The page content field stores the HTML content for your page. You can fairly easily remove the "<" and ">" Characters, but this will still leave the tag names. For example "<p>" would become "p". it will be pretty problematic to remove _all_ HTML tags from the page content.
The following is an example of how to remove all instances of the "<p>" tag and the "<br />" tag:
<?php echo substr(str_replace("<br />", "", str_replace("<p>", "", $row_getData['pageContent'])),1,50); ?>