Fractionated Stereotactic Radiosurgery for Reirradiation of Head-and-Neck Cancer

Keith R. Unger. IJROBP Volume 77, Issue 5, Pages 1411-1419 (1 August 2010)
Purpose

Stereotactic radiosurgery (SRS) is an appealing treatment option after previous radiotherapy because of its precision, conformality, and reduced treatment duration. We report our experience with reirradiation using fractionated SRS for head-and-neck cancer.  From 2002 to 2008, 65 patients received SRS to the oropharynx (n = 13), hypopharynx (n = 8), nasopharynx (n = 7), paranasal sinus (n = 7), neck (n = 7), and other sites (n = 23). Thirty-eight patients were treated definitively and 27 patients with metastatic disease and/or untreated local disease were treated palliatively. Nine patients underwent complete macroscopic resection before SRS. Thirty-three patients received concurrent chemoradiation. The median initial radiation dose was 67 Gy, and the median reirradiation SRS dose was 30 Gy (21–35 Gy) in 2–5 fractions.

Results

Median follow-up for surviving patients was 16 months. Fifty-six patients were evaluable for response: 30 (54%) had complete, 15 (27%) had partial, and 11 (20%) had no response. Median overall survival (OS) for all patients was 12 months. For definitively treated patients, the 2-year OS and locoregional control (LRC) rates were 41% and 30%, respectively. Multivariate analysis demonstrated that higher total dose, surgical resection, and nasopharynx site were significantly associated with improved LRC; surgical resection and nonsquamous histology were associated with improved OS. Seven patients (11%) experienced severe reirradiation-related toxicity, including one treatment-attributed death.

Conclusion

SRS reirradiation for head-and-neck cancer is feasible. This study demonstrates encouraging response rates with acceptable toxicity. Fractionated SRS reirradiation with concurrent chemotherapy in select patients warrants further study.
 
From May 2002 to January 2008, 65 consecutive patients were treated with SRS at Georgetown University Hospital for recurrent, second primary, or persistent cancers of the head and neck after previous radiation therapy. The CyberKnife SRS system uses a 6-MV X-band linear accelerator mounted on a fully articulated robotic arm. Patients were immobilized in the supine position with an Aquaplast facemask (WRF/Aquaplast Corp., Wyckoff, NJ). All patients underwent a treatment planning computed tomography (CT) scan, fused with a fluorodeoxyglucose-positron emission tomography (FDG-PET) scan with 1.0-mm-thick slices. If appropriate, magnetic resonance imaging (MRI) scans were also used in planning. The clinical tumor volume (CTV) consisted of gross disease with an expansion of 2–10 mm at the discretion of the treating physician. No additional margin was added for the planning target volume (PTV). In 13 cases, adjacent soft tissue and immediate draining lymph nodes were targeted as a separate PTV. In patients who underwent complete surgical resection, the PTV encompassed the entire surgical bed when feasible. The standard dose and fractionation scheme was 30 Gy in 5 fractions; however, this was individualized by the treating physician.