Craig L. Silverman

Preservation of Cranial Nerve Function after Treatment of Acoustic Neurinomas with Fractionated Stereotactic Radiotherapy

Twenty-seven acoustic tumors in 26 patients were treated with multiple fractionated linear-accelerator-based stereotactic radiotherapy (SRT). All patients with intact pretreatment facial nerve function with either small or large tumor volumes have thus far experienced no treatment-related facial neuropathy, including 9 patients with a mean follow-up of 22.4 +/- 1.6 months. The incidence of evaluable trigeminal neuropathy was 13%, and in 5 of 7 patients with serviceable pretreatment hearing, audiometry was unchanged in the immediate posttreatment period. Longer follow-up will be necessary to evaluate hearing preservation after SRT. Tumor response with central necrosis was seen in all assessable patients. SRT can be performed for cerebellopontine angle tumors with accuracy and reproducibility. It achieves a biological response similar to single fraction radiosurgery and may lower the incidence of facial and trigeminal neuropathies.

External Beam Irradiation as an Adjunctive Treatment in Failing Dialysis Shunts

PURPOSE To evaluate the utility of low-dose irradiation as adjunctive treatment for failing dialysis shunts related to stenoses. MATERIALS AND METHODS Thirty-one patients with 41 lesions in their dialysis shunts were successfully enrolled for this study. After imaging of the shunt and calculation of venous stenoses, each patient was randomized into one of two segments of the protocol: (i) angioplasty and/or stent placement alone, and (ii) angioplasty and/or stent placement followed by external beam irradiation. All patients with significant venous stenoses (> or =50%) were treated with appropriately sized PTA (percutaneous transluminal angioplasty) and Wallstents. Patients randomized to the external irradiation segment underwent localized irradiation via a Theratron cobalt unit of 7 Gy 0-24 hours and 24-48 hours after intervention. Those patients randomized to the control group received no additional treatment. Clinical follow-up included resumption of successful dialysis with appropriate hemodynamic parameters. Two follow-up shunt images were obtained, follow-up 1 (fu-1) from 90 to 179 days and follow-up 2 (fu-2) from 180 to 365 days. Percentages of significant recurrent stenoses, defined as greater than 50%, were recorded and re-treated as needed. RESULTS Sixteen of the 31 patients underwent external beam irradiation. There were 21 lesions in the test group that underwent irradiation after intervention, and 20 lesions were treated with intervention alone. There were seven native arteriovenous fistulas and 24 Gore-tex grafts. All stenoses were either venous outflow stenoses (68%) or central stenoses (32%). The authors utilized chi2 analysis to compare restenoses rates between the control and irradiated groups at fu-1 (P<.99) and fu-2 (P<.10). CONCLUSIONS Although the results show that external beam irradiation has minimal effects on the restenoses of dialysis grafts when used in conjunction with PTA and stent placement, further studies with a larger, more homogenous population are needed to assess the trend of improving patency rates after external beam irradiation.

Malignant myoepithelioma of the parotid gland: case report and review of the literature.

A 62-year-old male with a myoepithelioma of the right parotid gland was treated with surgical excision followed by adjuvant radiation therapy. Prior to the completion of radiation therapy, the patient developed progressive disease at local, regional, and distant metastatic sites. Combined modality treatment with radiation and chemotherapy resulted in a significant but transient shrinkage of the tumours at all sites. The patient succumbed to metastatic disease 212 days following the diagnostic biopsy. This case illustrates several of the distinctive clinical and pathological characteristics of this rare tumour.

Possible Early Emergence of In-Field Second Neoplasms Following Cranial Irradiation, Chemotherapy, and Stereotactic Irradiation: Report of Two Cases

We report two patients with intracranial mass lesions, both treated with initial external-beam cranial irradiation (EBRT), subsequent linear accelerator-based stereotactic irradiation, and chemotherapy, who developed second unrelated malignancies inside the field of both the conventional and the stereotactic irradiation within 13 months of completion of EBRT. One was a 48-year-old man with a right temporal glioblastoma who developed a neurofibrosarcoma of the ipsilateral temporal scalp, and the other was a 53-year-old woman who developed a glioblastoma that enveloped a previously successfully treated metastasis from a non–small cell lung primary. We believe that these cases may reflect radiation-induced neoplasms and that the early occurrence of such second malignancies may be a new toxicity attributable to the combination of stereotactic and conventional irradiation and, possibly, systemic chemotherapy.