Embedding Silverlight in a Browser

I have an application for a huge business that needs a lot of pages, controls, etc. The .xap file easily reaches 50 MB. I notice that every time I load the page, the .xap file is uploaded to the local one. However, my users can use the 3G network to connect, so it should be very slow if we open the application every time we open the page. So I was wondering if it is possible to somehow perform a deployment similar to WPF, which only loads locally when the version changes.

Any other suggestion for improving download speed is welcome.

Thank you so much