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Abstract
Neuroblastoma is the most common extracranial solid tumor in infancy. It is an embryonal malignancy of the sympathetic nervous system arising from neuroblasts (pluripotent sympathetic cells). In the developing embryo, these cells invaginate, migrate along the neuraxis and populate the sympathetic ganglia, adrenal medulla and other sites. The pattern of distribution of these cells correlates with the sites of primary disease presentation.
Neuroblastoma is a heterogeneous disease; Patients’ clinical courses can range from spontaneous regression to fatal progression of the disease. Accordingly, treatment protocols vary from ”wait and see” approaches to intensive multimodal therapies. Accurate risk estimation of the patients is therefore mandatory to choose the most adequate therapy. Current trials stratify by a number of clinical variables, such as stage of the disease and age of the patient at diagnosis, as well as molecular markers, such as amplification of the oncogene MYCN and loss of the short arm of chromosome 1. However, misclassifications of patients still occur, and thus, a precise prediction of the clinical courses remains a challenge of neuroblastoma research.
In North America, the COG is investigating a risk-based neuroblastoma treatment plan that assigns all patients to a low-, intermediate-, or high-risk group based on age (< 365 days versus 365 days), INSS stage (Stage 1, 2, 3, 4, 4s), MYCN status (genomic amplification versus nonamplified), Shimada histopathology (Favorable versus unfavorable) and tumor cell ploidy (DNA index= 1.0 versus > 1.0). Treatment is tailored according to risk.
European studies e.g. NB2004 trial suggests that the inclusion of chromosome 1p status of neuroblastoma cells may improve risk grouping and the clinical significance of additional tumor genetic characteristics including 17q gain, 1p deletion, and 11q deletion are under study.
The NB2004 protocol assesses Experimental induction with topotecan in management of high risk neuroblastoma.
Autologous stem cell transplantation (ASCT) is superior in the treatment of advanced neuroblastoma. In NB2004 protocol, all stage 4 patients >1 year at diagnosis and all MYCN amplified neuroblastoma patients regardless of age will undergo ASCT.