Role of interstitial therapy in the treatment of liver cancer.

Conventional palliative management of inoperable focal hepatic tumours remains unsatisfactory. Interstitial techniques such as cryotherapy, alcohol injection, low power laser hyperthermia and interstitial radiotherapy offer alternative approaches. Cryotherapy is an effective and precise technique for inducing tumour necrosis. It can only be performed at laparotomy making it relatively invasive and retreatment impractical. Alcohol is cheap and can be injected percutaneously. However, inhomogeneous distribution produces imprecise and nonreproducible lesions. Low power laser hyperthermia produces precise and reproducible areas of necrosis that are roughly spherical in shape. At present, this technique is most effective for small tumours. Interstitial radiotherapy remains the least evaluated of all the interstitial techniques. Unlike cryotherapy and low power laser hyperthermia, the biological effect of ethanol injection and interstitial radiotherapy cannot be monitored in real time by ultrasound. With the exception of cryotherapy, all methods can be applied percutaneously with low morbidity and mortality. None of these techniques is established, but they may offer the prospect of cure in cases where all areas of tumour can be positively identified and fully treated. However, in most instances the intention is to control the growth of relatively small discrete volumes of tumour within the hepatic parenchyma.