In Reply to Mitomycin‐C Is Ineffective in Laryngotracheal Surgery If Used Incorrectly

Abstract

He notes that we cannot conclude that mitomycin C (MMC) has no additional benefit in the management of laryngotracheal stenosis (LTS) because it was used in a conceptually incorrect manner, and that MMC should "be applied in a second stage surgery, approximately 1 week after making the surgical wound." We agree that the ideal timing of MMC application has not been fully investigated. However, application at the time of initial surgery, as was performed in our study, is standard procedure and is supported in animal models.We disagree with the statement that there are "almost no fibroblasts" in wounds prior to the proliferative phase. The correspondence cites a study that does not discuss the concentration of fibroblasts in tissue. The cited study describes MMC effects in cell culture. 2 Regardless of the cellular composition of tissue and our conceptual understanding of healing, in vivo models show that MMC results in lasting local tissue effects despite application prior to the proliferative phase. MMC application at the time of surgery in rabbits resulted in inhibited fibroblast outgrowth 3 and decreased cellular division up to 4 weeks after surgery. 4 In clinical practice, MMC is applied at the time of surgery in pterygium excision, 5 glaucoma surgery, 6 corneal refractive surgery, 7 esophageal stricture dilation, 8 and anal stricture dilation. 9 Similarly, the vast majority of otolaryngology literature, including those studies reporting efficacy with MMC use, describe its application at the time of initial surgery, 10-13 with just two exceptions: One randomized trial compared MMC application once versus twice in a series of staged dilations and found no difference in restenosis rates at 5 years. 14 Described three patients who received an application of MMC in-office 1 week after surgical dilation. The study's intention, however, was to report a technique to "facilitate the study of the ideal timing of topical MMC" rather than to support delayed application. Notably, all three patients required repeat surgeries at unreported intervals despite delayed MMC application. 15 In our study, it would have been more precise to conclude that the use of MMC in the standard manner has no additional benefit in the endoscopic treatment of LTS.It is possible that a different dose or timing of MMC application may show benefit; however, to our knowledge there currently are no well-designed studies that support this hypothesis.

Use of Mitomycin-C in Laryngotracheal Stenosis

“…The conventional approach is to perform the application immediately after the wound is formed from the initial incision and dilation. 35 However, some authors have argued that delaying the time to MMC use based on the phases of wound healing is potentially more efficacious. 36,37 These 4 partially overlapping phases include hemostasis, inflammation, proliferation, and maturation.…”

“…There is debate about the ideal timing of MMC use in airway stenosis. The conventional approach is to perform the application immediately after the wound is formed from the initial incision and dilation 35 . However, some authors have argued that delaying the time to MMC use based on the phases of wound healing is potentially more efficacious 36,37 .…”