Robotic Radiosurgery for Adrenal Gland Metastases

Abstract

IntroductionThe purpose of this study was to investigate the safety and efficacy of CyberKnife (CK) robotic radiosurgery for treatment of adrenal metastases.MethodsWe performed a retrospective analysis of 23 patients with adrenal metastases who had been treated with CK between October 2006 and December 2015. Fifteen patients received chemotherapy prior to radiosurgery, all patients underwent computer tomography (CT) fluoroscopically guided percutaneous placement of one to three gold fiducials into the adrenal gland. Nineteen patients were selected for single-fraction radiosurgery with a median dose of 22 Gy, four patients were treated in three fractions with a median dose of 13.5 Gy.ResultsMedian follow-up time was 23.6 months. Four patients (17%) experienced local relapse during the evaluation period with a mean time of 19 months to tumor progression. The actuarial local tumor control rate was 95% after one year and 81% after two years. Three of the four patients with local recurrence were retreated with CK radiosurgery. Dynamic tumor tracking enabled accurate treatment with correlation errors less than 2 mm, despite extensive respiration-induced target motion up to 22 mm. Apart from nausea directly after treatment in five patients, we observed no early or late treatment-related side effects.ConclusionsSingle fraction robotic radiosurgery for adrenal gland metastases is a safe and effective treatment option for patients who are not eligible for surgical resection.

Stereotactic body radiotherapy (SBRT) for adrenal metastases of oligometastatic or oligoprogressive tumor patients

“…When applying gating or tracking, the ITV-concept is no longer needed and PTV sizes can be substantially decreased. Haidenberger et al analyzed robotic radiosurgery using active tumor tracking at the CyberKnife for adrenal SBRT and reported much smaller PTV sizes of in median 48.6 cm 3 compared to the median PTV size of 95.9 cm 3 in our study, in which an ITV-based approach was applied [43]. Due to the smaller PTV sizes and hence the larger distance to surrounding radiosensitive OARs, higher doses potentially leading to superior LC could be delivered when active motion management strategies are used [40,46].…”

“…Limitations to this study were mainly caused by the retrospective nature of this analysis. Patient numbers were rather low, but similar to other studies, as adrenal SBRT is still not offered to many patients [3,21,22,24,36,43,45]. Furthermore, for increasing strength and homogeneity of our study, we only focused our analysis on truly oligometastatic or oligoprogressive patients and excluded all patients who were treated with palliative intent or dose.…”

“…The adrenal glands have been reported to show extensive respiration induced motion of more than 20 mm in several directions [22,43]. To account for target movement due to breathing, nearly all patients were treated with a 4-D-CTbased internal target volume (ITV) concept in our study.…”

Dynamic-arc respiratory-gated stereotactic radiotherapy — technique presentation

“…In the case of respiratory moving tumors, the technique can be successfully applied in the treatment of lung and liver cancers, often constituting an alternative to radical surgery or palliative care [2,[15][16][17][18]. Tumors located in organs affected by respiratory motion on both sides of the diaphragm (mediastinum, kidneys, adrenal glands, spleen) can also be treated with radiosurgery with the use of respiratory gating or tracking [19][20][21][22]. The basic limitation of the method is the size and location of the tumor.…”

Adrenal metastases

“…19 of 23 patients achieved single-fraction radiosurgery with a median dose of 22 Gy and four were treated in three fractions with a median dose of 13.5 Gy. During follow-up (median time 23.6 months), local relapse was observed in 17% of patients with a mean time of 19 months to tumor progression [64].…”