We included only patients with SCC (squamous cell carcinoma) of the oral cavity, confirmed by histopathological examination at our institution from 2010 to 2012. We used the AJCC Eighth Edition for the staging of the primary lesions and neck29. All participants were radiologically negative for lymphatic metastases by multi-slice CT scan with 128 detectors. Consecutive patients submitted to SLNB, which come out negative after extensive histopathological evaluation, were prospectively followed without subsequent neck dissection. Ethical Committee of XXXXXX approved the study under CAAE:0392.0.146.000–07. All participants signed informed consent.
Only negative sentinel lymph node patients without local recurrences were included in statistical analysis to avoid primary recurrence bias.
Patients with positive margins on a permanent section (despite negative results in frozen section), perineural invasion, or vascular emboli were treated with adjuvant radiation therapy on primary tumor bed and neck.
We used two peritumoral injections of technetium labeled nanocolloid for SLNB.
Lymphoscintigraphy and SPEC-CT were performed in all cases. The neck skin was marked accordingly, and a gamma probe was used to identify the sentinel lymph node intraoperatively. We obtained step serial sections at each 150 um of the sentinel lymph node stained with hematoxylin-eosin, and subsequently, immunohistochemistry for cytokeratin AE-1/AE-3 in negative SLNB on HE.
All patients were followed postoperatively with a CT scan every six months for the first two years and yearly.
The control group submitted to END was collected with reviewed medical charts of all consecutive patients with T1/T2 oral cancer, cN0 necks. All with radiologically negative necks, from 2000 to 2012 submitted to END of levels I to III. All pathological evaluation was performed with an extensive evaluation of all paraffin embedded blocks with step serial section of 150 um.
Both groups were match-paired by age, gender, stage, site, histopathological status of the primary lesion and neck dissection specimen, adjuvant treatment, and follow-up length. Only patients with negative surgical specimens for lymphatic metastases were included for pairing, without local recurrences.
Statistics were performed via IBM SPSS Statistics 17 (Windows) software. The odds ratio was used to compare groups by gender, stage, site, adjuvant treatment, and recurrence rate and T-test for continuous categories of age and length of follow-up. P-values < 0.05 were considered statistically significant.