Prognostic factors for survival and for biochemical cure in medullary thyroid carcinoma: results in 899 patients. The GETC Study Group. Groupe d'étude des tumeurs à calcitonine.
BACKGROUND
Prognostic factors of sporadic or inherited medullary thyroid carcinoma (MTC) are still controversial and have been assessed in old and small series. A better knowledge of these factors would improve patient management.


OBJECTIVE
To evaluate factors involved in the prognosis of MTC in a large series of cases, using uni- and multivariate analysis.


METHODS
Clinical, biological, surgical and epidemiological data on 899 MTC patients, diagnosed between 1952 and 1996, were collected by the French Calcitonin Tumors Study Group (GETC) with a standardized questionnaire, and processed in a national database.


METHODS
Survival and biochemical cure (i.e. normal basal post-operative serum calcitonin levels) were analysed with Kaplan and Meier and log-rank test statistical procedures. Data are presented as adjusted rather than observed survival, to consider only patients who died of MTC. Cox's forward-stepping proportional hazard model was used to analyse factors with a significant influence on survival by univariate analysis.


RESULTS
Apart from the large proportion of familial forms (43%), the general characteristics of our population were similar to those in other studies: mean age at surgery = 43.4 years; sex ratio = 1 male/1.35 female; stage I = 20.8%; stage II = 21.2%; stage III = 46.5% and stage IV = 11.5%. 863 (96%) patients underwent surgery; 43% of operated patients were biochemically cured. Adjusted survival was 85.7 +/- 1.5% at 5 years and 78.4 +/- 2.1% at 10 years. Multivariate analysis showed that age and stage were independent predictive factors of survival. Gender, type of surgery, type of familial form were predictive only in univariate analysis. Biochemical cure predicts a survival rate of 97.7% at 10 years. Authentic recurrence, that is subsequent elevation of calcitonin (CT) after post-operative normalization, was found in 4.9%. In non-cured patients (57%), survival was still good: 80.2% (+/- 2.2%) and 70.3% (+/- 2.9%) at 5 and 10 years, respectively. Similarly, prediction of biochemical cure was solely dependent on stage.


CONCLUSIONS
Survival of these medullary thyroid carcinoma patients appears better than expected even in non-cured patients. Considering the strong impact of stage, the necessity for pre-operative diagnosis of MTC is obvious.
Modigliani
E
E
Endocrinology Department, Hopital Avicenne, Bobigny, France.
Cohen
R
R
Campos
J M
JM
Conte-Devolx
B
B
Maes
B
B
Boneu
A
A
Schlumberger
M
M
Bigorgne
J C
JC
Dumontier
P
P
Leclerc
L
L
Corcuff
B
B
Guilhem
I
I
D000328:Adult; D000367:Age Factors; D000704:Analysis of Variance; D002116:Calcitonin / Q000097:blood; D018276:Carcinoma, Medullary / Q000097:blood / Q000401:mortality / Q000601:surgery*; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D016016:Proportional Hazards Models; D016019:Survival Analysis; D013964:Thyroid Neoplasms / Q000097:blood / Q000401:mortality / Q000601:surgery*
D002116:Calcitonin