Background Radioligand therapy is an important treatment option for neuroendocrine neoplasms. Although the use of internal dosimetry is recommended, its application in clinical routine is not widespread. This study aims to propose and evaluate a feasible method for determining the absorbed doses to organs at risk and tumour lesions in a large cohort of neuroendocrine neoplasm patients. Eighty patients who were treated as part of the FENET-2016 trial were enrolled in this study prospectively. The FENET-2016 protocol is based on two therapeutic schemes: a MONO therapy, consisting of five administrations (therapeutic cycles) of 177Lu-DOTATOC and a DUO therapy, consisting of three cycles of 177Lu-DOTATOC alternating with two cycles of 90Y-DOTATOC. A simplified method based on three-time-point SPECT/CT was first validated on a small cohort of patients and was then applied to all the eighty patients enrolled in the study to assess dosimetric evaluation for the organs at risk (kidneys, bone marrow, and tumours). Results Sixty-nine patients underwent a complete dosimetric evaluation. Absorbed doses per administered activity and cumulative absorbed doses were reported for organs at risk and tumours, as well as biologically effective doses for organs at risk. The results of this study are consistent with published data from other groups. The cumulative absorbed dose to the kidneys exceeded the threshold reported in the literature in ten cases out of sixty-nine cases, while no cases of a cumulative absorbed dose exceeding 2 Gy to the bone marrow were reported. High variability in tumour absorbed dose per unit activity was observed. Conclusions The proposed simplified dosimetric approach is feasible and easy to implement in clinical practice. This study demonstrated that dosimetry is a useful clinical tool, as it enables clinicians to guide patients towards combined radionuclide treatment or multiple treatments, which could improve patient outcomes.
Emerging need of dosimetry in radioligand therapy: a feasible method tested in a large cohort of patients affected by neuroendocrine neoplasms
Di Domenico, Giovanni
;Longo, Lorenzo;Panzini, Ilaria;Uccelli, Licia;Turra, Alessandro;Urso, Luca;Cittanti, Corrado;Bartolomei, MircoUltimo
2026
Abstract
Background Radioligand therapy is an important treatment option for neuroendocrine neoplasms. Although the use of internal dosimetry is recommended, its application in clinical routine is not widespread. This study aims to propose and evaluate a feasible method for determining the absorbed doses to organs at risk and tumour lesions in a large cohort of neuroendocrine neoplasm patients. Eighty patients who were treated as part of the FENET-2016 trial were enrolled in this study prospectively. The FENET-2016 protocol is based on two therapeutic schemes: a MONO therapy, consisting of five administrations (therapeutic cycles) of 177Lu-DOTATOC and a DUO therapy, consisting of three cycles of 177Lu-DOTATOC alternating with two cycles of 90Y-DOTATOC. A simplified method based on three-time-point SPECT/CT was first validated on a small cohort of patients and was then applied to all the eighty patients enrolled in the study to assess dosimetric evaluation for the organs at risk (kidneys, bone marrow, and tumours). Results Sixty-nine patients underwent a complete dosimetric evaluation. Absorbed doses per administered activity and cumulative absorbed doses were reported for organs at risk and tumours, as well as biologically effective doses for organs at risk. The results of this study are consistent with published data from other groups. The cumulative absorbed dose to the kidneys exceeded the threshold reported in the literature in ten cases out of sixty-nine cases, while no cases of a cumulative absorbed dose exceeding 2 Gy to the bone marrow were reported. High variability in tumour absorbed dose per unit activity was observed. Conclusions The proposed simplified dosimetric approach is feasible and easy to implement in clinical practice. This study demonstrated that dosimetry is a useful clinical tool, as it enables clinicians to guide patients towards combined radionuclide treatment or multiple treatments, which could improve patient outcomes.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
