Is it an indeterminate tomato? You could try the Lower and Lean method.

Three things. Please ignore the grass on the outside. I didn't expect everything to survive. And I know it needs to be weeded. P.S. the entire line of flowers behind it are really outside of the chicken wire fence. Got to keep the deer out. It's just marigolds, chilis, and a mini pumpkin tower with two tomatoes.

Now that that's established, how can I make your method work with the tomato on the right? I'm never this successful, so I'm really at a loss

Oh, and it's 'Black Krim'

Um, if you have room, just set up another cage next to it. Lateral expansion.

Oh. Okay. It's just crazy to be this successful this early. He'll probably get probably taken out by a hail storm or deer. Hopefully not. Thank you.

Are you pruning and taking off suckers? You don’t have to, but some do and like the plant to be trimmer & have more air circulation.

Sometimes I put a large center stake in the cage, with loosely tying the main stem for more stability , because I use a large diameter cage, and may add some stakes outside the cage also. My cage is fenced for deer also, and anything that protrudes through the fence gets pruned by the deer.

I've never did it to, because I've never gotten this big. I'm lucky if it survives hornworms. I don't even know that I would know what to look for to prune a sucker. Flowers, I have all day long. Vegetables not so much.

There are two approaches to the problem. (1) make the cage bigger, (2) make the plant smaller. It's a matter of deciding whether productivity can be compromised. Adding additional netting may be an issue, so the second option might well be more feasible.

I have a number of spiral stakes and use them to support long tomato vines when they top their cages - you just wind the stems into the spirals

IIRC, I got some of mine here:

https://www.gardeners.com/buy/spiral-plant-and-tomato-stakes/39-514.html

Lowes has them singly:

https://www.lowes.com/pd/Gardener-s-Blue-Ribbon-Tomato-Twist-Red/5005344769