Stereotactic radiosurgery for primary and metastatic brain tumors

Stereotactic radiosurgery in the management of intracranial gliomas

Glial neoplasms are the most common primary intracranial malignancies. Treatment of high-grade gliomas has been frustrating, with less than 5% of patients surviving 5 years after a diagnosis of glioblastoma multiforme (GBM). Stereotactic radiosurgery (SRS) and fractionated strereotactic radiotherapy (F-SRT) provide means to either escalate the dose in primary treatment or to palliate recurrences. Because of their lower alpha/beta ratios and more focal nature, low-grade gliomas (LGG) are more attractive targets for stereotactically focused radiation. Results of available phase I-II data are reviewed for both low and high-grade gliomas. In the case of high-grade gliomas disappointing preliminary phase III data from RTOG 93-05 are discussed. Toxicity of SRS is discussed. Acute treatment toxicity of significance is unusual and generally self-limited. Occasionally an exacerbation of existing symptoms occurs. Late complications attributable to SRS are usually defined as necrosis within the treatment volume. The rate of necrosis can be hard to define in high-grade gliomas as tumor cells are often present in surgical specimens. New strategies in the application of stereotactic radiation are touched upon, these include: changes in planning and fractionation, concurrent use of chemotherapy, use of radiation modifiers and biologic agents. After reviewing the current data for high-grade gliomas, it appears that any apparent improvement in outcome seen in phase I-II trials is attributable to patient selection. The best evidence available does not support the use of SRS for primary high-grade gliomas. The somewhat limited experience in LGG also indicates a lack of benefit for patients treated with stereotactic radiosurgery or F-SRT. For a very select group of patients with small recurrent lesions, F-SRT may represent a safe, reasonable treatment.

Carcinoma of the kidney, testis, and rare urologic malignancies

The purpose of this symposium was to provide a forum for discussion on current information on the etiology and diagnosis of, and therapy for, tumors of the kidney, testis, and several uncommon malignancies of the genitourinary tract. The most recent contributions in epidemiology and molecular genetics were discussed with specific reference to their importance for clinical practice. Contemporary treatment approaches with the emphasis on multidisciplinary patient management of tumors commonly seen in the clinic as well as those that are only rarely diagnosed by urooncologists were presented. Major stress was given to the management optimization as it pertains to short- and long-term quality of life issues of patients treated for these tumors. Methods to reduce treatment toxicity including carcinogenic potential of chemotherapy, radiotherapy, or their combination were found to be of nearly equal importance to patient survival. Symposium participants reached consensus on a number of important points: 1) The management of patients with several malignancies discussed requires the presence of a multidisciplinary team of specialist who are interested in diagnosis and treatment of genitourinary tumors; 2) Patients managed in such an environment are expected to have optimal survival and the best possible quality of life; 3) Real advances in the management of patients can be best obtained through well-designed prospective clinical trials; and 4) There is a need for timely introduction of relevant advances in epidemiology and molecular genetics to clinics.

Radiographic findings and morbidity in patients treated with stereotactic radiosurgery

PURPOSE

To determine the prognostic significance of pretreatment edema, lesion size and location on morbidity following stereotactic radiosurgery (SRS).

METHODS AND MATERIALS

Forty-seven evaluable patients with 63 lesions were treated on a 6-MV linear accelerator radiosurgery system at Memorial Sloan Kettering Cancer Center. All patients received a 10-mg intravenous bolus of dexamethasone sodium phosphate (Decadron) prior to SRS. Thirteen patients were treated for asymptomatic lesions while 34 were treated because of neurologic symptoms. The median dose delivered was 1800 cGy and the median prescription isodose curve was 85%. Pretreatment edema was measured on a transaxial T2-weighted MR image acquired within 1 month of the SRS.

RESULTS

Ten patients experienced morbidity as a result of their treatment. The complication rate was measured by neurologic events following SRS and was not significantly influenced by the extent of peritumoral edema. Lesion size was also unrelated to the development of post-treatment symptoms as assessed by the ease of tapering steroids. The only parameter found to influence post-SRS complications was lesion location. Four of six (66%) patients treated to lesions in the motor cortex suffered post-SRS seizure activity, whereas only 6 of 37 (16%) patients treated to lesions elsewhere in the brain parenchyma experienced seizure activity.

CONCLUSION

The presence of pretreatment edema and lesion size are not predictors of post-SRS complication rates or the ability to taper Decadron. Lesion location is predictive of post-SRS seizure activity.

Central nervous system metastases

OBJECTIVES

To review current management of individuals with metastases to the central nervous system and brachial nerve plexus, and to provide a scientific basis for nursing management of the effects of the disease and treatment.

DATA SOURCES

Published articles, book chapters, clinical trial data, and experience from nursing literature.

CONCLUSIONS

Central nervous system metastases are events that may create oncologic emergencies with neurologic impairment and pain. Treatment of patients with central nervous system metastases is generally palliative regardless of the type of the primary cancer. Early diagnosis and treatment improve the chances for optimal recovery of neurologic function and pain management.

IMPLICATIONS FOR NURSING PRACTICE

Central nervous system metastases may develop in patients with systemic disease. Disease and treatment effects present challenges to patients, family, and care providers. Nurses have a responsibility in educating the patient/family and in providing supportive care.