Diagnostic accuracy of both approaches
The Cohen kappa index for agreement was calculated to evaluate agreement
between the trans-oral approach and direct laryngoscopy methods,
accounting for possible random agreement. The value (k = 0.79) indicated
fair agreement between them. Also, the Cohen kappa index for agreement
was calculated to evaluate agreement between the trans-nasal approach
and direct laryngoscopy methods, accounting for possible random
agreement. The value (k = 0.14) indicated low agreement between them.
To calculate the sensitivity and specificity of the trans-oral approach
and the trans-nasal approach in the diagnosis of malignant laryngeal
lesions, we divided the biopsy results into two groups: (1) benign
lesions or inflammatory condition and (2) invasive carcinoma.
The sensitivity of trans-oral approach biopsies compared with that of
direct laryngoscopy biopsies was 95.8% and the specificity was 83.3%,
with a diagnostic accuracy of 93.3%.
The sensitivity of trans-nasal approach biopsies compared with that of
direct laryngoscopy biopsies was 26.3% and the specificity was 90.9%,
with a diagnostic accuracy of 50.0% (Table 2).
Discussion
Without doubt taking a biopsy via direct laryngoscopy in an operating
room under general anesthesia is the gold standard for diagnosis of
malignancy of the upper aero-digestive tract. However, with the
improvement of the technology of endoscopy, that enabled surgeons to
search for the use of office-based procedures via trans-oral or
trans-nasal approaches for taking these biopsies without the need for
general anesthesia and an operating room. [7]
This current cross-sectional study aimed to compare the diagnostic
accuracy of trans-oral and trans-nasal office-based laryngeal biopsies
against the direct laryngeal biopsies in operating room. The Cohen kappa
index for agreement was calculated to evaluate agreement between each
diagnostic approach the gold standard approach. The results of this
study showed that the trans-oral approach has a higher Chohen kappa
index (0.79) than the trans-nasal approach (0.14). Also, it has got
higher diagnostic accuracy (93.3%) than the trans-nasal approach
(50.0%).
The sensitivity of trans-oral approach biopsies compared with that of
direct laryngoscopy biopsies was 95.8% compared to 26.3% sensitivity
of trans-nasal approach. On the other hand, the specificity was 83.3%
& 90.9% for trans-oral and trans-nasal approaches, respectively. Both
approaches were tolerated by all patients with very few post-procedural
complications.
According to Cohen et al. (2013 & 2014) the specificity of
trans-nasal-laryngoscope in diagnosing invasive carcinoma is excellent
(96% & 96.6%), but the sensitivity of diagnosing a suspicious lesion
as being carcinoma in situ or invasive carcinoma is only 69.2% &
70.6% sensitivity. In retrospective analysis, some studies reported
somewhat different results as 60% sensitivity and 87% specificity.
[8-11]
In a retrospective analysis of consecutive 581 cases, office‐based
biopsies via trans-nasal approach for laryngeal lesions were evaluated
by Cha et al. (2016) and the results showed sensitivity of 78.2% and a
specificity of 100.0%. However, and unlike our study, not all the cases
have a confirmatory direct operating room laryngeal biopsy which is the
gold standard. [12]
The higher diagnostic accuracy and sensitivity of the trans-oral
approach in the results of our study is in accordance with the study ofHassan et al. (2018) which showed a 100% sensitivity and 75.6%
specificity. [13]
Healing after office-based superficial laryngeal biopsies generally
takes places very quickly and voice rest is not typically required after
the procedure [14]. Our study showed very few post-procedural
complications in both approaches as well as good tolerance of patients
which is in agreement with other studies. [4, 6, 15]
However, it was reported by Shah and Johns (2013) that the
trans-oral approach can be difficult to perform and is not well
tolerated by some patients. On the other hand, Trans-nasal is generally
better tolerated by most patients. [14]
In the current study the number of biopsies obtained was significantly
higher in the trans-oral group than in the trans-nasal group. Also, the
time needed for the procedure was insignificantly less in the trans-oral
group than in the trans-nasal group. The sizes of obtained biopsies were
comparable between groups.
Trans-nasal is often not advisable, as false-negative results are
possible because of the small size of the biopsy forceps [14].
However, in exophytic lesion it was easier to biopsy than in ulcerative
lesions; also, tumors whose surface was perpendicular to the endoscope
were easier to biopsy than tangential tumors. [16]
From our experience, as regard the visualization, the trans-nasal
approach is more applicable and easy for the patients but need
assistance; however, the trans-oral approach may increase the gag reflex
but does not need assistance. Also, we found that the trans-oral
approach was better than the trans-nasal approach as regard the number
of obtained biopsies.
Finally, we found that the combination of trans-nasal visualization,
trans-oral approach of obtaining the biopsy and the transcricothyroid
anesthesia was the best one in our practice.