The most common primary tumor of the adrenal gland is adrenocortical carcinoma (ACC). ACC is a highly rare malignancy, with an incidence of 0.7-2 per million population. 1 Although a diagnosis can be made at any age, ACC more frequently affects women, and its incidence peaks in the fourth to fifth decades of life. 2 ACCs are generally sporadic; how- ever, they are occasionally observed as a component of hereditary syndromes like Li-Fraumeni or Beck- with-Wiedemann syndrome. 3 Approximately 60% of patients present with symptoms owing to adrenal hor- mone secretion, where cortisol excess (Cushing syn- drome) is the leading manifestation followed by secretion of sex hormones (primarily androgen). 1,4 Non-functional ACCs cause symptoms owing to tumor burden, particularly abdominal pain and weight loss. Most ACC cases are diagnosed at an ad- vanced stage, and 5-year survival remains below 50%. 5 Primary treatment of localized ACC is the tumor resection with or without removal of regional lymph nodes. Adjuvant therapy with an oral adrenolytic agent, mitotane, for a minimum of 2 years is recom- mended in patients with no macroscopic residual dis- ease if a high risk of recurrence (large tumor size, Ki67>10% or R1 resection) persists. 1 Radiotherapy J Oncol Sci. 2021;7(3):133-8 133 133 133 Clinicopathological Features, Treatment Outcomes, and Prognostic Factors in Adrenocortical Carcinoma: A Single-Center Experience Nazım Can DEMİRCAN a , Tuğba AKIN TELLİ a , Tuğba BAŞOĞLU a , Rukiye ARIKAN a , Alper YAŞAR a , Abdussamet ÇELEBİ a , Özkan ALAN a,b , Selver IŞIK a , Özlem ERCELEP a , Faysal DANE a , Perran Fulden YUMUK a a Division of Medical Oncology, Marmara University Faculty of Medicine, İstanbul, TURKEY b Clinic of Medical Oncology, Tekirdağ State Hospital, Tekirdağ, TURKEY ABSTRACT Objective: The study aimed to analyze clinicopathological features, treatment outcomes, and prognostic factors of patients with adrenocortical carcinoma (ACC). Material and Methods: The records of 25 patients with confirmed ACC were retrospectively exam- ined who were followed up in our clinic. The clinical and pathological data were recorded. The prognosis was estimated using the Kaplan- Meier method, and prognostic variables were determined using Cox regression models. Results: The study included 21 patients, 19 (90.5%) of whom initially had Stage III or IV disease, and 18 (85.7%) had surgery for the primary tumor. In the subgroup with non-metastatic disease and primary tumor resection, patients who received adjuvant mitotane had significantly longer median disease-free survival than patients who had not (22.7 vs. 2.5 months, p=0.02). Five-year overall survival (OS) was 36%. De novo metastatic disease, primary tumor resection, and tumor functional status were the factors affecting OS significantly or having a trend in univariate analysis. Primary tumor resection was the only independent prognostic factor for OS after adjusting for other factors (hazard ratio=0.06, p=0.04). Conclusion: In our study population, adjuvant mitotane conferred a significant improvement in disease-free survival of patients with ACC who were operated on for localized dis- ease. Primary tumor resection persisted in being a significant prognostic factor for OS. Keywords: Adrenocortical carcinoma; prognosis; survival DOI: 10.37047/jos.2021-84514 Correspondence: Nazım Can DEMİRCAN Division of Medical Oncology, Marmara University Faculty of Medicine, İstanbul, TURKEY E-mail: ncdemircan@gmail.com Peer review under responsibility of Journal of Oncological Sciences. Received: 18 May 2021 Accepted: 28 Oct 2021 Available online: 12 Nov 2021 2452-3364 / Copyright © 2021 by Turkish Society of Medical Oncology. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Turkiye Klinikleri Journal of Internal Medicine Journal of Oncological Sciences ORIGINAL RESEARCH