Custom template for page_title block to add Topic to page title /application/blocks/page_title/templates/topics.php
<?php defined('C5_EXECUTE') or die("Access Denied.");
if (isset($currentTopic) && is_object($currentTopic)) {
$title = t('%s '.$title, $currentTopic->getTreeNodeDisplayName()); // e.g. if page title is Category - <h1>Topic Name Category</h1>
}
if (isset($title)) {
?>
<h1 class="h4 pageTitle"><?php echo h($title)?></h1><?php
}
?>