The number of sentinel nodes identified as prognostic factor in oral epidermoid cancer.

In patients with oral cavity epidermoid cancer without palpable nodes, the standard cervical treatment is supraomohyoid dissection; nevertheless, lymphatic mapping with sentinel node (SN) biopsy has been useful and allows the identification of a group of patients where neck dissection may be prevented. The objective of this study was to examine which factors diagnose the possibility of metastasis in SN. A non-randomized prospective study was performed during a two year period and included patients with T1-2, N0 oral cavity cancer >4 mm thick, SN was identified by blue dye and Rhenium colloid. All patients underwent pre-operatory lymphogammagraphy and elective-selective neck dissection. Age, gender, tumor site, T, tumor thickness and number of sentinel nodes found were evaluated. In 48 patients, at least one sentinel node was found, 2 per patient on average. 10.4% showed drainage outside the supraomohyoid region, 13/48 had nodular metastasis, 4 with negative SN(8.3%). T, location, thickness and number of SN are related to non-SN metastasis. Identification of 3SN or more was related to the possibility of SN metastasis p=0 (RR 10.1, I. C. 95% 1.1 91.2). The combined technique (dye-colloid) offers a high index of success in the identification of SN in patients with oral cavity cancer, while lymphogammagraphy identifies patients with anatomically unexpected drainage. Patients with T1 less than 2cm, not located on the tongue with thickness <5 mm and more than 2 SN were less likely to have metastasis in non-sentinel nodes. The identification of at least 3 sentinel nodes decreases the possibility of identifying patients with hidden metastasis (p=0.04).