Unfortunately no. As with most ISPs, Comcast email is proprietary. They don't offer free-standing email accouns like Gmail or Yahoo etc. Once you cancel service you will no longer have access to your Comcast email.
If you want to keep any emails you have on the Comcast server, you can export them to another email service. But you should open an account with Gmail, Outlook.com or some other and import your Comcast emails and contacts before you cancel service. You could also set up the Comcast account in an email client like Outlook or Thunderbird and then put important emails in local folders you create. That way you will have them on your computer. If you only have a small number you want to keep you could just forward them to the new account.