Kyle D. Weaver and Matthew G. Ewend
Kyle D. Weaver, Diane Armao, Joseph M. Wiley and Matthew G. Ewend
✓ This 10-year-old girl presented with a 1-month history of progressive bulbar palsy and a solitary enhancing mass originating within the floor of the fourth ventricle. Results of initial imaging studies and presentation were suggestive of neoplasia. Subtotal resection was performed and pathological examination revealed the mass to be a histiocytic lesion, with no evidence of a glioma. The patient had no other stigmata of histiocytosis and was treated with steroid medications, resulting in prolonged resolution of the lesion. This case demonstrates that for discrete brainstem lesions the differential diagnosis includes entities other than glioma for which treatment is available. Biopsy sampling should be considered when technically feasible.
John H. Sampson, Michael M. Haglund, Allan H. Friedman and Matthew G. Ewend
Eric K. Oermann, Marie-Adele S. Kress, Jonathan V. Todd, Brian T. Collins, Riane Hoffman, Huma Chaudhry, Sean P. Collins, David Morris and Matthew G. Ewend
Experience with whole-brain radiation therapy for metastatic tumors in the brain has identified a subset of tumors that exhibit decreased local control with fractionated regimens and are thus termed radioresistant. With the advent of frameless radiosurgery, fractionated radiosurgery (2–5 fractions) is being used increasingly for metastatic tumors deemed too large or too close to crucial structures to be treated in a single session. The authors retrospectively reviewed metastatic brain tumors treated at 2 centers to analyze the dependency of local control rates on tumor radiobiology and dose fractionation.
The medical records of 214 patients from 2 institutions with radiation-naive metastatic tumors in the brain treated with radiosurgery given either as a single dose or in 2–5 fractions were analyzed retrospectively. The authors compared the local control rates of the radiosensitive with the radioresistant tumors after either single-fraction or fractionated radiosurgery.
There was no difference in local tumor control rates in patients receiving single-fraction radiosurgery between radioresistant and radiosensitive tumors (p = 0.69). However, after fractionated radiosurgery, treatment for radioresistant tumors failed at a higher rate than for radiosensitive tumors with an OR of 5.37 (95% CI 3.83–6.91, p = 0.032).
Single-fraction radiosurgery is equally effective in the treatment of radioresistant and radiosensitive metastatic tumors in the brain. However, fractionated stereotactic radiosurgery is less effective in radioresistant tumor subtypes. The authors recommend that radioresistant tumors be treated in a single fraction when possible and techniques for facilitating single-fraction treatment or dose escalation be considered for larger radioresistant lesions.