title: Local treatment of colorectal liver metastases: a comparison of interstitial laser photocoagulation (ILP) and percutaneous alcohol injection (PAI).
abstract: The purpose of this study was to evaluate the relative merits of two physical methods of locally destroying colorectal liver metastases-interstitial laser photocoagulation (ILP) which causes thermal necrosis, and percutaneous alcohol injection (PAI) which causes cellular dehydration and coagulative necrosis. Seventy-six liver metastases in 22 patients were treated by ILP or PAI. Both techniques were performed using local anaesthesia and intravenous sedation/analgesia. Ultrasound was used to localize the tumours and guide the needles percutaneously. ILP: Up to eight 19 G needles were inserted into the tumour, and down each needle was passed a thin optical fibre; the tumour was heated using low power laser light (2 W) for 500 s from a Nd:YAG or diode laser. PAI: 0.5-1 ml of sterile 95% absolute alcohol was injected into multiple sites of the tumour using a single 19-22 G needle. Dynamic CT scan was used to evaluate the extent of treatment-induced necrosis. Ultrasound showed echogenic changes around the needles/fibre-tips during ILP and PAI; this gave a reasonable guide to the extent of thermal damage for smaller tumours during ILP, but not during PAI. ILP: 54 tumours were treated (median size 2.7 cm). Laser-induced necrosis was clearly seen 24 h after treatment as a well-defined area of non-enhancement on the dynamic CT scan; greater than 50% necrosis of tumour volume was achieved in 87% of tumours (complete necrosis was found in 52% of tumours). PAI: 22 tumours were treated (median size 1.5 cm). Dynamic CT showed patchy areas of non-enhancement in five tumours, decreased density in seven tumours, and no change in 10 tumours; complete tumour necrosis was never achieved. There were no major complications after ILP or PAI, but pain during treatment was more common and more severe with PAI. ILP is a simple, safe and effective treatment for colorectal liver metastases; PAI is relatively ineffective for these tumours (although it has been shown to be much more effective for small hepatocellular carcinomas).
authors.affiliation: Department of Radiology, Middlesex Hospital, London.
authors.forename: Z
authors.initials: Z
authors.lastname: Amin
authors.forename: S G
authors.initials: SG
authors.lastname: Bown
authors.forename: W R
authors.initials: WR
authors.lastname: Lees
mesh_terms: D000328:Adult; D000368:Aged; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging; D000431:Ethanol / Q000008:administration & dosage*; D006801:Humans; D015552:Injections, Intralesional; D008028:Light Coagulation; D008113:Liver Neoplasms / Q000473:pathology / Q000556:secondary* / Q000601:surgery / Q000628:therapy*; D008875:Middle Aged; D009336:Necrosis; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography
chemical_list: D000431:Ethanol