clinical application of tumour makers

Abstract

Background: Tumour markers have made a difference to oncology practice. They can be used in screening, diagnosis, prognostication and assessment of treatment efficacy. Reports on tumour marker usage suggest that many clinicians assume that a biomarker for a particular cancer can be effectively used for allthese indications. This assumption is incorrect. Several guidelines have been published to inform clinicians on effective utilisation of these tests. Objective: To outline the recommended uses of the most commonly requested tumours markers in clinical practice. Design: A hand search of literature on the recommended use of carcinoembryonic antigen (CEA), alphafetoprotein (AFP), prostate specific antigen (PSA), CA-125 and CA-19.9. Systematic reviews and prospective randomised clinical trials of tumour marker applications were also looked at. Data sources: Five key journals and reference lists of relevant studies were considered. Data extraction and synthesis: Two authors abstracted relevant data independently. Emphasis was given to guidelines from expert panels. The quality of the guidelines was assessed by availability of level of evidence supporting the recommendations. Results: Several national and international expert groups have developed guidelines for use of markers for most cancers. CEA, AFP, PSA, CA-125 and CA-19.9 are validated for use in treatment monitoring of colorectal, hepatocellular, prostatic, ovarian and pancreatic carcinomas respectively. AFP and PSA are also useful for cancer screening in high risk groups. CA-125 has limited role in screening while CEA and CA 19.9 are not recommended for cancer screening. Conclusions: Not all currently available tumour markers can be used for screening and diagnosis of malignancies. Adherence to recommendations on tumour marker utilisation will improve the cost-effectiveness of these tests. INTRODUCTION