As it is >12 years since your diagnosis of ovarian cancer
and there is no evidence of recurrence, I would not think that the current symptom is due to it. The vaginal walls actually get thin and fragile as they are deprived of normal estrogen
secreted by ovaries. This can lead to bleeding into the urine (though it is not actually blood in urine).
Sometimes local estrogen cream application can help in this (only if there is pain or burning sensation). If this is not bothering you we may just follow-up.