Topic: Force update to partial

I'm trying to figure out if it's possible to implement the following scenario:

1.  User adds multiple items to their shopping cart.  Each of which is added to the displayed page in a cart widget/partial.
2.  User goes to shopping cart detail page.  Removes one item.
3.  User hits back button. 

Here's the meat of the matter:  Now the cart widget doesn't reflect the actual state of the cart.  What's the best way for me  to force a refresh to ensure the cart is accurately displayed to the user?