E U R O P E A N U RO L O GY O P E N S C I E N C E 19 ( 2 0 2 0 ) 2 4 – 2 6 available at www.sciencedirect.com journal homepage: www.eu-openscience.europeanurology.com Brief Correspondence Serum Luteinizing Hormone Testing Can Identify Optimal Medica Castration Juan Morote a,b,c, Imma Comas d, Roser Ferrer d, Lucas Regis a,b, Anna Celma a,b, Anna Santamarı́a b, Jacques Planas a,b,*, Enrique Trilla a,b,c Prostate cancer (PCa) guidelines recommend serum testos- association between SLH and serum testosterone, measured terone testing to assess the efficacy of castration and to define with mass spectrometry and chemiluminiscence, in PCa castration resistance when biochemical or clinical progres- patients undergoing medical castration and to determine if sion is detected. The currently accepted serum testosterone SLH can define optimal castration. castrate level is 50 ng/dl, although levels below 20 ng/dl We prospectively measured serum testosterone with have been associated with longer castration resistance–free mass spectrometry and chemiluminiscence in 138 frozen survival [1]. This castrate level of serum testosterone was serum samples ( 80  C) selected among PCa patients established during the 1980s by the US Food and Drug undergoing continuous medical castration with a 3-mo Administration to evaluate products for castration. It arose depot LH-RH agonist. We used a Chromsystems reagent kit from previous studies on PCa patients who had undergone for the Shimadzu liquid chromatography/mass spectrome- surgical castration and corresponded to the lowest sensitivity try 8050 system (Izasa Scientific) with a sensitivity limit level of the radioimmunoassays available [2]. of 0.5 ng/dl and an Atellica Solutions chemiluminiscent In 2007, on the basis of previous studies [3,4], the assay (Siemens Inc.) with a sensitivity limit of 7.0 ng/dl for American Endocrine Society and the Centers for Disease measurement of serum testosterone. Selected serum Control and Prevention recommended only methods based samples had a previous LH measurement within the on mass spectrometry to measure testosterone, especially castration range. LH was measured using the Advia-Centaur for the low levels detected in women and children [5]. In XPi chemiluminiscent assay (Siemens Inc.) with a sensitivi- 2016, we highlighted that chemiluminiscence was used ty limit of 0.12 UI/l. We randomly selected 69 serum in all clinical studies analyzing the prognostic value of samples with LH 0.12 UI/l and 69 with SLH between >0.12 serum testosterone. Chemiluminiscent assays are the and 1.10 UI/l. The decision to use this threshold was based methods most used in clinical laboratories owing to high on our previous study, in which approximately 75% of sensitivity, automatability, high speed, and low cost; patients on active LH-RH agonist treatment had SLH however, their lack of accuracy and reproducibility at low 0.12 UI/l [8]. Optimal castration was defined as serum levels make these results uncertain [6]. We have observed testosterone <20 ng/dl [6]. The study was approved by our discrepancies in serum testosterone results from different ethics committee (PR/AG 048/2016). Associations were chemiluminiscent assays [7] and we have suggested mass analyzed using the median test between the SLH interval spectrometry as the appropriate method for measuring and quantitative serum testosterone measurements, and serum testosterone in PCa patients undergoing medical the McNemar test between the SLH interval and semi- castration [8]. Finally, we have observed that serum quantitative serum testosterone. SPSS v.20 was used for luteinizing hormone (SLH) is better associated with medical these analyses. castration activity than serum testosterone is, even when The median age was 72 yr (interquartile range [IQR] 63– measured with an appropriate method. We established a 78) for men with SLH 0.12 UI/l and 73 yr (IQR 66–80) for castrate level of SLH as 1.10 UI/l [9]. SLH has also been used those with SLH >0.12 UI/l (p = 0.136). For the groups with to monitor the switch between luteinizing hormone– SLH 0.12 versus >12 UI/l, serum testosterone measured releasing hormone (LH-RH) antagonist and agonist with mass spectrometry was 9.0 ng/dl (IQR 3.7–17.5) versus [10]. The aim of the present study was to analyze the 12.0 ng/dl (IQR 7.9–21.4; p = 0.028), and serum testosterone http://dx.doi.org/10.1016/j.euros.2020.06.002 2666-1683/© 2020 The Author(s). Published by Elsevier B.V. on behalf of European Association of Urology. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). E U R O P E A N U RO L O GY O P E N S C I E N C E 19 ( 2 0 2 0 ) 2 4 – 2 6 25 Table 1 – Analysis of the association between ST levels and SLH by ST measurement method. Method Median ST, ng/dl (interquartile range) p value All patients SLH 0.12 UI/l SLH 0.13–1.10 UI/l LC-MSMS 11.1 (5.9–19.8) 9.0 (3.7–17.5) 12.0 (7.9–21.4) 0.028 Chemiluminiscence 17.4 (10.0–32.0) 17.6 (7.0–39.8) 17.2 (13.0–24.1) 0.918 LC-MSMS = liquid chromatography-tandem mass spectrometry; SLH = serum luteinizing hormone; ST = serum testosterone. Table 2 – Distribution of patients with ST <20 ng/dl by SLH interval levels of SLH, especially after immunoassay calibration and ST measurement method. according to the World Health Organization international ST method Patients with ST <20 ng/dl, n (%) p value standard for human pituitary luteinizing hormone (WHO/ BS/2014.2240). This difference in immunoassay testing SLH 0.12 UI/l SLH 0.13–1.10 UI/l between testosterone and SLH may be due to the specific LC-MSMS 54 (78.3) 15 (21.7) <0.001 chemical structure of LH, in contrast to the similar Chemiluminiscence 37 (53.6) 32 (46.4) 0.295 chemical structure of testosterone and many other steroids LC-MSMS = liquid chromatography-tandem mass spectrometry; [12]. SLH = serum luteinizing hormone; ST = serum testosterone. We conclude that in patients with PCa undergoing medical castration, SLH is significantly associated with serum testosterone if it is appropriately measured. We found that SLH 0.12 UI/l was associated with optimal measured with chemiluminiscence was 17.6 ng/dl (IQR 7.0– castration, defined as serum testosterone <20 ng/dl. Future 39.8) versus 17.2 ng/dl (IQR 13.0–24.1; p = 0.918; Table 1). studies should verify the hypothesis that SLH may be better The distribution of serum testosterone results measured at predicting castration resistance–free survival than serum with both methods is presented by SLH interval in testosterone is. Table 2. For testosterone measured with mass spectrometry, Author contributions: Jacques Planas had full access to all the data in the 78.3% of patients with SLH 0.12 UI/l and 21.7% with SLH study and takes responsibility for the integrity of the data and the >0.12 UI/l had serum testosterone <20 ng/dl (p = 0.001). For accuracy of the data analysis. Study concept and design: Morote, Comas, Ferrer. testosterone measured with chemiluminiscence, the corre- Acquisition of data: Celma, Planas, Regis, Comas, Ferrer. sponding rates with testosterone <20 ng/dl were 53.6% and Analysis and interpretation of data: Morote, Comas, Ferrer. 46.4% (p = 0.295). No patients had serum testosterone Drafting of the manuscript: Morote. >50 ng/dl when measured with mass spectrometry, while Critical revision of the manuscript for important intellectual content: Trilla, five patients (3.6%) had serum testosterone >50 ng/dl when Santamaría. measured with chemiluminiscence, of whom three (4.3%) Statistical analysis: Morote. had SLH 0.12 UI/l and two (2.9%) had SLH >0.12 UI/l. Obtaining funding: None. We observed a significant association between SLH and Administrative, technical, or material support: None. serum testosterone only when it was measured with mass Supervision: Morote. spectrometry. Moreover, the proportion of patients with Other: None. serum testosterone <20 ng/dl was significantly higher in the group with SLH 0.12 UI/l (78.3%). This proportion is Financial disclosures: Jacques Planas certifies that all conflicts of interest, similar to the 75% observed in our previous study, in which including specific financial interests and relationships and affiliations we concluded that SLH was more efficient than serum relevant to the subject matter or materials discussed in the manuscript testosterone in identifying patients with active medical (eg, employment/affiliation, grants or funding, consultancies, honoraria, castration [9]. These are the reasons why we proposed SLH stock ownership or options, expert testimony, royalties, or patents filed, testing for assessing the efficacy of medical castration and received, or pending), are the following: None. defining castration resistance [11]. The present study is limited by its retrospective design and the lack of randomized selection of frozen serum Funding/Support and role of the sponsor: None. samples. The SLH threshold of 0.12 UI/l was based on our previous results, according to which 75% of patients on medical castration therapy had SLH below the lowest References sensitivity level. The size of the study for statistical power was not calculated owing to the absence of previous data [1] Mottet N, van den Bergh RCN, Briers E , et al. Guidelines on prostate analyzing the association between SLH and serum testos- cancer. Arnhem, The Netherlands. European Association of Urology; terone measured with mass spectrometry. 2019 http://uroweb.org/guideline/prostatecancer/2019 [2] The Leuprolide Study Group. Leuprolide versus diethylstilbestrol In contrast to testosterone measurement, chemilumi- for metastatic prostate cancer. N Engl J Med 1984;311:1281–6. niscence is an appropriate method for measuring low 26 E U RO P E A N U R O L O GY O P E N S C I E N C E 19 ( 2 0 2 0 ) 2 4 – 2 6 [3] Taieb J, Mathian B, Millot F , et al. Testosterone measured by efficacy of medical castration in prostate cancer patients. J Biomed 10 immunoassays and by isotope-dilution gas chromatography- Sci 2017;24:81–6. mass spectrometry in sera from 116 men, women, and children. [10] Garnick MB, Mottet N. New treatment paradigm for prostate Clin Chem 2003;49:1381–95. cancer: abarelix initiation therapy for immediate testosterone sup- [4] Wang C, Catlin DH, Demers LM , et al. Measurement of total serum pression followed by a luteinizing hormone-releasing hormone testosterone in adult men: comparison of current laboratory meth- agonist. BJU Int 2012;110:499–504. ods versus liquid chromatography-tandem mass spectrometry. [11] Morote J, Comas I, Planas J. Re: Nicolas Mottet, Joaquim Bellmunt, J Clin Endocrinol Metab 2004;89:534–43. Erik Briers, et al. EAU-ESTRO-ESUR-SIOG guidelines on prostate [5] Rosner W, Auchus RJ, Azziz R , et al. Position statement: utility, cancer. European Association of Urology; 2017. http://uroweb.org/ limitations, and pitfalls in measuring testosterone: an Endocrine guideline/prostate-cancer: how to assess the efficacy of medical Society position statement. J Clin Endocrinol Metab 2007;92: castration. Eur Urol 2018;73:e134–5. 405–13. [12] Nishiyama T. Serum testosterone levels after medical or surgical [6] Morote J, Regis L, Celma A, Planas J. Measurement of serum androgen deprivation: a comprehensive review of the literature. testosterone during androgenic suppression in patients with Urol Oncol 2014;32, 38.e17–e28. prostate cancer: a systematic review. Actas Urol Esp 2016;40: 477–84. [7] Morote J, Comas I, Planas J , et al. Behavior of chemiluminescent a Department of Urology, Vall d’Hebron Hospital, Barcelona, Spain assays to measure serum testosterone during androgen deprivation b Urology Research Unit, Vall d’Hebron Research Institute, Barcelona, Spain therapy. Int J Urol 2016;23:957–8. c Universitat Autònoma de Barcelona, Barcelona, Spain [8] Morote J, Comas I, Planas J , et al. Serum testosterone levels d Department of Biochemistry, Vall d’Hebron Hospital, Barcelona, Spain in prostate cancer patients undergoing luteinizing hormone- releasing hormone agonist therapy. Clin Genitourin Cancer *Corresponding author. Department of Urology, Vall d’Hebron Hospital, 2017;16:e491–6. Paseig Vall d’Hebron 119–129, 08035, Barcelona, Spain. [9] Morote J, Comas I, Ferrer R , et al. Accuracy of serum luteinizing Tel.: +34 93 2746100; Fax: +34 932746058. hormone and serum testosterone measurements to assess the E-mail address: jplanas@vhebron.net (J. Planas). Received 15 April 2020