Lengthy-Time period Outcomes After Stereotactic Radiosurgery for Backbone Metastases: Radiation Dose-Response for Late Toxicity.
Int J Radiat Oncol Biol Phys. 2018 Mar 06;:
Authors: Ling DC, Flickinger JC, Burton SA, Heron DE, Quinn AE, Bejjani GK, Engh JA, Gerszten PC, Amankulor NM, Vargo JA
PURPOSE: To doc the 5- and 10-year charges of late toxicity and vertebral compression fracture (VCF) in long-term survivors after stereotactic radiosurgery for backbone metastases.
METHODS AND MATERIALS: A retrospective assessment was carried out on 562 sufferers handled with SRS for backbone metastases between April 2001 and July 2011. Deciding on these with not less than 5-year survival after SRS, included have been 43 sufferers who collectively underwent 84 remedies at 54 backbone websites. Most have been handled with single-fraction stereotactic radiosurgery to a median dose of 16 Gy (vary, 12-24 Gy), and 56% of websites had acquired prior exterior beam radiation remedy. Late toxicities and VCFs occurring within the absence of tumor development have been recorded. Binary logistic regression was used to establish predictors of late problems.
RESULTS: 9 sufferers (17% of therapy websites) developed grade ?2 late toxicities at a median time of 12.eight months (vary, four.2-59.zero months). Actuarial 5- and 10-year charges of grade ?2 late toxicity have been 17% and 17%, respectively. On multivariate evaluation, solely cumulative biologically efficient dose (BED3) > 200 Gy (or EQD22Gy [2-Gy equivalent dose calculated using an ?/? ratio of 2] > 130 Gy) was related to grade ?2 late toxicity (P = .036). Most level BED3 > 110 Gy (or EQD22Gy > 70 Gy) to spinal twine or cauda equina was related to grade ?2 late neuropathy (P = .zero17). 9 VCFs (18%) occurred at a median time of 10.2 months (vary, three.2-57.2 months), with 5- and 10-year VCF charges of 17% and 17%, respectively.
CONCLUSION: Stereotactic radiosurgery for major therapy and reirradiation of spinal metastases is related to a average danger of late toxicity with 10-year follow-up. Threat of late toxicity considerably will increase with cumulative BED3 > 200 Gy and spinal twine or cauda equina level BED3 > 110 Gy. Sufferers stay at average danger of VCF as much as 5 years after therapy, with a plateau in incidence thereafter as much as 10 years.
PMID: 29678526 [PubMed – as supplied by publisher]