For psoriasis patients, dermatologists are told, liver biopsy results may be misleading after methotrexate treatment. Noninvasive methods of assessment are no worse, but need improving and standardizing.
Strober BE. Methotrexate-Induced Liver Toxicity: Replacing the Liver BiopsyJAMA Dermatol (2014) 150:862-863. doi:10.1001/jamadermatol.2014.681.
The liver biopsy should be abandoned as the means to assess damage from methotrexate use, says the author, referring specifically here to psoriasis patients. It should be replaced with a panel of noninvasive tests – once we’ve validated such a panel.
Current recommendations for monitoring methotrexate-induced hepatotoxicity in psoriasis patients are poorly substantiated by rigorous data, he asserts.
• Cumulative methotrexate dosage is irrelevant.
• Liver biopsy is of limited value, because 50% of patients with moderate to severe psoriasis have nonalcoholic fatty liver disease, whose histopathology is indistinguishable from methotrexate-induced toxicity.
• Serial procollagen III peptide levels lack specificity.
• FibroTest, an evaluation of five serum markers, has low sensitivity.
• Transient elastography measures liver parenchymal stiffness, has acceptable specificity, and variable sensitivity. Unfortunately, obesity often renders transient elastography unreliable or impossible.
Noninvasive tests often disagree, the author concludes. Therefore, current noninvasive measures should be used in combination and evaluated in large, prospective, well-controlled studies.
Moreover, static assessments of liver abnormalities are meaningless, and tests should determine the magnitude of change from baseline.