PhD ceremony Mr. S.A.H.J. de Visscher: mTHPC mediated PDT of head and neck cancer. Modifying pharmacokinetics using liposomal drug carriers
| When: | We 08-01-2014 at 16:15 |
| Where: | Academiegebouw, Broerstraat 5, Groningen |
PhD ceremony: Mr. S.A.H.J. de Visscher
Dissertation: mTHPC mediated PDT of head and neck cancer. Modifying pharmacokinetics using liposomal drug carriers
Promotor(s): prof. J.L.N. Roodenburg, prof. H.J.C.M. Sterenborg
Faculty: Medical Sciences
This thesis shows that photodynamic therapy mediated by the photosensitizer mTHPC, dissolved in ethanol (Foscan), can be used in the palliative treatment of patients with end-stage squamous cell carcinoma of the head and neck area. The results after curative treatment of small squamous cell carcinomas (T1) by either Foscan mediated PDT or surgical treatment are similar. However, randomized, prospective studies on the results of photodynamic therapy compared to standard treatment are lacking.
Liposomal carriers of mTHPC, in particular Fospeg, have shown in tumor models a higher and earlier uptake in tumor tissue compared to Foscan. The improved properties of Fospeg are due to the polymer coating of the liposomal carrier of mTHPC. Because of this coating, the recognition and the clearance of mTHPC from the circulation is reduced. The results warrant further research into the effectiveness of Fospeg mediated PDT compared to Foscan mediated PDT. This will show whether a lower dose of mTHPC and past exposure causes the desired tissue damage.
Fluorescence Differential Path Length Spectrsocopy (fDPS) proved to be a reliable, non-invasive method to measure mTHPC concentration in homogeneous tissue. However, due to a different interrogation volume of fDPS and the gold standard, chemical extraction, the correlation between the two measurement methods was low. Probably this is based on the greater accuracy of the FDPS measurements compared to the averaging extraction measurements. FDPS provides by its real- time, non-invasive nature information on the mTHPC tissue concentration and the oxyugen saturation, the ability to optimize the complex PDT reaction.