In:
International Journal of Cancer, Wiley, Vol. 151, No. 3 ( 2022-08), p. 412-421
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.
Type of Medium:
Online Resource
ISSN:
0020-7136
,
1097-0215
Language:
English
Publisher:
Wiley
Publication Date:
2022
detail.hit.zdb_id:
218257-9
detail.hit.zdb_id:
1474822-8
