Main Session
Sep
29
PQA 07 - Head and Neck Cancer, Lung Cancer/Thoracic Malignancies, and Nursing and Supportive Care
3489 - Dosimetric Evaluation of Arterial Branches Used In Flap Reconstruction In Locally-Advanced Laryngeal Cancer
Presenter(s)
Krishna Hanubal, MD - UC Irvine Health, Orange, CA
K. S. Hanubal1, K. Tawk2, J. S. Feier2, J. Park1, A. Cervantez-Inda1, E. Chen1, Q. A. Ho1, E. Kuoy3, J. P. Harris1, and Y. Haidar2; 1Department of Radiation Oncology, University of California - Irvine, Orange, CA, 2Department of Otolaryngology-Head & Neck Surgery, University of California - Irvine, Orange, CA, 3Department of Radiology, University of California - Irvine, Orange, CA
Purpose/Objective(s):
Patients with locally advanced laryngeal cancer (LALC) are generally managed with postoperative radiotherapy (PORT) or definitive chemoradiation (CRT). Patients with recurrence after definitive treatment are often managed with total laryngectomy (TL) with microvascular reconstruction. It is unclear if prior RT to small vessels of the head & neck (H&N) may impact free flap (FF) outcomes. These vessels used in FF reconstruction include: the transverse cervical artery (TCA), superior thyroid artery (STA), and facial artery (FA). The purpose of this study was to conduct a dosimetric analysis to these vessels.Materials/Methods:
A single-institution retrospective review was performed on patients with LALC (stage III-IV) who underwent intensity-modulated radiation therapy (PORT or CRT) between 10/1/19 and 4/1/25. Exclusion criteria were prior H&N RT, or if patients did not have contrast-enhanced imaging available. Vessels were contoured from anatomic references and input from radiation oncologists, neuroradiologist, and H&N surgeons. Doses to vessels were then computed and compared using linear mixed effects modeling. Secondary outcomes assessed included need for surgical salvage, and post-operative outcomes.Results:
Twenty patients were included. Average age was 65 years and 18 were male. 14 patients had PORT and 6 had CRT. RT prescription doses ranged from 54 Gray (Gy) to 70 Gy in 30-35 fractions. The average D0.03cc, D0.3cc, and DMean, respectively, to the vessels were: TCA 62.2 Gy, 60.0 Gy, and 59.1 Gy; STA 65.7 Gy, 61.1 Gy, and 64.4 Gy; FA 59.0 Gy, 46.4 Gy, and 43.5 Gy. Compared to FA, D0.3cc was significantly higher for both STA (+13.3 Gy, p = 0.009) and TCA (+11.9 Gy, p = 0.005). The same was found for DMean of STA (+19.2 Gy, p < 0.0001) and TCA (+15.1 Gy, p < 0.0001). No significant difference was found for D0.03cc. One patient had recurrence 19.2 months after CRT, and underwent salvage TL with FF reconstruction with anastomosis to right TCA. This vessel received a D0.03cc, D0.3cc, and DMean of 65.3 Gy, 62.5 Gy and 61.5 Gy. The postoperative course was complicated by surgical-site infection and fistula, requiring wound vac application (8 weeks). Patient subsequently required FF revision with left FA anastomosis (D0.03cc 68.5 Gy, D0.3cc 55.5 Gy, DMean 53.2 Gy), and had no further complications.Conclusion:
In patients with LALC, the level 3 and 4 neck vessels (STA and TCA) tended to receive higher DMean and D0.3cc compared to those in level 2 (FA). One patient in our cohort who underwent salvage TL with FF anastomosed to TCA developed a fistula and required a second FF reconstruction anastamosed to the FA, possibly related to prior RT to the recipient vessel. Further investigation of reconstruction patterns in patients requiring surgical salvage following RT may reveal a stronger association between RT dose and postoperative complications. This could influence RT planning and choice of donor artery in salvage FF reconstruction.