Interstitial laser photocoagulation for the treatment of prostatic cancer

Interstitial laser photocoagulation (ILP) is a new percutaneous technique for local ablation of deep-seated tumours. We have applied this to treat a focal abnormality in a patient with prostatic carcinoma, under local anaesthesia and sedation. Transrectal ultrasound and computed tomography (CT) were used to guide three 18G needles, inserted transperineally, into the abnormal area. A thin (0.8 mm outer diameter) optical fibre was passed down each needle, so that the tip of the fibre lay within the tumour. The other end of the fibre was connected to a portable diode laser, which was activated at 2 W for 500 s. Real-time monitoring with ultrasound showed a gradually enlarging echogenic zone around the fibre-tip and a marked increase in colour Doppler signal; the echogenicity and Doppler signal decreased within a few minutes of completing treatment. Dynamic CT treatment 10 days later showed the treated area as a non-enhancing, avascular zone. Biopsies from this region confirmed the presence of necrosis. There were no complications. ILP appears to be a safe and effective way of ablating areas of focal abnormality in the prostate.