exclude category to Breadcrumbs

Hello, (sorry for my English) I’m looking for a way to exclude certain categories from the function breadcrumb but I can not find a solution, so I ask for your help. this is my code: (thanks in advance for the help)

function the_breadcrumb() {
global $post;
	if (!is_home()) {
		echo '<a href="'.get_option('home').'">'.home.'</a>';
		if (is_category()) {
			echo " / ";
			echo single_cat_title();
		} elseif(is_single() && !is_attachment()) {
			$cat = get_the_category(); $cat = $cat[0];
			echo " / ";
			echo get_category_parents($cat, TRUE, ' ' . $delimiter . ' ');
			echo " / ";
			echo the_title();
		}
		elseif (is_search()) {
			echo " / " . cerca;
		}
		elseif (is_page() && $post->post_parent) {
			echo ' / <a href="'.get_permalink($post->post_parent).'">';
			echo get_the_title($post->post_parent);
			echo "</a> / ";
			echo the_title();
		}
		elseif (is_page() OR is_attachment()) {
			echo " / ";
			echo the_title();
		}
		elseif (is_author()) {
			echo wp_title(' / Profilo');
			echo "";
		}
		elseif (is_404()) {
			echo " / ";
			echo errore_404;
		}
		elseif (is_archive()) {
			echo wp_title(' / ');
		}
	}
}