Better than constants, create a `isSaved()` method in your entity and call it here.
While `form.vars.value.status` is valid, I advise you to directly pass the entity to the view to make your code more explicit.
Also, you shouldn't use inlined conditions:

```jinja
    {% if announcement.isSaved %}
        <span>Update</span>
    {% else %}
        <span>Preview</span>
    {% endif %}
```