Medullary thyroid carcinoma: multivariate analysis of prognostic factors influencing survival.
BACKGROUND
Medullary thyroid carcinoma (MTC) is a rare development of thyroid cancer with a no negligible mortality rate. Our aim was to determine factors that predict outcome in patients with MTC.


METHODS
We reviewed the records of all patients with MTC (n=56) who underwent treatment at our institution between January 1990 and December 2000. Univariate and multivariate analysis of clinicopathologic predictors of MTC outcome were performed to identify subsets of patients with different probabilities in terms of overall survival, local recurrence, and distant metastases.


RESULTS
Multivariate analysis demonstrated that a statistically significant decrease in overall survival is associated with T4b tumours (p=0.06), the presence of distant metastases at the time of presentation (p=0.033), lymphatic invasion (p=0.099), and postoperative treatment (p=0.045).


CONCLUSIONS
The analysis of survival curves of patients with MTC shows that the occurrence of locoregional and distant metastases occurs preferentially within the first 5 years, which identifies this as a crucial period for follow-up. In this series of patients with MTC, the tumours classified as T4b, metastases at presentation, the presence of lymphovascular invasion, and postoperative treatment were the most important prognostic features. At present, there is no available beneficial adjuvant therapy. However, as the development of molecular therapy progresses, it should be tested in clinical trials with the purpose of achievement of novel targeted therapies for selected MTC patients with risk factors.
Peixoto Callejo
Isabel
I
Department of Head and Neck Surgery, Portuguese Institute of Cancer, Lisbon, Portugal. isabelcallejo@hotmail.com
Américo Brito
José
J
Zagalo
Carlos Manuel
CM
Rosa Santos
Jorge
J
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood; D002116:Calcitonin / Q000097:blood; D018276:Carcinoma, Medullary / Q000097:blood / Q000401:mortality*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008197:Lymph Node Excision / Q000379:methods; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D018813:Multiple Endocrine Neoplasia Type 2a / Q000401:mortality; D015999:Multivariate Analysis; D037981:Neck Dissection; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local; D011174:Portugal / Q000453:epidemiology; D011379:Prognosis; D016019:Survival Analysis; D013964:Thyroid Neoplasms / Q000097:blood / Q000401:mortality*; D013965:Thyroidectomy; D013997:Time Factors
D014408:Biomarkers, Tumor; D002116:Calcitonin