I had brachytherapy last May after endometrial cancer stage 1b. It has become painful with flare ups once a week usually. I am on oxbutynin 3 times a day. I have haematuria but a cystoscopy and scan showed no infection. However oddly Nitrofurantoin seemed to help. Doc reluctant to prescribe it now we know there's no infection but pain wakes me up a lot at night and is severe.