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.