The role of PDT in nasopharyngeal cancer in Indonesia
NPC is a rare disease in the Western world, but is endemic in certain parts of south East Asia and China.
The last decades the outcome of the treatment has improved considerable. Concurrent chemo-radiation has become the treatment of choice in advanced NPC. Five years survival figures of 80-90% for T1-T2 and 60-80% for T3-T4 are not exceptional. However, figures in low income countries are less favorable.
Under capacity of radiotherapy units and poor compliance to treatment are the main concerns. A study in a tertiary university hospital in Yogyakarta Indonesia showed 3yrs survival of 30% with many patients with residual disease.
Photo Dynamic Therapy (PDT) has been shown to be effective in residual and recurrent nasopharyngeal cancer with 3 year survival rates of over 65%. It’s noninvasive and only limited infra-structure is needed. Future research should focus on innovative treatment strategies like immunotherapy in combination with PDT as an induction therapy to reduce the tumor load during the waiting time.
The objective of this study was to evaluate the performance of a dedicated light applicator for light delivery and fluence rate monitoring during Foscan®-mediated photodynamic therapy of nasopharyngeal carcinoma in a clinical phase I/II study. We have developed a flexible silicone applicator that can be inserted through the mouth and fixed in the nasopharyngeal cavity. Three isotropic fibers, for measuring of the fluence (rate) during therapy, were located within the nasopharyngeal tumor target area and one was manually positioned to monitor structures at risk in the shielded area. A flexible black silicon patch tailored to the patient's anatomy is attached to the applicator to shield the soft palate and oral cavity from the 652-nm laser light. Fourteen patients were included in the study, resulting in 26 fluence rate measurements in the risk volume (two failures). We observed a systematic reduction in fluence rate during therapy in 20 out of 26 illuminations, which may be related to photodynamic therapy–induced increased blood content, decreased oxygenation, or reduced scattering. Our findings demonstrate that the applicator was easily inserted into the nasopharynx. The average light distribution in the target area was reasonably uniform over the length of the applicator, thus giving an acceptably homogeneous illumination throughout the cavity. Shielding of the risk area was adequate. Large interpatient variations in fluence rate stress the need for in vivo dosimetry. This enables corrections to be made for differences in optical properties and geometry resulting in comparable amounts of light available for Foscan® absorption.