Experimental assessment of photodynamic therapy with chlorins for malignant mesothelioma

Abstract

PDT with pegylated mTHPC reveals the potential of selective tumour destruction in this experimental setting and deserves further evaluation for intraoperative application in patients with malignant mesothelioma.

Experimental evaluation of possible side effects of intra‐operative photodynamic therapy on rabbit blood vessels and nerves

“…Ris et al [2] described similar histological findings for blood vessels and nerve structures as described in the present study. They performed intra-operative PDT to the thoracic cavity and the intra-thoracic structures in mini pigs using mTHPC as a photosensitiser (0.1 mg/kg mTHPC, 20 J/cm 2 , drug-light interval from 12 hour-6 days).…”

“…After surgical tumour resection intra-operative PDT is applied to the tumour bed in order to destroy any remaining tumour cells which might be responsible for tumour recurrence. This technique was already used for various different tumours like chest malignancies, intra-peritoneal malignancies or rectal cancers with varying success [1][2][3][4][5][6].…”

“…Several clinical studies have reported the intra-operative application of PDT in mesothelioma, brain tumours, rectal cancer or tumours of the head and neck [1][2][3][4][5][6]. Despite the range of indications, two methods to use intra-operative PDT have been used.…”

Correlation of photodynamic activity and fluorescence signaling for free and pegylated mTHPC in mesothelioma xenografts

“…Additionally, the activation wavelength of 652 nm wavelength light penetrates tissue deeply [8]. However, intracavitary mTHPC-PDT of the chest cavity was associated with relevant side effects and normal tissue damage indicating poor selectivity under unfavorable treatment conditions [9][10][11]13,17]. In an attempt to increase poor selectivity of free mTHPC for tumor, macromolecular derivatives of mTHPC were arranged by linking hydroxyl (polyethylene glycol) chains of varying lengths to the photosensitizer (i.e., pegylation) [19,20].…”

“…This has led to relevant morbidity after PDT of the chest cavity after surgery for pleural mesothelioma [1][2][3][4][5][6], even in the presence of new second generation sensitizers [7][8][9][10][11][12][13]. Several experimental studies focusing on PDT for mesothelioma have shown that enhanced tumor selectivity may be obtained by modulating treatment conditions [14][15][16][17][18] and by pegylation of the sensitizer [19,20].…”