Application of Tumour Marker Testing in Cancer Diagnosis and Management at a Specialist Hospital in Abuja

Tumour markers are biochemical substances measurable in blood or tissue whose levels correlate with tumour presence, response to therapy, and recurrence, and their application in oncology practice at Nigerian tertiary facilities requires professional evaluation to ensure appropriate clinical use. This study evaluates the application, clinical utility, and quality of tumour marker testing at the National Hospital Abuja, covering a two-year audit period from 2022 to 2024. A retrospective review of four hundred tumour marker test requests was conducted, covering prostate-specific antigen (PSA), carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP), CA-125, CA 19-9, and HER2 receptor testing. Audit criteria evaluated appropriateness of test indication, test result documentation in patient records, clinical action taken in response to abnormal results, and serial monitoring protocol adherence where applicable. Findings reveal that 78 percent of PSA requests and 72 percent of AFP requests met established clinical indication criteria, while 54 percent of CEA and 61 percent of CA-125 requests were for monitoring rather than screening, reflecting appropriate primary use. However, 33 percent of abnormal tumour marker results lacked documented clinical follow-up actions in patient records. Serial monitoring intervals were inconsistent with published guidelines in 41 percent of cases where serial results were available. False-positive rate estimation for PSA using age-stratified reference ranges suggested that approximately 25 percent of total PSA referrals could be avoided with age-specific PSA reference application. The study recommends development of a national hospital tumour marker requesting protocol and clinician education programme. Keywords: tumour markers, cancer diagnosis, PSA, clinical audit, Abuja.