Role of surgery for optic pathway/hypothalamic astrocytomas in children

Abstract

Optic pathway/hypothalamic pilocytic astrocytomas in children are usually treated with chemotherapy following a surgical biopsy. In this report, we retrospectively considered the role of surgical intervention. In a series of 25 patients without neurofibromatosis type 1, the median age at initial treatment was 3.1 years (range, 0-15 years). Twenty cases were verified by histology, and five cases were diagnosed by MRI findings. Twenty-three patients received chemotherapy. All patients were alive at median follow-up of 66 months. Aims of surgery at the initiation of treatment were biopsy in 12 cases (1 stereotactic and 11 craniotomies) and debulking in 7 cases. The 11 open biopsies revealed pilocytic astrocytoma; however, noticeable complications occurred in five children after the biopsies. Review of preoperative MRIs showed that all had typical findings indicating pilocytic astrocytoma. The open biopsy offered no noteworthy benefit for the patients despite surgical risk and delay of chemotherapy. The extent of the seven resection surgeries was 70% or less removal, and postoperative adjuvant therapy was needed for six of the seven patients. The remaining six children who did not undergo surgery obtained remission with chemotherapy alone. After relapse in nine patients, 15 bulk-reduction surgeries were performed. Surgical resection was not curative in any patient. In five patients, mostly older children, cystic expansion of tumor was partially resected, resulting in additional remission. In conclusion, considering the risk of open surgery and the effectiveness of chemotherapy, the role of surgical intervention is restricted to bulk-reduction surgery only when it is inevitable, especially at relapse after chemotherapy.

The role of surgery in optic pathway/hypothalamic gliomas in children

“…8,12,17,23,25,26,35 Nevertheless, these tumors present a considerable and often life-long challenge for the neuro-oncology team. A proportion of these tumors behave in a dormant fashion and require no treatment.…”

“…21,26 Although it is accepted that radiotherapy can often be effective in controlling growth in these tumors, the late side effects of radiotherapy have led to a reduction in its use, particularly as most of these patients should be expected to survive into adulthood. There remains controversy over the precise role of neurosurgery, 16,18,19,24,35,[39][40][41][42]47 with many teams regarding this as an intervention of last resort with potentially unacceptable morbidity.…”

“…Neurosurgery to debulk or excise OPHG has been the subject of much debate, particularly with regard to the timing of surgery. [17][18][19]22,24,26,29,30,34,35,[39][40][41][42]47 These tumors are rare, and it is clear that surgeons need appropriate expertise to safely plan and perform this surgery.…”

“…The majority are pilocytic astrocyto mas (WHO Grade I), although a proportion will be pilomyxoid astrocytomas and rarely WHO Grade II neoplasms. 6,8,12,17,23,25,35 A significant proportion (10%-70%) occur in patients with neurofibromatosis Type 1 (NF1). 7,14,17,18,23,26,29,31,41 Up to half of OPHGs are reported to remain stable and not require intervention; hence an initial watch-andwait policy is often employed.…”

The role of early intra-operative MRI in partial resection of optic pathway/hypothalamic gliomas in children

“…Presentation tends to be due to compression of the optic pathways and diencephalon, but obstructive hydrocephalus is also a common feature [2,24]. Histologically, OPHGs are nearly always low-grade tumours, with pilocystic astrocytomas (WHO grade I) accounting for the majority, along with a proportion of pilomyxoid astrocytomas (WHO grade II) [5,7,9,11,17,22,30]. A strong association with Neurofibromatosis Type 1 (NF1) is observed, which tends to correlate with a more benign course [6,10,11,13,17,[24][25]28,34].…”