Stereotactic body radiotherapy of adrenal metastases—A dose‐finding study. Issue 3 (13th April 2022)

• Record Type: Journal Article
• Authors: Buergy, Daniel; Würschmidt, Florian; Gkika, Eleni; Hörner‐Rieber, Juliane; Knippen, Stefan; Gerum, Sabine; Balermpas, Panagiotis; Henkenberens, Christoph; Voglhuber, Theresa; Kornhuber, Christine; Barczyk, Steffen; Röper, Barbara; Rashid, Ali; Blanck, Oliver; Wittig, Andrea; Herold, Hans‐Ulrich; Brunner, Thomas Baptist; Sweeney, Reinhart A.; Kahl, Klaus Henning; Ciernik, Ilja Frank; Ottinger, Annette; Izaguirre, Victor; Putz, Florian; König, Laila; Hoffmann, Michael; Combs, Stephanie Elisabeth; Guckenberger, Matthias; Boda‐Heggemann, Judit
• Is Part Of: International journal of cancer. Volume 151:Issue 3(2022)
• Page Start: 412
• Page End: 421
• Publication Date: 2022-04-13
• Subjects: adrenal -- dose‐finding -- oligometastases -- SBRT; Cancer -- Periodicals; Cancer -- Prevention -- Periodicals; 616.994
• DOI: 10.1002/ijc.34017
• Languages: English
• ISSNs: 0020-7136

Abstract

Abstract: Optimal doses for the treatment of adrenal metastases with stereotactic radiotherapy (SBRT) are unknown. We aimed to identify dose‐volume cut‐points associated with decreased local recurrence rates (LRR). A multicenter database of patients with adrenal metastases of any histology treated with SBRT (biologically effective dose, BED10 ≥50 Gy, ≤12 fractions) was analyzed. Details on dose‐volume parameters were required (planning target volume: PTV‐D98%, PTV‐D50%, PTV‐D2%; gross tumor volume: GTV‐D50%, GTV‐mean). Cut‐points for LRR were optimized using the R maxstat package. One hundred and ninety‐six patients with 218 lesions were included, the largest histopathological subgroup was adenocarcinoma (n = 101). Cut‐point optimization resulted in significant cut‐points for PTV‐D50% (BED10: 73.2 Gy; P = .003), GTV‐D50% (BED10: 74.2 Gy; P = .006), GTV‐mean (BED10: 73.0 Gy; P = .007), and PTV‐D2% (BED10: 78.0 Gy; P = .02) but not for the PTV‐D98% ( P = .06). Differences in LRR were clinically relevant (LRR ≥ doubled for cut‐points that were not achieved). Further dose‐escalation was not associated with further improved LRR. PTV‐D50%, GTV‐D50%, and GTV‐mean cut‐points were also associated with significantly improved LRR in the adenocarcinoma subgroup. Separate dose optimizations indicated a lower cut‐point for the PTV‐D50% (BED10: 69.1 Gy) in adenocarcinoma lesions, other values were similar (<2% difference). Associations of cut‐points with overall survival (OS) and progression‐free survival were not significant but durable freedom from local recurrence was associated with OS in a landmark model ( P < .001). To achieve a significant improvement of LRR for adrenal SBRT, a moderate escalation of PTV‐D50% BED10 >73.2 Gy (adenocarcinoma: 69.1 Gy) should be considered. Abstract : What's new? Stereotactic body radiation therapy (SBRT), a method of precisely targeting tumors with radiation, has been successful in treating adrenal metastases. However, the optimal dose has not yet been established. Here, the authors retrospectively analyzed 218 lesions in 196 patients who had been treated with SBRT and for whom dose‐volume parameters were available. They identified dose‐volume cut points above which higher doses did not provide additional benefit. Moderate escalation to 73.2 Gy for the PTV‐D50% achieved a clinically relevant improvement in recurrence rate.