All four of these are expressing some degree of sadness or wistfulness that a trip was cancelled. There might be very little difference in meaning between them, although:
I'm sorry that the trip was cancelled.
could be indicating some apology on behalf of the speaker. For example, if a travel agent was calling a customer with bad news – that arranged travel plans would need to be cancelled for some reason – the agent would be more likely to use "I'm sorry that..." than any of your other three options.
However, suppose the would-be traveler announces at her weekly bridge game that her trip had to be cancelled. Her fellow bridge players could easily go around the table and say:
I'm sorry that your trip was cancelled.
It's too bad that your trip was cancelled.
Such a shame that your trip was cancelled.
and they all pretty much mean the same thing:
It's so sad that your trip was cancelled.
Among friends, "I'm sorry that..." often means, "I'm sorry to hear that..." However, in the case of the travel agent, "I'm sorry that..." means, "I apologize for saying this, but..."
As for any other nuances, I'd be inclined to say that "It's a pity that..." sounds a bit old-fashioned, or perhaps a little stilted for everyday conversation. That said, all of them can be used as expressions of empathy.