Bladder cancer is a heterogeneous disease with a variable natural history. At one end of the NMIBC spectrum, low-grade Ta tumors have a low progression rate and require initial transurethral resection of bladder tumors (TURBT) and surveillance but rarely are life-threatening. At the other extreme, high-grade tumors have a high malignant potential associated with significant progression and cancer death rates.

In the western world, bladder cancer is the fourth most common malignancy in men and the eighth most common in women.

In Europe and in US, bladder cancer accounts for 5% to 10% of all malignancies in man.

More than 90% of all malignant bladder tumors are transitional cell carcinomas (TCC). NMIBC is characterized by high risk of recurrence (30%-85%) after TURBT.

Despite this high risk of recurrence, the 5-year survival rate is 85% to 90%. Unfortunately 10% to 30% of the superficial tumors will progress to a muscle-invasive tumor, which has a poorer prognosis. The greatest concern in patients with NMIBC is therefore twofold: to lower the number of recurrences and to prevent progression.

To reduce recurrence in NMIBC, bladder instillations of chemotherapy (usually MMC) or immunotherapy (usually BCG) become standard care.

In the last 15 years a combined treatment of hyperthermia with bladder chemotherapy instillation (thermo-chemotherapy) proved to be very effective in two protocols: