Multivariate analysis of prognostic factors in sporadic medullary carcinoma of the thyroid. A retrospective study of 109 consecutive patients.
BACKGROUND
Because of the rarity of medullary thyroid carcinoma, adequate information for determination of the prognostic characteristics and clinical course of this disease can be obtained only from a database that serves a large population.


METHODS
A retrospective review of 109 patients with sporadic medullary thyroid carcinoma was conducted; all were diagnosed and treated at a single institution over a 30-year period. The series included 57 males and 52 females with a median follow-up of 5.3 years. Statistical univariate analysis of relapse free survival and overall survival was done for 18 clinicopathologic variables, including sex, age, TNM staging, completeness of surgical resection, postoperative calcitoninemia, histologic subtype, tumor size, thyroid capsule invasion, amyloid, katacalcin, calcitonin, and calcitonin gene-related peptide immunostaining patterns of the primary tumor.


RESULTS
Risk factors for unfavorable outcome were male sex, age > 60 years, incomplete tumor resection, mixed cell subtype, tumor size > 4 cm, extrathyroid tumor invasion, lack of amyloid, N1 and M1 categories, and heterogeneous calcitonin and katacalcin immunostaining pattern. In the multivariate analysis, only capsule status, M category, and age at diagnosis remained in the final model for overall survival. In the final model for relapse free survival, capsule status remained, together with sex and amyloid status.


CONCLUSIONS
Extrathyroid tumor invasion, the presence of distant metastases, and age > 60 years are characteristic of patients at high risk of death from disease sooner, whereas extrathyroid invasion, male sex, and the absence of amyloid characterize patients who are at high risk for recurrence. Extrathyroid tumor invasion appears to be the worst prognostic factor and may allow for the breakdown of patients into two categories, amenable to different therapeutic regimens.
Scopsi
L
L
Endocrinology Unit, Istituto Nazionale Tumori, Milan, Italy.
Sampietro
G
G
Boracchi
P
P
Del Bo
R
R
Gullo
M
M
Placucci
M
M
Pilotti
S
S
D000328:Adult; D018276:Carcinoma, Medullary / Q000737:chemistry / Q000401:mortality* / Q000473:pathology / Q000556:secondary; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D013964:Thyroid Neoplasms / Q000737:chemistry / Q000401:mortality* / Q000473:pathology