Objective: To investigate SOAT1 protein expression as a marker of treatment response to mitotane.
Patients: 231 ACC patients treated with single agent mitotane as adjuvant (n=158) or advanced disease therapy (n=73) from twelve ENSAT centers were included. SOAT1 protein expression was determined by immunohistochemistry on formalin-fixed paraffin-embedded (FFPE) specimens.
Setting: Retrospective study at 12 ACC referral centers
Main outcome measure: recurrence-free survival (RFS), progression-free survival (PFS), disease-specific survival (DSS)
Results: 61/135 patients (45%) with adjuvant mitotane treatment had recurrences and 45/68 patients (66%) with mitotane treatment for advanced disease had progressive disease. After multivariate adjustment for sex, age, hormone secretion, tumour stage and Ki67 index, RFS (HR=1.07, 95% CI 0.61-1.85, p=0.82) and DSS (HR=1.30, 95% CI 0.58-2.93, p=0.53) in adjuvantly treated ACC patients did not differ significantly between tumors with high and low SOAT1 expression. Similarly, in the advanced stage setting, PFS (HR=1.34, 95% CI 0.63-2.84, p=0.45) and DSS (HR=0.72, 95% CI 0.31-1.70, p=0.45) were comparable and response rates not significantly different.
Conclusions: SOAT1 expression was not correlated with clinical endpoints RFS, PFS and DSS in ACC patients with mitotane monotherapy. Other factors appear to be relevant for mitotane treatment response and ACC patient survival.
|Journal||The Journal of clinical endocrinology and metabolism|
|Early online date||25 May 2020|
|Publication status||E-pub ahead of print - 25 May 2020|
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