Radiation Therapy to the Primary and Postinduction Chemotherapy MIBG-Avid Sites in High-Risk Neuroblastoma

Abstract

Purpose/Objective(s)While it is generally accepted that consolidation therapy for high-risk neuroblastoma includes irradiation of the primary tumor bed and any remaining MIBG-avid metastatic sites, limited information has been published whether this approach affects disease progression and overall survival (OS) for high-risk neuroblastoma patients.Materials/MethodsFrom January 2006 to June 2011, 30 patients with high-risk neuroblastoma were treated at one radiation therapy (RT) department. All patients received induction therapy with 5 cycles of chemotherapy and surgical resection. Patients with at least a partial response after induction therapy, based upon the international neuroblastoma response criteria, were subsequently treated with 24-30 Gy to the primary site and most MIBG-avid sites remaining after induction. RT was followed by high-dose chemotherapy with autologous stem cell rescue. Treatment concluded with 6 months of maintenance therapy using cis-retinoic acid.ResultsWithin our retrospective cohort of high-risk patients, 50% of the patients were male. The median age at diagnosis was 32 months (range, 8 months to 19 years). Gross total and subtotal resections were performed in 22 and 8 patients, respectively. The median number of sites irradiated, including the primary site, was 1 (range, 1 to 4). With a median follow-up of 33 months (range, 10 to 77 months), the 5-year progression free survival (PFS) and OS were 48% and 59%, respectively. The 5-year local control rate at the primary site was 85%. There was no difference in primary site local control according to degree of resection. The 5-year control rate for irradiated MIBG-avid sites was 82.4%, with 5-year PFS for patients with 0, 1, 2, ≥ 3 MIBG-avid sites were 66%, 57%, 20%, and 0%, respectively (p < 0.001). The 5-year OS for patients with 0, 1, 2, ≥ 3 MIBG-avid sites were 80%, 57%, 50%, and 0%, respectively (p < 0.001).ConclusionsThe current standard of care for children with high-risk neuroblastoma includes irradiating the local tumor bed and any remaining MIBG-avid metastatic disease sites during consolidation therapy. We found that for radiated lesions, the 5-year local and metastatic site PFS was > 82%. Furthermore, the number of MIBG-avid sites irradiated after induction chemotherapy was predictive of 5-year PFS and OS as no patients with 3 or more MIBG-avid sites survived despite the use of RT. Purpose/Objective(s)While it is generally accepted that consolidation therapy for high-risk neuroblastoma includes irradiation of the primary tumor bed and any remaining MIBG-avid metastatic sites, limited information has been published whether this approach affects disease progression and overall survival (OS) for high-risk neuroblastoma patients. While it is generally accepted that consolidation therapy for high-risk neuroblastoma includes irradiation of the primary tumor bed and any remaining MIBG-avid metastatic sites, limited information has been published whether this approach affects disease progression and overall survival (OS) for high-risk neuroblastoma patients. Materials/MethodsFrom January 2006 to June 2011, 30 patients with high-risk neuroblastoma were treated at one radiation therapy (RT) department. All patients received induction therapy with 5 cycles of chemotherapy and surgical resection. Patients with at least a partial response after induction therapy, based upon the international neuroblastoma response criteria, were subsequently treated with 24-30 Gy to the primary site and most MIBG-avid sites remaining after induction. RT was followed by high-dose chemotherapy with autologous stem cell rescue. Treatment concluded with 6 months of maintenance therapy using cis-retinoic acid. From January 2006 to June 2011, 30 patients with high-risk neuroblastoma were treated at one radiation therapy (RT) department. All patients received induction therapy with 5 cycles of chemotherapy and surgical resection. Patients with at least a partial response after induction therapy, based upon the international neuroblastoma response criteria, were subsequently treated with 24-30 Gy to the primary site and most MIBG-avid sites remaining after induction. RT was followed by high-dose chemotherapy with autologous stem cell rescue. Treatment concluded with 6 months of maintenance therapy using cis-retinoic acid. ResultsWithin our retrospective cohort of high-risk patients, 50% of the patients were male. The median age at diagnosis was 32 months (range, 8 months to 19 years). Gross total and subtotal resections were performed in 22 and 8 patients, respectively. The median number of sites irradiated, including the primary site, was 1 (range, 1 to 4). With a median follow-up of 33 months (range, 10 to 77 months), the 5-year progression free survival (PFS) and OS were 48% and 59%, respectively. The 5-year local control rate at the primary site was 85%. There was no difference in primary site local control according to degree of resection. The 5-year control rate for irradiated MIBG-avid sites was 82.4%, with 5-year PFS for patients with 0, 1, 2, ≥ 3 MIBG-avid sites were 66%, 57%, 20%, and 0%, respectively (p < 0.001). The 5-year OS for patients with 0, 1, 2, ≥ 3 MIBG-avid sites were 80%, 57%, 50%, and 0%, respectively (p < 0.001). Within our retrospective cohort of high-risk patients, 50% of the patients were male. The median age at diagnosis was 32 months (range, 8 months to 19 years). Gross total and subtotal resections were performed in 22 and 8 patients, respectively. The median number of sites irradiated, including the primary site, was 1 (range, 1 to 4). With a median follow-up of 33 months (range, 10 to 77 months), the 5-year progression free survival (PFS) and OS were 48% and 59%, respectively. The 5-year local control rate at the primary site was 85%. There was no difference in primary site local control according to degree of resection. The 5-year control rate for irradiated MIBG-avid sites was 82.4%, with 5-year PFS for patients with 0, 1, 2, ≥ 3 MIBG-avid sites were 66%, 57%, 20%, and 0%, respectively (p < 0.001). The 5-year OS for patients with 0, 1, 2, ≥ 3 MIBG-avid sites were 80%, 57%, 50%, and 0%, respectively (p < 0.001). ConclusionsThe current standard of care for children with high-risk neuroblastoma includes irradiating the local tumor bed and any remaining MIBG-avid metastatic disease sites during consolidation therapy. We found that for radiated lesions, the 5-year local and metastatic site PFS was > 82%. Furthermore, the number of MIBG-avid sites irradiated after induction chemotherapy was predictive of 5-year PFS and OS as no patients with 3 or more MIBG-avid sites survived despite the use of RT. The current standard of care for children with high-risk neuroblastoma includes irradiating the local tumor bed and any remaining MIBG-avid metastatic disease sites during consolidation therapy. We found that for radiated lesions, the 5-year local and metastatic site PFS was > 82%. Furthermore, the number of MIBG-avid sites irradiated after induction chemotherapy was predictive of 5-year PFS and OS as no patients with 3 or more MIBG-avid sites survived despite the use of RT.