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Medullary thyroid carcinoma in Hong Kong Chinese
patients
SM Chow, JKC Chan, SC Tiu,
KL Choi, DLC Tang, SCK Law
Department of Clinical Oncology, Queen Elizabeth Hospital, 30 Gascoigne
Road, Hong Kong
OBJECTIVE. To study the clinical parameters and
treatment outcome of medullary thyroid carcinoma in Hong Kong Chinese
patients.
DESIGN. Retrospective study.
SETTING. Regional oncology unit, Hong Kong.
PATIENTS. Patients with medullary thyroid carcinoma
who were identified among 1656 patients with thyroid malignancies
seen in a single institute in Hong Kong from January 1960 to June
2003.
MAIN OUTCOME MEASURES. Ten-year cause-specific survival,
locoregional failure-free survival, and distant metastasis failure-free
survival.
RESULTS. Twenty-two (1.3%) patients with medullary
thyroid carcinoma were identified. The mean age at diagnosis was
43.7 (standard deviation, 16.5) years. The sex ratio was 1:1. The
10-year cause-specific survival, locoregional failure-free survival,
and distant metastasis failure-free survival were 75.4%, 82.0%,
and 62.4%, respectively. Lymph node metastasis was present in seven
(31.8%) patients at diagnosis. Distant metastasis developed in nine
(40.9%) patients: lung, 3 (13.6%); bone, 5 (22.7%); liver, 2 (9.1%);
mediastinum, 4 (18.2%). Seven (31.8%) patients died of distant metastasis.
Mediastinal (n=3) and bone metastases (n=3) were important causes
of death. Genetic study confirmed multiple endocrine neoplasia type
2A in 3 (25.0%) of 12 patients who all had bilateral and multifocal
diseases. Younger age (<45 years) was associated with better
survival, better locoregional control, and less distant metastasis.
Patients with pT1N0 disease (n=3) had an excellent prognosis: all
were disease-free following total thyroidectomy. Among eight patients
who received external radiation therapy, seven achieved good locoregional
control. In seven patients with lymph node metastasis, external
radiation therapy gave 100% (4/4) locoregional control compared
with 33.3% (1/3) in those without external radiation therapy. Chemotherapy
using dacarbazine and 5-fluorouracil was tried in three patients
with poor response.
CONCLUSIONS. Early stage (T1N0) medullary thyroid
carcinoma is associated with a very good prognosis. Postoperative
external radiation therapy can achieve good locoregional control
in patients with lymph node metastasis or locally advanced disease.
Hong Kong Med J 2005;11:251-8
Key words: Carcinoma, medullary; Multiple endocrine
neoplasia; Radiotherapy; Thyroid neoplasms
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