What Causes White,sticky Mucous In Urine?

Hi, recently I have been passing a white, or clear, sticky mucous through my urine. I have been tested and ruled out for all std's. I was also treated for UTI with doxycycline and cephalexin. Still the mucous persists. There is very little in the urine, however, it remains. I also experience pelvic pain, usually in the join area to both thighs. Also, after sitting for long amounts of time, I feel pain in my rectum and groin area, very persistent and uncomfortable. My WBC is elevated, however infection has already been treated and ruled out. Could this be cancer?