Discordance between testosterone measurement methods in castrated prostate cancer patients

Autor: Mélanie Rouleau, Francis Lemire, Michel Déry, Benoît Thériault, Gabriel Dubois, Yves Fradet, Paul Toren, Chantal Guillemette, Louis Lacombe, Laurence Klotz, Fred Saad, Dominique Guérette, Frédéric Pouliot
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Endocrine Connections, Vol 8, Iss 2, Pp 132-140 (2019)
Druh dokumentu: article
ISSN: 2049-3614
DOI: 10.1530/EC-18-0476
Popis: Failure to suppress testosterone below 0.7 nM in castrated prostate cancer patients is associated with poor clinical outcomes. Testosterone levels in castrated patients are therefore routinely measured. Although mass spectrometry is the gold standard used to measure testosterone, most hospitals use an immunoassay method. In this study, we sought to evaluate the accuracy of an immunoassay method to measure castrate testosterone levels, with mass spectrometry as the reference standard. We retrospectively evaluated a cohort of 435 serum samples retrieved from castrated prostate cancer patients from April to September 2017. No follow-up of clinical outcomes was performed. Serum testosterone levels were measured in the same sample using liquid chromatography coupled with tandem mass spectrometry and electrochemiluminescent immunoassay methods. The mean testosterone levels were significantly higher with immunoassay than with mass spectrometry (0.672 ± 0.359 vs 0.461 ± 0.541 nM; P < 0.0001). Half of the samples with testosterone ≥0.7 nM assessed by immunoassay were measured 0.7 nM was significantly higher with immunoassay (22.1%) than with mass spectrometry (13.1%; P < 0.0001). Quantitative measurement of serum testosterone levels >0.7 nM by immunoassay can result in an inaccurately identified castration status. Suboptimal testosterone levels in castrated patients should be confirmed by either mass spectrometry or an immunoassay method validated at low testosterone levels and interpreted with caution before any changes are made to treatment management.
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