Bladder cancer lesions are thought to be the result of a combination of environmental exposure and genetic susceptibility. Clinically, morphologically and pathologically, bladder tumors can be classified as superficial, low-grade papillary tumors and high-grade carcinoma in situ or invasive malignancies.
The majority of bladder tumors (70-80%) are superficial and can be surgically removed confined to the mucosal layer. Following resection, recurrence occurs in approximately 50-70% of patients, mostly 12 months after diagnosis. Approximately 5-20% of patients with recurrence will progress to the muscle-infiltrating stage.
Two hypotheses provide explanations for the frequent recurrence of bladder tumors.
The first, the “soil effect or soil malignancy” hypothesis, suggests that exposure to various toxins increases the susceptibility of the entire uroepithelium, increasing the risk of subsequent development of multiple, unique tumors.
The other “seed” hypothesis suggests metastasis of clonal tumor cells into the adjacent normal bladder mucosa.
Conceptually, both models provide new ideas for adjuvant implementation strategies to prevent tumor formation.