Preheat oven to 350 degrees F. Slice loaf in half lengthwise. Hollow out each half by scooping bread out of the middle; reserve removed bread in a large bowl. Set the halves on a large baking sheet and set aside. Tear removed bread in the large bowl into small chunks and set aside. In a large skillet over medium-high heat, brown ground beef and onion; drain and discard any grease. To the skillet add garlic and stir briefly, then add soup, milk, and Worcestershire sauce. Season to taste with salt and pepper and cook 5 minutes or until thoroughly warm. Add hot beef mixture to large bowl and stir to combine. Pour beef mixture into the hollow in one half loaf. Top with shredded cheese and the other half loaf to make a submarine shape. Bake for 10 to 15 minutes, or until cheese is melted. Remove from oven and let stand 5 minutes before slicing and serving.