bbp_forum_last_topic_title Max Characters

Hi
I am currently using this code to show the last topic on the main index.
<a href="<?php bbp_forum_last_topic_permalink(); ?>" title="<?php bbp_forum_last_topic_title(); ?>"><em><?php bbp_forum_last_topic_title(); ?></em></a>
I was wondering if there is a way to make the title of bbp_forum_last_topic_title a max amount of characters, so the title is smaller.
Thanks