alpha-fetoprotein and beta-human chorionic gonadotropin - Their clinical significance as tumour markers

Tumour markers can aid in areas such as diagnosis, surveillance of recurren ce, staging and prognosis. This article focuses on 2 tumour markers, alpha- fetoprotein (AFP) and beta-human chorionic gonadotropin (HCG). These tumour markers have been examined for their utility as prognostic indicators in 2 different manners. First, the marker level at diagnosis has been studied t o determine if it is prognostic of outcome presumably because of its relati on to tumour bulk or to the biological nature of the tumour. A more recent trend has been to investigate tumour marker decline. The finding of a delay ed rate of decline suggests a poorer response of the malignancy to chemothe rapy. The major focus of the article will be on marker decline of AFP and H CG as prognostic tools in peripheral and central nervous system (CNS) germ cell tumours (GCTs) and hepatic tumours (hepatoblastoma and hepatocellular carcinoma). The articles reviewed here suggest that HCG and AFP can correlate with surv ival if examined in specific ways, and could potentially be used to tailor treatment for individual patients. One group of authors presents data on pa tients with GCTs suggesting that satisfactory marker regression is an indep endent prognostic factor for survival. In a study of hepatoblastoma, data d emonstrate that both the magnitude and rate of decline are associated with survival. Marker decline studies in hepatocellular carcinoma do not exist a nd marker levels at diagnosis do not appear to have a role in potential the rapeutic changes. However, data on fucosylated subtype of AFP, Lens culinar is agglutinin A reactive AFP, has shown prognostic significance in hepatoce llular carcinoma. The data for CNS GCTs are limited and studies examining s erial cerebrospinal fluid HCG/AFP are ongoing. In some diseases, issues relating to timing of marker sampling when examini ng marker decline need to be studied in greater detail. Hopefully, marker d ecline studies can be duplicated in the other diseases, to document a poten tial role in determining outcome. Further studies are needed to test the ab ility to alter therapy in attempts to improve survival while decreasing tox icity to patients.