Interstitial tumour photocoagulation.

Interstitial laser photocoagulation (ILP) is a new technique of in situ tumour destruction, using low power laser light energy, delivered percutaneously via thin optical fibres. We have applied this to treat patients with tumours of the liver, breast, and prostate, using sedation and local anaesthesia, and an Nd:YAG (1064 nm) laser or a new portable diode (805 nm) laser. Tumour necrosis has been optimized by using a 1 x 4 fibre coupler which splits the laser beam, and allows equal delivery of energy down 4 fibres simultaneously; the most promising results to date are with treating liver metastases with smaller tumours (< 3 cm) often being completely destroyed. With further improvements in laser parameters and fibre-tips, and in the evaluation of the thermal effects of ILP by imaging, it may be possible to apply this technique to completely destroy small deep-seated tumours in other organs. With optimal technique, ILP may in the future become a practical, minimally invasive treatment option for patients with tumours of the liver and breast, in conjunction with systemic therapy.