11 Lip and buccal mucosa

Lip and buccal mucosa

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THE GEC ESTROHANDBOOKOF BRACHYTHERAPY | Part II Clinical Practice Version 1 - 10/05/2019

the upper limits are the naso-labial groove at the skin and the gingivo-labial groove at the mucosa side; the lower limits are the mento-labial and the lower gingivo-labial groove. Its lymphatic drainage goes to the sub-mental, sub-mandibular and sub-digastric lymph nodes. The submandibular nodes are the most frequently involved (level IA and IB). In a study of 617 patients, the lymph node involvement was 7.9% in T1-2 and 27.9% in T3-4 [5]. All patients affected with tumours reaching the median line are at high risk for bilateral nodal involvement. The buccal mucosa is bounded by the lower and upper gum sulcus; the lip commissure constitutes its anterior limit; the posterior limit is the intermaxillar commissure and the retromolar trigone [6]. Lymphatic drainage is to the submandibular nodes or directly to the jugular nodes (level IB- IIA). Nodal involvement is found at the time of initial diagnosis in about 40% of patients. Critical organs for both, lip and cheek, are the mandibular bone, the gingiva and the tongue, but also, in the case of very infiltrating tumours, soft tissues such as muscles and skin [7-8]. The ease of brachytherapy depends on the exact position in the cheek and the commissure involvement. Most lip cancers are squamous cell cancers (90%). The remaining 10% are basal cell cancer (starting from the cutaneous area). Sarcomas, adenoid cystic carcinoma, melanomas are very rare. Pre-cancerous conditions, such as actinic cheilitis, leucoplakia, Bowen’s disease, are frequently associated. They often constitute a diagnostic and an additional therapeutic problem. In general these associated lesions can be adequately treated by radiotherapy but are a contraindication to limited surgery. Macroscopically, tumours may be exophytic, ulcerating, infiltrating or nodular or any combination. In buccal mucosa cancers, most tumours are squamous cell carcinomas. Other histopathological types are: glandular carcinomas, non-Hodgkin lymphomas, melanomas. Precancerous lesions are observed in one third of patients [6-9]. 4. PATHOLOGY

are often poorly defined. Associated lesions are far from rare and should actively be sought for and noted as well. Detailed drawings or photographs will help to document the exact size and localisation. From every tumour and any suspected extension adequate biopsies should be taken. For buccal mucosa tumours, clinical symptoms are discomfort, mass, pain, trismus, neck node [6]. The work-up is comparable to other cancers of the oral cavity, but the particular carcinogenetic and epidemiological factors must be evaluated [7]. Because of the frequent association of malignant and premalignant tumours, the tumour site must be accurately described by diagrams, biopsies, ultrasound, CT scan and MRI [10-11]. Tumour must be staged, according to the TNM staging system. T1 ≤ 2cm, T2 >2 ≤4cm, T3 >3cm, T4a involvement of bone, floor of mouth, alveolar rim, skin of nose or chin. Lymph node involvement is rare but can be bilateral in lip cancers. A bi-digital palpation with a finger inside the mouth is necessary to better estimate the nature of submandibular lymph nodes. In case of clinical doubt, fine-needle aspiration is a simple procedure to assess involvement. A CT-scan is usually employed to identify lymph nodes, that have been reported in 2% of T1, 6% of T2 and 15- 30% of T3 cases [12]. Lymph node involvement is more frequent when there is tumour extension to the wet mucosa [13], to the skin, to the lateral commissure and in tumours greater than 2cm, and an elective treatment of the neck should be considered in these cases [14]. The sentinel node technique is a good option for T1 to T2 tumours [15]. For buccal mucosa tumours, lymph node extension is unilateral. Lip cancer can be treated with brachytherapy in over 90% of cases, depending on the tumour size. A simple surgical wedge excision is indicated for superficial, small tumours less than 0.5 cm in their major axis. Different techniques of wedge surgery are currently being used, but the local recurrence rate, varies between 10 and 30% according to different authors [16-17]. Larger tumours (over 5 cm in their major axis) are treated by external beam radiation followed by brachytherapy, or surgical excision followed by reconstruction surgery with an Abbe-Estlander lip flap rotation or derived techniques. Tumours invading adjacent bone usually require surgery if feasible. All other cases of lip carcinoma from T1 to T3 can be successfully managed with brachytherapy alone. Postoperative brachytherapy is indicated after surgery with a positive or close margin or perineural involvement, at lower total doses, but may result in functional compromise due to previous surgery, and should include the whole surgical scar. For lesions of the anterior and central part of the buccal mucosa, interstitial brachytherapy is strongly indicated, for tumours < 40 mm, well-defined, located in the anterior two thirds of the buccal mucosa without involvement of the gingiva or intermaxillary commissure. For tumours ≥ 40 mm, or tumours involving the 6. INDICATIONS, CONTRA-INDICATIONS

5. WORK UP

An accuratemedical examination should always include a systematic examination of the head and neck region, of the skin and teeth as well as X-rays of chest andmandible when indicated. It is mandatory to carefully inspect and palpate the tumour area and the whole affected lip, the other lip and the commissural areas. The tumour itself may be exophytic, nodular, ulcerated, or infiltrating. These forms can sometimes co-exist. The size (inmm) and site of the tumour: (cutaneous lip, vermilion, wet mucosa), invasion of lip muscles or commissura should be carefully assessed and noted. Any infiltration of the wet mucosa significantly increases the risk of nodal metastases. Lip cancers