Assessment of salivary free cortisol levels by liquid chromatography with tandem mass spectrometry (LC-MS/MS) in patients treated with mitotane.
OBJECTIVE
Mitotane is an adrenocytolytic agent used in adrenocortical carcinoma, inducing adrenal insufficiency, requiring replacement treatment. Such therapy is not easy to monitor because of mitotane interference. Salivary cortisol reflects a free fraction of plasma cortisol and may be useful in such patients.


METHODS
The aim of our study was to evaluate salivary cortisol by HPLC coupled to tandem-mass spectrometry (LC-MS/MS) and by an electrochemiluminescence immunoassay (ECLIA) in patients treated with mitotane. We enrolled 6 patients receiving mitotane and 2 Addison disease patients as negative controls and determined salivary cortisol rhythm. We also determined the salivary cortisol rhythm in 8 healthy subjects. Salivary samples (n=112) were assayed by ECLIA, using Roche Modular E170, and by LC-MS/MS.


RESULTS
The mean values obtained by ECLIA were significantly higher than those obtained by LC-MS/MS in the mitotane group (p<0.001). In fact, in the group measured by LC-MS/MS, we observed several peaks eluting at a retention time different from the cortisol group, presumably due to cortisol-like analogues. In Addison disease, since steroidogenesis is absent, salivary cortisol values measured by the two methods did not show any significant difference (p=0.61).


CONCLUSIONS
Salivary cortisol measured by LC-MS/MS is a selective method, excluding cortisol analogues accumulating in treated patients. Therefore, LC-MS/MS offers an effective system to monitor replacement therapy in mitotane treated patients.
Institute of Biochemestry and Clinical Biochemestry, Università Cattolica del Sacro Cuore, Largo A Gemelli 8, Rome, Italy. ccarrozza@rm.unicatt.it
Cinzia
C
Carrozza
Rosa
R
Lapolla
Jacopo
J
Gervasoni
Carlo Antonio
CA
Rota
Pietro
P
Locantore
Alfredo
A
Pontecorvi
Cecilia
C
Zuppi
Silvia
S
Persichilli
D000224:Addison Disease / Q000378:metabolism; D000306:Adrenal Cortex Neoplasms / Q000188:drug therapy; D000309:Adrenal Insufficiency / Q000139:chemically induced / Q000188:drug therapy; D000328:Adult; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis* / Q000627:therapeutic use; D008163:Luminescent Measurements; D008297:Male; D008875:Middle Aged; D008939:Mitotane / Q000627:therapeutic use*; D012189:Retrospective Studies; D012463:Saliva / Q000737:chemistry*; D053719:Tandem Mass Spectrometry / Q000379:methods
D008939:Mitotane; D006854:Hydrocortisone