Abstract
OBJECTIVE: This study aimed to summarize and analyze the clinical and pathological features and prognostic risk factors of adrenocortical carcinoma (ACC). METHODS: We retrospectively analyzed clinical and pathological data and the prognoses of 39 adult ACC patients confirmed by pathologic diagnosis at the Affiliated Hospital of Qingdao University between August 2009 and October 2021. Kaplan-Meier curves and univariate and multivariate Cox regression models were used to analyze correlations between clinical and pathological parameters and prognosis. A nomogram prediction model was constructed for overall survival (OS) based on the independent prognostic factors and externally validated it with The Cancer Genome Atlas (TCGA) dataset. RESULTS: The mean age of the patient cohort was 53.87 ± 11.1 years (range: 29-80 years), which included 17 men and 22 women. The 1-, 2-, and 5-year OS rates were 83.7%, 64.4%, and 59.8%, respectively; the recurrence-free survival (RFS) rates at the same time points were 76.1%, 45.8%, and 23.5%, respectively. Kaplan-Meier curves showed that patients with poor OS were associated with M1 stage (P = 0.008), late ENSAT stage (P = 0.017), presence of venous tumor thrombus (P = 0.015), Ki67 >20% (P = 0.006), R1/R2 status (P = 0.018), and poorly differentiated tumors (P = 0.047). Patients with late ENSAT stage (P = 0.017), combined with venous tumor thrombus (P = 0.008), Ki67 >20% (P = 0.022) were more likely to have tumor recurrence. However, age, gender, BMI, tumor diameter, clinical symptoms and postoperative treatment were not correlated with OS or RFS (P > 0.05). Univariate and multivariate COX analyses showed that Ki67 >20% (P = 0.013) and R1/2 status (P = 0.040) were independent risk factors for OS, while only Ki67 >20% (P = 0.032) was an independent risk factor for RFS. A nomogram for predicting OS was constructed based on the above factors, and the area under the receiver characteristic curve (ROC)-1, 3, and 5-year survival were 0.8, 0.825 and 0.902, respectively. The C-index of the predicted nomogram was 0.813 and a high C-index value of 0.846 could still be achieved in the external validation of TCGA. CONCLUSION: ACC is a rare and deadly endocrine malignancy with a high rate of recurrence. High Ki67 index (>20%) and R1/R2 resection status were independent risk factors for poor prognosis in ACC patients. A novel nomogram with a relatively good accuracy was established to assist clinicians in assessing the risk of OS in patients with ACC.