Avoid ordering tumor markers, particularly CEA, CA-125, HE4, AFP, and CA19-9, unless there is a known cancer diagnosis, a specific suspicion of a particular cancer type, or a strong underlying predisposition

Rationale:

Tumor marker testing can be useful for guiding treatment decisions, monitoring cancer progression, assessing treatment response, or detecting cancer recurrence. In some cases, they serve as valuable tools for detecting specific cancers in individuals with a strong, known predisposition, such as screening for liver cancer in patients with chronic hepatitis C and cirrhosis. However, scientific literature does not support the use of these tumor markers in diagnosing patients with nonspecific symptoms, as their diagnostic accuracy is low. 

References:

• Duffy, M. J. (2013). "Tumor markers in clinical practice: a review focusing on common solid cancers." Med Princ Pract 22(1): 4-11.

• Welch, H.G. (2017). “Income and Cancer Overdiagnosis –When too much care is harmful.” NEJM2017;376:2208-2209

• Nasjonalt handlingsprogram: Kreft i tykktarm og endetarm (oppdatert 20. Des 2023),

• Diagnoseveileder: Gynekologisk kreft, Pankreaskreft. Hepatitt C [nettdokument]. Oslo: Helsedirektoratet (sist faglig oppdatert 05. april 2019, lest 21. oktober 2024). Tilgjengelig fra https://www.helsedirektoratet.no/faglige-rad/hepatitt-c