Transurethral Resection of Non-Muscle Invasive Bladder Tumors Combined with Fluorescence Diagnosis and Photodynamic Therapy with Chlorin e6-Type Photosensitizers

Bladder cancer is a common disease with a high recurrence rate. In order to improve the treatment of superficial bladder tumors, we evaluated the efficacy and safety of transurethral resection (TURB) followed by fluorescence diagnosis (FD) and photodynamic therapy (PDT) with chlorin e6 photosensitizers (PSs), viz. “Fotoran e6” and “Fotoditazin”. It was found that both PSs generated singlet oxygen and revealed moderate affinity toward the lipid-like compartment. Between November 2018 and October 2020, 12 patients with verified non-muscle invasive bladder cancer (NMIBC) were treated by TURB combined with FD and PDT. Eight patients received “Fotoran e6” intravenously, while four patients received intravesical PSs. The patient ages were between 31 and 79 years, with a median age of 64.5 years (mean 61.3 ± 14.2). The total light dose was 150 J/cm2 for the local irradiation of the tumor bed with a red light at the λ = 660 nm wavelength, and 10–25 J/cm2 were additionally delivered for diffuse irradiation of the entire bladder mucosa. At the median follow-up period of 24 months (mean 24.5 ± 5.4 months, range 16–35 months), 11 patients remained tumor-free. One 79-year-old patient developed a recurrence without progression to the muscle layer. This pilot study shows that the TURB + FD + PDT technique is an effective and safe option for the first-line treatment of superficial bladder tumors.

Preoperative AI-Driven Fluorescence Diagnosis of Non-Melanoma Skin Cancer

The diagnosis and treatment of non-melanoma skin cancer remain urgent problems. Histological examination of biopsy material—the gold standard of diagnosis—is an invasive procedure that requires a certain amount of time to perform. The ability to detect abnormal cells using fluorescence spectroscopy (FS) has been shown in many studies. This technique is rapidly expanding due to its safety, relative cost-effectiveness, and efficiency. However, skin lesion FS-based diagnosis is challenging due to a number of single overlapping spectra emitted by fluorescent molecules, making it difficult to distinguish changes in the overall spectrum and the molecular basis for it. We applied deep learning (DL) algorithms to quantitatively assess the ability of FS to differentiate between pathologies and normal skin. A total of 137 patients with various forms of primary and recurrent basal cell carcinoma (BCC) were observed by a multispectral laser-based device with a built-in neural network (NN) “DSL-1”. We measured the fluorescence spectra of suspected non-melanoma skin cancers and compared them with “normal” skin spectra. These spectra were input into DL algorithms to determine whether the skin is normal, pigmented normal, benign, or BCC. The preoperative differential AI-driven fluorescence diagnosis method correctly predicted the BCC lesions. We obtained an average sensitivity of 62% and average specificity of 83% in our experiments. Thus, the presented “DSL-1” diagnostic device can be a viable tool for the real-time diagnosis and guidance of non-melanoma skin cancer resection.

STMO-08 Validation of the endoscopic 5-ALA fluorescence diagnosis for intraventricular tumors

Intraoperative 5-ALA fluorescence diagnosis (PDD) has been shown to improve tumor resection rates in surgery for malignant glioma. Recently, the usefulness of PDD has been reported in tumors other than malignant glioma. However, the fluorescence of intraventricular tumors is not easy to observe under the microscope, because excitation light could not reach enough to the deepest part of the brain. Therefore, we performed endoscopic 5-ALA fluorescence diagnosis of intraventricular tumors and evaluated its usefulness. Ten cases of intraventricular tumors were included in the study. There were 3 germ cell tumors, 2 metastatic brain tumors, 2 pilocytic astrocytomas, 1 malignant lymphoma, 1 subependymoma, and 1 medulloblastoma (recurrent). The tumors were located in the third ventricle in four cases, the lateral ventricle in three cases, the lateral ventricle and the third ventricle in two cases, and the aqueduct in one case. Tumor removal was performed in 6 cases and tumor biopsy in 4 cases. Intraoperative fluorescence could be observed in eight cases: three germ cell tumors, two metastatic brain tumors, two pilocytic astrocytomas, and one malignant lymphoma. Subependymoma and medulloblastoma did not show fluorescence. Among the cases with confirmed fluorescence, the fluorescent sites were targeted for biopsies for germ cell tumors and malignant lymphomas. For metastatic brain tumors and pilocytic astrocytomas, the extent of removal was determined at the time of removal, and the presence of residual tumor was confirmed by fluorescence after removal. Endoscopic 5-ALA fluorescence diagnosis for intraventricular tumors was useful in determining the target of biopsy or the extent of excision and in assessing residual tumors.