Objective: Salivary duct carcinoma (SDC) is highly aggressive, with high rates of recurrence and nodal and distant metastases. The aim of the current study was to evaluate the clinical implication of EGFR and HER2 expression for predicting prognosis and to identify the factors associated with outcome.
Methods: The medical records of 28 patients with SDC underwent surgery and adjuvant RT. Expression of c-erbB-2 and EGFR was determined immunohistochemically on the 25 SDC specimens. Disease-free survival (DFS), overall survival (OS) and distant metastasis-free survival (DMFS) were analyzed.
Results: Three-year DFS, OS and DMFS rates were 38.3%, 78.1% and 45.7%, respectively. Expression of c-erbB-2 and EGFR was seen in 64% and 40%. c-erbB-2 and EGFR expression did not correlate with recurrence or metastasis. Advanced N classification and perineural invasion (PNI) were significant predictors of DFS and DMFS.
Conclusion: c-erbB-2 and EGFR expression did not correlate with recurrence or metastasis. Despite aggressive surgery and RT, approximately 50% of SDCs failed systemically. More effective therapy to inhibit distant metastases in patients with advanced N classification and PNI should be considered.
Keywords: Distant metastasis; EGFR; Radiotherapy; Salivary duct carcinoma; c-erbB-2.
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