Gamma knife stereotactic radiosurgery for salivary gland neoplasms with base of skull invasion following neutron radiotherapy

Abstract

Patients with primary salivary gland neoplasms that involve the base of skull and are treated with neutron radiotherapy alone are at high risk of local recurrence. A gamma knife boost improves local control and adds little additional toxicity. These preliminary results suggest that all patients with salivary neoplasms and base of skull invasion should be considered for a gamma knife boost after primary treatment with neutron radiotherapy.

High-LET radiotherapy for adenoid cystic carcinoma of the head and neck: 15 years’ experience with raster-scanned carbon ion therapy

“…The combination treatment of IMRT plus C12 boost results in good LC rates with 83.7% at 3 years (estimated 5a-LC: 58.5%), which is supported by our institution's earlier research [14] and other centers' neutron [6,10,31] or carbon ion [12,32] data. Pommier et al treated 29 patients with more than 74% T4 and 87% gross residual disease with protons in passive beam application.…”

Proton therapy for head and neck adenoid cystic carcinoma: Initial clinical outcomes

“…Patients treated more intensively, either with high-dose photon 6 or proton 22 therapy, or neutron therapy with radiosurgical boost, 17 appear to have improved disease control compared to older series of non-operative management with lower dose photon therapy, raising the possibility of using more conformal radiotherapy techniques for non-surgical management in patients for whom radical resection would be excessively morbid. The comparatively poor results seen in series of patients treated with radiation therapy alone for advanced disease may reflect delivery of insufficient dose of radiotherapy for gross disease, often complicated by proximity of unresectable disease to critical normal structures that have a lower tolerance dose to radiotherapy.…”

“…Neutron therapy has been used to provide a biologically more potent dose of radiation therapy for patients with unresectable salivary gland tumors: although the 5-year locoregional control rate for patients with ACC and skull base involvement was a disappointing 15-23%, 11,12 though improved with addition of a gamma knife radiosurgery boost. 17 Proton therapy is a modality of radiation therapy with a biologic effect normalized to be identical to megavoltage Xrays, but with superior dose localization, facilitating dose-escalation while respecting the dose constraints of surrounding normal structures. 18 We report initial clinical outcomes of proton therapy at our institution for head and neck ACC.…”

Role of particle radiotherapy in the management of head and neck cancer

“…CNS structures are more sensitive to fast neutrons than most other normal tissues and so keeping them within tolerance levels required reducing the neutron dose to the superior aspect of the tumor resulting in lower overall tumor control. Preliminary data evaluating the subsequent use of a stereotactic radiosurgery boost to areas of skull-base disease following neutron radiotherapy show a dramatically improved tumor control along the skull base [16]. At the 40-month follow-up point, the local control rate was 82% for patients receiving the stereotactic radiosurgery boost compared with 39% for a historical control group treated without a radiosurgery boost.…”