Criteria for low risk group:
(1) all younger patients (men < 41 years, women < 51) without distant metastases, OR
(2) all older patients (men >= 41 years, women >= 51 years) with
(2a) intrathyroidal papillary carcinoma OR follicular carcinoma with minor tumor capsular involvement; AND
(2b) primary tumor < 5 cm in diameter; AND
(2c) no distant metastases
Criteria for high risk group:
(1) presence of distant metastases, OR
(2) all older patients (men >= 41 years, women >= 51 years) with
(2a) extrathyroidal papillary carcinoma OR follicular carcinoma with major tumor capsular involvement; OR
(2b) primary tumor >= 5 cm in diameter regardless of extent of disease
where:
• Distant metastases do not include metastases to regional, cervical or mediastinal lymph nodes.
NOTE: In Table I, page 948 of Cady (1988) the high risk group definition uses AND rather than OR for the 2 subgroups under older patients. However, in context the OR seems more appropriate.
Interpretation:
• The original authors (Cady and Rossi, 1988) found a mortality rate ratio of 26:1 between the high and low risk groups.
• Davis et al (1995) found little difference between low and high risk groups when applied to patients with follicular carcinoma. However, it is unclear if they limited metastatic sites to other than lymph nodes in the neck and mediastinum.
References;
