Optimising Photodynamic Therapy for the Treatment of Head and Neck Cancer

mTHPC mediated Photodynamic therapy (PDT) is an EMEA approved therapy for
palliative treatment of head and neck cancers . While superficial tumors are
treated with surface illumination deeper tumors can be treated with
interstitial PDT . There is a variation of clinical response with some tumors
not fully responding . The response to PDT depends on the presence of three
components; light, photosensitizer and oxygen . If any one is missing, there is
no biological effect. Studies have shown that inter-and intra-subject
differences in parameters such as tissue optical properties, uptake/synthesis
of photosensitizer and tissue response to PDT can lead to wide variations in
the light dose delivered during PDT . In pre-clinical models, we and others
have shown that monitoring of PDT is possible non-invasively by using
fluorescence and reflectance spectroscopy, in combination with state of the art
light dosimetry. While very important advances have been made in these models,
it is now necessary to translate these approaches to the clinic where the
relationship between treatment parameters and delivered PDT dose can be
significantly different.

The main objective of the study is to monitor the factors effecting success of
PDT, namely oxygen, photosensitizer concentration and, light dose before and
during illumination to gather data that can be clinically correlated and later
implemented.

The proposed study is an observational study which wil be conducted on the
patients taking part in PDT arm of the study: *A multi-centre
cost-effectiveness evaluation of a novel treatment option in the Netherlands:
Photo Dynamic Therapy with temoporfin for the treatment of advanced incurable
head and neck cancers, for whom prior conventional treatments have failed.
Short title: Cost-effectiveness of temoporfin-PDT*; PTC09.1229/M09PDT. The
oxygen saturation and photosensitizer concentration of the tumor tissue will be
measured by using non-invasive spectroscopic techniques, each day between
injection of MTHPC and illumination (4 days) and before and after
illumination. Light dosimetry will be conducted during illumination. The
collected data will be correlated with clinical results of the aforementioned
study.

There are no medical risks associated with the study. The patients will have to
come to the hospital three extra days for non-invasive measurements. The travel
costs will be reimbursed.