Purpose: To determine whether radiation-induced fibrosarcoma (RIF) in patients with a history of radiotherapy for nasopharyngeal carcinoma (NPC) was associated with an inferior prognosis compared to sporadic fibrosarcoma of the head and neck.
Methods: Forty-two patients with RIF who previously received radiotherapy for NPC and 124 patients with sporadic fibrosarcoma of the head and neck were identified between January 1965 and December 2013 at our institution. Information on clinicopathologic characteristics and treatment was abstracted from medical records. The primary end point was disease-specific survival (DSS).
Results: The median latency from NPC diagnosis to RIF diagnosis was 9.9 years (range 3.1-36.8 years). RIF was diagnosed at an older age than sporadic fibrosarcoma. Treatment modality was significantly different between the two groups, with only 64.3 % of the RIF group receiving surgery ± adjuvant treatment versus 91.1 % in the sporadic fibrosarcoma group (P < 0.001). Patients with RIF had poorer 5-year DSS compared to the sporadic fibrosarcoma group (36.2 vs. 50.4 %; P = 0.026). Multivariate analysis of the combined group indicated that patient group (P = 0.032), tumor, node, metastasis classification system stage (P = 0.019), histologic grade (P = 0.046) and treatment modality (P < 0.001) were independent variables affecting DSS.
Conclusions: Compared to patients with sporadic fibrosarcoma, NPC survivors who develop RIF are older at diagnosis of fibrosarcoma and have an inferior prognosis.