The purpose of this study is to determine the efficacy and safety of Hyperthermic Intravesical Chemotherapy (HIVEC) with Gemcitabine (GEM) after Transurethral Resection of Bladder Tumors (TURBT) in the treatment of medium or high-risk group Non-Muscle-Invasive Bladder Cancer (NMIBC).

In this study, patients with Non-Muscle-Invasive Bladder Cancer (NMIBC) and planed to undergo Transurethral Resection of Bladder Tumors (TURBT) are randomized into HIVEC group and control group. In HIVEC group, HIVEC is performed with Gemcitabine Gemcitabine (3g/150ml NS) at 45 °C for 60 minutes within 4 weeks, once a week (±5 days) for 6 to 8 times, once a month to 1 year. For the patients in the control group, Intravesical Chemotherapy is administered after TURBT. The primary endpoint is 2-year recurrence rate. Secondary end points include 1-year recurrence rate, recurrence-free survival (RFS) rate, disease free survival (DFS) rate, time to treatment failure (TTF), Success rate of therapeutic operation, Instrument performance evaluation, quality of international prostate symptom score, quality of Urinary Symptoms Distress Score. All efficacy analyses are conducted in the intention-to-treat population. Safety analysis include only patients who receive their randomly assigned treatment.

Inclusion Criteria:

1. Patients who did not receive induction perfusion within 4 weeks after complete resection of bladder tumor with TURBT (Patients who were judged by the investigator to be in need of secondary electrotomy, for the last time).
2. Recurrence risk and prognosis of Non-Muscle-Invasive Bladder Cancer were divided into medium-risk group or high-risk group (patients who underwent multiple electrosurgical biopsies, and the pathological results were based on higher grade tumors).
3. KPS score ≥80, expected survival > 30 months.
4. Pathological suggested non-myoinvasive urothelial carcinoma of the bladder.
5. Age between 18 and 70 years, all genders.
6. Volunteer to participate in this clinical trial and written informed consent.

Exclusion Criteria:

1. Patients with bladder cancer in situ.
2. Combined with proven upper urinary tract or urethral tumors.
3. The patients were complicated with bladder perforation, gross hematuria or urinary tract infection of grade 3-4.
4. Patients with urethral discontinuity, urethral stricture, or inability to use a three lumen catheter normally affect perfusion therapy.
5. Patients who had undergone partial cystectomy or abnormal bladder structure were judged by the investigator to be unsuitable for perfusion therapy.
6. Patients with severe coagulation dysfunction.
7. A history of allergy to injected drugs (gemcitabine).
8. History of pelvic radiation, systemic chemotherapy, or immunotherapy.
9. Complicated with cardiovascular, cerebrovascular, hematopoietic, immune system and other serious diseases.
10. Patients with mental illness, substance abuse, alcoholism, and inability to cooperate.
11. Breastfeeding, pregnant, or planning to have a baby in the near future.
12. Recurrent patients with a prior history of BCG or bladder thermoperfusion therapy.
13. Participated in other clinical trials 1 month before the trial.
14. Vesicoureteral regurgitation.
15. The investigator considered it inappropriate to participate in this clinical trial.