For the first example, there are a couple of ways to do it:
echo "$title ($year)" . ($edition)?" - $edition":"";
$display_edition = ($edition)?" - $edition":"";
The second method probably involves less code for your second example:
$display_edition = ($edition)?" ($edition)":"";
. . .
<TD CLASS='rindex-link'><a href='reviews/DVD/read.php?id=$id'><b>$title</b></a>$display_edition</TD>
. . .";
Hope that helps. If I've misunderstood the question, just keep asking.
I just realized that I pasted your BBCode tags into mt answer and they got seen as BOLD tags for this post. Sorry. I'll bet you get the point, though.