Background: The extracapsular spread of disease in modal metastasis of head and neck tumors is an important prognostic factor. However, the implications of the degree of capsular involvement are rarely mentioned. This is a prospective study which intends to investigate the role of transcapsular spread in metastatic lymph nodes on the outcome of patients with laryngeal or hypopharyngeal carcinoma.
Methods: This is a prospective study of 170 consecutive cases of previously untreated patients with squamous cell carcinoma of the larynx or the hypopharynx treated from January 1981 through January 1988 at the Head and Neck Service of the Heliópolis Hospital Complex, São Paulo, Brazil. In an attempt to understand better the influence of the extension of capsular lymph node involvement on recurrence and actuarial survival rates, the Kaplan-Meier method and Mantel-Cox test were used.
Results: The nodal cervical relapse was associated only to a macroscopic transcapsular spread (confidence interval, 1.7-7.0). When the carcinoma was confined to the lymph node or only a microscopic transcapsular spread was present, no statistically significant differences were found in recurrence or in death rates. The 5-year global and disease-free actuarial survival rates were, respectively, 52.0% and 56.8% for cases without metastasis and 5.8% and 10.2% when macroscopic transcapsular spread was present (p < .0001). The capsular rupture was the most important independent prognostic factor associated with the N categories of the TNM clinical classification and with metastatic lymph node diameter.
Conclusions: The risks of recurrence and death are higher when there is macroscopic extracapsular extension. When the tumor is confined to the lymph node or shows a microscopic invasion beyond the capsule, there are no statistically significant differences in risk rates. The risk of capsular rupture is related to the N category of the classification TNM and the diameter of the metastatic lymph node, from 3 cm and larger.