<div>Key Points:</div><div>1. The current research is the first to present combined data concerning
the alterations in structure and vascularisation of fPap with respect to
the variations in EGM-thresholds in HNC patients when they are receiving
radiochemotherapy as well as after the treatment.</div><div>2. Patients experience a deterioration in taste acuity when they are
receiving radiochemotherapy and after the treatment.</div><div>3. Taste disorders associated with chemotherapy have a multifactorial
aetiology.</div><div>4. There is not an improvement in EGM-thresholds concurrently with the
morphology and vascularisation of fPap.</div><div>5. As a result of the limited number of studies, it is challenging to
make suitable recommendations concerning diagnosis, therapy, and the
expected development of taste deterioration in oncology environments.</div><div>Keywords: Contact endoscopy; radiochemotherapy; electrogustometry;
fungiform papillae; vascularisation, taste.</div><div>Introduction</div><div>When chemotherapeutic (CT) drugs are systemically administered, this can
frequently lead to serious acute adverse impacts. For instance, as a
result of their cytotoxic effects and suppression of the immune system,
patients may become more susceptible to oral mucositis and bleeding as
well as a reduction or impairment of salivary gland function or oral
infections [1,2]. Furthermore, as many as 89% of patients with head
and neck cancer (HNC) experience taste dysfunction prior to being
treated because of the malignancy [1].</div><div>After receiving radiation therapy (RT), alterations to taste could
persist as a result of hyposalivation and damage to the cellular taste
receptors [3]. A patient’s taste recovery after receiving treatment
can vary between 2 and 6 months subsequent to oncologic therapy,
although it may persist for an extended period [4,5].</div><div>Hence, this study aimed to evaluate the electrogustometric thresholds
and related alterations of form in addition to the vascularisation of
the tongue mucosa in patients with tonsillar squamous cell carcinoma and
RCT.</div><div>Method</div><div>To reach this aim, a total of 20 patients with HNC receiving
electrogustometry (EGM) treatment along with contact endoscopy were
recruited (after obtaining approval from the local ethics committee as
well as informed consent from all patients). In particular,
EGM-thresholds, vascularisation of the end of the tongue, as well as
fPap morphology were measured. Prior to starting the therapy, baseline
(initial) measurements were made; subsequently, the second set of
measurements were made after the initial CT had been completed, followed
by the third measurements a week after the second CT cycle had been
completed. Additionally, we scheduled follow-up measurements that would
be performed in the 2<sup>nd</sup> and 4 months post-RCT. Every
patient included in the evaluation received concurrent RCT (cisplatin,
5-FU) treatment as a result of the diagnosis of malignancy in the
tonsils. The primary tumour was targeted with a dose of radiation
varying between 50.4 Gy and 72 Gy. CT was delivered in 2 cycles (each
with a duration of 1 week).</div><div>EGM was conducted according to previous reports using a single, flat,
circular stainless-steel stimulus probe (with a diameter of 5mm)
[6]. The device generates low-amplitude stimuli with a fixed time
period (0.5, 1, 1.5, and 2 seconds). The output current is controlled by
a feedback circuit where the error is &lt; 1%. Measurements of
the electric threshold scores were performed at six sites: the vallate
papillae on either side of the tongue, innervated by the
glossopharyngeal nerve, para-medially on either side of the tongue (both
2cm from the end), at an area innervated by the chorda tympani as well
as the soft palace, innervated by the greater petrosal nerve
bilaterally.</div><div>A non-contact method was firstly used to identify fPap. Subsequently,
contact endoscopy was conducted utilising a 30° contact endoscope
(magnification × 60 and × 150; Karl Storz, Tuttlingen, Germany).
Patients were asked to rinse their mouth with water prior to the contact
endoscopy. A contact method was firstly utilised with no staining in
order to image the subepithelial vessels. Once the saliva had been
carefully suctioned, the epithelia and taste pores were stained with
methylene-blue 1% solution. A strip of filter paper covering an area of
1 cm<sup>2</sup> was situated in a paramedian orientation on the
tip of the tongue. Heat at the end of the endoscope was minimised using
a cold source of light. CE examinations did not reveal any changes
(increases of decreases) in vascularisation.</div><div>The fungiform papillae form was categorised into four different types in
increasing order of damage: Type 1, (egg-shaped or long ellipse type –
with no surface thickness), Type 2 (surface thickness is slightly more
than Type 1), Type 3 (surface is thicker with increased irregularity),
and Type 4 (surface is notably flat and shows signs of atrophy). It is
important to note that papillae with a mushroom form and horned tips
were categorised as filiform rather than fungiform papillae. As a result
of their minimal level of staining, it was relatively easy to
differentiate fungiform papillae from filiform papillae, as their
staining was darker.</div><div>The morphology of the blood vessels at the end of the anterior tongue
apex was classified based on the classification of Negoro et al.
[7]. Five types of morphology were found for the vessels,
categorised in increasing order of morphological changes: Type A (clear
loop and wooden branch shape), Type B (clear loop and wooden branch
shape), Type C (stretched blood vessels), Type D (dotted or granular
shape), and Type E (unclear blood vessels).</div><div>For the purpose of statistical analysis, where it was not possible to
measure the EGM-threshold, a numerical value of 36 dB was assigned. IBM®
SPSS®Statistics 26.0 software was used and significance level was fixed
at p &lt; 0.05. STROBE statement was followed as reporting
guideline for this study.</div><div>Results</div>