Clinical impact and prognostic value of metaiodobenzylguanidine imaging inchildren with metastatic neuroblastoma

Purpose: The clinical value of metaiodobenzylguanidine (mIBG) scintigraphy in patients with disseminated neuroblastoma (NB) at the time of diagnosis a nd after induction chemotherapy was evaluated. Patients and Methods: The medical records and imaging studies of 30 patient s with stage 4 NE who underwent mIBG scintigraphy and Tc-99m hydroxy methyl ene diphosphonate bone scintigraphy at the time of diagnosis were reviewed. Scores were calculated for the mIBG and bone scintigrams, and outcome acco rding to the initial and follow-up imaging studies was determined. Results: Discrepancies between bone scintigraphy and mIBG osteomedullary lo calization were seen in six patients. For the entire cohort, 2-year event-f ree survival did not significantly differ for the group of patients with in itial mIBG or bone scintigraphy scores greater than or equal to 10 compared to those with scores < 10 (P = 0.23 and 0.61, respectively). However, for patients older than 1 year, a trend associating worse outcome with mIBG sco res greater than or equal to 10 at diagnosis was seen (P = 0.08). A trend c orrelating abnormal mIBG scintigraphy after induction therapy and poor outc ome was also observed (P = 0.09). Outcome did not correlate with the result s of the bone scintigram studies performed after induction chemotherapy (P = 0.68). Conclusion: Because a discordance between mIBG and bone scintigraphy result s were seen in a subset of stage 4 NE patients, both imaging studies should be performed at the time of diagnosis. mIBG imaging studies performed at t he rime of diagnosis and after induction chemotherapy may be of prognostic value, particularly in stage 4 patients older than 1 year.