Photodynamic Therapy for Bladder Cancers, A Focused Review†

Bladder cancer is the first cancer for which PDT was clinically approved in 1993. Unfortunately, it was unsuccessful due to side effects like bladder contraction. Here, we summarized the recent progress of PDT for bladder cancers, focusing on photosensitizers and formulations. General strategies to minimize side effects are intravesical administration of photosensitizers, use of targeting strategies for photosensitizers and better control of light. Non-muscle invasive bladder cancers are more suitable for PDT than muscle invasive and metastatic bladder cancers. In 2010, the FDA approved blue light cystoscopy, using PpIX fluorescence, for photodynamic diagnosis of non-muscle invasive bladder cancer. PpIX produced from HAL was also used in PDT but was not successful due to low therapeutic efficacy. To enhance the efficacy of PpIX-PDT, we have been working on combining it with singlet oxygen-activatable prodrugs. The use of these prodrugs increases the therapeutic efficacy of the PpIX-PDT. It also improves tumor selectivity of the prodrugs due to the preferential formation of PpIX in cancer cells resulting in decreased off-target toxicity. Future challenges include improving prodrugs and light delivery across the bladder barrier to deeper tumor tissue and generating an effective therapeutic response in an In vivo setting without causing collateral damage to bladder function.

Development of a high-precision bladder hyperthermic intracavitary chemotherapy device for bladder cancer and pharmacokinetic study

BACKGROUND

Bladder hyperthermic intracavitary chemotherapy (HIVEC) has good effectiveness for bladder cancer, but conventional HIVEC systems lack precision and convenient application. To test the safety of a new HIVEC device (BR-TRG-II-type) in pigs and to perform a preliminary clinical trial in patients with bladder cancer.

METHODS

This device was tested on six pigs to optimize the temperature and time parameters. Then, 165 patients (HIVEC after transurethral resection (TUR), n = 128; or HIVEC, n = 37) treated between December 2006 and December 2016 were recruited. Mitomycin C (MMC) was the chemotherapeutic agent. A serum pharmacokinetic study was performed. The primary endpoints were tumor recurrence, disease-free survival (DFS), and cumulative incidence rate (CIR) during follow-up. The adverse effects were graded.

RESULTS

The animal experiment showed that 45 °C for 1 h was optimal. HIVEC was successful, with the infusion tube temperature stably controlled at about 45 °C, and outlet tube temperature of about 43 °C in all patients, for three sessions. Serum MMC levels gradually increased during HIVEC and decreased thereafter. The mean DFS was 39 ± 3.21 months (ranging from 8 to 78 months), and the DFS rate was 89.1% during follow-up. No adverse events occurred.

CONCLUSION

The use of the BR-TRG-II-type HIVEC device is feasible for the treatment of bladder cancer. Future clinical trials in patients with different stages of bladder cancer will further confirm the clinical usefulness of this device.

TRIAL REGISTRATION

chictr.org.cn: ChiCTR1900022099 (registered on Mar. 252,019). Retrospectively registered.

Can bladder preservation therapy come to the center stage?

Decision-making in urological cancer care requires a multidisciplinary approach for refinement, but its impact on urothelial carcinoma of the bladder has not been fully addressed for the past three decades, except for the latest immunological checkpoint inhibitor approved by the U.S. Food and Drug Administration for metastatic muscle-invasive bladder cancer that is resistant to platinum-based chemotherapy. For the time being, radical cystectomy is the gold standard of curative therapy for muscle-invasive bladder cancer. Trimodal therapy that combines chemotherapy for the purpose of radiation sensitization, external beam radiotherapy and transurethral resection of bladder tumor has emerged as a potential alternative treatment option that preserves the bladder. In lack of randomized studies for bladder preservation therapy compared with surgery, the principles of management of urothelial carcinoma of the bladder have evolved in recent times, with an emphasis on bladder preservation. A number of bladder preservation techniques are available to the surgeon; however, appropriately selected patients with muscle-invasive bladder cancer should be offered the opportunity to discuss various treatment options, including organ-sparing trimodal therapy. The aim of the present study was to compare the primary outcomes of the available treatment methods and identify the sources of variance among studies. A review of various bladder preservation techniques in vogue for the management of urothelial carcinoma of the bladder is discussed.

Bladder intracavitary hyperthermic perfusion chemotherapy for the prevention of recurrence of non-muscle invasive bladder cancer after transurethral resection

Preventing the recurrence of non-muscle invasive bladder cancer (NMIBC) post-transurethral resection (TUR) remains challenging. The aim of the present study was to investigate the effectiveness and safety of bladder intracavitary hyperthermic perfusion chemotherapy (BHPC) for prevention of NMIBC recurrence post-TUR. Between December 2006 and December 2014, 53 patients with NMIBC who underwent TUR were randomly assigned to receive BHPC (BHPC group, 28 patients) or intravesical chemotherapy alone (chemotherapy group, 25 patients) at the Intracelom Hyperthermic Perfusion Therapy Center of Guangzhou Medical University Cancer Hospital (Guangzhou, China). BHPC was performed by combining perfusion-based hyperthermia with chemotherapeutic agent mitomycin C (MMC) in the bladder, and the chemotherapy group of patients received bladder MMC perfusion. The concentration of MMC in the perfusion fluid and serum were assessed at different time-points. Tumor recurrence, disease-free survival (DFS), and side-effects were recorded and compared between the 2 groups. Results revealed that BHPC was performed smoothly, at ~44̊C in the bladder cavity. Patients tolerated BHPC, and no side-effects were observed. Both BHPC and intravesical chemotherapy achieved a high MMC concentration in the bladder perfusion liquid, but low MMC concentration in the serum, although serum MMC concentrations in the BHPC group were significantly higher (P<0.05). The tumor recurrence rate was significantly lower (10.7 vs. 28.0%; P=0.02) and the DFS period was significantly longer (37±1.2 vs. 19±0.9 months; P=0.001) in the BHPC group than in the chemotherapy group. Our results demonstrated that BHPC is safe and effective for preventing NMIBC recurrence post-TUR and prolongs DFS.