Uterine thickening and bioidentical HRT

[wishcat]

I am 58 and have been on a bioidentical Estrogen skin gel for about 8 years now.  Every two months, I take a packet of progesterone pills over a 12 day period for my progesterone and have never had any problems, with a normal transvaginal ultrasound 3 years ago.

This month, though, I started my progesterone a week later than usual and missed one of my pills, then ended up with some mid-cycle light bleeding.  It's been about 6 weeks since I started my last packet of progesterone pills and, due to the light bleeding, my gyno did a transvaginal ultrasound, which said I had some nabothian cysts and a thickness of 9&1/2mm for my uterine lining.  She said that my uterine lining should be no thicker than 5mm and did an endometrial biopsy, the results for which I'm still waiting.  How likely is it that this is cancerous?  Could it be due to the long period of time between taking my progesterone packets?