In vivo Growth Kinetics of the Natural Course of an Undifferentiated Untreated Endometrial Cancer: An Observational Case Report

We describe a patient with a histologically verified undifferentiated endometrial cancer who initially declined treatment, thus permitting study of the in vivo growth kinetics of the tumor. 266 days later, the patient was diagnosed with extensive symptomatic pelvic, abdominal, mediastinal, lung and supraclavicular metastases confirmed by imaging. During the untreated phase of 9.2 months, the tumor volume doubling time was estimated to be 56 + 3.5 (SD; standard deviation) days when an exponential tumor growth was assumed. This rapid growth was paralleled by immunohistochemistry showing a higher mitotic rate in the metastasis than in the primary tumor. At a late stage of the disease, laparotomy showed pelvic extension of the endometrial tumor, parenchymal liver metastasis and peritoneal carcinomatosis. The patient died 1.5 years after the initial diagnosis. To the authors´ knowledge, this is the first analysis of hypothetically generated exponential tumor kinetics of an untreated gynecological cancer in vivo. This report may serve as a reference for assessing future clinical interventions in endometrial cancer.