Purpose: To assess the activity of intravesical chemotherapy and local microwave hyperthermia (ICLMH) in increasing the disease-free interval (DFI) in patients with non-muscle-invasive bladder cancer (NMIBC) and treatment toxicity.
Methods: Forty-two patients with a diagnosis of high-risk NMIBC, according to the European Organization for Research and Treatment of Cancer (EORTC) criteria, were treated with an intensive schedule of ICLMH using 40 mg mitomycin C. The treatment consisted of 4 weekly sessions, followed by 6 sessions delivered every 2 weeks, and by 4 monthly sessions, for a total of 14 sessions over 8 months. The DFIs before and after treatment were compared in each patient.
Results: The schedule was completed as planned by 32 patients (76.2 %). The percentage of disease-free patients the year before study was 14.9 % (95 % CI 5.5-28.8) versus 88.8 % (95 % CI 73.7-94.8) after ICLMH (p < 0.0001). Patient EORTC scores, multifocality, and tumour stage were all associated significantly and independently with a higher risk of recurrence after ICLMH treatment with HR of 41.1 (p = 0.01), 17.7 (p = 0.02), and 8.5 (p = 0.02), respectively. After a median follow-up of 38 months, 24 patients (57.1 %) did not show evidence of disease, whereas 13 patients (30.9 %) underwent disease recurrence and 5 patients (11.9 %) showed also stage progression. Toxicity consisted in grades 1 and 2 frequency, non-infectious cystitis, and haematuria.
Conclusions: ICLMH significantly increases the DFI of NMIBC patients with high EORTC score for recurrence and progression. Toxicity of the intensive treatment schedule was generally mild.