Outcomes and Prognostic Factors of Post-irradiation and de novo Sarcomas of the Head and Neck: A Histologically Matched Case-Control Study

Background This study was designed to compare post-irradiation sarcomas (PIS) and de novo sarcomas (DN) of the head and neck in terms of tumor characteristics, prognostic factors, and survival outcomes. Methods All ( N = 83) head and neck sarcoma patients treated at National Cancer Centre, Singapore (Feb 2002–May 2011) were included: DN ( N = 60; 72 %); PIS ( N = 23; 28 %). Clinicopathologic features and outcomes of all patients and histologically matched pairs were compared. Prognostic factors were identified using univariate and multivariate analyses. Results Median age, gender, smoking status, and tumor size were not significantly different. Significant differences were seen in histology (most prevalent: PIS–sarcoma-NOS; DN–angiosarcoma) and tumor subsite (most prevalent: PIS–nasal cavity and sinuses; DN–skin). Median latency of PIS development was 16.7 years. PIS patients had shorter overall survival (OS) and disease-specific survival (DSS) compared with DN patients, most clearly seen on histologically matched pair analysis: 2-year OS (PIS: 54 %; DN: 83 %; P = 0.028). Multivariate analyses showed that age >50 years (hazard ratio (HR) = 3.68; P = 0.007), ever-smokers (HR = 2.79; P = 0.017), and larger tumor-size (cm) (HR = 1.12; P = 0.045) were associated with worse OS, and age at >50 years (HR = 2.77; P = 0.04) and ever-smokers (HR = 2.94; P = 0.021) were associated with worse DSS. When treated with curative intent, no significant survival difference was noted between DN and PIS patients. Conclusions In our cohort, PIS constituted 28 % of head and neck sarcomas. Poorer prognosis traditionally associated with PIS compared with DN was not seen amongst patients treated with curative intent.