On the Horizon for Pineal Region Tumors in Children

A number of technological advances and current lines of research inquiry relevant to the management of pineal region tumors are worthy of discussion. 

• Minimally invasive resection: With continued improvement of neuroendoscopy and technology, surgeons are able to resect pineal tumors purely endoscopically (15, 82, 92, 96). Reports describe complete removal of both solid and cystic lesions reached via a suboccipital or interhemispheric approach with good clinical result (15, 43, 92, 96). Some groups have used minimally invasive tubular retraction systems to reach tumors in the pineal region in order to improve visualization and disperse retractive forces to minimize damage to surrounding brain parenchyma (71).  While open surgical approaches currently are used more often for tumor resection, the use of endoscopy will undoubtedly continue to increase with the goal of safer and more effective surgical management of these deep-seated lesions.
• Molecular biology of pineal region tumors: Recent investigations into the molecular biology of pineal region tumors reveal distinct genetic abnormalities that may facilitate greater understanding of tumor formation and enable development of improved therapeutics.  For example, mRNA analysis has revealed differential gene expression in supratentorial PNETs compared to cerebellar medulloblastomas, implicating divergent intracellular signaling cellular differentiation pathways (67). 
• Dose efficacy of adjuvant treatments: Studies are investigating chemotherapy and radiation fractionation regimens for pineal region tumors, including primary parenchymal and germ cell tumors, with reports of long-term follow-up.  Recent reports suggest favorable outcomes for patients with germinomas treated with chemotherapy and low-dose radiation (89).  The use of stereotactic radiosurgery for management of pineal region tumors in children has been reported with good clinical results (46, 66).  Stereotactic radiosurgery has been proposed as an alternative to surgical resection or as a component of multimodal therapy for more aggressive lesions (46, 57, 66).  Interstitial radiosurgery is being investigated, with reports of primary parenchymal tumor management via iodine-125 brachytherapy (57).  Promising chemotherapeutic regimens and more focused radiation techniques, if proven clinically effective, can potentially minimize the dose and field of traditional radiation therapy, in turn minimizing radiation-induced morbidity for the treated children.