Speech and swallowing following tongue cancer surgery and free flap reconstruction--a systematic review

This was a systematic review of the current research on speech and swallowing outcomes and the factors affecting these outcomes after primary resection of tongue cancer and free flap reconstruction. A structured search in various electronic databases and relevant journals was performed. Retrieved articles were critically appraised in three rounds according to the level of evidence, the methodological quality, and the specific domain of speech and swallowing. A total of 21 articles were in the final review and the findings were categorized according to the area of tongue resection. For patients with resection and free flap reconstruction limited to either the oral tongue or the base of tongue (BOT), significant decline in speech and swallowing function was evident in the early postoperative phase, but the majority recovered close to preoperative level after 1 year. Poorer speech and swallowing outcomes were found following resections involving both oral and base of tongue (OBOT) regardless of the type of free flap reconstruction. Results overall were influenced by multiple factors including tumor size, area of resection, method of reconstruction and the use of adjuvant therapy. The use of free flaps in the immediate reconstruction of the tongue after tumor resection should aim at the maintenance of the mobility of the residual tongue and restoration of tongue bulk in order to optimize the recovery of speech and swallowing function. Future research in this field should employ standardized and reliable evaluation of speech and swallowing outcomes using multiple modalities in well-designed cohort studies with longer follow-up.