What type of pen? Waacom?
Sometimes you can press and hold on a word with the tip and two blue circles pop up on the word and you adjust the blue circles to the end and beginning of he word which also highlights the word. Once you have it hightlighted you can press and hold again with the tip at the center of the highlighted word and it should bring up a menu to allow you to copy or cut.
Also, with the Waacom pen, you should be able to just place the point of the pen at the beginning of the word and then quickly run across the word with the pen and it should hightlight eveything you run the tip across.