By James Mitchell Crow
Recurring prostate cancers can be subdued with a blast of laser light, say Swedish researchers who presented their latest research at the Australian Institute of Physics conference in Melbourne.
Katarina Svanberg and colleagues at Lund University Hospital use lasers to build 3D maps of the tumours, and then to kill the cancerous cells in them.
She reported early success in managing what is usually a fatal condition. More work remains to be done, however, before the technique is used routinely in hospitals.
Prostate cancer is one of the most common cancers in men—70% are affected by the disease by the age of 70. The current treatment for recurrent prostate cancer involves hormone therapy, which has particularly unpleasant side effects, so new treatments are urgently sought.
As light can only penetrate the skin so far, the researchers deliver their laser therapy by inserting a network of optic fibres into the tumour. This ensures all the cancerous cells are treated. Using this strategy, the limited penetration of light becomes an advantage, as sensitive healthy tissues surrounding the prostate are left unscathed.
Svanberg’s team also recently has shown that a similar set-up can treat skin and oesophageal cancers effectively.
Diagnostics and Treatment of Tumours using Laser Techniques
Katarina Svanberg, Department of Oncology, Lund University Hospital, Lund University,SE-221 85 Lund, Sweden
Lund University Medical Laser Centre, Lund University, S-221 85 Lund, Sweden
Applications of optical and laser spectroscopy to the medical field, including photodynamic therapy and laser-induced fluorescence diagnostics for cancer treatment and diagnostics, respectively, will be presented. Applications of optical and laser spectroscopy to the medical field, including photodynamic therapy (PDT) and laser-induced fluorescence diagnostics (LIF) for cancer treatment and diagnostics, respectively, will be presented.
Photodynamic therapy, when delivered as a superficial illumination to the target area, has a limitation due to restricted light penetration through tissue. One way of overcoming this is interstitial illumination (IPDT) in which the light is transmitted to the tumour via optical fibres. Interactive feedback dosimetry is of importance for optimising the modality and such a concept has been developed and will be presented. Superficial illumination for non-melanoma skin tumours as well as interstitial therapy for prostate cancer will be discussed.
The most important prognostic factor for cancer patients is early tumour discovery. If malignant tumours are detected during the non-invasive stage, most tumours show a high cure rate of more than 90%. There is a variety of conventional diagnostic procedures, such as X-ray imaging. More advanced results are given in computerised investigations, such as CT-, MRI- or PET-scanning. Laser-induced fluorescence (LIF) for tissue characterisation is a technique that can be used for monitoring the biomolecular changes in tissue under transformation from normal to dysplastic and cancer tissue before structural tissue changes are seen at a later stage. The technique is based on UV or near-UV illumination for fluorescence excitation. The fluorescence from endogenous chromophores in the tissue alone, or enhanced by exogenously administered tumour seeking substances can be utilised. The technique is non-invasive and gives the results in real-time. LIF can be applied for point monitoring or in an imaging mode for larger areas, such as the vocal cords or the portio of the cervical area. The possibility to combine LIF and PDT will be discussed and illustrated with clinical examples from many specialities, such as dermatology, gynaecology and laryngology.
A new method where free gas (oxygen or water vapour) in the human sinus cavities is detected will be described. The technique is based on gas absorption spectroscopy in scattering media. The method can also be used to study the gas exchange in between the nasal cavity and the different sinuses in the facial region.
Katarina Svanberg, email@example.com