How Effective Is Hydomorphine For Pelvic Pain?

My daughter has a series of health problems from cervical cancer, endometriosis so severe that it caused damage to her stomach, and bowels. She has had nearly fifteen surgeries to remove tumours and growths from her reproductive organs. She lives in constant pain. She was given hydomorphine contin however she can t seem to find relief on that dose most days. She is under hospital care regularly attending a pelvic pain clinic two to three times a week which only adds to her pain.. She has been on the same prescription of morphine for the past six years and at least every three months, especially on the third month, she loses the battle and runs out of her medication early. How do I help her with the withdrawals since I can t help her with her pain? I would also like to mention that my precious girl was really smart. She study hard and got three degrees from University, she had a really good job that paid well now she lives on a disability pension.