Investigation of brachial plexus dose that exceeds RTOG constraints for apical lung tumors treated with four- or five-fraction stereotactic body radiation therapy

Bindu V. Manyam, Kyle Verdecchia, Kevin Rogacki, Chandana A. Reddy, Tingliang Zhuang, Gregory M.M. Videtic, Joseph Azok, Kevin Stephans

Research output: Contribution to journalReview articlepeer-review

1 Scopus citations

Abstract

Purpose/objectives(s): We sought to determine the rate of brachial plexopathy (BPX) in patients exceeding RTOG dose constraints for treatment of apical lung tumors. Materials/methods: Patients with apical lung tumors treated with four- or five-fraction SBRT were identified from a prospective registry. Dosimetric data were obtained for ipsilateral subclavian vein (SCV) and anatomic BP (ABP) contours. Cumulative equivalent dose in 2 Gy equivalents (EQD2) was calculated for the SCV contour in patients with a history of prior ipsilateral RT. Five-fraction SBRT RTOG constraints of D0.03cc ≤32.0 Gy and D3cc ≤30.0 Gy were used. BPX was graded according to Common Terminology Criteria for Adverse Events 3.0. Results: A total of 64 patients met inclusion criteria. Median follow-up was 21 months. Six patients (9.4%) had prior ipsilateral conventional fractionated RT with varying degrees of overlap with subsequent SBRT field. Eleven patients without prior ipsilateral RT exceeded D0.03cc ≤32.0 Gy to SCV (mean 43.8 Gy ± 5.8). No BPX was observed in these patients. Out of the six patients who had prior ipsilateral RT, three patients exceeded D0.03cc ≤32.0 Gy to SCV (44.2 Gy ± 11.3), with two of these patients developing Grade 2 BPX within one year of SBRT. The EQD2 cumulative maximum point dose to BP was 122.6 Gy and 184.7 Gy for the two patients who developed Grade 2 BPX. The D0.03cc was >10 Gy higher to the ABP contour than the SCV contour in 14 patients. Conclusion: Without a history of prior ipsilateral RT, no BPX was observed at 21 month follow-up in 11 patients who exceeded the RTOG five-fraction BP constraint. This observation is hypothesis generating and more experience with longer follow-up is necessary to validate these findings. For tumors located in close proximity to apical structures, there was substantial variation in dose between the ABP and SCV contours.

Original languageEnglish (US)
Pages (from-to)189-197
Number of pages9
JournalJournal of Radiosurgery and SBRT
Volume6
Issue number3
StatePublished - 2019
Externally publishedYes

Keywords

  • Apical tumors
  • Brachial plexus
  • SBRT

ASJC Scopus subject areas

  • Surgery
  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging

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