Brachytherapy as an Adjuvant for Recurrent Atypical and Malignant Meningiomas

BACKGROUND

Recurrent atypical and malignant meningiomas have poor outcomes with surgical therapy alone. Neither adjuvant chemotherapy nor postoperative radiation therapy remedies this problem.

OBJECTIVE

To evaluate our experience with the treatment of 15 patients treated with I-125 or Cs-131 brachytherapy radiation seeds as an adjuvant in these difficult cases.

METHODS

Patients with high-grade recurrent meningioma who underwent resection and intraoperative placement of brachytherapy seeds at our institution from 2002 to 2014 were identified and studied by retrospective chart review.

RESULTS

Fifteen patients with median age of 68.8 yr were treated with I-125 (n = 13) or Cs-131 (n = 2) brachytherapy seeds for cases of recurrent, grade II (n = 8), or grade III (n = 7) meningioma at our institution from 2002 to 2014. These lesions originated from a variety of locations including, convexity (3), falcine (3), frontal (2), occipital (1), parietal (2), 2 sphenoid wing (2), and temporal (2), based recurrent meningiomas. Patients had a median of 2 prior open surgical interventions and received local radiation therapy with a median dose of 55 Gy prior to brachytherapy. Survival at 2.5 yr was 56% for grade II and 17% for grade III lesions. Survival was significantly associated with patient age but not tumoral pathology. Forty percent of patients required reoperations for wound complications following brachytherapy.

CONCLUSION

Brachytherapy with implantation of permanent radiation seeds provides a viable alternative treatment for recurrent meningioma while carrying a significant clinical risk of wound infection and need for reoperation.

Intraoperative dural irradiation by customized 192iridium and 90yttrium brachytherapy plaques

PURPOSE

After vertebral or paravertebral tumor resection, tumor cells may remain on the dura. Because a tumoricidal dose is difficult to achieve using external beam radiotherapy without exceeding the spinal cord tolerance, we developed intraoperative applicators to deliver additional dose to the dura.

METHODS AND MATERIALS

Eight patients with vertebral or paravertebral tumor underwent conformal external beam radiotherapy, tumor resection, and intraoperative radiotherapy to the dura involved by tumor. At surgery, vertebra, soft tissue, and epidural tumor were resected. A radioactive applicator plaque was placed on the dura to deliver 7.5-15 Gy, and then removed. Vertebral reconstruction and stabilization was completed. Chemotherapy was administered for large, high-grade sarcomas.

RESULTS

We progressed through three plaque designs, initially (192)Ir, subsequently liquid (90)Y, and finally (90)Y foil in a semicylindrical polycarbonate plaque, in the treatment of 8 patients. The low-energy (90)Y beta-emissions provided a more attractive depth dose profile than that achievable with iridium and gave negligible staff radiation exposure. The (90)Y depth dose measured 29% at 2 mm and 9% at 4 mm from the surface of the foil plaque, with acceptable surface dose homogeneity. The average surface dose rate ranged from 18.7 to 47.6 cGy/min for the iridium plaques and 45.2 to 187.5 cGy/min for the (90)Y plaques. The treatments have been without acute or late neurologic complications. The disease of 6 of 8 patients was locally controlled at median potential follow-up of 24 months.

CONCLUSIONS

The (90)Y foil applicator is technically elegant, easy to use, and superior to the earlier models. It has been incorporated into a protocol for spinal tumor treatment.