use strict;
use warnings;

local $/ = "<br>";
while ( <DATA> ) {
   print $1 if /Title:(.*?)<br>/s;
}

__DATA__
a whole
lot of  worthless
stuff
<b>Title:
</b>
STRING_I_WANT<br>
more worthless
meaningless stuff
or sometimes
<b>Title:
</b>ANOTHER STRING_I_WANT<br>