Endobronchial photodynamic therapy under fluorescence control: Photodynamic theranostics.

BACKGROUND: Photodynamic therapy (PDT) has several advantages. However, one of the disadvantages is its inability to be individualized according to biological characteristics of malignant tumors. The objective of this study was to investigate a strategy for individualized endobronchial PDT in the treatment of centrally located non-small cell lung cancer. METHODS: New approach suggests taking fluorescence-based measurements of chlorine E6 photosensitizer (PS) accumulation in the malignant tumor tissue, and assess PS consumption rate during PDT. Two randomized groups of 45 patients took part in the comparative study of standard PDT procedure, 662nm, pulse-periodic mode, therapeutic light (reference group - RG) versus the investigated individualized approach under fluorescence control after irradiation with violet light, 408nm, diagnostic light (study group - SG). The PDT-treatment parameters and results of follow-up bronchoscopy were compared between the groups. RESULTS: 43 (96%) of 45 patients in SG demonstrated intense fluorescence in the area of the tracheal/bronchial tumor stenosis. 4 (9%) of 45 patients (SG) demonstrated fluorescence of mucosa areas distant from the main tumor lesion after violet light irradiation. Mean fluence during the whole PDT procedure was 95±20J/cm2 (range 60-130J/cm2), which was significantly lower than in RG (p=0.01). Total exposure time was significantly lower in SG (365±65s), compared with RG (690±65s), P=0.001. According to the follow-up bronchoscopy the difference in the PDT-treatment results between the groups is statistically insignificant. CONCLUSIONS: The investigated strategy suggests using fluorescence control of the efficacy of PDT-treatment (photodynamic theranostics) to optimize and individualize the PDT procedure.

Preoperative endobronchial photodynamic therapy improves resectability in initially irresectable (inoperable) locally advanced non small cell lung cancer.

OBJECTIVES: This report describes the result of prospective randomized trial to assess effectiveness and safety of neoadjuvant photodynamic therapy (PDT) and chemotherapy as well as possibility for further surgery for locally advanced NSCLC. METHODS: Patients with stage IIIA and IIIB central NSCLC (main bronchus/distal trachea involvement) who were not initially eligible for surgery but might be considered as surgery candidates after neoadjuvant therapy were enrolled in the study. They were randomized to either neoadjuvant chemotherapy and endobronchial PDT or chemotherapy alone followed by surgical resection. PDT was done with photosensitizer agent chlorine E6 and 662nm laser light before each of the three courses of chemotherapy. RESULTS: From January 2008 to December 2011, 42 patients were assigned to PDT arm (n=21) and No-PDT arm (n=21). Groups were similar with respect to age, sex, tumor stage, and histology. No PDT major complications were observed. After neoadjuvant treatment partial response revealed in 19pts (90%) in PDT arm and 16pts (76%) in No-PDT arm (p=0.460), these patients underwent thoracotomy. After thoracotomy tumor was unresectable in 3pts of No-PDT arm (19%). There were 14 pneumonectomies and 5 lobectomies in PDT arm vs. 10 pneumonectomies and 3 lobectomies in No-PDT arm. Completeness of resection was significantly higher in PDT arm (R0-89%, R1-11%) vs. No-PDT arm (R0-54%, R1-46%), p=0.038. CONCLUSIONS: The study demonstrated that neoadjuvant PDT along with chemotherapy is effective, safe and it makes possible to convert to surgery candidates and to improve resection completeness in stage III central NSCLC patients.