13 Head and Neck - Oropharynx

Head and Neck - Oropharynx

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THE GEC ESTROHANDBOOKOF BRACHYTHERAPY | Part II Clinical Practice Version 1 - 15/02/2021

6. INDICATIONS, CONTRA-INDICATIONS

• Fibro-optic endoscopic evaluation of swallowing may be considered if facilities are available as oropharyngeal cancer and treatment can have impact on the swallowing. • PreRT video-fluoroscopic evaluation may also be considered for swallowing assessment if facilities are available. • Dietician evaluation and diet plan is necessary so as tomaintain the nutrition during the treatment. • Pre-anaesthetic evaluation for general anaesthesia for BT should be done. Staging of carcinoma of the oropharynx should be done as per the UICC TNM staging 8th edition [4]. For the first time different staging system for a single subsite has been adopted.The preference of HPV for the oropharynx may be related to the presence of transitional mucosa in the oropharynx similar to the cervical mucosa [22]. Another possibility lies in the genetic features of HPV16 whichmay facilitate its survival in the tonsillar crypts [23] . The differences in the prognosis of HPV positive and negative oropharyngeal cancers has led to the change in the UICC TNM staging. The details of TNM staging for HPV negative and HPV positive tumours is as shown in Table 1 and table 2 .

Tumours of up to 5 cm can be considered for BT. Due to the high propensity of nodal involvement the vast majority of the tumours are considered for combined EBRT with BT approach. Radical BT alone is considered for small up to 1 cm tumours of tonsil, soft palate and uvula [24]. All other tumours are considered for combined EBRT and BT. Generally BT is considered for patients with N0-1 nodal status. In situations where patients with bulky nodes are considered for BT, the neck has to be addressed with surgery after EBRT. Patients who are considered for a combined EBRT and BT approach receive EBRT first. Typically, the primary target and bilateral nodal volumes are treated to a dose of 46-50Gy in conventional fractionation. IMRT is the preferred modality for EBRT [25,26]. Small T1 lesions of tonsil and lateralized tumours of soft palate can be considered for ipsilateral nodal irradiation [27,28]. Attempts should be made to keep the overall treatment time similar to that of EBRT alone.

Figure 2: Clinical diagram showing 3x2.5 cm ulcero-proliferative growth involving left tonsil, anterior and posterior tonsillar pillar extending superiorly to soft palate just short of midline, uvula uninvolved. No neck nodes. Diagnosis: Ca Tonsil T2N0M0

Figure 3: Radio-opaque markers 0.6mm diameter and 2mm length used for marking 4 corners of the tumour

Figure 4a: Clinical photograph of a patient with carcinoma of uvula considered for radical brachytherapy

Figure 4b: Clinical photograph of a patient with carcinoma of right tonsil T1N0 M0 considered for brachytherapy