Photodynamic versus white-light-guided resection of first-diagnosis non-muscle-invasive bladder cancer: PHOTO RCT

BACKGROUND

Around 7500 people are diagnosed with non-muscle-invasive bladder cancer in the UK annually. Recurrence following transurethral resection of bladder tumour is common, and the intensive monitoring schedule required after initial treatment has associated costs for patients and the NHS. In photodynamic diagnosis, before transurethral resection of bladder tumour, a photosensitiser that is preferentially absorbed by tumour cells is instilled intravesically. Transurethral resection of bladder tumour is then conducted under blue light, causing the photosensitiser to fluoresce. Photodynamic diagnosis-guided transurethral resection of bladder tumour offers better diagnostic accuracy than standard white-light-guided transurethral resection of bladder tumour, potentially reducing the chance of subsequent recurrence.

OBJECTIVE

The objective was to assess the clinical effectiveness and cost-effectiveness of photodynamic diagnosis-guided transurethral resection of bladder tumour.

DESIGN

This was a multicentre, pragmatic, open-label, parallel-group, non-masked, superiority randomised controlled trial. Allocation was by remote web-based service, using a 1 : 1 ratio and a minimisation algorithm balanced by centre and sex.

SETTING

The setting was 22 NHS hospitals.

PARTICIPANTS

Patients aged ≥ 16 years with a suspected first diagnosis of high-risk non-muscle-invasive bladder cancer, no contraindications to photodynamic diagnosis and written informed consent were eligible.

INTERVENTIONS

Photodynamic diagnosis-guided transurethral resection of bladder tumour and standard white-light cystoscopy transurethral resection of bladder tumour.

MAIN OUTCOME MEASURES

The primary clinical outcome measure was the time to recurrence from the date of randomisation to the date of pathologically proven first recurrence (or intercurrent bladder cancer death). The primary health economic outcome was the incremental cost per quality-adjusted life-year gained at 3 years.

RESULTS

We enrolled 538 participants from 22 UK hospitals between 11 November 2014 and 6 February 2018. Of these, 269 were allocated to photodynamic diagnosis and 269 were allocated to white light. A total of 112 participants were excluded from the analysis because of ineligibility (n = 5), lack of non-muscle-invasive bladder cancer diagnosis following transurethral resection of bladder tumour (n = 89) or early cystectomy (n = 18). In total, 209 photodynamic diagnosis and 217 white-light participants were included in the clinical end-point analysis population. All randomised participants were included in the cost-effectiveness analysis. Over a median follow-up period of 21 months for the photodynamic diagnosis group and 22 months for the white-light group, there were 86 recurrences (3-year recurrence-free survival rate 57.8%, 95% confidence interval 50.7% to 64.2%) in the photodynamic diagnosis group and 84 recurrences (3-year recurrence-free survival rate 61.6%, 95% confidence interval 54.7% to 67.8%) in the white-light group (hazard ratio 0.94, 95% confidence interval 0.69 to 1.28; p = 0.70). Adverse event frequency was low and similar in both groups [12 (5.7%) in the photodynamic diagnosis group vs. 12 (5.5%) in the white-light group]. At 3 years, the total cost was £12,881 for photodynamic diagnosis-guided transurethral resection of bladder tumour and £12,005 for white light. There was no evidence of differences in the use of health services or total cost at 3 years. At 3 years, the quality-adjusted life-years gain was 2.094 in the photodynamic diagnosis transurethral resection of bladder tumour group and 2.087 in the white light group. The probability that photodynamic diagnosis-guided transurethral resection of bladder tumour was cost-effective was never > 30% over the range of society's cost-effectiveness thresholds.

LIMITATIONS

Fewer patients than anticipated were correctly diagnosed with intermediate- to high-risk non-muscle-invasive bladder cancer before transurethral resection of bladder tumour and the ratio of intermediate- to high-risk non-muscle-invasive bladder cancer was higher than expected, reducing the number of observed recurrences and the statistical power.

CONCLUSIONS

Photodynamic diagnosis-guided transurethral resection of bladder tumour did not reduce recurrences, nor was it likely to be cost-effective compared with white light at 3 years. Photodynamic diagnosis-guided transurethral resection of bladder tumour is not supported in the management of primary intermediate- to high-risk non-muscle-invasive bladder cancer.

FUTURE WORK

Further work should include the modelling of appropriate surveillance schedules and exploring predictive and prognostic biomarkers.

TRIAL REGISTRATION

This trial is registered as ISRCTN84013636.

FUNDING

This project was funded by the National Institute for Health and Care Research ( NIHR ) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 40. See the NIHR Journals Library website for further project information.

Downregulation of homeodomain-interacting protein kinase-2 contributes to bladder cancer metastasis by regulating Wnt signaling

Homeodomain-interacting protein kinase-2 (Hipk2) has been shown to have important regulatory roles in cancer biology, such as cancer cell proliferation, cell cycle, and cell invasion. However, the contributions of Hipk2 to bladder cancer metastasis remain largely unknown. In the current study, we assayed the expression level of Hipk2 in bladder cancer tissues by real-time PCR, and defined its biological functions. We found that Hipk2 levels were downregulated in most bladder cancer tissues compared with adjacent normal tissues, and Hipk2 levels were remarkably decreased in metastasized tumor tissues when compared with primary tumors. SiRNA-mediated Hipk2 silencing increased bladder cancer cell invasion. Hipk2 knockdown resulted in decrease of E-cadherin expression and increase of N-cadherin and fibronectin expression, indicated that epithelial-mesenchymal transition (EMT) was induced. We further demonstrated that Hipk2 knockdown induced Wnt signaling activation and β-catenin nuclear localization. Finally, we confirmed that Hipk2 inhibition promoted EMT and subsequent cell invasion, at least in part by activating Wnt signaling. These data suggest an important role of Hipk2 in regulating metastasis of bladder cancer and implicate the potential application of Hipk2 in bladder cancer therapy.