Photodynamic application in diagnostic procedures and treatment of non-melanoma skin cancers

OPINION STATEMENT

Skin tumors commonly seen in dermatology are involved in all layers of the skin and appendages. While biopsy of affected skin remains an essential method to confirm diagnosis and to predicate tumor prognosis, it has its limitations. Recently, photodynamic diagnosis (PDD) has demonstrated high sensitivity in detecting affected skin and mucosal tissues, providing valuable guidance for precision surgery to resect skin and mucosal tumors. In this review, we summarized the literatures concerning the applications of PDD in diagnostic process and treatment of skin and mucosal conditions such as actinic keratoses (AK), basal cell carcinoma (BCC), squamous cell carcinoma (SCC), Bowen's disease (BD) and extramammary Paget's disease (EMPD). The findings suggest that PDD holds substantial promise for expanding clinical applications and deserves further research exploration.

Patient characteristics correlate with diagnostic performance of photodynamic diagnostic assisted transurethral resection of bladder tumors: A retrospective, single-center study

BACKGROUND

Identification of patient subclasses that correlate with the diagnostic performance of photodynamic diagnostic (PDD)-assisted transurethral resection of bladder tumors (TURBT) may improve outcomes.

METHODS

Data were extracted from patients that underwent PDD-assisted TURBT at the University of Tsukuba Hospital between 2018 and 2023. Sensitivity and specificity were evaluated based on PDD findings (excluding WL findings) and pathology results. Cluster analysis using uniform manifold approximation and projection and k-means methods was performed, focusing on patients with malignant lesions.

RESULTS

A total of 267 patients and 2082 specimens were extracted. Sensitivity was lowest with regard to BCG treatment (53.7 %), followed by flat lesions (57.2 %), urine cytology class ≥ III (62.9 %), and recurrent tumors (64.5 %). In the cluster analysis of 231 patients with malignant lesions, two showed lower sensitivity: Cluster 3 (62.4 %), consisting of patients with recurrent tumors and post-BCG treatment, and Cluster 4 (55.7 %), consisting of patients with primary tumors and urine cytology class ≥ III. Clusters 1 and 2, consisting of patients without BCG treatment and patients with lower urine cytology classes, exhibited higher sensitivities (94.4 % and 87.7 %). Among all clusters, Cluster 4 had the highest proportion of specimens which were negative for both PDD and white light (WL) findings but actually had malignant lesions (20.8 %).

CONCLUSIONS

PDD-assisted TURBT sensitivity was lower in subclasses after BCG treatment or with cytology class III or higher. Random biopsy for PDD/WL double-negative lesions may improve diagnostic accuracy in these subclasses.

Repeat Transurethral Resection for Non-muscle-invasive Bladder Cancer: An Updated Systematic Review and Meta-analysis in the Contemporary Era

CONTEXT

Repeat transurethral resection (reTUR) is a guideline-recommended treatment strategy in high-risk non-muscle-invasive bladder cancer (NMIBC) patients treated with transurethral resection of bladder tumor (TURBT); however, the impact of recent procedural/technological developments on reTUR outcomes has not been assessed yet.

OBJECTIVE

To assess the outcomes of reTUR for NMIBC in the contemporary era, focusing on whether temporal differences and technical advancement, specifically, photodynamic diagnosis and en bloc resection of bladder tumor (ERBT), affect the outcomes.

EVIDENCE ACQUISITION

Multiple databases were queried in February 2023 for studies investigating reTUR outcomes, such as residual tumor and/or upstaging rates, its predictive factors, and oncologic outcomes, including recurrence-free (RFS), progression-free (PFS), cancer-specific (CSS), and overall (OS) survival. We synthesized comparative outcomes adjusting for the effect of possible confounders.

EVIDENCE SYNTHESIS

Overall, 81 studies were eligible for the meta-analysis. In T1 patients initially treated with conventional TURBT (cTURBT) in the 2010s, the pooled rates of any residual tumors and upstaging on reTUR were 31.4% (95% confidence interval [CI]: 26.0-37.2%) and 2.8% (95% CI: 2.0-3.8%), respectively. Despite a potential publication bias, these rates were significantly lower than those in patients treated in the 1990-2000s (both p < 0.001). ERBT and visual enhancement-guided cTURBT significantly improved any residual tumor rates on reTUR compared with cTURBT based on both matched-cohort and multivariable analyses. Among studies adjusting for the effect of possible confounders, patients who underwent reTUR had better RFS (hazard ratio [HR]: 0.78, 95% CI: 0.62-0.97) and OS (HR: 0.86, 95% CI: 0.81-0.93) than those who did not, while it did not lead to superior PFS (HR: 0.74, 95% CI: 0.47-1.15) and CSS (HR: 0.94, 95% CI: 0.86-1.03).

CONCLUSIONS

reTUR is currently recommended for high-risk NMIBC based on the persistent high rates of residual tumors after primary resection. Improvement of resection quality based on checklist applications and recent technical/procedural advancements hold the promise to omit reTUR.

PATIENT SUMMARY

Recent endoscopic/procedural developments improve the outcomes of repeat resection for high-risk non-muscle-invasive bladder cancer. Further investigations are urgently needed to clarify the potential impact of the use of these techniques on the need for repeat transurethral resection in the contemporary era.

Real-world experience with 5-aminolevulinic acid for photodynamic diagnosis of bladder cancer (3rd report): Cost impact of transurethral resection of bladder tumor in Japan

BACKGROUND

Photodynamic diagnosis-assisted transurethral resection of bladder tumor (PDD-TURBT) showed improvement of diagnostic accuracy and treatment efficacy compared to white light TURBT (WL-TURBT). While PDD-TURBT is highly effective, PDD-TURBT requires the use of PDD device and light-sensitive substance precursor, which increases the medical cost compared to WL-TURBT. In this study, the impact on health care economic costs were examined between PDD-TURBT and WL-TURBT.

METHODS

Of the total 265 patients, 88 patients for WL-TURBT and 105 patients for PDD-TURBT were available for analysis. Costs were also examined between 34 patients without false-positives and 36 patients with false-positives with a follow-up period of at least 200 days. To compare costs between the two treatments, we calculated the cost/person/year of TURBT using Japanese Diagnosis Procedure Combination and Per-Diem Payment System (DPC/PDPS).

RESULTS

The total number of surgeries including the first TURBT was 135 (47 recurrences) in the WL-TURBT group and 133 (28 recurrences) in the PDD-TURBT group. The cost per person for hospitalization and surgery was 366,310 Japanese yen (JPY) for the WL-TURBT and 501,930 JPY for the PDD-TURBT. The cost per person per year was 491,622 JPY in the WL-TURBT group and 506,405 JPY in the PDD-TURBT group. Regarding false-positives, the cost per person per year was 494,544 JPY in the group without false-positives and 328,086 JPY in the group with false-positives.

CONCLUSIONS

Although PDD-TURBT is cost more than WL-TURBT for one surgical hospitalization, the cost per person per year for PDD-TURBT and WL-TURBT is cost-neutral.

Fluorescence imaging of lymphangioma circumscriptum of the vulva with aminolevulinic acid and target-type narrow band ultraviolet light

Lymphangioma circumscriptum of the vulva is a rare lymphatic disorder. Defining the precise location of the lesion is required to select an appropriate treatment. Herein we present photodynamic diagnosis of lymphangioma circumscriptum of the vulva with aminolevulinic acid and target-type narrow band ultraviolet light device.

Photodynamic Diagnosis-guided Transurethral Resection of Bladder Tumour in Participants with a First Suspected Diagnosis of Intermediate- or High-risk Non-muscle-invasive Bladder Cancer: Cost-effectiveness Analysis Alongside a Randomised Controlled Trial

Background

Recurrence of non-muscle-invasive bladder cancer (NMIBC) is common after transurethral resection of bladder tumour (TURBT). Photodynamic diagnosis (PDD) may reduce recurrence. PDD uses a photosensitiser in the bladder that causes the tumour to fluoresce to guide resection. PDD provides better diagnostic accuracy and allows more complete tumour resection.

Objective

To estimate the economic efficiency of PDD-guided TURBT (PDD-TURBT) in comparison to white light-guided TURNT (WL-TURBT) in individuals with a suspected first diagnosis of NMIBC at intermediate or high risk of recurrence on the basis of routine visual assessment before being scheduled for TURBT.

Design setting and participants

This is a health economic evaluation alongside a pragmatic, open-label, parallel-group randomised trial from a societal perspective. A total of 493 participants (aged ≥16 yr) were randomly allocated to PDD-TURBT (n = 244) or WL-TURBT (n = 249) in 22 UK National Health Service hospitals.

Outcome measurements and statistical analysis

Cost effectiveness ratios were based on the use of health care resources associated with PDD-TURBT and WL-TURBT and quality-adjusted life years (QALYs) gained within the trial. Uncertainties in key parameters were assessed using sensitivity analyses.

Results and limitations

On the basis of the use of resources driven by the trial protocol, the incremental cost effectiveness of PDD-TURBT in comparison to WL-TURBT was not cost saving. At 3 yr, the total cost was £12 881 for PDD-TURBT and £12 005 for WL-TURBT. QALYs at three years were 2.087 for PDD-TURBT and 2.094 for WL-TURBT. The probability that PDD-TURBT is cost effective was never >30% above the range of societal cost-effectiveness thresholds.

Conclusions

There was no evidence of a difference in either costs or QALYs over 3-yr follow-up between PDD-TURBT and WL-TURBT in individuals with suspected intermediate- or high-risk NMIBC. PDD-TURBT is not supported for the management of primary intermediate- or high-risk NMIBC.

Patient summary

We assessed overall costs for two approaches for removal of bladder tumours in noninvasive cancer and measured quality-adjusted life years gained for each. We found that use of a photosensitiser in the bladder was not more cost effective than use of white light only during tumour removal.

A Novel Non-invasive Qualitative Assay Using Urinary Fluorescence Imaging to Assess Kidney Disease

In patients with chronic kidney disease, it is necessary to identify the etiology of glomerular disease. Renal biopsy is the gold standard for assessing the underlying pathology; however, it has the risk of potential complications. We have established a urinary fluorescence imaging technique to assess enzymatic activity using an activatable fluorescent probe targeting two enzymes: gamma-glutamyl transpeptidase and dipeptidyl-peptidase. The urinary fluorescence images can be easily obtained by adding an optical filter to the microscope with short incubation of the fluorescent probes. Urinary fluorescence imaging could help to assess underlying etiologies of kidney diseases and is a potential non-invasive qualitative assessment technique for kidney diseases in patients with diabetes. Key features Non-invasive assessment of kidney disease. Urinary fluorescent imaging with enzyme-activatable fluorescent probes. Enables differentiation of diabetic kidney disease and glomerulonephritis.

Is a restaging TURBT necessary in high-risk NMIBC if the initial TURBT was performed with blue light?

OBJECTIVES

To evaluate whether a restaging transurethral resection of bladder tumor (TURBT) is necessary in high-risk nonmuscle invasive bladder cancer (NMIBC) if the initial TURBT was performed using blue light (BL) technology.

METHODS AND MATERIALS

Using the multi-institutional Cysview registry between 2014 and 2021, all consecutive adult patients with known NMIBC (Ta and T1 disease) who underwent TURBT followed by a restaging TURBT within 8 weeks were reviewed. Patients were stratified according to their initial TURBT, BL vs. white light (WL), and compared to determine rates of residual disease and upstaging. Univariate analysis was performed using Mann-Whitney U and chi-square tests, with P < 0.05 considered significant.

RESULTS

Overall, 115 patients had TURBT for NMIBC followed by a restaging TURBT within 8 weeks and were included in the analysis. Patients who underwent BL compared to WL for their initial TURBT had higher rates of benign pathology on restaging TURBT, although this was not statistically significant (47% vs. 30%; P = 0.08). Of patients with residual tumors on restaging TURBT, there were no differences in rates of Ta (22% vs. 26.5%; P = 0.62), T1 (22% vs. 26.5%; P = 0.62), or CIS (5.5% vs. 13%; P = 0.49) when the initial TURBT was done using BL compared to WL. Rates of upstaging to muscle invasive disease were also not different when initial TURBT was performed using BL compared to WL (3% vs. 4%; P = 0.78).

CONCLUSIONS

TURBT using BL does not reduce rates of residual disease or risk of upstaging on restaging TURBT in Ta or T1 disease. Thus, a restaging TURBT is still necessary even if initial TURBT was performed using BL.

5-Aminolevulinic acid-based photodynamic diagnosis for detection of urothelial carcinoma cells in bladder washing sediment suspension: A pilot study

BACKGROUND

Bladder cancer is a common malignant disease in developed countries. Early detection of malignancy is important using urine cytology. The 5-aminolevulinic acid (ALA)-based photodynamic diagnosis (ALA-PDD) has not been routinely applied in urine cytology analysis yet, although it has been well accepted for tumor lesion marking in cystoscopy.

METHODS

A total of eight volunteers were enrolled in this study. The cells of sediment suspension from bladder washing fluid and random urine were stained by ALA-induced protoporphyrin IX (ALA-PpIX) and the fluorescent intensity of ALA-PpIX was analyzed by ImageJ.

RESULTS

The cutoff value of fluorescent intensity was 90.260 per pixel. The proposed protocol provided an objective fluorescent intensity for evaluation. Sensitivity was 0.931 and specificity was 1.000.

CONCLUSIONS

The staining procedure applied was ALA-PpIX for suspicious cells in the cellular suspension from bladder wash fluid and random urine. ImageJ was applied to the objective measurement for the fluorescent intensity of the stained cells. The cutoff value for the positive result was 90.260 per pixel. Therefore, the protocol proposed in this study provides a potential means to enhance accuracy for urine cytology analysis.

Comparison between 5-aminolevulinic acid photodynamic diagnosis and narrow-band imaging for bladder cancer detection

BACKGROUND

To compare 5-aminolevulinic acid (5-ALA)-mediated photodynamic diagnosis (PDD) with narrow-band imaging (NBI) for cancer detection during transurethral resection of bladder tumour (TURBT).

METHODS

Between June 2018 and October 2020, 114 patients and 282 lesions were included in the analysis. Patients were orally administered 5-ALA (20 mg/kg) 2 h before TURBT. The bladder was inspected with white light (WL), PDD, and NBI for each patient, and all areas positive by at least one method were resected or biopsied. The imaging data were then compared to the pathology results.

RESULTS

The sensitivities of WL, PDD, and NBI for detecting urothelial carcinoma were 88.1%, 89.6%, and 76.2%, respectively. The specificity, positive predictive value, and negative predictive value for detecting urothelial carcinoma were 47.5%, 80.9%, and 61.3%, respectively, for WL; 22.5%, 74.5%, and 46.2%, respectively, for PDD; and 46.3%, 78.2%, and 43.5%, respectively, for NBI. PDD was significantly more sensitive than NBI for all lesions (p < 0.001) and carcinoma in situ (CIS) lesions (94.6% vs. 54.1%, p < 0.001).

CONCLUSIONS

PDD can increase the detection rate of bladder cancer, compared to NBI, by greater than 10%. Therefore, 100% of CIS lesions can be detected by adding PDD to WL.

Variations in photodynamic diagnosis for bladder cancer due to the quality of endoscopic equipment

BACKGROUND

Photodynamic diagnosis (PDD)-assisted transurethral resection of bladder tumor (TURBT) has different treatment outcomes across institutions, as seen in conventional TURBT. We retrospectively compared the difference in quality between the two types of endoscopic equipment used for PDD-assisted TURBT in our institution.

METHODS

This study enrolled 205 consecutive patients who underwent PDD-assisted TURBT. Patients were divided into two groups according to the endoscopic equipment used for PDD-assisted TURBT: Group A using the conventionally used endoscopic system and Aladuck LS-DLED and Group S using the Storz PDD system. Cystoscopy findings of white light (WL), fluorescence light (FL), and combination (positive if either WL or FL was positive) were recorded, and diagnostic quality of PDD was compared between both groups.

RESULTS

Group A had 105 cases and 336 specimens, while Group S had 100 cases and 361 specimens, with no significant differences between patient characteristics. The tumor sensitivities of WL, FL, and combination in Group A was 71.9%, 77.1%, 90.5%, respectively, while in Group S, these were 71.5%, 92.2%, 96.1%, respectively. Group S had significantly higher sensitivity of FL and combination than Group A, as well as higher detection of carcinoma in situ lesions.

CONCLUSION

Both endoscopic systems had improved sensitivity with PDD-assistance versus WL only, with Group S having higher sensitivity. Differences in the quality of endoscopic equipment may influence the differences in treatment results with PDD-assisted TURBT across institutions.

Identification of risk factors associated with oral 5-aminolevulinic acid-induced hypotension in photodynamic diagnosis for non-muscle invasive bladder cancer: a multicenter retrospective study

Background

To investigate risk factors for orally administered 5-aminolevulinic acid (ALA)-induced hypotension for bladder cancer patients receiving photodynamic diagnosis (PDD)-assisted transurethral resection of bladder tumor (TURBT).

Methods

Patients were categorized into two groups intraoperatively: a hypotensive group (minimum systolic blood pressure (SBP) ≤80 mmHg) and a non-hypotensive group (minimum SBP > 80 mmHg). We examined differences between the hypotensive group and non-hypotensive groups to identify clinical risk of ALA-induced hypotension using multivariate logistic regression analysis and decision tree analysis.

Results

Among 282 cases with ALA-PDD-assisted TURBT from three institutions who were screened, 245 patients were included in the final analysis. In total, 156 patients (63.7%) showed any grade of hypotension during ALA-PDD-assisted TURBT. General anesthesia and spinal anesthesia were induced intraoperatively in 113 patients (46.1%) and 132 patients (53.9%), respectively. Median SBP at baseline (before taking ALA) and at the beginning of anesthesia was 127 mmHg (range, 69–186 mmHg) and 124 mmHg (range, 69–186 mmHg), respectively. Median minimum SBP during ALA-PDD-assisted TURBT was 75 mmHg (range, 43–140 mmHg). Multivariate logistic regression analysis revealed that history of hypertension (odds ratio (OR) 7.568, p < 0.05) and general anesthesia (OR 14.435, p < 0.05) as significantly associated with an increased risk of hypotension incidence. Use of calcium antagonist showed significant negative associations with hypotension (OR 0.183, p < 0.05). Decision tree analysis showed presence of general anesthesia, age ≥ 74 years and American Society of Anesthesiologists physical status (ASA-PS) ≥2 as the most important discriminators.

Conclusions

General anesthesia and hypertension were independent risk factors related to ALA-induced hypotension. In contrast, use of calcium antagonists was identified as a factor associated with reduced risk of ALA-induced hypotension.

Underutilization of Blue Light Cystoscopy for Bladder Cancer in the United States

Blue light cystoscopy (BLC) during transurethral resection of bladder tumor (TURBT) is guideline-recommended as it improves cancer detection and decreases recurrence of the disease. However, the extent to which BLC is used has not been established. We studied BLC use in the Premier Healthcare Database, a large, national sample that captured 158 870 index TURBT procedures between January 2011 and March 2020. Billing data were queried for the administration of hexaminolevulinate at TURBT as a proxy for BLC, and logistic regression models were constructed to identify variables associated with BLC use. BLC was used in 1.2% of index TURBT procedures over the study period. Its use increased following the American Urological Association non-muscle-invasive bladder cancer guideline publication in October 2016 but plateaued in late 2018. After adjusting for patient characteristics, higher odds for BLC use were found for academic hospitals and hospitals with higher TURBT volumes and higher radical cystectomy volumes. Within hospitals with BLC capability, predictors of a surgeon never using BLC included low surgeon TURBT volumes, low surgeon radical cystectomy volumes, and lack of mitomycin C use. Our findings highlight a concerning underutilization and stagnation in the adoption of evidence and guideline-supported intervention. PATIENT SUMMARY: Use of blue light visualization of the bladder improves the detection of cancer during removal of bladder tumors via the urethra. We reviewed records in a large US database for use of this technique and found that it is being underutilized. Since this technique improves detection of cancer in the bladder so that it can be removed to reduce recurrence, blue light visualization should be more widely used.

Hysteroscopic treatment assisted by photodynamic diagnosis for atypical polypoid adenomyoma: A report of two cases

Atypical polypoid adenomyoma (APA) is an intrauterine tumor for which hysteroscopic tumor resection allows for fertility preservation. Complete resection is important because of the high recurrence rate of APA, but is difficult due to the lack of characteristic hysteroscopic findings. We previously reported a case in which photodynamic diagnosis (PDD) was useful for detection of APA. Here, we report two additional cases of APA treated by hysteroscopic resection with PDD. The procedure was approved by the ethical committee. Case 1: A 35-year-old female who underwent hysteroscopic surgery for a submucosal tumor suspected to be APA with hypermenorrhea. Case 2: A 37-year-old female in whom hysteroscopic surgery was performed for a residual APA lesion after hormone therapy. In Case 1, PDD identified the tumor borders and this enabled as complete resection as possible. In Case 2, lesions could not be identified clearly under white light, but some areas were PDD-positive and were excised. Among 19 specimens from these two cases and the previously reported case, all PDD-positive specimens were pathologically diagnosed as APA. The sensitivity and specificity of PDD for APA were 76.9% and 100%, respectively. These results suggest that PDD can contribute to identification of APA.

[Transurethral resection of the urinary bladder : Status quo and outlook on new developments]

BACKGROUND

Transurethral resection of the urinary bladder (TURB) is the standard intervention in the diagnostic workup and treatment of non-muscle invasive bladder cancer. In order to minimize cancer recurrence and potential complications, continuous technical development of TURB is of high clinical interest.

OBJECTIVES

Presentation of the current standards and discussion of technological changes.

MATERIALS AND METHODS

Analysis of the current guideline recommendations and literature research.

RESULTS

The limitations of classic monopolar TURB is supplemented by new resection methods (en bloc) and technologies (bipolar and laser resection). Along with improved visualization through partially established technologies of photodynamic and digital image enhancement, there is potential for optimization regarding the likelihood of recurrences and complications as well as the histological quality of the resected material.

CONCLUSION

A positive impact on the oncological value and safety of TURB seems possible through the use of modern technologies. Further establishment up to evidence-based guideline recommendations are necessary.

Significance of 5-Aminolevulinic Acid-mediated Photodynamic Diagnosis Following Standard Transurethral Resection in Non-muscle Invasive Bladder Cancer

BACKGROUND/AIM

Transurethral resection of bladder tumors (TURBT) guided by photodynamic diagnosis (PDD) with 5-aminolevulinic acid (5-ALA) has been shown to be superior to conventional white light (WL) cystoscopy with regard to diagnostic accuracy, for non-muscle invasive bladder cancer (NMIBC); however, PDD is usually performed prior to WL TURBT. The objective of this study was to investigate the diagnostic significance of 5-ALA-mediated PDD following TUR of NMIBC.

PATIENTS AND METHODS

In 83 NMIBC patients, all visible tumors were completely resected under the conventional WL guidance followed by additional resection if fluorescent lesions were observed under the blue light (BL) guidance, and random biopsy was further conducted.

RESULTS

With the BL source, 39 (47.0%) patients were judged to have fluorescent lesions. Twenty (51.3%) of the 39 patients with positive findings by PDD were diagnosed with residual cancer by additional resection, while random biopsy detected cancers in 2 (4.5%) of the 44 patients with negative findings by PDD. Accordingly, the sensitivity, specificity, positive predictive value and negative predictive value in diagnosing residual cancer by our PDD system were 90.9, 68.9, 51.3 and 95.5%, respectively. Univariate analysis showed that the presence of residual cancers shown by WL TURBT was significantly associated with the preoperative findings of urinary cytology, tumor multiplicity, pathological T stage and tumor grade, of which only the preoperative finding on urinary cytology was shown to have an independent impact on the diagnosis of residual cancer.

CONCLUSION

5-ALA-mediated PDD following standard WL TURBT could improve the diagnostic accuracy in NMIBC patients, particularly those who are positive for preoperative urinary cytology.

Development of a high payload, cancer-targeting liposomes of methyl aminolevulinate for intraoperative photodynamic diagnosis/therapy of peritoneal carcinomatosis

Methyl aminolevulinate (MAL) is a photosensitizer topically used for photodynamic diagnosis (PDD) and photodynamic therapy (PDT) of skin pre-cancers and cancers. In this study, our goal is to expand the application of MAL to dual intraoperative PDD and PDT of peritoneal carcinomatosis. A new liposomal MAL formulation (lipMAL) designed for systemic or intraperitoneal administration was developed. LipMALs prepared by ammonium sulfate gradient technique achieved MAL payload up to 18% (w/w) with drug encapsulation efficiency in the range of 15.1-31.5%. All lipMALs demonstrated controlled MAL release behavior, and achieved strong fluorescence in cancer cells (SKOV3) but minimal fluorescence in non-cancer peritoneal cells (B14FAF28-G3). LipMALs led to significantly higher fluorescence levels than free MAL groups (P < 0.05), up to 6.8-fold of the free MAL fluorescence levels in SKOV3 cells. The PDD performance of lipMALs was also compared with free MAL in SKOV3/ B14FAF28-G3 co-cultures simulating ovarian cancer micrometastases on peritoneal surface. The lipMAL-treated cancer colonies glew more brightly than the free MAL treated colonies and were clearly distinguishable from the dim peritoneum background with unaided eyes. LipMAL also achieved significantly stronger anticancer PDT effects than free MAL both in terms of cell viability and colony-formation (P < 0.05) while demonstrating minimal dark toxicity. To conclude, a new promising aid for the surgeons to achieve more complete resection of tumors and PC micrometastases and clean up any residual cancer cells undetected was developed.

The sustaining of fluorescence in photodynamic diagnosis after the administration of 5-aminolevulinic acid in carcinogen-induced bladder cancer orthotopic rat model and urothelial cancer cell lines

BACKGROUND

The administration of 5-aminolevulic acid hydrochloride (5-ALA·HCl) 3 h (range: 2-4 h) before photodynamic diagnosis (PDD) is recommended for detecting bladder tumors. However, there is insufficient evidence on the time duration for the fluorescence of PDD after oral administration of 5-ALA. We investigated the sustainability of the photodynamic effect and protoporphyrinⅨ (PpⅨ) after 5-ALA administration in a carcinogen-induced bladder tumor rat model and bladder cancer cell lines.

METHODS

The carcinogen-induced bladder tumor orthotopic rat model was established by the administration of N-butyl-N-(4-hydroxybutyl) nitrosamine.

RESULTS

Red fluorescence was visible 2-8 h after the oral administration of 5-ALA in the carcinogen-induced bladder tumor rat model. Plasma and intratissue PpⅨ (nM) progressed to a higher level at 2 h and remained almost constant 2-8 h after oral administration of 5-ALA. The peak fluorescence intensity of PpⅨ was observed 3-4 h after the administration of 5-ALA in bladder cancer cell lines. The accumulated PpⅨ remained for 4 h after the removal of 5-ALA in UMUC3 cells. It was not clearly visible 3 h after the removal of 5-ALA in MGHU3 and T24 cells. The expression level of ferrochelatase was significantly lower in UMUC3 cells than in other cells. Our findings suggest that 5-ALA-assisted PDD (ALA-PDD) can aid in detecting non-muscle-invasive bladder cancer 2-8 h after 5-ALA administration.

CONCLUSION

Urologists might not be required to make excess effort to start ALA-PDD-assisted transurethral resection of bladder tumor after the administration of 5-ALA.

Photodynamic Diagnosis-guided Dual Laser Ablation for Upper Urinary Tract Carcinoma: Preoperative Preparation, Surgical Technique, and Clinical Outcomes

Background

Although ureteroscopic surgery (URS) is beneficial for low-risk upper urinary tract carcinoma (UTUC), there is no standardized URS technique or navigation system for challenging cases.

Objective

To present a URS technique for UTUC using thulium (Tm):YAG and holmium (Ho):YAG lasers under photodynamic diagnosis (PDD) guidance, named PDD-guided dual laser ablation (PDD-DLA) and compare its efficacy with that of conventional Ho:YAG laser ablation (HLA; historical control).

Design, setting, and participants

The study included ten consecutive UTUC patients who underwent PDD-DLA between 2017 and 2019. The control group comprised 16 consecutive patients who underwent HLA between 2006 and 2016.

Surgical procedure

After oral administration of 5-aminolevulinic acid (20 mg/kg), UTUC tumors were endoscopically resected via PDD-DLA.

Measurements

Clinical data were prospectively collected for our institutional UTUC data set. Disease progression, UTUC recurrence, and clinical outcomes were assessed.

Results and limitations

PDD-DLA was successfully performed in all patients. The median tumor size was 23.5 mm (interquartile range [IQR] 12.8–30.0) and there were four cases (40.0%) of high-grade tumor. The median operative time was 120 min (IQR 98.5–142.5). No Clavien-Dindo grade ≥3 complications were observed. There were no differences in most clinical characteristics between the PDD-DLA and HLA groups. The 2-yr progression-free survival rate was 100% in the PDD-DLA group and 58.7% in the HLA group (p = 0.0197), and the 2-yr recurrence-free survival rate was 57.1% and 41.3%, respectively (p = 0.072). The PDD-DLA group had a lower incidence rate of salvage RNU compared with the HLA group (0.0% vs 50%; p = 0.009). The small sample size might affect the reproducibility of these results.

Conclusions

PDD-DLA seems to be an effective and feasible endoscopic technique for UTUC treatment with favorable oncological outcomes.

Patient summary

We investigated a new laser technique for treating cancer of the upper urinary tract called photodynamic diagnosis–guided dual laser ablation. Our strategy was effective in removing tumors and stopping bleeding. Further studies in larger groups of patients are needed to confirm whether this technique improves cancer outcomes.

Photodynamic diagnostic ureteroscopy using the VISERA ELITE video system for diagnosis of upper-urinary tract urothelial carcinoma: a prospective cohort pilot study

Background

The advantages of photodynamic diagnostic technology using 5-aminolevulinic acid (ALA-PDD) have been established. The aim of this prospective cohort study was to evaluate the usefulness of ALA-PDD to diagnose upper tract urothelial carcinoma (UT-UC) using the Olympus VISERA ELITE video system.

Methods

We carried out a prospective, interventional, non-randomized, non-contrast and open label cohort pilot study that involved patients who underwent ureterorenoscopy (URS) to detect UT-UC. 5-aminolevulinic acid hydrochloride was orally administered before URS. The observational results and pathological diagnosis with ALA-PDD and traditional white light methods were compared, and the proportion of positive subjects and specimens were calculated.

Results

A total of 20 patients were enrolled and one patient who had multiple bladder tumors did not undergo URS. Fifteen of 19 patients were pathologically diagnosed with UT-UC and of these 11 (73.3%) were ALA-PDD positive. Fourteen of 19 patients were ALA-PDD positive and of these 11 were pathologically diagnosed with UC. For the 92 biopsy specimens that were malignant or benign, the sensitivity for both traditional white light observation and ALA-PDD was the same at 62.5%, whereas the specificities were 73.1% and 67.3%, respectively. Of the 38 specimens that were randomly biopsied without any abnormality under examination by both white light and ALA-PDD, 11 specimens (28.9%) from 5 patients were diagnosed with high grade UC. In contrast, four specimens from 4 patients, which were negative in traditional white light observation but positive in ALA-PDD, were diagnosed with carcinoma in situ (CIS).

Conclusions

Our results suggest that ALA-PDD using VISERA ELITE is not sufficiently applicable for UT-UC. Nevertheless, it might be better particularly for CIS than white light and superior results would be obtained using VISERA ELITE II video system.

Trial registration: The present clinical study was approved by the Okayama University Institutional Review Board prior to study initiation (Application no.: RIN 1803–002) and was registered with the UMIN Clinical Trials Registry (UMIN-CTR), Japan (Accession no.: UMIN000031205).

Fluorescent cystoscopy-assisted en bloc transurethral resection versus conventional transurethral resection in patients with non-muscle invasive bladder cancer: study protocol of a prospective, open-label, randomized control trial (the FLEBER study)

Background

Transurethral resection of bladder tumor (TURBT) is an essential procedure both for the treatment and staging of bladder cancer, particularly non-muscle invasive bladder cancer (NMIBC). The dissemination of cancer cells during resection and the consequent seeding into the bladder mucosa is the main cause of post-TURBT intravesical recurrence. Although the tumor dissemination is inevitable during conventional TURBT (cTURBT), this drawback can be overcome by tumor resection in one piece with intact surrounding normal tissues, referred to as en bloc resection. We previously described the photodynamic diagnosis (PDD)-assisted en bloc TURBT (EBTUR) technique and its favorable outcomes. Based on our preliminary studies, this randomized controlled trial was designed to evaluate the superiority of PDD-EBTUR to PDD-cTURBT.

Methods

The FLEBER study is a single-center randomized controlled trial in NMIBC patients who require TURBT. The longest diameter of the tumor must be between 6 and 30 mm. A total of 160 eligible patients will be enrolled after screening and randomly allocated to the PDD-EBTUR (experimental) and PDD-cTURBT (control) groups in a 1:1 ratio (80 cases to 80 cases). All patients will be treated using a single, immediate postoperative intravesical chemotherapy with epirubicin. The primary endpoint of this trial is the 2-year recurrence-free survival after surgery in pathologically proven low- or intermediate-risk NMIBC. All patients will be monitored by cystoscopy and urine cytology every 3 months for 2 years. Patient data including adverse events and complications, and data from frequency volume charts, pain scales, and health-related QOL questionnaires will be collected before and after the TURBT at indicated visits.

Discussion

The goal of this trial is to determine the potential benefits of PDD-cTURBT and PDD-EBTUR followed by a single immediate postoperative intravesical chemotherapy in patients with low- or intermediate-risk NMIBC who undergo TURBT. Ultimately, our findings will lead to the development of better interventions and potentially change the standard of care.

Trial registration

This clinical trial was prospectively registered with the UMIN Clinical Trials Registry on 1 August 2020. The reference number is UMIN000041273, and the Ethics Committee of Nara Medical University Approval ID is 2702.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05094-y.

Retrospective German claims data study on initial treatment of bladder carcinoma (BCa) by transurethral bladder resection (TURB): a comparative analysis of costs using standard white light- (WL-) vs. blue light- (BL-) TURB

Purpose

Photodynamic diagnosis using hexaminolevulinate (HAL)—guided BL-TURB may reduce the recurrence risk in non-muscle invasive BCa compared to standard WL-TURB due to more sensitive tumor detection. The impact of the initial use of WL- vs. BL-TURB on follow-up costs was evaluated in this real-world data analysis.

Methods

Anonymous claims data of German statutory health insurances (GKV) from 2011 to 2016 were analyzed in a primary and adjusted study population. Selection criteria included five quarters before enrolment, one index quarter (InQ) of initial TURB and BCa diagnosis, either within two years for the primary analysis or within four years for the adjusted analysis, and a follow-up period (FU) of either eleven or three quarters, respectively.

Results

In the primary analysis (n = 2331), cystectomy was identified as an important cost driver masking potential differences between cohorts. Therefore, patients undergoing cystectomy (InQ + FU) were excluded from the adjusted study population of n = 4541 patients (WL: 79%; BL: 21%). Mean total costs of BL-TURB were initially comparable to WL-TURB (WL: EUR 4534 vs. BL: EUR 4543) and tended to be lower compared to WL-TURB in the first two quarters of FU. After one year (3rd FU quarter), costs equalized. Considering total FU, mean costs of BL-TURB were significantly lower compared to WL-TURB (WL: EUR 7073 vs BL: EUR 6431; p = 0.045).

Conclusion

This retrospective analysis of healthcare claims data highlights the comparability of costs between BL-TURB and WL-TURB.

Impact of age, body mass index, and renal function for severe hypotension caused by oral 5-aminolevulinic acid administration in patients undergoing transurethral resection of bladder tumor

BACKGROUND

Severe hypotension is a notable adverse event caused by administration of 5-aminolevulinic acid (5-ALA) during photodynamic diagnosis-assisted transurethral resection of bladder tumor (PDD-TURBT). Hypotension can be prolonged following induction of anesthesia and may require continuous administration of a vasopressor. Here, we investigated the risk factors for severe hypotension caused by oral administration of 5-ALA.

METHODS

A total of 128 patients with bladder tumors who underwent PDD-TURBT using 5-ALA were included in this study. Clinicopathological data were collected retrospectively and the correlations between the incidence of severe hypotension and clinicopathological factors were analyzed.

RESULTS

Severe hypotension developed in 8 cases (6.3 %). Age ≥ 80 years, body mass index (BMI) ≥ 25 (kg/m²), and estimated glomerular filtration rate (eGFR) < 45 (mL/min/1.73 m²) were significantly correlated with severe hypotension (P = 0.003, 0.017, and 0.027, respectively). Severe hypotension developed in 1 of 89 cases (1.1 %) which have 0 or 1 risk factor, and in 3 of 31 cases (9.7 %) which have 2 risk factors, whereas it developed in 4 of 8 cases (50 %) which have all risk factors. Patients with all risk factors developed severe hypotension significantly more frequently compared with patients with 1 or fewer risk factors (P < 0.001).

CONCLUSION

Age ≥ 80 years, BMI ≥ 25, and eGFR < 45 are risk factors for severe hypotension in PDD-TURBT using 5-ALA. The risk of developing severe hypotension is extremely high in patients who have all factors. Adjustment of the 5-ALA dose may be desirable in those patients.

A novel laparoscopic near-infrared fluorescence spectrum system for photodynamic diagnosis of peritoneal dissemination in pancreatic cancer

BACKGROUND

Diagnosing peritoneal dissemination is essential for selecting the appropriate therapeutic strategy for patients with pancreatic cancer. Intraoperative laparoscopic diagnosis enables the selection of less invasive surgical strategies. Photodynamic diagnosis using 5-aminolevulinic acid may improve gastrointestinal cancer diagnostic accuracy, although weak fluorescence is not easily detected. Here we aimed to improve this sensitivity using laparoscopic spectrophotometry.

METHODS

Photodynamic diagnosis was performed using serial dilutions of protoporphyrin IX, and its detectability using laparoscopic spectrophotometry was compared with that using naked-eye observation. Five-aminolevulinic acid-photodynamic diagnosis was performed for pancreatic cancer cell lines, and a murine peritoneal disseminated nodule model was established. We compared laparoscopic spectrophotometry and naked-eye observation results using white and fluorescent lights and compared them to routine histopathological examination results. Photodynamic diagnoses were made in 2017 and 2018 in eight patients with pancreatic cancer.

RESULTS

Weaker fluorescence of the diluted protoporphyrin IX samples was better detected with spectrophotometry than with naked-eye observation. Moreover, a spectrograph of protoporphyrin IX in multiple cell lines was detected by spectrophotometry. In the murine model, the detection rates were 62 %, 78 %, and 90 % for naked-eye observation with white light, fluorescent light, and spectrophotometry, respectively. Comparisons of fluorescent light-negative peritonea with and without pathological metastases showed significantly higher spectrophotometric intensities in the former (P < 0.010). In clinical studies, three fluorescent light-negative spectrophotometry-positive pathologically metastatic lesions were observed.

CONCLUSIONS

Laparoscopic spectrophotometry in the murine model and extraperitoneally photodynamic diagnoses using spectrophotometry in clinical practice are sensitive photodynamic diagnostic techniques.

Photodynamic Diagnosis and Therapy for Peritoneal Carcinomatosis from Gastrointestinal Cancers: Status, Opportunities, and Challenges

Selective accumulation of a photosensitizer and the subsequent response in only the light-irradiated target are advantages of photodynamic diagnosis and therapy. The limited depth of the therapeutic effect is a positive characteristic when treating surface malignancies, such as peritoneal carcinomatosis. For photodynamic diagnosis (PDD), adjunctive use of aminolevulinic acid- protoporphyrin IX-guided fluorescence imaging detects cancer nodules, which would have been missed during assessment using white light visualization only. Furthermore, since few side effects have been reported, this has the potential to become a vital component of diagnostic laparoscopy. A variety of photosensitizers have been examined for photodynamic therapy (PDT), and treatment protocols are heterogeneous in terms of photosensitizer type and dose, photosensitizer-light time interval, and light source wavelength, dose, and dose rate. Although several studies have suggested that PDT has favorable effects in peritoneal carcinomatosis, clinical trials in more homogenous patient groups are required to identify the true benefits. In addition, major complications, such as bowel perforation and capillary leak syndrome, need to be reduced. In the long term, PDD and PDT are likely to be successful therapeutic options for patients with peritoneal carcinomatosis, with several options to optimize the photosensitizer and light delivery parameters to improve safety and efficacy.

Diagnostic accuracy of photodynamic diagnosis for upper urinary tract urothelial carcinoma: A systematic review and meta-analysis

BACKGROUND

This study aimed to evaluate the effectiveness of photodynamic diagnosis (PDD) for upper urinary tract urothelial carcinoma (UTUC) by performing a meta-analysis.

METHOD

Relevant articles were retrieved from the Cochrane Library, PubMed, and Embase databases. Studies evaluating the accuracy of PDD for the diagnosis of upper UTUC were included. The pooled sensitivity, specificity, and area under the curve (AUC) were calculated by STATA 16.0 at the per-lesion level.

RESULTS

Six studies with 289 lesions were included in this systematic review and meta-analysis. The pooled results showed that PDD can differentiate upper UTUC from benign lesions with a sensitivity of 0.96 (95 % confidence interval: 0.85-0.99) and a specificity of 0.86 (95 % confidence interval: [0.64-0.95]; AUC, 0.97). Compared with white-light ureterorenoscopy, PDD can significantly improve the additional detection rate of UTUC (RR 0.16, 95 % CI 0.07-0.34 P = 0.000).

CONCLUSIONS

PDD is a valid technique that improves the diagnostic accuracy of UTUC compared with standard white-light ureterorenoscopy at the per-lesion level. PDD is a promising endoscopic technique for upper UTUC.

Cancer cell detection device for the diagnosis of bladder cancer from urine

Bladder cancer is common and has one of the highest recurrence rates. Cystoscopy, the current gold standard diagnosis approach, has recently benefited from the introduction of blue light assisted photodynamic diagnostic (PDD). While blue light cystoscopy improves diagnostic sensitivity, it remains a costly and invasive approach. Here, we present a microfluidic-based platform for non-invasive diagnosis which combines the principle of PDD with whole cell immunocapture technology to detect bladder cancer cells shed in patient urine ex vivo. Initially, we demonstrate with model cell lines that our non-invasive approach achieves highly specific capture rates of bladder cancer cells based on their Epithelial Cell Adhesion Molecule expression (>90%) and detection by the intensity levels of Hexaminolevulinic Acid-induced Protoporphyrin IX fluorescence. Then, we show in a pilot study that the biosensor platform successfully discriminates histopathologically diagnosed cancer patients (n = 10) from non-cancer controls (n = 25). Our platform can support the development of a novel non-invasive diagnostic device for post treatment surveillance in patients with bladder cancer and cancer detection in patients with suspected bladder cancer.

Key transporters leading to specific protoporphyrin IX accumulation in cancer cell following administration of aminolevulinic acid in photodynamic therapy/diagnosis

The administration of aminolevulinic acid allow the formation and accumulation of protoporphyrin IX specifically in cancer cells, which then lead to photocytotoxicity following light irradiation. This compound, when accumulated at high levels, could also be used in cancer diagnosis as it would emit red fluorescence when being light irradiated. The concentration of protoporphyrin IX is pivotal in ensuring the effectiveness of the therapy. Studies have been carried out and showed the importance of various transporters in regulating the amount of these substrates by controlling the transport of various related metabolites in and out of the cell. There are many transporters involved and their expression levels are dependent on various factors, such as oxygen availability and iron ions. It is also important to note that these transporters may also have different expression levels depending on their organ. Understanding the mechanisms and the roles of these transporters are essential to ensure maximum accumulation of protoporphyrin IX, leading to higher efficiency in photodynamic therapy/diagnosis. In this review, we would like to discuss the roles of various transporters in protoporphyrin IX accumulation and how their involvement directly affect cancerous microenvironment.

Evolution of photodynamic medicine based on fluorescence image-guided diagnosis using indocyanine green and 5-aminolevulinic acid

New diagnostic techniques based on photodynamic medicine, such as near-infrared fluorescence using indocyanine green (NIR-ICG) and 5-aminolevulinic acid-mediated photodynamic diagnosis (ALA-PDD), are aiding navigation tasks across various fields of surgery. Specifically, NIR-ICG is being used for the intraoperative identification of sentinel lymph nodes or blood vessels in organ resection and for blood flow evaluation in surgery. These ICG-fluorescent imaging techniques could provide an additional and potentially valuable way to identify vascular and lymphatic structures in surrounding tissue. 5-Aminolevulinic acid is a precursor of a photosensitizing substance with affinity for tumors; thus, diagnostic laparoscopy using ALA-PDD in combination should improve the accuracy of detecting peritoneal dissemination in patients with advanced gastric cancer. The ability to overlay fluorescent imaging with conventional color images in real time using ALA-PDD and NIR with ICG would be of immense benefit to surgeons, providing good visualization and detection of target lesions not seen with the naked eye. A multi-center clinical study examining the safety and efficacy of ALA-PDD during laparoscopic examination for patients with advanced gastric cancer is currently underway in the form of doctor-initiated trials, and further verification studies will be conducted. Such imaging capability could have broad potential across cancer and vascular surgery.

Hysteroscopic Photodynamic Diagnosis Using 5-Aminolevulinic Acid: A High-Sensitivity Diagnostic Method for Uterine Endometrial Malignant Diseases

STUDY OBJECTIVE

To examine the diagnostic accuracy of hysteroscopic photodynamic diagnosis (PDD) using 5-aminolevulinic acid (5ALA) in patients with endometrial cancer and premalignant atypical endometrial hyperplasia.

DESIGN

A single-center, open-label, exploratory intervention study.

SETTING

University Hospital in Japan.

PATIENTS

Thirty-four patients who underwent hysteroscopic resection in the Department of Obstetrics and Gynecology at Keio University Hospital.

INTERVENTIONS

Patients were given 5ALA orally approximately 3 hours before surgery and underwent observation of the uterine cavity and endometrial biopsy using 5ALA-PDD during hysteroscopic resection. Specimens were diagnosed histopathologically and the diagnostic sensitivity and specificity of hysteroscopic 5ALA-PDD for malignancy in the uterine cavity was determined. Red (R), blue (B), and green (G) intensity values were determined from PDD images, and the relationships of histopathological diagnosis with these values were used to develop a model for objective diagnosis of uterine malignancy.

MEASUREMENTS AND MAIN RESULTS

Three patients were excluded from the study because of failure of the endoscope system. A total of 113 specimens were collected endoscopically. The sensitivity and specificity of 5ALA-PDD for diagnosis of malignancy in the uterine cavity were 93.8% and 51.9%, respectively. The R/B ratio in imaging analysis was highest in malignant lesions, followed by benign lesions and normal uterine tissue, with significant differences among these groups (p <.05). The R/B and G/B ratios were used in a formula for prediction of malignancy based on logistic regression and the area under the receiver operating characteristic curve for this formula was 0.838. At a formula cutoff value of 0.220, the sensitivity and specificity for diagnosis of malignant disease were 90.6% and 65.4%, respectively.

CONCLUSION

To our knowledge, this is the first study of the diagnostic accuracy of 5ALA-PDD for malignancies in the uterine cavity. Hysteroscopic 5ALA-PDD had higher sensitivity and identifiability of lesions. These findings suggest that hysteroscopic 5ALA-PDD may be useful for diagnosis of minute lesions.

Inverted papilloma of the urinary bladder shows fluorescence on photodynamic diagnosis using 5-aminolevulinic acid

Photodynamic diagnosis (PDD) of non-muscle invasive bladder cancer using 5-aminolevulinic acid (5-ALA) has recently attracted attention as a diagnostic method for observing cancer lesions based on fluorescence emission using a fluorescent endoscope. However, there are few reports of false positives associated with benign bladder neoplasms. Here, we provide report of two cases of inverted papillomas of the bladder that were fluorescent on PDD using 5-ALA. In each case, a surface-smooth, pedunculated bladder tumor was observed, which fluoresced red on PDD after oral administration of 5-ALA. Histopathological findings demonstrated inverted papilloma of the bladder. Although inverted papilloma of the bladder is usually regarded as a benign neoplasm, some recent studies have revealed that it could be a risk factor for urothelial carcinoma. Our present report may support the hypothesis that inverted papilloma of the bladder has malignant potential.

Photodynamic diagnosis and therapy for urothelial carcinoma and prostate cancer: new imaging technology and therapy

Photodynamic technology using light-sensitive and fluorescent substances has an important role in an accurate diagnosis for a variety of malignancies, including bladder cancer and prostate cancer. Light-sensitive and fluorescent substances accumulate specifically in tumor cells compared to normal tissue, and by light irradiation and excitation at each specific wavelength, tumor lesion, blood flow, lymph node and so on show fluorescence. 5-Aminolevulinic acid (ALA) is converted to protoporphyrin IX (PpIX) into mitochondria. PpIX is excited by blue light, red fluorescence is emitted in the mitochondria. This phenomenon is the mechanism of ALA-mediated photodynamic diagnosis (ALA-PDD). ALA-PDD has made it possible to visualize smaller lesions and flat lesions that were previously difficult to visualize by endoscope using a white-light source. So accurate diagnosis and complete resection become possible during operation. The accumulation of PpIX in the mitochondria also induces direct mitochondrial damage and subsequent cell death by red and green light. This biological reaction is the ALA-mediate photodynamic therapy (ALA-PDT). ALA-PDT has been developed as a modality for minimum invasive cancer treatment that utilizes low-energy light and photosensitizer. Vascular-activated photosensitizer induces rapid tumor ablation by PDT involving direct tumor cell killing as well as damage to the exposed microvasculature. We summarize the clinical outcomes of PDD and PDT for urothelial carcinoma and prostate cancer.

Two diagnostic criteria of optical spectroscopy for bladder tumor detection: Clinical study using 5-ALA induced fluorescence and mathematical modeling

BACKGROUND

The study proposes to improve bladder cancer diagnosis by photodynamic diagnosis (PDD) using red-light excitation (632.8 nm) of 5-ALA induced-protoporphyrin IX. Employing 9 patients' bladders, two types of signals were used to improve diagnostic accuracy for malignancy and we also present numerical modeling of the scattering coefficient to provide biological explanation of the results obtained.

METHODS

Two modalities of bladder cancer spectral diagnosis are presented: conventional PDD and intensity assessment of the diffusely reflected laser light by fiber-optic spectroscopy. Experiments are done in clinical conditions and as a series of numerical simulations.

RESULTS

High-grade cancerous bladder tissues display twice a higher relative fluorescence intensity (mean value 1, n = 9) than healthy (0.39, n = 9), dysplastic (0.44, n = 5) tissues and CIS (0.39, n = 2). The laser back-scattering signal allows to discriminate most effectively high-grade cancerous and dysplastic tissues from normal. Numerical modeling of diffuse reflectance spectra reveals that spectral behavior of the back-scattered light depends on both, nuclear size and nuclear density of tumoral cells.

CONCLUSIONS

Unlike the fluorescence signal, where its value is higher in the case of pathological tissues, the tendency of the laser signal to, both, decrease or increase in comparison with the signal from normal urothelium, should be perceived as a sign towards neoplasm. Numerical simulation reveals that such a double-analysis at a multiwavelength mode potentially may be used to provide diagnostic accuracy.

Next-generation laser-based photodynamic endoscopic diagnosis using 5-aminolevulinic acid for early gastric adenocarcinoma and gastric adenoma

Background

Photodynamic diagnosis (PDD) is an optical imaging technology based on the fundamental biological features of porphyrin metabolized in cancer cells. We reported the usefulness of laser-based photodynamic endoscopic diagnosis (LPDED) with 5-aminolevulinic acid (5-ALA) for early gastric cancers. However, the first-generation prototype endoscope system had the flaw that the images captured were rather dark. To overcome this, we constructed a next-generation endoscope system for LPDED.

Methods

We evaluated the usefulness of the next-generation prototype endoscope system, called Sie-P2, for brighter LPDED to detect early gastric cancer (EGC) and gastric adenoma. The 14 patients diagnosed with EGC and/or gastric adenoma who underwent endoscopic submucosal dissection (ESD) at our hospital between April 2018 and March 2019 were enrolled consecutively in this study. Patients were administered 5-ALA orally and LPDED was performed 3 h later. The primary endpoint was the presence of fluorescence in tumors when we performed LPDED. The secondary endpoint was to assess the adverse events related to each LPDED procedure.

Results

One patient was excluded because of a contraindication, while the remaining 13 patients (median 72 years, range 56-77; one female) with 16 lesions were assessed. There were 10 elevated lesions and 6 flat/depressed lesions; there were 10 EGCs and 6 adenomas. LPDED-fluorescence was detected in all 16 lesions (sensitivity 100%, 95% confidence interval 79-100%). Two cases showed temporary, though not substantial, elevation in blood liver function tests.

Conclusion

All lesions examined were LPDED-positive, indicating that the Sie-P2 system could be useful.

Evaluation of autofluorescence and photodynamic diagnosis in assessment of bladder lesions

The ability to detect and diagnose bladder cancer early and precisely is crucial for effective treatment. The aim of this study is to assess the utility of optical biopsy performed with autofluorescence cystoscopy (AFC) using the Onco-LIFE system with numerical color values (NCVs) and by ALA/PDD. Histopathological examination of material obtained during TURBT and/or biopsy of the bladder was carried out in 251 patients. In the case of 35 patients, the selection of the specimen collected for histopathological examination was based using ALA/PDD. In the remaining 216 patients, tissue was collected based on the findings of AFC with NCV. Using AFC, the observed NCV ranged from 0 to 3.86; the highest mean NCV was observed in neoplastic muscle invasive lesions and was equal to 3.18. Furthermore, non-muscle invasive tumors were characterized by a mean NCV equal to 1.54. Tissue with inflammation, metaplasia, and healthy tissue demonstrated significantly lower mean NCV values. The presence of a muscle-invasive tumor increased the NCV by approximately 2.86 compared to healthy tissue. The rates of postoperative complications depend on the examining operator and are observed more often, as much as 65.7 % during ALA/PDD. AFC with NCV using the Onco-LIFE system, as well as ALA/PDD are helpful tools for early diagnosis of bladder precancerous and cancer lesions and for performing targeted biopsies. A significant correlation was found between lesion NCV index and the grade of dysplasia or tumor malignancy. Tissue with inflammation, metaplasia, and healthy tissue demonstrated significantly lower mean NCV values. AFE with NCV have a significantly higher sensitivity than specificity. Low rates of postoperative complications are correlated to the experience of the endoscopist and with AFE/NCV in comparison of ALA/PDD.

5-aminolevulinic acid-mediated photodynamic diagnosis using fluorescence ureterorenoscopy for urinary upper tract urothelial carcinoma ∼Preliminary prospective single centre trial∼

OBJECTIVE

To investigate the diagnostic accuracy of 5- aminolevulinic acid-mediated photodynamic diagnosis (ALA-PDD) for upper urinary tract tumor (UTUC) including carcinoma in situ (CIS) lesions using flexible fluorescence ureterorenoscopy.

METHODS

A solution of ALA was orally administrated at 20 mg/kg body weight at 3 h prior to surgery. Fluorescence observation was carried out with IMAGE1S OPAL1 PDD system. Positive lesions that were identified as abnormal changes under white light and/or blue light were biopsied, followed by cold-cup biopsy of negative lesions that were normal-looking mucosa under white light and/or blue light. Diagnostic accuracy was analysed by comparing ureterorenoscopic observations under white light or blue light with pathological analysis results.

RESULTS

A total of 31 biopsy specimens were obtained from 10 patients. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for PDD to detect UTUC was 100 %, 50 %, 52.4 % and 100 %, respectively. The sensitivity of PDD ureterorenoscopy was significantly higher than that of white light ureterorenoscopy by statistics (p < 0.05). Especially, 5 CIS lesions were detected only by ALA-PDD ureterorenoscopy (p < 0.05). Of 10 patients, one patient (10 %) experienced hypotension during the ALA-PDD.

CONCLUSIONS

ALA-PDD for UTUC is a feasible and safe techniques with acceptable adverse events. Additional advantage of ALA-PDD for UTUC is the high sensitivity to detect CIS lesions with blue light mode.

Preanesthetic severe postural hypotension following 5-aminolevulinic acid pretreatment in patients for photodynamic diagnosis-assisted urological surgery

BACKGROUND

5-Aminolevulinic acid (5-ALA) is utilized for photodynamic diagnosis-assisted (PDD) surgery. However, it has been associated with vasodilation, hence, occasional hypotension.

CASE PRESENTATION

We encountered two patients who had severe postural hypotension following 5-ALA pretreatment prior to an operation. They were scheduled for urological PDD surgery, but upon standing to walk to the operation room, they felt sick because of severe hypotension. One of them underwent the surgery after recovery, but the other surgery was canceled due to a prolonged hypotension that lasted for more than a day.

CONCLUSIONS

Severe postural hypotension may develop as a result of the high concentration of porphyrin precursors, which may affect the nervous system. Severe postural hypotension may be due to 5-ALA-induced autonomic dysfunction as well as vasodilative action of 5-ALA. These observations suggest that in addition to the careful monitoring of patients' vital signs, standing should be avoided following 5-ALA pretreatment.

Significance of in vitro photodynamic cytodiagnosis using 5-aminolevulinic acid in solid pancreatic tumors extracted by endoscopic ultrasound-guided fine-needle aspiration

BACKGROUND

Recently, photodynamic diagnosis using 5-aminolevulinic acid (5-ALA) has gained attention for the diagnosis of neoplastic diseases. In the present study, an in vitro method of photodynamic cytodiagnosis (PDCD) performed using the reagent 5-ALA in the cytodiagnosis of solid pancreatic tumors was developed. Here, we assess the accuracy of PDCD for malignancy.

MATERIALS AND METHODS

EUS-FNA was performed from September 2015 to March 2018 in patients with solid pancreatic tumors at Osaka Rosai Hospital. Samples were diagnosed independently by an expert pathologist and a medical doctor with conventional cytology and PDCD.

RESULTS

A total of 53 patients (35 males, average age: 70.2 years old) were enrolled. The definitive diagnoses were 7 benign lesions and 46 malignant lesions. Using the in vitro PDCD method, the detection of reddish fluorescence in cell samples indicated cancer cells. PDCD had a sensitivity of 91.3% (42/46) and a specificity of 100% (7/7), while conventional cytology had a sensitivity of 93.5% (43/46) and a specificity of 85.7% (6/7). Two patients were successfully diagnosed with malignancy only by the PDCD method.

CONCLUSIONS

In vitro PDCD performed using the 5-ALA method can effectively and safely identify a diagnosis of pancreatic cancer without requiring an expert pathologist. The sensitivity of this technique could be increased in the diagnosis of pancreatic malignancy by combining it with the conventional method.

[Cost-effectiveness analysis of blue light cystoscopy with hexylaminolevulinate in transurethral resection of the bladder]

BACKGROUND

Photodynamic diagnosis using the optical imaging agent hexaminolevulinate (HAL, Hexvix®, Ipsen Pharma GmbH, Ettlingen, Germany) as an adjunct to white light cystoscopy (WLC) during the initial transurethral resection of bladder tumours (TURB) improves the detection rate of bladder cancer and leads to fewer recurrences.

OBJECTIVES

A cost-effectiveness analysis was carried out in order to calculate the consequences for the German healthcare system.

METHODS

We combined a short-term decision tree and a Markov model to evaluate outcomes over a long period of time. The alternatives investigated were HAL-assisted blue light cystoscopy (BLC) as adjunct to WLC (HAL + BLC/WLC) compared with WLC alone in patients undergoing TURB.

RESULTS

HAL + BLC/WLC compared to WLC alone was associated with 0.07 incremental quality-adjusted life years (QALYs) and cost savings of 537 € per patient.

CONCLUSION

HAL + BLC/WLC compared with WLC alone resulted in both cost savings and improved patient outcome rendering it the "dominant" strategy.

Atypical polypoid adenomyoma treated by hysteroscopy with photodynamic diagnosis using 5-aminolevulinic acid: A case report

Surgical resection for atypical polypoid adenomyoma (APA) is an option for fertility preservation. Due to the high recurrence rate of APA, studies have been conducted to improve total resection of tumors. Photodynamic diagnosis (PDD) using 5-aminolevulinic acid (5-ALA) improves tumor resection, but this has not been applied for APA. The patient was 35-year-old. After initial treatment, the APA lesion did not disappear. We performed hysteroscopic tumor resection using 5-ALA-PDD. Only one PDD-positive lesion was found and histopathologically diagnosed as APA. Other areas were PDD-negative and showed no histopathologic APA or malignant findings. This is the first report of hysteroscopic 5-ALA-PDD for APA. This method makes it easy to identify morbid lesions, and may lead to improved total resection and decreased recurrence.

Biosensor device for the photo-specific detection of immuno-captured bladder cancer cells using hexaminolevulinate: An ex-vivo study

Exogenous administration of the photodynamic agent hexaminolevulinate induces Protoporphyrin IX (PpIX) accumulation in malignant tissue. This may enable differentiation from healthy tissues by emission of a distinctive red fluorescence. It provides the photo-specific detection when excited with blue light at 405 nm. This study determines the ex-vivo processing conditions (time, concentration, temperature and addition of a fluorescent dye) required for HAL-induced PpIX fluorescence to successfully discriminate between bladder cancer and benign fibroblast cells shed in urine at the single cell level. HAL-induced fluorescence was 4.5 times brighter in cancer cells than non-cancer cells when incubated in the optimum conditions, and could be used to correctly identified bladder cancer cells captured within a newly developed immunofunctionalized biosensor with 88% efficiency. This biosensor is designed to facilitate the immuno-capture of cancer cells by interaction with carcinoma specific anti Epithelial Cell Adhesion molecule (anti-EpCAM) antibodies. Anti-EpCAM antibodies were immobilized on polyoxazoline (POx) plasma polymers by covalent bonds in microfluidic channels. Combining photodynamic and immunoselective approach therefore constitute a promising approach for the non-invasive diagnosis of bladder cancer with two independent level of confidence.

OBJECTIVE

This study investigate the relationship between different regulatory factors (time, concentration, temperature and addition of a fluorescent dye) and Hexaminolevulinate (HAL)-mediated photodynamic diagnosis of bladder cancer (PDD) in vitro. We examine the natural photosensitizer Protoporphyrin IX (PpIX) fluorescence induced by HAL in several human bladder cancer cell lines and one non-cancer foreskin fibroblast cell line and identify the processing conditions that maximise the difference in fluorescence intensity between malign and benign cell types. The detection of HAL induced fluorescence at a single cell level by a selective cancer cell capture platform is also tested.

MATERIALS AND METHODS

Experiments were performed on cultured monolayer cells and cells in suspension. The cell lines examined included the transitional epithelium carcinoma cell lines HT1197, HT1376, EJ138 and RT4, and the non-cancer foreskin fibroblasts HFF. Cells were incubated with HAL in various doses, time and temperature settings. We also used the nuclear red as a tool to study the PpIX subcellular localization. PpIX fluorescence intensities were measured and analysed using fluorescence microscope software. Finally, we evaluated the possibility of using HAL to discriminate between cancer and non-cancer cells from a mixed cell population using a newly developed immunofunctionalized microfluidic platform.

RESULTS

The accumulation of PpIX in bladder cancer cells was significantly higher than in non-cancer cells, both cultured monolayer cells and cells in suspension. Effectively, the fluorescence intensity was 4.5 times brighter in bladder cancer cells than non-cancer foreskin fibroblast cells when incubated in the optimum condition, in which the nuclear stain adjuvant acted as a fluorescence enhancer. Cancer cells displayed PpIX accumulated mainly in mitochondria but none or very little PpIX was observed in non-cancer cells. HAL-induced fluorescence could be used to correctly identify bladder cancer cells within the EpCAM conjugated POx based microfluidic sensor with an 88% capture selectivity rate.

CONCLUSIONS

These findings prove that the application of HAL-induced PpIX fluorescence can successfully distinguish between cancer and non-cancer cells in vitro. This test can provide advanced second level of confidence on the cancerous nature of cells captured by the immunofunctionalized bladder cancer diagnostic platform.

Fluorescence spectroscopy of Candida albicans biofilms in bone cavities treated with photodynamic therapy using blue LED (450 nm) and curcumin

Fluorescence spectroscopy may assisst in the diagnosis and control of infectious processes associated with bone lesions of the oral cavity. The aim of this study was to analyze, through fluorescence spectroscopy, Candida albicans biofilms formed in artificial bone cavities treated with photodynamic therapy (PDT) mediated with 450-nm blue light-emitting diode (LED) and curcumin. Another aim of this study was to analyze the existence of a correlation between the effectiveness of the photodynamic treatments and the fluorescence spectroscopy images. Artificial bone lesions (n = 40) were made in bovine bones and inoculated with standard suspensions of Candida albicans (ATCC 18804) for biofilm formation (14 days / 36 °C ± 1 °C). The 40 specimens were distributed among four experimental groups (n = 10): L-C- (control), L + C- (LED for 5 min), L-C+ (curcumin for 5 min), and L + C+ (PDT). Aliquots of 100 μL were collected from the bone cavities after treatments and were seeded in duplicate on Sabouraud dextrose agar for 24 h at 36 °C ± 1 °C and the colony-forming units (CFU/ mL) were counted. Before and after each treatment, the specimens were subjected to spectral fluorescence and the images were compared using the Image J program. The log₁₀ CFU/mL were compared with Kruskal-Wallis and Dunn's Multiple Comparison post-test (significance level at 0.05). The fluorescence histogram values before and after treatment were compared using Wilcoxon test (95%).The correlation between Candida albicans log₁₀ CFU/mL and the number of the fluorescence red pixels spectroscopy was verified using Spearman correlation test. The reduction of Candida albicans log₁₀ CFU/mL in the L + C+ (PDT) group was the most relevant and the fluorescence spectroscopy was correlated to the microbiological result. It was concluded that there was a consistency between the number of Candida albicans log₁₀ CFU/mL and the red pixel data of the fluorescence images, demonstrating that the fluorescence diagnostic device reflects the true microbiological condition of Candida albicans biofilms in the bone cavities during the pre-treatment and post-treatment, thus providing the clinician the ability to dynamically, simply, and instantaneously verify the performance of the treatment used.

Atypical endometrial hyperplasia diagnosed by hysteroscopic photodynamic diagnosis using 5-aminolevulinic acid

Endometrial cancer is diagnosed by endometrial biopsy, imaging and hysteroscopy, but it is sometimes difficult to find small lesions. 5-aminolevulinic acid (5ALA) forms protoporphyrin IX, which accumulates in tumors and fluoresces upon light irradiation. 5ALA is used for photodynamic diagnosis (PDD) for detecting malignant diseases. A 60-year-old female was suspected to have endometrial cancer by magnetic resonance imaging. Endometrial biopsy was performed repeatedly, but no malignant lesion was detected. We performed hysteroscopic 5ALA-PDD and could detect a small lesion. The lesion was excised and diagnosed as atypical endometrial hyperplasia histopathologically. This is the first report that showed hysteroscopic 5ALA-PDD can contribute to diagnosis of early-stage neoplastic lesion in the uterine cavity.

Bright spot analysis for photodynamic diagnosis of brain tumors using confocal microscopy

BACKGROUND

In a previous study of photodynamic tumor diagnosis using 5-aminolevulinic acid (5-ALA), the authors proposed using fluorescence intensity and bright spot analyses under confocal microscopy for the precise discrimination of tumorous brain tissue (such as glioblastoma, GBM) from normal tissue. However, it remains unclear if bright spot analysis can discriminate infiltrating tumor in the boundary zone and whether this method is suitable for GBM with no 5-ALA fluorescence or for other tumor types.

METHODS

Brain tumor tissue resected from 5-ALA-treated patients was sectioned to evaluate bright spots under confocal microscopy with a 544.5 - 619.5 nm band-pass filter, which eliminated the fluorescence induced by 5-ALA. Border regions and adjacent normal tissues were observed for differences in bright spot distribution. Histopathology was also conducted by hematoxylin and eosin (H&E) staining of serial slices from the same samples to confirm the locations of tumorous, infiltrating, and normal regions. Bright spot areas were then calculated for the same regions evaluated by histopathology. This method was applied for GBM with and without 5-ALA-induced fluorescence as well as for lower-grade gliomas and other brain tumor types.

RESULTS

The bright spot area was substantially smaller in the GBM body than in normal brain tissues. Bright spot area was also smaller in infiltrating tumors than in normal tissue at the margin. The same bright spot pattern was observed in tumorous tissues with no 5-ALA-induced fluorescence and in non-GBM tumors. The bright spot fluorescence is suggested to arise from lipofuscin based on emission spectra (mainly within 544.5 - 619.5 nm) and optimum excitation wavelength (about 405 nm).

CONCLUSIONS

Bright spot analysis is useful for discriminating infiltrating tumor from bordering normal tissue as an alternative or complement to photodynamic diagnosis with 5-ALA. This method is also potentially useful for tumors with no 5-ALA-derived red fluorescence and other nervous system tumors.

Bibliographic review.]

OBJECTIVES

Bladder tumors are thesecond highest incidence urological tumor in the adultpopulation. In recent years, new techniques such as photodynamicdiagnosis have arisen in order to improvethe sensitivity for the detection of non muscle invasivebladder cancer (NMIBC). We intend to update the roleof photodynamic diagnosis in the diagnosis of NMIBC,in cases refractory to BCG and as a treatment in therecurrent bladder cancer.

MATERIAL AND METHOD

We performed a descriptivestudy and bibliographic review on the usefulness of photratatodynamicdiagnosis in NMIBC, early recurrence andrefractoriness to BCG published in the universal medicalliterature.

RESULTS

Photodynamic cystoscopy increases the detectionsensitivity for NMIBC, especially carcinoma in situ(CIS) from 15% to 30% according to the different seriespublished. Regarding high-grade bladder cancer recurrence,photodynamic therapy increases disease-freetime in 20% of patients. In the use of photodynamictechniques for the detection of CIS after BCG, studiesindicate an increase in sensitivity with an increase in therate of false positives.

CONCLUSION

Photodynamic diagnosis could improvesensitivity for the early detection of patients withCIS and/or T1G3. May be, at the same time, an alternativein the recurrence of bladder cancer, especiallyCIS.

Recent advances in optical imaging technologies for the detection of bladder cancer

White-light cystoscopy (WLC) is the diagnostic standard for the detection of bladder cancer (BC). However, the detection of small papillary and subtle flat carcinoma in situ lesions is not always possible with WLC. Several adjunctive optical imaging technologies have been developed to improve BC detection and resection. Photodynamic diagnosis, which requires the administering of a photoactive substance, has a higher detection rate than WLC for the detection of BC. Narrow-band imaging provides better visualization of tumors by contrast enhancement between normal mucosa and well-vascularized lesions. A technology called confocal laser endomicroscopy can be used to obtain detailed images of tissue structure. Optical coherence tomography is a high-resolution imaging process that enables noninvasive, real-time, and high-quality tissue images. Several other optical imaging technologies are also being developed to assist with the detection of BC. In this review, we provide an overview of the strengths and weaknesses of these imaging technologies for the detection of BC.

Topical application of Photofrin® for photodynamic diagnosis of malignant cutaneous neoplasms

OBJECTIVES

The prognosis of patients suffering from malignant cutaneous neoplasms can be improved by early diagnosis. Exact demarcation of tumor margins could contribute to optimum results in surgical excision and reconstruction. The purpose of our study is to evaluate Photofrin^® with a new diagnostic procedure, photodynamic diagnosis (PDD), for the detection of Bowen's disease (squamous cell carcinoma (SCC) in situ), SCC, and basal cell carcinoma (BCC).

MATERIALS AND METHODS

Sixty patients with cutaneous neoplasms received 2.5 mg/mL Photofrin^® solution topically. After a period of 3 hours, the patients underwent fluorescence illumination (λex = 370-450 nm). Guided by their visible fluorescence, lesions were biopsied at four suspicious sites in each patient. All specimens were analyzed and measured by a pathologist. A quantitative analysis of the fluorescence contrast between the neoplasms and healthy tissue was performed using the Red, Blue, and Green (RGB) Mode and Gray Scale (GS). Statistical analysis was performed by the analysis of variance (ANOVA) test for multiple comparisons.

RESULTS

Of the 60 patients (20 Bowen's disease, 20 SCC, and 20 BCC), malignant neoplasms could be clearly distinguished from adjacent healthy tissue under fluorescence illumination (P < 0.0001). The sensitivity of the malignant neoplasms evaluated using the RGB and GS modes combined showed 92.74% in image results. The specificity of the malignant neoplasms evaluated using the RGB and GS modes combined showed 95.77%.

CONCLUSION

Light-induced fluorescence detection using topical Photofrin^® provides a sensitive, noninvasive technique for the early identification of malignant cutaneous neoplasms.

Spectrophotometric photodynamic diagnosis of prostate cancer cells excreted in voided urine using 5-aminolevulinic acid

To evaluate the feasibility of photodynamic diagnosis using 5-aminolevulinic acid (PDD-ALA) for detection of prostate cancer (PCa) cells in urine samples after prostate massage in patients who were suspected to have PCa. One hundred and eighty-nine patients with abnormal digital rectal examination and/or an elevated prostate-specific antigen (PSA) level who underwent initial prostate biopsy were recruited. After prostate massage, the first 60 mL of voided urine was collected. For PDD-ALA, 50 mL was used. The rest of collected urine was used for polymerase chain reaction (PCR) of PSA and glyceraldehyde 3-phosphate dehydrogenase (GAPDH). After incubation for 2 h, the intensity was measured at 635 nm under a 405-nm wavelength excitation. The results of PDD-ALA were compared with those of an initial transrectal ultrasound (TRUS)-guided prostate biopsy. Overall, 126/189 (67%) samples that showed bands of both PSA and GAPDH on PCR in urine samples were analyzed. The area under the curve, sensitivity, and specificity of PDD-ALA were 0.74, 77, and 67%, respectively. The value of PDD-ALA was significantly higher in patients with Gleason scores of 6 (p = 0.03), 7 (p = 0.005), and 8-10 (p = 0.0002) than in those with negative biopsy results. In the multivariate analysis, high PSA density, abnormal findings on TRUS, and a high value of PDD-ALA were significant markers for prediction of positive biopsy results. PDD-ALA was useful to predict positive biopsy results in patients who underwent initial prostate biopsy with suspected PCa. This PCa-detection method has potential for clinical use.

Clinical application of photodynamic medicine technology using light-emitting fluorescence imaging based on a specialized luminous source

The natural amino acid 5-aminolevulinic acid (ALA) is a protoporphyrin IX (PpIX) precursor and a new-generation photosensitive substance that accumulates specifically in cancer cells. When indocyanine green (ICG) is irradiated with near-infrared (NIR) light, it shifts to a higher energy state and emits infrared light with a longer wavelength than the irradiated NIR light. Photodynamic diagnosis (PDD) using ALA and ICG-based NIR fluorescence imaging has emerged as a new diagnostic technique. Specifically, in laparoscopic examinations for serosa-invading advanced gastric cancer, peritoneal metastases could be detected by ALA-PDD, but not by conventional visible-light imaging. The HyperEye Medical System (HEMS) can visualize ICG fluorescence as color images simultaneously projected with visible light in real time. This ICG fluorescence method is widely applicable, including for intraoperative identification of sentinel lymph nodes, visualization of blood vessels in organ resection, and blood flow evaluation during surgery. Fluorescence navigation by ALA-PDD and NIR using ICG imaging provides good visualization and detection of the target lesions that is not possible with the naked eye. We propose that this technique should be used in fundamental research on the relationship among cellular dynamics, metabolic enzymes, and tumor tissues, and to evaluate clinical efficacy and safety in multicenter cooperative clinical trials.

Assessment of safety of 5-aminolevulinic acid-mediated photodynamic therapy in rat brain

BACKGROUND

Oral 5-aminolevulinic acid (ALA) induces biosynthesis/accumulation of the natural photo-sensitizer protoporphyrin IX (PpIX) in cancer cells. ALA is used widely in photodynamic diagnosis (PDD) and therapy (PDT) during malignant glioma surgery, but few studies have examined the effects of photodynamics plus ALA on normal brain tissue in vivo. We investigated the effects of ALA-mediated PDD and PDT on normal brain tissue.

METHODS

We established a rat model in which the brain surface was irradiated through the skull by light-emitting diode (635 nm) after ALA administration. Using this model, we investigated the effects of various amounts of light irradiation with various ALA doses on brain tissue.

RESULTS

Neurological symptoms developed with administration of ALA at 240 or 120 mg/kg accompanied by irradiation at 100 or 400 J/cm², respectively. Dye leakage occurred due to disruption of the blood-brain barrier (BBB) at 90 mg/kg and 100 J/cm², respectively. Thickness of the cortex increased significantly at 240 mg/kg and 400 J/cm², respectively. The number of neurons appeared to decrease at 200 mg/kg plus 400 J/cm², respectively, and there was an increase in the number of cells that were positive for terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick-end labeling (TUNEL) staining.

CONCLUSIONS

ALA-mediated PDT is safe at doses of 90 mg/kg or less followed by light irradiation of 100 J/cm² in rat brains. At doses above this threshold, ALA-PDT led to irreversible BBB and brain damage in rats.