Pruning suckers that grow in the axils where side branches meet the stem was the only form of tomato pruning I knew about. I doubt my brother, Bubba, or his wife, Flip Flops, have ever heard of tomato suckers. The two of them don’t know the difference between a plant and a weed. As a result, they didn’t prune anything on their patio tomato. Not even yellowed leaves. Amazingly, it was still blooming despite temperatures in the mid-90’s.
By July, the plant was full of brown leaves and ugly, sick-looking stems. It was hideous looking. Despite my own lack of knowledge, I told Bubba we should attempt to preserve the bush for cooler weather and a second crop. With him watching, I proceeded to remove all the ugliness. I hope he learned something. I sure did. Within weeks, the plant had put on all new growth that became so heavy, the center limbs toppled over.
Bonnie Plants and Wikipedia both have good tips for pruning tomatoes including the warning not to prune determinate varieties. I don’t know whether or not the patio tomato was determinate but it survived the pruning I gave it.