Are tomato plants supposed to be pruned?
A light pruning can be done on tomatoes to help yield more fruit and extend the growing season. Understand though that pruning is not just cutting away at the plant anywhere! Only prune the suckers away from where the main stem and the branches meet.
The disadvantage of pruning is the lack of foliage to help shade the fruit which protects them from sun scald.
To achieve the early fruit and keep enough foliage for shading, prune suckers from the lower 14 to 18 inches of the plant and let the rest of the tomato bush out and produce a bountiful harvest.