DISCUSSION
The optimal treatment for early-stage glottis cancer must include accurate evaluation of the range of the cancer, multidisciplinary consultation, consideration of patient expectations, analysis of surgical pattern, and expertise in surgical techniques [16]. Voice quality is also an important consideration. In this study, we reviewed 93 patients with stage T1 glottis cell carcinoma who received RFA endoscopic surgery or open surgery, 52 of whom had anterior commissure invasion.
Our open surgery and RFA groups had similar OS, although the 5-year DFS was better in the open surgery group. This outcome was comparable to previous studies [9,17,18]. More specifically, Zhang et al. [17] conducted a single-blind randomized clinical study that compared treatment of stage T1a glottis cancer using RFA and a CO2 laser, and reported a 3-year OS of 96%, similar to our result. Shuang et al. [9] performed a retrospective study and reported the local recurrence rate in patients with anterior commissure involvement who received RFA was 31.2%, also comparable to our results (32.4%). Philipp et al. [18] compared the oncological results of open surgery and trans-oral laser micro-resections (TLM) in patients with early-stage glottis squamous cell carcinoma. The local recurrence rate was 20.4% (10 of 49) for TLM and 10.7% (3 of 28) for open surgery. Similarly, our results indicated that open surgery provided a reduced recurrence rate. However, the considerable disadvantages associated with open procedures must be considered, especially poor preservation of voice quality, increased risk for complications, and greater costs.
Previous researchers have considered tumor involvement of the anterior commissure as an important parameter affecting the oncologic outcomes of patients with early-stage glottis carcinoma. However, we found that the impact of anterior commissure involvement had no significant impact on outcome, in contrast to several previous studies [18, 19, 20]. In particular, a recent study of 130 patients who received radiation therapy for stage T1/2/N0 glottis tumors reported that anterior commissure involvement was the main factor affecting local control [19]. Wolber et al. [18] compared patients who received trans-oral laser micro-surgery or open surgery and found a significant difference in local recurrence rate only for tumors invading the anterior commissure; based on endoscopy, the recurrence rate of tumors with involvement of the anterior commissure was 38.1%, but the recurrence rate without involvement was 7.1%. Steiner et al. [20] reviewed 263 patients with stage T1a, T1b, or T2a glottis lesions and reported that local recurrence was more common if there was initial involvement of the anterior commissure (14% in T1a tumors with involvement vs. 5% in T1a tumors without involvement).
There are several possible explanations for our discrepant results. First, we used a 0- and 70-degree endoscope and had the advantage of an RFA cutting blade that could be bent and provide better exposure in the laryngoscope. There is good evidence that tumors with involvement of the anterior commissure can be treated effectively using endoscopy. For example, Peretti et al. [21] reported that an adequately designed laryngoscope optimizes effective surgery in this region when the patient is placed in the Boyce-Jackson position and multiple perspectives of the lesion can be provided at 0°, 30°, 70°, and 120°. Besides, resection of the anterior portion of the false vocal cords can provide better visualization of the anterior commissure and allows evaluation of tumor invasion of the underlying cartilage framework . RFA also has a hemostatic function, making the operation field very clear [17]. Second, to reduce the risk of positive margins, some surgical teams use frozen section analysis [22, 23]. Surgeons in our study also maintained a safe margin during surgery especially when anterior commissure was invaded, because we believed that tumor involvement of the anterior commissure was an important parameter affecting oncologic outcome of these patients.
As mentioned above, the preservation of voice quality is also an important consideration. Our analysis of vocal outcomes indicated that open surgery led to poorer voice quality than RFA. Our further analysis of the open surgery group indicated that patients who had anterior commissure invasion had poorer vocal outcomes than those without invasion, similar to the results of Taylor et al. [24]. The poorer vocal outcome in these patients is due to the extended resection and injury to both vocal folds. A study by Demir et al. [25] compared voice-related quality of life for patients treated by RFA, CO2 laser, and radiation. Their RFA group had the worst voice outcome, and the CO2 laser and radiation groups had comparable outcomes. To our knowledge, no previous study has directly compared the VHI-30 scores of patients who received open surgery or RFA.