Stereotactic Radiosurgery/Stereotactic Body Radiotherapy for RCC:
Radiosurgery and hypofractionated stereotactic body radiotherapy have been extensively applied against renal cell carcinoma (23, 24, 25, 26, 27). Paradoxically, although the response of metastatic RCC brain lesions to conventional radiotherapy has been virtually nil, the long-term response rate of RCC brain metastases to radiosurgery exceeds 90% in some series (24, 25, 26). The addition of conventional whole brain radiotherapy to stereotactic radiosurgery does not appear to improve the intracranial local control or recurrence-free survival in RCC patients with intracranial metastatic lesions (25,26).
Highly successful stereotactic radiotherapy results have been described for both primary and extracranial metastatic RCC by the Radiumhemmet group, with only 3 documented recurrences among 162 treated RCC lesions, using a variety of hypofractionated treatment regimens of 3-4 treatments (23). Similarly, spinal metastatic lesions have been successfully radiosurgically ablated in a single fraction with CyberKnife® in 89% of cases, a figure that seems even more impressive when one considers that the majority of these lesions had already recurred after “conventional” spinal radiotherapy prior to their CyberKnife® radiosurgical treatment ( 27).
In summary, it appears that RCC is far more sensitive to hypofractionated ablative radiotherapy/radiosurgery approaches than it is to “conventionally fractionated” radiotherapy.
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