Tumour markers in internal medicine: a low-cost test or an unnecessary expense? A retrospective study based on appropriateness

In the last 35 years tumour markers (TM) have gained currency in clinical practice. However, in the light of indications by international guidelines, their use is often unjustified. Our aim was to quantify the use of some of the most common TM, assessing their appropriateness and their efficacy in an Internal Medicine Unit. METHODS: In the three Internal Medicine Units of the Department of Internal Medicine of Policlinico of Modena we have carried out a retrospective analysis of the assessment of the main TM (CEA, CA19.9, CA 125, CA 15.3, NSE). The analysis was divided into two distinct phases: (I) quantitative phase, in order to assess the scale of the problem in economical terms; (II) qualitative phase, in order to assess the efficacy of the tests and the appropriateness of their use. RESULTS: (I) At last one of the considered TM was requested in 5102 out of the 8253 admitted patients (62%) (period 2001-2003). The trend was similar in all three units examined. (II) The qualitative analyses revealed: (1) the most common motivation for their use (79%) was diagnostic, mostly prior to any other test; (2) a mere 5% of the requests were appropriate according to the international literature; and (3) TM showed a low positive predictive value when used for diagnosis in an unselected population such as that of an Internal Medicine unit. CONCLUSIONS: The results of our study showed that TM determination represents an overall cost for Internal Medicine units and that there is a high inappropriateness in their use compared to what it is suggested by international guidelines. Though the TM is a low-cost test when used correctly, it seems an unnecessary expense if not adequately incorporated into the decision making process.