Conclusions are as follows: 1) The incidence of second primary tumors is independent from the primary tumor staging and distant and delayed regional metastases. The highest incidence occurred in patient groups with the highest disease-free survival rates (P =.0378). 2) Highest incidence of delayed and distant metastases occurred in hypopharyngeal tumors and was three times greater than in laryngeal cancers (P =.028). 3) Salvage therapeutic rates were poor for delayed metastases to the ipsilateral treated nodes and distant metastases as compared with contralateral neck metastases and second primary tumors (P =.001). 4) Delayed and distant lymph node metastases were significantly higher in advanced primary disease (T4 stage), locoregional recurrences, and regional disease (N2 and N3) (P =.028) in both the larynx and hypopharynx. 5) The higher incidence of delayed and distant metastatic disease was related to more advanced initial tumor presentation in hypopharyngeal cancer as compared with laryngeal cancer (P =.039). 6) Incidence of distant metastases was greatest between 1.5 and 6 years after initial treatment with a mean incidence being less than or equal to 3.2 years.
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