Non-Rigid Surface oil painting

Hello all!

I know it is best practice for oil paintings to be made on a rigid substrate, to reduce the cracking you get with a flexible surface that also reacts to humidity and temperature changes over time. This would include painting on a wood panel, hardboard, aluminium and paperboard, with a well sized and primed surface, with or without a layer of canvas on the top or muslin embedded in a genuine gesso ground.

But, is there anything that can be done to help make a more permanent painting when a rigid substrate cannot be used, as with large paintings where a lightweight surface is required? What is best practice for oil painting on a stretched canvas?

Thank you for any help.