Neck lymph node metastases to the posterior triangle apex: evaluation of clinical and histopathological risk factors.
BACKGROUND
Dissection of posterior triangle apex (APEX) is a surgical step in supraomohyoid and lateral neck dissections. The prevalence of lymphatic metastases at this site and the clinicohistopathologic conditions that influence their occurrence have not been established. We have evaluated the prevalence and the risk factors for cervical metastases in lymph nodes of the APEX.


METHODS
Sixty-two neck dissections were performed in 51 patients with squamous cell carcinoma of the oropharynx, hypopharynx, oral cavity, glottic larynx, and supraglottic larynx or with primary occult tumor. We correlated the presence of positive metastases in the APEX with the neck level involved either clinically (CLIN) or histopathologically (H/P) and with the number of CLIN- or H/P-positive neck levels with metastases. The prevalence of metastases in the APEX in elective (N0) and therapeutic (N+) neck dissections was also compared. This prevalence was also compared with that for each neck level. The histopathologic comparisons between the APEX and the neck levels were calculated for N0, N+, and all neck dissections. The primary site of tumor was correlated with the presence of H/P-positive nodes in the APEX.


RESULTS
The overall prevalence of lymphatic metastases in the APEX was 6.5%. The prevalence in N0 neck dissections was 2.3% and in N+ neck dissections it was 16.7%. The prevalence of lymphatic metastases in the APEX for primary tumors of pharynx was 23.1%, for the oral cavity it was 3.6%, and it was 0% for other sites. Metastases in the APEX were not influenced by the neck level with CLIN or H/P metastases in N+ necks. The number of CLIN- or H/P-positive neck levels had no influence on histopathologic metastases in the APEX. Factors that influenced metastases in the APEX were positive histopathologic metastases at level II for N0 neck dissections and positive histopathologic metastases at level II or III for all neck dissections. All the comparisons were analyzed using Fisher's or Poisson's test.


CONCLUSIONS
The prevalence of histopathologic metastases in the APEX in N+ necks is 7.3 times greater than that of N0 necks and for primary tumors of pharynx it was 6.4 times greater than for the oral cavity and significantly greater than for the larynx. Histopathologic metastases at level II for clinically N0 necks and histopathologic metastases to level II or III for all neck dissections are risk factors for metastases in the APEX. The number of positive levels did not influence the prevalence of metastases in the APEX. There are no isolated metastases in the APEX of the posterior triangle.
Department of Otolaryngology and Head and Neck Surgery, State University of Campinas, Rua Major Solon 685, Cambui, Campinas, São Paulo, Brazil 13024-091.
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Altemani
D002294:Carcinoma, Squamous Cell / Q000473:pathology* / Q000601:surgery; D005260:Female; D006258:Head and Neck Neoplasms / Q000473:pathology* / Q000601:surgery; D006801:Humans; D007822:Laryngeal Neoplasms / Q000473:pathology / Q000601:surgery; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000473:pathology*; D008297:Male; D009062:Mouth Neoplasms / Q000473:pathology / Q000601:surgery; D037981:Neck Dissection; D010610:Pharyngeal Neoplasms / Q000473:pathology / Q000601:surgery; D012307:Risk Factors