Stereotactic radiotherapy for malignancies involving the trigeminal and facial nerves.

Involvement of a cranial nerve caries a poor prognosis for many malignancies. Recurrent or residual disease in the trigeminal or facial nerve after primary therapy poses a challenge due to the location of the nerve in the skull base, the proximity to the brain, brainstem, cavernous sinus, and optic apparatus and the resulting complex geometry. Surgical resection caries a high risk of morbidity and is often not an option for these patients. Stereotactic radiosurgery and radiotherapy are potential treatment options for patients with cancer involving the trigeminal or facial nerve. These techniques can deliver high doses of radiation to complex volumes while sparing adjacent critical structures. In the current study, seven cases of cancer involving the trigeminal or facial nerve are presented. These patients had unresectable recurrent or residual disease after definitive local therapy. Each patient was treated with stereotactic radiation therapy using a linear accelerator based system. A multidisciplinary approach including neuroradiology and surgical oncology was used to delineate target volumes. Treatment was well tolerated with no acute grade 3 or higher toxicity. One patient who was reirradiated experienced cerebral radionecrosis with mild symptoms. Four of the seven patients treated had no evidence of disease after a median follow up of 12 months (range 2-24 months). A dosimetric analysis was performed to compare intensity modulated fractionated stereotactic radiation therapy (IM-FSRT) to a 3D conformal technique. The dose to 90% (D90) of the brainstem was lower with the IM-FSRT plan by a mean of 13.5 Gy. The D95 to the ipsilateral optic nerve was also reduced with IM-FSRT by 12.2 Gy and the D95 for the optic chiasm was lower with FSRT by 16.3 Gy. Treatment of malignancies involving a cranial nerve requires a multidisciplinary approach. Use of an IM-FSRT technique with a micro-multileaf collimator resulted in a lower dose to the brainstem, optic nerves and chiasm for each case examined.

Decreased cochlear DNA receptor staining in MRL.MpJ-Fas(lpr) autoimmune mice with hearing loss.

OBJECTIVES: Previous studies of decreased cochlear DNA binding in autoimmune mice suggested that antibodies against a cochlear cell surface DNA receptor cause autoimmune hearing loss. However, the presence of a cochlear DNA receptor has not been determined. Therefore, immunohistochemistry with an anti-DNA receptor antibody was performed on MRL.MpJ-Fas(lpr) (MRL/lpr) autoimmune mice to determine 1) which inner ear structures contain DNA receptors and 2) whether the receptor staining pattern changes as autoimmune disease progresses and hearing thresholds increase. STUDY DESIGN: A prospective study of the progression of hearing loss in autoimmune mice and correlated alterations in immunostaining for the inner ear DNA receptor. METHODS: One group of MRL/lpr mice (n = 10) was allowed to develop autoimmune disease, and auditory brainstem response (ABR) audiometry was performed at 4, 6, and 9 months of age to measure the progression of hearing loss. A second group (n = 5) was tested for ABR thresholds at 2 months of age and immediately killed to assess receptor staining before the onset of autoimmune disease and hearing loss. The inner ears from all mice were immunohistochemically stained with an anti-DNA receptor antibody, and a qualitative analysis of the staining of cochlear structures was performed. RESULTS: Auditory brainstem response audiometry revealed a significant 20- to 30-dB elevation of thresholds as systemic disease progressed. Anti-DNA receptor staining was heaviest in the spiral ligament and less intense in the spiral ganglion and cochlear nerve. Both groups showed a similar pattern of staining in these structures. The stria vascularis and hair cells also stained in both groups. However, the stria cells of normal-hearing mice showed diffuse intracellular immunoreactivity, whereas older mice displayed less staining that was confined to the cell membranes. CONCLUSIONS: The inner ears of MRL/lpr mice contain DNA receptors. Autoimmune hearing loss was correlated with weaker overall intracellular staining in the stria vascularis and hair cells but increased staining of the cell membranes. This suggested DNA receptors have impaired endocytosis and more receptors remain on the cell membrane, possibly as a result of binding by circulating autoantibodies.

Acoustic neuroma surgery outcomes.

OBJECTIVE: The outcomes of surgery for acoustic neuromas have improved dramatically since the development of modern surgical techniques, the operating microscope, magnetic resonance imaging (MRI), and cranial nerve monitoring. The goals of acoustic neuroma surgery are now preservation of facial nerve function and, when feasible, hearing preservation. Many large series do not report standardized hearing and facial function grading, and they include patients who did not benefit from the most modern techniques. The purpose of this study was to present the results of acoustic neuroma surgery using the most modern techniques and equipment, using standardized grading systems. STUDY DESIGN: Retrospective review. SETTING: Tertiary referral center. PATIENTS: 97 patients who underwent surgical removal of acoustic neuromas from 1992 to 1998. INTERVENTION: All patients underwent acoustic neuroma surgery and had preoperative audiograms and MRI with contrast. In addition, all patients had preoperative and postoperative facial function graded by the House-Brackmann scale and intraoperative facial nerve monitoring. Hearing preservation was attempted in patients with tumors of any size who had preoperative function of grade A or B according to the Committee on Hearing and Equilibrium guidelines for reporting results of acoustic neuroma surgery. MAIN OUTCOME MEASURES: Hearing preservation was considered successful if the patient retained serviceable hearing grade A or B. House-Brackmann grade 1 or 2 was considered excellent facial function. Complications were recorded. RESULTS: Facial nerve integrity was preserved in 96 of 97 patients (99%). Eight of 8 (100%) patients with intracanalicular tumors had excellent facial nerve function (HB 1-2). Fifty-two of 55 (95%) of patients with small tumors had excellent facial nerve function, and 15 of 24 (63%) with medium tumors had HB grade 1-2. Hearing was preserved in 29% of patients with tumors under 2 cm. The overall complication rate was 20%; cerebrospinal fluid leak was the most common. CONCLUSION: These results show that with modern imaging and surgical techniques, acoustic neuroma surgery is extremely safe and outcomes are very good. Surgery remains the treatment of choice for most tumors until alternative therapies, such as gamma knife, use uniform grading scales and show long-term facial and hearing results.

A meta-analysis comparing outcomes of microsurgery and gamma knife radiosurgery.

OBJECTIVES/HYPOTHESIS: Surgery has been the most common treatment for acoustic neuromas, but gamma knife radiosurgery has emerged as a safe and efficacious alternative to microsurgery. This meta-analysis compares the outcomes of the two modalities. STUDY DESIGN: A retrospective MEDLINE search was used to find all surgical and gamma knife studies published from 1990 to 1998 and strict inclusion criteria were applied. RESULTS: For tumors less than 4 cm in diameter, there is no difference in hearing preservation (P = .82) or facial nerve outcome (P = .2). Surgery on all sized tumors has a significantly lower complication rate than radiosurgery performed on tumors smaller than 4 cm (P = 3.2 x 10(-14)). Surgery also has a lower major morbidity rate than gamma knife radiosurgery (P = 2.4 x 10(-14)). Tumor control was defined as no tumor recurrence or no tumor regrowth. Surgery has superior tumor control when tumors are totally resected (P = 9.02 x 10(-11)). Assuming that all partially resected tumors will recur, surgery still retains a significant advantage over radiosurgery for tumor control (P = .028). CONCLUSION: Data from these studies date back to the late 1960s and do not completely reflect outcomes using current imaging and procedures. A major difficulty encountered in this study is inconsistent data reporting. Future surgical and radiation reports should use standardized outcomes scales to allow valid statistical comparisons. In addition, long-term results from gamma knife radiosurgery using lower dosimetry have not been reported. Surgery should remain the therapy of choice for acoustic neuromas until tumor control rates can be established.

External beam radiation followed by planned neck dissection and brachytherapy for base of tongue squamous cell carcinoma.

BACKGROUND: Surgical resection of tongue base cancer can leave the patient with significant functional deficits. Other therapies, such as external beam radiation followed by neck dissection and radiation implants, have shown equal tumor control with good functional outcome. METHODS: Between March 1991 and July 1999, 12 patients at Oregon Health Sciences University, the Portland Veterans Administration Medical Center and West Virginia University School of Medicine Hospital were treated with external beam radiation followed by neck dissection and Ir192 implants. Two patients had T1 disease, two had T2, five patients had T3 tumors, and three had T4 tumors. Six had N2a necks, three had N2b necks, and three had N2c. Follow-up ranged from 13 months to 8 years. RESULTS: After external beam radiation, five patients had complete response and seven had partial response in the neck without complications. One patient underwent a unilateral radical neck dissection, eight had unilateral selective neck dissections involving levels I to IV, and three had dissections involving levels I to III. One of the five patients who had a complete clinical response in the neck had pathologically positive nodes. One patient had a pulmonary embolus that was treated and had no permanent sequelae. There were three complications from brachytherapy. Two patients had soft tissue necrosis at the primary site and one patient had radionecrosis of the mandible. All healed without further therapy. One patient had persistent disease and underwent a partial glossectomy but died of local disease. Distant metastasis developed in two patients. All others show no evidence of disease and are able to eat a normal diet by mouth. CONCLUSION: This combination of therapies should be considered when treating tongue base cancer.

Current treatment practices for early laryngeal carcinoma.

OBJECTIVE: Controversy regarding the management of early laryngeal carcinoma persists in the absence of a definitive comparison of treatment modalities. This study examines the basic management practices for early laryngeal cancer among the American Academy of Otolaryngology-Head and Neck Surgery membership with an emphasis on the role of conservation surgery. METHODS: Questionnaires were randomly distributed to 3000 members with 1000 responses. The results were collated and statistically evaluated with multivariable frequency analysis. RESULTS: For operable supraglottic tumors, supraglottic laryngectomy was advocated by 41.6% of those responding. Definitive radiation therapy was suggested by 5.3% of participants and total laryngectomy by 1.4%. Explanation of treatment options with the patient deciding the therapy was selected by 48.3% of responders. For suitable glottic tumors, hemilaryngectomy was recommended by 37.1%, definitive radiation therapy by 8.1%, total laryngectomy by 1.9%, and patient choice by 50.4% of members completing the survey. When patients were left to weigh the treatment options, surgery was much less likely to be chosen than if it was advocated by the physician. Trends were evident according to practice region and setting, but these variables did not correlate strongly with physician recommendations. However, date of residency completion and rating of available radiation oncology services were significant factors. The evaluation of postoperative considerations in laryngeal conservation surgery demonstrated large variability in the definition of a close margin and the perceived need for additional therapy. CONCLUSIONS: The varied practice patterns among the American Academy of Otolaryngology-Head and Neck Surgery membership reflect the lack of a comparative outcome analysis for the treatment of early laryngeal carcinoma. Consequently, the full reliance on patient choice, which is more pronounced among young physicians, and cost considerations may have the greatest impact on the future treatment of this disease.