浸潤性膀胱癌に対する放射線化学療法―治療成績と予後予測因子としてのBcl-2 family―

Abstract

We investigated the long-term results and molecular markers of outcome with selective organ preservation in invasive bladder cancer using chemoradiation therapy. We examined locally invasive bladder cancer in 32 patients (30 men, 2 women; mean age at treatment 68.1 years) who underwent bladder-sparing protocols in the Department of Urology at Sumitomo Hospital between 2000 and 2005. The clinical stage was T2, T3, and T4 in 13, 16, and 3 patients, respectively. Our protocol includes aggressive transurethral resection of the bladder tumor (TURBT) and 46 Gy radiotherapy (2 Gy/fraction, 5 fractions/week) to the pelvis with concurrent cisplatin chemotherapy (20 mg/body/day, 5 days/week, the first and fourth week, intravenously). The initial evaluation included magnetic resonance imaging (MRI), urine cytology, and cystoscopy with a biopsy. During follow-up, if the patients developed superficial recurrence, they was treated with TURBT and intravesical Bacillus Calmette-Guérin (BCG), while patients with invasive recurrence were advised to undergo a salvage cystectomy. We examined the association between the expression of the Bcl-2 family in pretreatment TUR specimens and patient outcome. The mean follow-up was 54.6 months. The first assessment after the induction chemoradiotherapy showed that bladder preservation was achieved in 27 patients (84.4%). The actuarial local control rate with an intact bladder was 56.3% (18 patients) at 3 years. The 1-, 3-, and 5-year cancer-specific survival rate was 90.6, 84.0, and 66.9%, respectively. The 5-year cancer-specific survival rate was 75.0, 67.2, and 33.3% in T2, T3, and T4, respectively. Bcl-x positivity was significantly associated with a poor cancer-specific survival rate (log-rank test, p = 0.038). Chemoradiation therapy for invasive bladder cancer can achieve survival rates similar to those in patients treated with radical cystectomy, with successful bladder preservation. Our results suggest that the expression of Bcl-x is a potential prognostic marker for chemoradiation therapy in invasive bladder cancer.