mTHPC mediated PDT of head and neck cancer
PhD ceremony: | Mr S.A.H.J. (Sebastiaan) de Visscher |
When: | January 08, 2014 |
Start: | 16:15 |
Supervisors: | prof. dr. J.L.N. (Jan) Roodenburg, prof. dr. H.J.C.M. Sterenborg |
Co-supervisors: | prof. dr. M.J.H. Witjes, dr. D.J. Robinson, dr. A. Amelink |
Where: | Academy building RUG |
Faculty: | Medical Sciences / UMCG |
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.