Cutworms are different than the horned tomato caterpillars.
The cutworms are smallish and kind of brown colored, live in the soil near the base of the plant, they come out and encircle the stem of a young tomato (or other plant) and chew in a circle and the plant keels over. The tomato hornworm caterpillars are big, fat, beautiful green buggers, they eat the leaves and even the green tomatoes.
Here is our 'best' tomato from 2013 which was eaten by the dreaded hornworm caterpillar.