 Pain intensity level on a 0-10 visual analog scale VAS, patients will be instructed about the use of a 10-cm visual analog scale VAS 0 no pain to 10 worst possible pain. frequency of Breakthrough pain throughout the day, onset of relief 0-5, 6-10, 11-15, or over 16 min, time required for dose titration, patient satisfaction and adverse effects were assessed at 3, 7, 15, and 30 days after starting the treatment. 