Repeated 5-aminolevulinic Acid Instillations During Follow-up in Non-muscle-invasive Bladder Cancer: A Randomized Study

Effect of 5-Aminolevulinic Acid (5-ALA) in "ALADENT" Gel Formulation and Photodynamic Therapy (PDT) against Human Oral and Pancreatic Cancers

Oral squamous-cell and pancreatic carcinomas are aggressive cancers with a poor outcome. Photodynamic therapy (PDT) consists of the use of photosensitizer-induced cell and tissue damage that is activated by exposure to visible light. PDT selectively acts on cancer cells, which have an accumulation of photosensitizer superior to that of the normal surrounding tissues. 5-aminolevulinic acid (5-ALA) induces the production of protoporphyrin IX (PpIX), an endogenous photosensitizer activated in PDT. This study aimed to test the effect of a new gel containing 5% v/v 5-ALA (ALAD-PDT) on human oral CAL-27 and pancreatic CAPAN-2 cancer cell lines. The cell lines were incubated in low concentrations of ALAD-PDT (0.05%, 0.10%, 0.20%, 0.40%, 0.75%, 1.0%) for 4 h or 8 h, and then irradiated for 7 min with 630 nm RED light. The cytotoxic effects of ALAD-PDT were measured using the MTS assay. Apoptosis, cell cycle, and ROS assays were performed using flow cytometry. PpIX accumulation was measured using a spectrofluorometer after 10 min and 24 and 48 h of treatment. The viability was extremely reduced at all concentrations, at 4 h for CAPAN-2 and at 8 h for CAL-27. ALAD-PDT induced marked apoptosis rates in both oral and pancreatic cancer cells. Elevated ROS production and appreciable levels of PpIX were detected in both cell lines. The use of ALA-PDT as a topical or intralesional therapy would permit the use of very low doses to achieve effective results and minimize side effects. ALAD-PDT has the potential to play a significant role in complex oral and pancreatic anticancer therapies.

Development of a plant-based surgical training model for fluorescence-guided cancer surgery

BACKGROUND

Fluorescence-guided surgery (FGS) can help surgeons to discriminate tumor tissue from adjacent normal tissues using fluorescent tracers.

METHODS

We developed a surgical training model, manufactured using sustainable vegetable organic material with indocyanine green (ICG)-containing "tumor." Surgeons evaluated the model with both the closed-field and endoscopic fluorescence imaging devices and assessed its efficacy to identify residual tumor after enucleation using electrocautery.

RESULTS

Strong correlations of fluorescence were obtained at all working distance (3, 5, 7, and 10 cm), showing the robustness of fluorescence signal for the closed-field and endoscopic fluorescence imaging devices. The higher fluorescence signals were obtained in the wound bed in the closed-field fluorescence imaging device and the residual tumor could be clearly identified by fluorescence endoscopy.

CONCLUSIONS

Our FGS training model may provide experience for surgeons unfamiliar with optical surgery and subsequent tissue interactions. The model seemed particularly helpful in teaching surgeons the principles of FGS.

Validation of a surgical training model containing indocyanine green for near‐infrared fluorescence imaging

Objective

To determine the efficacy of a surgical training model for fluorescence‐guided cancer surgery and validate its utility to detect any residual tumors after tumor resection using electrocautery.

Methods

We developed surgical training models containing indocyanine green (ICG) for near‐infrared (NIR) fluorescence imaging using a root vegetable organic material (konjac). After the fluorescence assessment for the models, the surgical simulation for fluorescence‐guided cancer surgery using electrocautery was performed. ICG‐containing tumors were divided into two surgical groups: “Enucleation” (removal of the entire visible tumor) and “Complete resection” (removal of the tumor with an appropriate 5‐mm surgical margin).

Results

All 12 ICG‐containing tumors were clearly visible from the normal view but not from the flipped view. The tumor resection time was significantly longer in the “Complete resection” group than in the “Enucleation” group (p < .001). The ICG‐containing tumors showed a high tumor‐to background ratio from the normal (average = 45.8) and flipped (average = 19.2) views, indicating that the models including ICG‐containing tumors were useful for a surgical simulation in fluorescence‐guided surgery. The average mean fluorescence intensity of the wound bed was significantly higher in the “Enucleation” group than in the “Complete resection” group (p < .01). No decrease in fluorescence signal was found in the wound bed even at 2 days postresection.

Conclusion

Our surgical training model containing a fluorescent agent is safe, inexpensive, not harmful for humans, and easy to dispose after use. Our model would be beneficial for surgeons to learn NIR fluorescence imaging and to accelerate fluorescence‐guided cancer surgery into clinical application.