1、Characteristics of the Patients
As shown in Table1, there were 179 males and 3 females with an average age of 63.19 years. The follow-up time was in the range of 371-3939 days, with an average follow-up time of 1748.6 days. The baselines of the two groups were basically the same. For laryngoscopy mirror group, there were 26 cases, 59 cases, 65 cases, and 21 cases in grades I, II, III, and IV, respectively. Eleven cases were lost during the follow-up (loss rate of 6%). All lost cases had metastasis or relapses, with 2 cases of TLM , 1 case death, and 1 case relapse; Nine cases had OPL, of which 2 cases of T1b death, 1 case of T1a and T2 death, and 5 cases of T1b relapse. None of the included cases received radiotherapy.
2、 Local control rate and disease-free survival rate of different airway classifications
As shown in Table2, among the 182 patients, the local control rates of MMT-Ⅰ, Ⅱ, Ⅲ, and Ⅳ patients 5 years post operation were 100%, 94.3%, 91.3%, and 84.2%, respectively. Based on the laryngoscope mirror classification the 5-year local control rates of I, II, Ⅲ and Ⅳpatients 5 years post operation were 100%, 95.0%, 93.5%, and 78.5%, respectively. The 5-year local control rate of Ⅲ and IV patients based on both classification methods was 88.8%. In terms of disease-free survival rates, the results were consistent with the above data. The higher the airway rating, the worse the local control rate.
Single indicator to assess the local control and disease-free survival rates of the two groups
MMT
As shown in Tables 3and 4 and Figure 1, no significant difference was found between the two groups in terms of the local control rates and disease-free survival rates of class I, II, or III patients according to the MMT. The 5-year local control rate of class IV patients was significantly different between the two groups (log-rank test: χ2=4.020, P=0.045). The local control rates of class IV patients in the OPL and TLM groups according to the MMT were 90.9% and 71.4%, respectively. The difference in disease-free survival between the two groups was similar to the difference in local control.
Table 2. Local control rates and Disease-free survival rates of different airway gradings (%).
|
TIME
|
|
Modified Mallampati Test
|
|
Indirect Laryngoscopy
|
|
United rating
|
|
Class I
|
Class II
|
Class III
|
Class IV
|
|
Grade I
|
Grade II
|
Grade III
|
Grade IV
|
|
DA1
|
DA2
|
DA3
|
DA4
|
TLM
|
1 year
|
|
100
|
97.3
|
98.8
|
100
|
|
100
|
100
|
96.9
|
100
|
|
98.6
|
100
|
92.3
|
100
|
|
3 year
|
|
100
|
94.3
|
94.7
|
91.8
|
|
100
|
98.2
|
93.5
|
78.5
|
|
92.6
|
100
|
92.3
|
97.9
|
|
5 year
|
|
100
|
94.3
|
91.3
|
84.2
|
|
100
|
95
|
93.5
|
78.5
|
|
88.8
|
93.3
|
92.3
|
97.9
|
OPL
|
1 year
|
|
100
|
97.3
|
98.8
|
100
|
|
100
|
100
|
96.9
|
100
|
|
98.6
|
100
|
92.3
|
100
|
|
3 year
|
|
100
|
94.3
|
94.7
|
91.8
|
|
100
|
98.2
|
93.5
|
78.5
|
|
92.6
|
100
|
92.3
|
97.9
|
|
5 year
|
|
100
|
94.3
|
91.3
|
84.2
|
|
100
|
95
|
93.5
|
78.5
|
|
88.8
|
93.3
|
92.3
|
97.9
|
Abbreviations: TLM, transoral carbon dioxide laser microsurgery; OPL, open partial laryngectomy. DA1 grades 3 and 4 were determined via indirect laryngoscopy and modified Mallampati test classes III and IV; DA2 grades 1 and 2 were determined via indirect laryngoscopy and modified Mallampati test classes III and IV; DA3 grades 3 and 4 were determined via indirect laryngoscopy and modified Mallampati test classes I and II; and DA4 grades 1 and 2 were determined via indirect laryngoscopy and modified Mallampati test classes I and II.
Table 3. Local control rates of different airway gradings between the two treatment groups (%).
|
TIME
|
|
Modified Mallampati Test
|
|
Indirect Laryngoscopy
|
|
United rating
|
|
Class I
|
Class II
|
Class III
|
Class IV
|
|
Grade I
|
Grade II
|
Grade III
|
Grade IV
|
|
DA1
|
DA2
|
DA3
|
DA4
|
TLM
|
1 year
|
|
100
|
100
|
94.87
|
100
|
|
100
|
100
|
96
|
100
|
|
96.77
|
100
|
100
|
100
|
|
3 year
|
|
100
|
83.3
|
83.95
|
72.92
|
|
100
|
94.12
|
85.87
|
54.69
|
|
75.47
|
100
|
100
|
92.31
|
|
5 year
|
|
100
|
83.3
|
83.95
|
72.92
|
|
100
|
94.12
|
85.87
|
- *
|
|
75.47
|
100
|
- *
|
92.31
|
OPL
|
1 year
|
|
100
|
96.55
|
100
|
100
|
|
100
|
100
|
97.5
|
100
|
|
100
|
100
|
90
|
100
|
|
3 year
|
|
100
|
96.55
|
94.96
|
100
|
|
100
|
100
|
97.5
|
91.67
|
|
97.14
|
100
|
90
|
100
|
|
5 year
|
|
100
|
96.55
|
94.65
|
90.91
|
|
100
|
96.55
|
97.5
|
91.67
|
|
97.14
|
91.67
|
90
|
100
|
Abbreviations: TLM, transoral carbon dioxide laser microsurgery; OPL, open partial laryngectomy. DA1 grades 3 and 4 were determined via indirect laryngoscopy and modified Mallampati test classes III and IV; DA2 grades 1 and 2 were determined via indirect laryngoscopy and modified Mallampati test classes III and IV; DA3 grades 3 and 4 were determined via indirect laryngoscopy and modified Mallampati test classes I and II; and DA4 grades 1 and 2 were determined via indirect laryngoscopy and modified Mallampati test classes I and II.
a Follow-up time of the study subjects did not reach the required time length.
Table 4. Disease-free survival rates of different airway gradings between the two treatment groups (%).
|
TIME
|
|
Modified Mallampati Test
|
|
Indirect Laryngoscopy
|
|
United Rating
|
|
Class I
|
Class II
|
Class III
|
Class IV
|
|
Grade I
|
Grade II
|
Grade III
|
Grade IV
|
|
DA1
|
DA2
|
DA3
|
DA4
|
TLM
|
1 year
|
|
100
|
97.37
|
100
|
100
|
|
100
|
100
|
96
|
100
|
|
96.77
|
100
|
100
|
100
|
|
3 year
|
|
92.86
|
86.16
|
72.92
|
72.92
|
|
100
|
94.12
|
85.87
|
54.69
|
|
75.47
|
100
|
100
|
92.31
|
|
5 year
|
|
92.86
|
86.16
|
72.92
|
72.92
|
|
100
|
94.12
|
85.87
|
- *
|
|
75.47
|
100
|
- *
|
92.31
|
OPL
|
1 year
|
|
97.92
|
100
|
100
|
100
|
|
100
|
100
|
97.5
|
100
|
|
100
|
100
|
90
|
100
|
|
3 year
|
|
97.92
|
92.46
|
94.12
|
100
|
|
100
|
100
|
97.5
|
91.67
|
|
97.14
|
100
|
90
|
100
|
|
5 year
|
|
97.92
|
92.46
|
85.56
|
90.91
|
|
100
|
96.55
|
97.5
|
91.67
|
|
97.14
|
91.67
|
90
|
100
|
Abbreviations: TLM, transoral carbon dioxide laser microsurgery; OPL, open partial laryngectomy. DA1 grades 3 and 4 were determined via indirect laryngoscopy and modified Mallampati test classes III and IV; DA2 grades 1 and 2 were determined via indirect laryngoscopy and modified Mallampati test classes III and IV; DA3 grades 3 and 4 were determined via indirect laryngoscopy and modified Mallampati test classes I and II; and DA4 grades 1 and 2 were determined via indirect laryngoscopy and modified Mallampati test classes I and II.
a Follow-up time of the study subjects did not reach the corresponding time.
Indirect laryngoscopy
As shown in Tables 3and 4 and Figure 2, there was no significant difference in the local control and disease-free survival rates between the two groups among grade I, II, and III patients according to indirect laryngoscopy at 5 years. However, the 5-year local control rates of patients with grade IV airways (indirect laryngoscopy) were significantly different between the OPL and TLM groups (log-rank test: χ2=4.076, P=0.044), with 5-year local control rates of 91.7% and 54.7%, respectively. The same pattern was observed for disease-free survival rates between the two groups.
Local control rate and disease-free survival rate based on a combination of indicators
As shown in Tables 3and 4 and Figure 3, when indirect laryngoscopy was combined with the MMT, there was no significant difference in the local control and disease-free survival rates at 5 years between class I/II and grade I/II patients. However, when grade III or IV patients according to indirect laryngoscopy were combined with class III or IV patients according to the MMT, the 5-year local control rate was significantly different between the OPL and TLM groups (97.14% vs. 75.47%, respectively; log-rank test: χ2=8.037, P=0.005). The results for disease-free survival rate were similar.
In the TLM group, when grade III or IV patients according to indirect laryngoscopy were combined with class III or IV patients according to the MMT, the 5-year local control rate was significantly different between the OPL and TLM groups (97.14% vs. 75.5%, respectively; log-rank test: χ2=4.028, P=0.045).
Correlation between indirect laryngoscopy and the MMT
Data analysis showed that there was a moderate correlation between indirect laryngoscopy and the MMT (r=0.646, P<0.05).