Outcomes and toxicities following stereotactic ablative radiotherapy for pulmonary metastases in patients with primary head and neck cancer

Background: Metastatic head and neck cancers (HNCs) predominantly affect the lungs and have a two-year overall survival (OS) of 15% to 50%, if amenable for pulmonary metastasectomy.

Methods: Retrospective review of the two-year local control (LC), local-regional control (LRC) within the same lobe, OS, and toxicity rates in consecutive patients with metastatic pulmonary HNC who underwent stereotactic ablative radiotherapy (SABR) January 2007 to May 2018.

Results: Evaluated 82 patients with 107 lung lesions, most commonly squamous cell carcinoma (SCC; 64%). Median follow-up was 20 months (range: 9.0-97.6). Systemic therapy administered in 34%. LC, LRC, and OS rates were 94%, 90%, and 62%. Patients with oligometastatic disease had a higher OS than polymetastatic disease, 72% vs 44% (HR = 0.30, 95% CI: 0.14-0.64; P = .008). OS in oligometastatic non-SCC and SCC were 100% and 66% (P = .03). There were no grade ≥3 toxicities.

Conclusions: Metastatic pulmonary HNCs after SABR have a two-year OS rate comparable to pulmonary metastasectomy.