Stereotactic Body Radiation Therapy for Pulmonary Oligometastasis from Head and Neck Cancer: The Potential Survival Benefits from PD-1 Inhibitors

Abstract

Objective: Stereotactic body radiotherapy is suitable for most pulmonary oligometastasis, but there is little data that reported the different values of SBRT combined with systemic therapy between NP and non-NP cancers. Method: This was a retrospective study on patients with pulmonary oligometastatic HNC treated with SBRT at Zhejiang Cancer Hospital. Main Results: A total of 43 patients with 65 pulmonary metastatic lesions were included in the study.24 cases originated from NP cancer, and 19 originated from non-NP cancer. The median follow-up time was 29.7 months. The 1-year local control rate was 95.4%, and 3-year PFS and OS2 were 68.7% and 46.0% in the whole group. Subgroup analysis showed local control rates were 95.1% and 95.8% in the NP group and non-NP group (p=1.000). Median PFS times were 47.0 months and 13.3months (p=0.006), and 3-year OS2 was 87.1% and 47.9% in the two groups (p=0.011). Primary tumor location, time to metastasis, number of pulmonary lesions, BED, and systemic therapy were found to be significant predictors for PFS and (or) OS2 in univariate analysis. Systemic therapy and the number of pulmonary lesions were maintained in Cox regression analysis. No SBRT-related toxicity above grade 3 was observed. Conclusion: SBRT is an effective and tolerable therapy for patients with pulmonary oligometastasis from HNC. On the basis of systemic treatment, radical curative-intent with SBRT could be achieved in selected HNC patients.