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. patient underwent palliative chemotherapy (starting on day 275 after initial diagnosis; Table 1). Metastases partially responded to chemotherapy but the patient died of bowel obstruction 1.5 years after initial diagnosis. Autopsy confirmed primary undifferentiated endometrial carcinoma. Calculating tumor growth kinetics At first presentation, the primary tumor was estimated to measure 36 × 36 mm in diameter. The patient initially denied treatment and remained untreated until 266 days after diagnosis. At that time, the patient returned with signs of extensive tumor progression (Table 1). 24 lesions were diagnosed by CT of the chest and abdomen and MRI of the pelvis. All lesions were radiologically reviewed and systematically measured. The complete tumor volume was calculated as the sum of all lesions on day 266. The three largest lesions were measured in three dimensions. The remaining lesions were measured in 2 dimensions and the third dimension was estimated as the mean of the two other measured dimensions with 20% scattering. Total tumor burden was estimated with the established standardized exponential model [1-3] using the formula: Increase of tumor volume over time (dV) from time t (day 0) to dt (day 266) in proportion (=λ= growth parameter) to tumor volume at the time of diagnosis = V(t):