Theragnostic Aspects and Radioimmunotherapy in Pediatric Tumors

Abstract

The use of theragnostic radiopharmaceuticals in nuclear medicine has grown rapidly over the years to combine the diagnosis and therapy of tumors. In this review, we performed web-based and desktop literature research to investigate and explain the potential role of theragnostic imaging in pediatric oncology. We focused primarily on patients with aggressive malignancies such as neuroblastoma and brain tumors, to select patients with the highest chance of benefit from personalized therapy. Moreover, the most critical and groundbreaking applications of radioimmunotherapy in children's oncology were examined in this peculiar context. Preliminary results showed the potential feasibility of theragnostic imaging and radioimmunotherapy in pediatric oncology. They revealed advantages in the management of the disease, thereby allowing an intra-personal approach and adding new weapons to conventional therapies.

Keywords: neuroblastoma; nuclear medicine; pediatric brain tumors; pediatric tumors; personalized therapy; positron emission tomography; radioimmunotherapy; radiopharmaceuticals; single-photon emission computed tomography; theragnostics.

Figure 1

Pre-therapeutic staging in a 4-year-old child with neuroblastoma, performed with ¹²³I MIBG scintigraphy/ single-photon emission computed tomography (SPECT). Planar images (A, anterior; B, posterior) show high uptake of the tracer in the right adrenal gland (white arrow), corresponding to the primary site of the tumor. Moreover, SPECT images of the skull (C–F) demonstrate the presence of metastasis in the occipital bone. Figures E and F display the physiological activities in the salivary glands and in the heart.

Figure 2

A 13-year-old boy suffering from hypertension, with evidence of slightly increased levels of catecholamine metabolites in urine. ¹²³I-MIBG scintigraphy was carried out for the suspicion of pheochromocytoma. Whole Body scan in anterior (A) and posterior (B), abdominal planar (C, anterior; D, posterior) did not show any area of abnormal tracer uptake. Co-registered corresponding axial (E) and coronal (F) SPECT/MRI images confirmed the absence of pathological hyperactive masses in both adrenal glands.

Figure 3

A 17-year-old male with mental retardation due to perinatal hypoxia, suffering from carcinoid syndrome due to ileal NET with hepatic metastases. Since symptomatology persisted despite somatostatin analog therapy and CT gave evidence of tumor progression, PRRT with 177Lu-DOTATATE was considered. Whole Body scan in anterior (A) and posterior (B) view, as well as the planar (C, anterior; D, posterior), acquired with gamma camera centered on the ¹⁷⁷Lu photopeak at 113 KeV, well-demonstrated tracer incorporation both in the tumor (C,D, white arrow) and in the liver lesions (C,D, white-bordered arrow). Three further focuses of increased accumulation of the radiopharmaceutical are visible under the primary tumor in the pelvic region, especially evident in the anterior view (C), to be referred to peritoneal carcinomatosis.