Usefulness of Stereotactic Body Radiation Therapy for Treatment of Adrenal Gland Metastases

Abstract

Purpose: This study aimed to describe our institutional experience in the use of stereotactic body radiation therapy (SBRT) for the management of adrenal gland metastases from multiple primary cancers. Materials and Methods: We retrospectively reviewed 31 patients who underwent SBRT as treatment for 33 adrenal gland lesions in the academic radiotherapy department of Oscar Lambret cancer center between May 2011 and September 2018. The primary study endpoints were 1- and 2-year local control rates, defined as the absence of progression at the treatment site based on the response evaluation criteria in solid tumors (RECIST). Toxicities were graded in accordance with the Common Terminology Criteria for Adverse Events version 4.03. Results: The average tumor volume was 33.5 cm 3 (standard deviation: 51.7 cm 3 ), and the prescribed dose ranged from 30 to 55 Gy given in 3–9 fractions. The median biological effective dose was 112.5 Gy (range: 45–115.5 Gy), assuming α/β = 10. Considering progression at distant sites or death as competing events, the 1- and 2-year actuarial local control rates were 96.5% (95% confidence interval: 84.9–99.7) and 92.6% (95% confidence interval: 79.2–98.7), respectively. According to RECIST, a complete response was achieved in 10 (32.3%) lesions, a partial response in 10 (32.3%) lesions, and stability in 8 (25.8%) lesions. Three patients presented with local relapse at 8.8, 14, and 49.4 months. After a median follow-up of 18 months (range: 4.4–66.4), the median overall survival was 33.5 months (95% confidence interval: 17–not reached), while the median progression-free survival was 7.4 months (95% confidence interval: 3.8–14.1). Treatment-related toxicity was grade 1 or 2 in 42.4% of patients, including nausea (27.3%), abdominal pain (18.2%), vomiting (15.2%), and asthenia (9.1%). None of the patients developed acute grade ≥3 or late toxicity. Conclusion: SBRT seems to be a safe and effective treatment for adrenal gland metastases in patients whose primary tumor and metastatic spread are controlled by systemic treatment. With a 2-year local control rate of 92.6%, SBRT may be considered as one of the first-line treatments in oligometastatic patients with adrenal metastases.

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

“…In line with these results, another analysis demonstrated that adrenal SBRT with a BED 10 ≥ 85.5 Gy correlated with superior LC [41]. Notably, the patients in the study by Scouarnec et al were treated with higher total doses in BED 10 (median 112.5 Gy) compared to the median BED 10 in our analysis (75.0 Gy), which might also have impaired our results [40]. We also detected a non-significant trend for superior LC if a BED 10 ≥ 75.0 Gy was applied (p = 0.101), both patients diagnosed with a local recurrence were treated with a BED 10 < 67.5 Gy.…”

“…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]. However, as gating and tracking technologies are usually applied in combination with X-ray based image-guidance, the invasive implantation of fiducial markers in the well vascularized adrenal glands becomes necessary.…”

“…Another recently published study included 33 patients and demonstrated a 1year LC of 58.1% and 2-year LC of 50% for the patients who were still alive [37]. Both Scouarnec et al and Toesca et al demonstrated slightly superior local control rates of 92.4-96.5% after 1 year and 80.8-92.6% after 2 years [23,40]. However, their irradiated tumors showed a median tumor volume of 13.1 and 19 ml, while the median tumor volume in our study was considerably higher with 42 ml for the GTV and 96 ml for the PTV.…”

“…However, as gating and tracking technologies are usually applied in combination with X-ray based image-guidance, the invasive implantation of fiducial markers in the well vascularized adrenal glands becomes necessary. Scouarnec et al reported about severe side-effects in 10.7% of the patients following fiducial implantation in the adrenal glands including hematomata and pneumothoraces [40].…”

Adrenal Gland Irradiation Causes Fatigue Accompanied by Reactive Changes in Cortisol Levels

“…There is sparse literature considering the adrenal glands as organs at risk in RT. The evaluation of toxicity pro les was mostly from SBRT for adrenal metastases [31][32][33]. We regarded healthy adrenal glands, but not metastatic ones, as essential organs to spare in RT planning, which differed from previous studies.…”