ANALYSIS OF THE PATTERNS OF CERVICAL LYMP H-NODE METASTASES IN OROPHARYNGEAL CARCINOMAS IN RELATION TO THE EXTENSION OF THE PRIMARY TUMOR

To assess the incidence and patterns of cervical lymph node involvemen t according to the location and the relation of the primary tumour to the parapharyngeal fasciae, compartments and tissues arising from diff erent branchial arches. Patients and Methods: The findings of clinical and CT examinations of 143 patients with histological evidence of oro pharyngeal carcinoma were evaluated retrospectively. Local tumour spre ad, relation of the primary to the parapharyngeal fasciae, compartment s and to the borders of tissues arising from different branchial arche s were analysed and related to cervical lymph node involvement. Result s: Lymph drainage of the oropharynx and neighbouring neck regions is d eterminated by the embryological development of the branchial arches a nd somites. Oropharyngeal carcinomas are tumours arising from tissues of the 2 nd and 3 rd branchial arches. The lymph of these tissues is c ollected by the vessels of the jugular neck node chains. If tumour inv ades tissues arising from the 1 st branchial arch (structures of the o ral cavity and floor of the mouth) tumour spreads into the ipsilateral lymphatic vessels arising from the 1 st branchial arch and the submax illary lymph nodes. If tumour invades tissues arising from occipital a nd cervical somites (posterior wall of the nasopharynx, retropharyngea l compartment and recessus submuscularis) metastases in the retrophary ngeal and spinal-accessorial lymph nodes may appear. Regarding the tum our invasion of the subdistricts of the oropharynx totally different t umours were found. Tumour invasion of neighbouring structures was docu mented for the nasopharynx in 15%, for oral cavity and the floor of th e mouth in 34%, the larynx in 24% and the hypopharynx in 22% of the ca ses, From these different patterns of local tumour spread different pa tterns of lymph node involvement resulted. Nodal involvement was found in 71%. In all these cases metastases in the ipsilateral upper jugula r lymph nodes were present. The frequency of metastases in the jugular lymph node chains decreased in cranio-caudad direction (upper jugular group 100%, middle 18%, lower jugular group 5%). The frequency of bil ateral jugular lymph node involvement (25%) increased in the some meas ure as the tumour approached the midline or crossed it. Conclusions: K nowledge of regular patterns of spread of oropharyngeal carcinoma is i mportant for treatment procedures, especially for 3-dimensional radiot herapy.