I have seen pics on this website where the vines actually went over the tops of the cages, reached the ground, and started growing up again. Yes, they can break with the weight of the tomatoes, which has happened to me before. That's why I looked for an alternative. You can still grow determinate tomatoes with the regular size cages in pots. The indeterminates are the ones that keep growing. My cherry tomato that I grow, called purple bumble bee has vines that can reach a length of eighteen feet in one season.