Incidence of Occult Metastases

occult metastatic rate is > 20% for all sites examined. It is also important to note that up to 35% of microscopic metastases contain extracapsular spread (ECS),12 a finding that has a significant impact on the regional recurrence and distant metastatic rate, and patient outcome.30

Patients who are staged pN+ after END have been shown to have a poorer prognosis than do those who do not harbor occult metastases.24'30 Therefore, it may be advantageous to identify patients with occult disease.

An estimate of the incidence of occult cervical metastases is available by reviewing studies that have reported the regional metastatic rate in patients who were observed clinically. Patients who develop cervical metastases subsequent to treatment of their primary tumor, and who have their primary site controlled, can be assumed to have had occult disease at the time of diagnosis. Table 1-1 presents the data reported for oral cavity lesions and suggests that the occult metastatic rate is 40 to 50%.17'18'27'28

Another way to assess the incidence of occult metastases is to review studies that have reported pathologic staging data on patients whose necks were dissected electively. Data from three studies23,24,29 are shown in Table 1-2 and suggest that the

TABLE 1-1

Regional Metastatic Rate: T1-T4 NO Oral Cavity Squamous Cell Carcinoma-Neck Followed Clinically after Treatment of the Primary Tumor

Regional Metastatic

Study/Reference Rate (%)

McGuirt et al. (1995)17 40

Fakih et al. (1989)27 66

Vandenbrouck et al. (1980)28 47

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