Recommended oral sodium bicarbonate administration for urine alkalinization did not affect the concentration of mitomycin-C in non-muscle invasive bladder cancer patients

Sodium bicarbonate has been reported to maximize the efficacy of intravesical instillation of mitomycin-C (IVI-MMC) therapy by urine alkalinization in non-muscle-invasive bladder cancer (NMIBC). This study aimed to analyze the changes in MMC concentration according to urinary pH and evaluate the efficacy of sodium bicarbonate to maintain the concentration of active form of MMC during IVI-MMC.

We prospectively enrolled 26 patients with NMIBC after transurethral resection of bladder tumor. Patients with very high-risk and low-risk NMIBC were excluded. Urinary creatinine, volume, pH, and concentrations of MMC and its degraded form were measured immediately before and after IVI-MMC. The patients were administered 1.5 g of oral sodium bicarbonate during the preceding evening, in the morning, and immediately before the fourth cycle of the six-cycle IVI-MMC. The correlation between MMC concentration and urinary pH changes was explored with or without oral bicarbonate therapy.

Recurrence without progression to muscle-invasive disease was noted in 4 of 26 patients in a 23.7-month follow-up. The mean urinary pH before and after the therapy increased from 6.03 to 6.50, and 6.46 to 7.24, without or with oral SB therapy, respectively. Despite this increase, the concentration of active form of MMC did not change significantly. No correlation was found between urinary pH and MMC concentration. Urine alkalinization by SB administration did not maintain the high concentration of urinary MMC.

Urine alkalinization by sodium bicarbonate administration for IVI-MMC did not maintain the high concentration of active urinary MMC in NMIBC.

Oncotarget. 2017 Oct 09*** epublish ***

Ho Kyung Seo, Sung Han Kim, Kyung-Ohk Ahn, Sang-Jin Lee, Weon Seo Park, Sohee Kim, Sang-Hyun Hwang, Do Hoon Lee, Jae Young Joung, Jinsoo Chung, Jungnam Joo, Kyung-Chae Jeong

Department of Urology, Center for Prostate Cancer, Hospital, National Cancer Center, Goyang, Gyeonggi-do, Korea., Translational Research Branch, Research Institute, National Cancer Center, Goyang, Gyeonggi-do, Korea., Immunotherapeutics Branch, Research Institute, National Cancer Center, Goyang, Gyeonggi-do, Korea., Department of Pathology, Center for Prostate Cancer, Hospital, National Cancer Center, Goyang, Gyeonggi-do, Korea., Biometrics Research Branch, Research Institute and Hospital, National Cancer Center, Goyang, Gyeonggi, Korea., Department of Laboratory Medicine, Center for Diagnostic Oncology, National Cancer Center, Goyang-si, Korea., Department of Laboratory Medicine and Hematologic Malignancy Branch, Research Institute and Hospital of National Cancer Center, Goyang-si, Korea.