Recurrent bladder cancers following upper-tract tumors mostly come from intraluminal seeding.The recurrence, progression, and prognosis of the two different tumors were analyzed.

• 另一个多发性形成的原因是尿液中的致癌物，造成整个泌尿上皮的癌化，形成多个独立不同来源的肿瘤。