So you're saying that a prescription for something like Provera (a progestin) taken for a certain number of days doesn't trigger a bleed after stopping the med?
I don't understand the hysterectomy recommendation if the biopsy was negative. At what point in your cycle was your lining 17mm? The lining gets around 16mm thick every cycle so 17mm wouldn't seem concerning. Of course, if your lining is never thinning out then there is risk of abnormal cells developing. Was the 17mm determined from the D&C or an ultrasound? Polyps and some fibroids can make the lining appear thicker than it is.
Did you know that VERY FEW hysterectomies (only about 10%) are necessary? Although it is a common surgery it is inherently damaging because the uterus has LIFE LONG functions - anatomical, skeletal, hormonal and sexual. The side effects don't necessarily occur right away.
I had an unwarranted hysterectomy after my gyn said it was necessary and rushed me into surgery. I wish I had done things very differently. Unfortunately, with the overuse and profitability of hysterectomy, it can be difficult to get accurate information and conservative / organ-sparing treatment.
If your lining is staying too thick for long periods of time, have you considered taking birth control pills to keep it thinned out (if this is an option based on your health history)? A periodic prescription of a progestin may also be an option. These would be much less drastic than hysterectomy.