This study focuses on adrenocortical carcinoma, a rare cancer that develops in the outer layer of the adrenal glands, which are small organs located above the kidneys that produce important hormones. The study will test different treatment approaches after surgical removal of the tumor in patients who have a high risk of the cancer returning. The treatments being studied include mitotane, a medication specifically used for adrenocortical carcinoma, either used alone or in combination with two chemotherapy drugs called cisplatin and etoposide. Additional medications will be used to support treatment and manage side effects, including fludrocortisone to help maintain hormone balance, filgrastim to support white blood cell production, ondansetron and metoclopramide to prevent nausea and vomiting, and electrolyte solutions to maintain proper body fluid balance.

The purpose of this study is to compare how well mitotane alone works compared to mitotane combined with cisplatin and etoposide in preventing the cancer from returning after surgery. Patients in the combination treatment group will receive four cycles of chemotherapy, with each cycle lasting 21 days, alongside their mitotane therapy. Throughout the study, participants will have regular check-ups that include physical examinations, blood tests to monitor general health and hormone levels, and imaging scans such as CT scans with contrast medium, MRI, or PET-CT scans to check for any signs of cancer recurrence. These imaging tests use different technologies to create detailed pictures of the inside of the body to detect any abnormal changes.

During the study, researchers will also evaluate how blood levels of mitotane, the stage of disease, certain tumor characteristics, and the completeness of surgical removal affect treatment outcomes. The study will assess how the timing of starting treatment after surgery may influence results, and participants will be asked to complete questionnaires about their quality of life at several time points. Safety will be carefully monitored by tracking any serious side effects that occur during treatment and for one year after treatment ends.