Gangliogliomas: experience with 34 patients and review of the literature.

Ganglioglioma is an uncommon central nervous system tumor. The role of adjuvant postoperative radiation therapy is undefined. The authors retrospectively reviewed the clinicopathologic features and results of therapy for 34 patients with ganglioglioma treated at the University of California at Los Angeles. There were 18 women and 16 men. Median age was 18 years. Twenty-five tumors were low grade. Twenty-one patients underwent gross total resection. Three patients received adjuvant radiotherapy. The 4-year actuarial progression free and overall survival rates were 67% and 75%, respectively. The median time to progression was 14 months and all relapses were local. Factors significantly influencing progression-free or overall survival according to univariate analysis included degree of resection and tumor grade. Survival and relapse were not significantly influenced by any factor according to multivariate analysis. The progression-free survivals after gross total resection of low- and high-grade tumors were 78% and 75%, respectively. Respective rates after subtotal resection were 63% and 25%. Review of the literature demonstrates no role for radiotherapy after total resection of ganglioglioma or after partial removal of low-grade tumor. Radiation therapy appears to reduce the relapse rate after partial removal of high-grade lesions. A dose in excess of 5,000 cGy is necessary for ganglioglioma.

Treatment results of unresected or partially resected desmoid tumors.

The authors compare the progression-free survival of patients with unresected or partially resected desmoid tumors treated with radiotherapy with those not given radiotherapy. A retrospective analysis and pathologic review was performed on 14 patients treated at the University of California Los Angeles School of Medicine from 1965 through 1992. Median follow-up was 6 years. The 6-year progression-free survival for irradiated patients was 100%, compared with 50% for those not irradiated (p = 0.04). Of the seven patients irradiated, only two had a complete response and one had a partial response. There was no difference in disease-specific survival between patients irradiated and those not irradiated, because only 1 of 14 patients died of desmoid tumor progression, which caused airway obstruction. This data suggest that radiotherapy may improve the progression-free survival of patients with unresected or partially resected desmoid tumor; however, the number of patients in this series is small. Most patients did not have a complete response to radiotherapy. For patients with tumor adjacent to the airway in the neck or upper thorax, the authors recommend radiotherapy because of the potential for mortality. Otherwise, because tumor progression rarely causes death, one must consider whether the morbidity of treatment would outweigh the morbidity of disease progression.

Cerebral gangliogliomas: preoperative grading using FDG-PET and 201Tl-SPECT.

PURPOSE: To date there have been only scattered case reports comparing the nuclear medicine characteristics of gangliogliomas with their histologic grade. We sought to determine the relative usefulness of nuclear medicine scanning, CT, and MR imaging in predicting the histologic grade of these tumors. METHODS: Eleven cases of pathologically proved ganglioglioma were analyzed retrospectively. Preoperative positron emission tomography with 18-fluorodeoxyglucose (FDG-PET), thallium chloride Tl 201 single-photon emission computed tomography (201Tl-SPECT), CT, and MR imaging studies were reviewed and compared with histologic tumor grade. FDG-PET scans were inspected visually for tumor metabolic activity relative to activity of normal gray and white matter. 201Tl-SPECT scans were analyzed for tumor activity using regions of interest and activity ratios. CT and MR studies were reviewed for the presence of conventional radiologic features of malignancy (ie, enhancement and edema). RESULTS: Eleven patients had a total of 15 nuclear scans. Eight of nine gangliogliomas scanned with FDG-PET showed tumor hypometabolism, the ninth was normal. All nine were low-grade gangliogliomas. Increased 201Tl-SPECT activity was seen in two high-grade gangliogliomas. The third 201Tl-SPECT scan, of a low-grade ganglioglioma, was normal. CT and MR studies showed enhancement in four gangliogliomas, of which two were high grade and two low grade. Edema was seen only in conjunction with the two high-grade gangliogliomas. CONCLUSION: FDG-PET and 201Tl-SPECT are 100% correlative in preoperative prediction of histologic grade of ganglioglioma. Tumors with decreased or normal PET or SPECT activity were low grade; tumors with increased SPECT activity were high grade. These results may be more reliable than CT and MR imaging findings in assessing tumor grade, and they may be of value for surgical planning and determining patient prognosis.

The role of adjuvant radiotherapy in the treatment of resectable desmoid tumors.

PURPOSE: Desmoid tumors have a high propensity for local recurrence with surgical resection. There are many reports describing good responses of desmoid tumors to irradiation, but none have clearly established the indications for adjuvant radiotherapy in treating resectable desmoid tumors. METHODS AND MATERIALS: A retrospective analysis was performed on 61 patients with resectable desmoid tumor(s) who were treated at our institution from 1965 to February of 1992. Five patients had multifocal disease and are analyzed separately. Fifty-six patients had unifocal disease, of which 34 had positive surgical margins. Forty-five of the 56 patients with unifocal disease were treated with surgery alone, while 11 were treated with surgery plus adjuvant radiotherapy. Median follow-up was 6 years. Local control was measured from the last day of treatment, and all cases were reviewed by our Department of Pathology. RESULTS: Multivariate analysis of the 56 patients with unifocal disease revealed that positive margins independently predicted for local recurrence (p < or = 0.01). Only 3 of 22 patients with clear margins experienced a local recurrence, with a 6-year actuarial local control of 85%. Multivariate analysis of the 34 patients with positive margins revealed that adjuvant radiotherapy independently predicted for improved local control (p = 0.01), and patients with recurrent disease had a slightly higher risk of local recurrence (p = 0.08). The 6-year actuarial local control determined by Kaplan-Meier for patients with unifocal disease and positive margins was 32% (+/-12%) with surgery alone, and 78% (+/-14%) with surgery plus adjuvant radiotherapy (p = 0.02). Subgroup analysis of the patients with positive margins and recurrent disease revealed that those treated with surgery alone had a 6-year actuarial local control of 0% vs. 80% for those treated with surgery plus radiotherapy (p < or = 0.01). Patients with positive margins and primary disease had a trend towards improved local control with adjuvant radiotherapy, but this was not statistically significant. None of the patients treated with radiotherapy developed serious complications or a secondary malignancy. CONCLUSIONS: Margin status is the most important predictor of local recurrence for patients with resectable, unifocal desmoid tumor. Adjuvant radiotherapy is indicated in the treatment of patients with positive margins following wide excision of recurrent disease. The role of adjuvant radiotherapy in patients with positive margins following resection of primary disease is controversial, and should be based on a balanced discussion of the potential morbidity from radiotherapy compared to the potential morbidity of another local recurrence. Adjuvant radiotherapy is less likely to benefit those with clear margins due to the excellent results for these patients treated with surgery alone. The local control of desmoid tumor in the adjuvant setting is excellent with total doses ranging from 50-60 Gy, with acceptable morbidity. Field sizes should be generous to prevent marginal recurrences, and large volume MRIs of patients with extremity lesions should be used to identify those patients with multifocal disease.