Does Water Irrigation Control Pleomorphic Adenoma Cell Growth Better Than Saline?

Objective: Sterile water irrigation is anecdotally noted as a method to lyse pleomorphic adenoma (PA) cells in the surgical bed and reduce the rate of recurrence if the tumor is ruptured. Surgeons often presume that the hypotonicity of water lyses residual tumor cells in the surgical bed; however, its effect on the viability of tumor cells remains unclear. This study aims to determine if water causes increased tumor cell death compared to saline. Study Design: Prospective, laboratory-based study. Setting: Tertiary academic center. Methods: Surgically resected PA biospecimens were processed into a single-cell suspension and made into cell lines. Cells were exposed to sterile water or saline for 5, 10, or 15 minutes at room temperature (26°C), 37°C, or 44°C. After exposure, samples were analyzed for cell death by flow cytometry. Additional tumor cells were cultured after saline or water exposure to assess proliferation by tracking time to confluence. Three additional tumors were exposed to water or saline immediately after processing into cell suspensions, then cultured to determine time to confluence. Results: Exposure of PA cells to water induced cell death and prevented cell proliferation in vitro. Higher water temperatures and longer exposure times further reduced cell viability in one cell line. Conclusion: Study findings support the anecdotal claims that water irrigation can reduce the recurrence of PAs by increasing tumor cell lysis and suggest that the use of water irrigation might help to eliminate residual disease in the surgical bed. Further investigation is needed to confirm these results.