[A retrospective study of 96 cases of adrenal metastases]

Objective: To analyze the clinical characteristics, etiological composition, imaging features, and prognosis of adrenal metastases. Methods: This study is a retrospective case series that included 96 patients with pathologically confirmed adrenal metastases who were treated at West China Hospital, Sichuan University, from 2007 to 2017. Clinical features such as sex, age, tumor size, biochemical tests, imaging characteristics, postoperative pathology, treatment methods, and prognosis were collected and analyzed. The prognosis of patients and its influencing factors were analyzed by Kaplan-Meier survival curve and single-factor Cox risk proportional model. Results: Among the 96 included patients, 64 were male and 32 were female, with a median age of 60 years. There were 89 cases of unilateral adrenal metastases, five cases of bilateral metastases, and two cases with unspecified laterality. The median diameter of the metastases was 3.5 cm×2.9 cm, with an average CT value of 31 HU. Thirty-four cases of adrenal hormones were evaluated, and no abnormality was found.The primary tumor sites were as follows: lung (n=36), kidney (n=19), liver (n=12), pancreas (n=7), rectum (n=3), stomach (n=2), and one case each of tumor in the esophagus, skin, thyroid, left maxillary muscle, breast, bladder, cervix, chest wall, and gastrointestinal tract. There were three cases with unknown primary tumors. The most common pathological type was lung adenocarcinoma (20.8%, 20/96), followed by hepatocellular carcinoma (9.4%, 9/96) and high-grade invasive urothelial carcinoma of the kidney (8.3%, 8/96). Thirty-nine cases were diagnosed concurrently with the primary tumor, while 37 cases were diagnosed after the primary tumor, with a median interval of 15 months (range: 2-144 months). There was no significant correlation between the death risk of adrenal metastatic tumor patients and gender, age, and the size of the metastatic tumor (all P>0.05). There were 4 patients with radiotherapy and chemotherapy alone, 19 patients with surgery alone, and 6 patients with combined radiotherapy and chemotherapy. The median overall survival was 1, 3, and 7 years, respectively. Conclusions: Adrenal metastases were mostly diagnosed at the same time as the primary tumor or within 15 months after the diagnosis of the primary tumor. Unilateral metastasis is common. The lungs are the most common primary lesion, followed by the kidney and liver. CT is the preferred method for the diagnosis of adrenal metastases, and the plain CT value is more than 30 HU. The overall prognosis of adrenal metastases is poor. The prognosis was better for patients who underwent surgery combined with radiotherapy and chemotherapy than those who received only surgery or radiotherapy and chemotherapy alone.