Role of PET/CT in Staging and Evaluation of Treatment Response After 3 Cycles of Chemotherapy in Locally Advanced Retinoblastoma: A Prospective Study

Abstract

The present study prospectively evaluated the role of 18 F-FDG PET/CT for staging, neoadjuvant chemotherapy response evaluation, and final outcome assessment in International Retinoblastoma Staging System (IRSS) stage III retinoblastoma. Methods: Twenty-five consecutive IRSS stage III patients, with a median age of 3 y, were prospectively enrolled after ethics approval. All patients received neoadjuvant chemotherapy followed by enucleation, radiotherapy, and adjuvant chemotherapy. PET/CT was performed at baseline (PET/CT-1) and after 3 cycles of neoadjuvant chemotherapy (PET/CT-2). All 25 patients underwent PET/CT-1, and 21 of 25 patients underwent PET/CT-2. PET/CT-1 was compared with routine staging, and response on PET/CT-2 was assessed by criteria from the European Organization for Research and Treatment of Cancer response. Eventfree survival (EFS) and overall survival (OS) were calculated using Kaplan-Meier survival analysis, and differences between the groups were compared using log-rank test. A P value of 0.05 or less was considered significant. Results: Increased 18 F-FDG uptake was noted in primary extraocular tumor in all patients, except 5 with bilateral retinoblastoma (one eye with advanced and the other eye with intraocular disease) in whom the intraocular tumor did not show 18 F-FDG uptake. Five of 22 IRSS stage IIIA patients with clinically negative cervical lymph node involvement were found to have uptake in cervical lymph nodes on PET/CT-1, and 2 of 3 IRSS stage IIIB patients with pathologically confirmed cervical lymph node involvement did not show any uptake in the involved lymph nodes. No significant difference in EFS and OS was seen between IRSS stage IIIA and IIIB patients using routine staging or PET/CT staging (P $ 0.05); however, there was a trend toward better OS in patients with IRSS stage IIIB disease on PET/CT (P 5 0.065). There was no significant discordance between routine staging and PET/CT staging (P 5 0.256). The 8 patients with optic nerve uptake had lower EFS (P 5 0.0001) and OS (P 5 0.0009) than did 17 patients without optic nerve uptake on PET/CT-1. The 17 patients with complete response or partial response had better EFS (P 5 0.042) and OS (P 5 0.026) than did the 4 patients with progressive disease on PET/CT-2. Conclusion: Optic nerve uptake at baseline on PET/CT and response after neoadjuvant chemotherapy according to criteria from the European Organization for Research and Treatment of Cancer are strong predictors of EFS and OS in IRSS stage III retinoblastoma.

[18F]-Fluorodeoxyglucose Positron Emission Tomography and Computed Tomography in Response Evaluation of Oncolytic Adenovirus Treatments of Patients with Advanced Cancer

“…Increased consumption of glucose is a characteristic of most cancers and therefore uptake of FDG is a sign of tumor cell viability, whereas reductions in tumor FDG uptake can represent antitumor efficacy (Young et al, 1999). Therefore, FDG-PET is a useful tool for diagnosis, staging, restaging, and treatment monitoring of many tumor types (Hoh, 2007;Kumar et al, 2009;Bakhshi et al, 2012;Radhakrishnan et al, 2012). In fact, the biological predictive value of PET appears greater than anatomic imaging studies in certain cancer types, especially early during therapy (Wahl et al, 2009).…”

Rare case of trilateral retinoblastoma with spinal canal drop metastasis detected with fluorine-18 fluorodeoxyglucose positronemission tomography/computed tomography imaging

“…[6] To the best of our knowledge, the role of 18F-FDG PET/CT in TRb has not been reported in the published literature. There has been previous report on the use of 18F-FDG PET alone without CT in 4 patients with retinoblastoma[7] and Radhakrishnan et al ,[8] described the role of PET/CT in staging and evaluation of treatment response after three cycles of chemotherapy in locally advanced retinoblastoma. This is the first case of identifying TRb with drop metastasis in PET/CT.…”

PET/CT and PET/MRI in ophthalmic oncology (Review)

“…Radhakrishnan et al, in a prospective evaluation of the role of 18 F-FDG PET/CT in staging and assessment of the response to neoadjuvant chemotherapy, demonstrated that intraocular RB did not take up the radiotracer, in contrast to the 18 F-FDG avidity of extraocular RBs (63). Furthermore, no significant difference was revealed between staging with CT or MRI and staging based on 18 F-FDG PET/CT findings.…”