Perineural invasion of the lower alveolar nerve by oral cancer: a follow-up study of 12 cases

Twelve previously untreated cases of oral cancer with perineural infiltration were studied retrospectively. Age, sex, site, clinical stage and outcome were evaluated. Management of the neoplasm in each case involved surgical removal and six patients required adjuvant radiotherapy, The most frequent site was the lip. At the time of diagnosis, five patients had sensory complaints and palpable lymphadenopathy was observed in three patients. The 5-year crude survival rate,vas 16.7%, In the cases with postoperative assessment of perineural infiltration, a median survival time of 30.8 months was observed; while in the case of preoperative assessment of nerve infiltration, extensive surgery was performed with a consequent median survival time of 44.5 months, The perineural infiltration of the lower alveolar nerve is more common (6.3%) than is generally thought. This frequency is due to the relationship with the lower lip and the mandibular region. In carcinoma of the lip, spread is generally limited to 10-15 mm along the lower alveolar nerve. In carcinoma of the mandibular region, spread is entirely dependent on the location of the tumour; the absence of clinical fixation to the bone and the small size of the carcinoma does not preclude the possibility of bone involvement. Neurological symptoms should be evaluated carefully, and a radiographic investigation of the nerve canal is mandatory.