivot table, it could be done with a small Python script using the SetTitleText api applied either to, say, the most recent pivot table or to all pivot tables at once.