Hello and welcome to HCM.
Thank you for your query.
Bleeding in a post-menopausal woman with endometrial thickness carries a 10-20 % chance of turning out to be cancer. And with further investigations, this can be confirmed or ruled out. A 10 mm endometrial thickness is a tad bit more than the cutoff, which is why a
hysterectomy has been advised to you.
Before going in to the details and regardless of the details, a hysterectomy would be advised either way. Which will ensure complete discontinuation of whatever condition has caused the bleeding, whether cancer or anything else.
Even if it is cancer, which as I mentioned earlier, carries a 10-20 % chance, a hysterectomy would be the best and most effective treatment, preventing any form of spreading. So please go ahead with the procedure, and I am sure all will be well after.
I hope I have succeeded in providing the information you were looking for. Please feel free to write back to me for any further clarifications. I would gladly help you.
Best wishes