Predicting eligibility for outpatient 177 Lu-DOTATATE-targeted radionuclide therapy in patients with neuroendocrine...

177 Lu-DOTATATE-targeted radionuclide therapy (TRT) is effective for patients with somatostatin receptor (SSTR)-positive neuroendocrine tumors; however, radiation safety regulations often necessitate hospitalization, particularly in countries with stringent discharge criteria. This study aimed to identify pretreatment factors predicting outpatient eligibility.

We retrospectively analyzed 26 patients who underwent their first cycle of 177 Lu-DOTATATE TRT with complete data for analysis. The external dose rate at 1 m (EDR-1 m) was measured 6 h after administration. Patients were divided into two groups: EDR-1 m greater than or equal to 18 μSv/h and less than 18 μSv/h. Characteristics, including age, sex, BMI, body surface area, estimated glomerular filtration rate, administered dose, and tumor site, were compared. In addition, the whole-body washout rate from pretreatment SSTR imaging was evaluated as a potential predictor. Logistic regression and receiver operating characteristic (ROC) analyses were conducted.

Fourteen of the 26 (53.8%) patients met the discharge criterion at 6 h. No significant differences were observed in demographic or clinical characteristics between groups. The median washout rate was significantly higher in those meeting the criterion (57.6 vs. 35.0%; P  < 0.001). The area under the ROC curve for the washout rate was 0.929, indicating excellent predictive ability. An optimal cut-off value of 53.5% predicted same-day discharge with a sensitivity of 92.9% and specificity of 91.7%.

The whole-body washout rate derived from pretreatment SSTR imaging is a strong, practical predictor for outpatient eligibility following 177 Lu-DOTATATE TRT. Incorporating this simple, noninvasive marker into clinical workflow could support individualized discharge planning and improve patient access under strict radiation safety regulations.