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Prognostic factors in papillary and follicular thyroid carcinoma:
their implications for cancer staging.Ann
Surg Oncol. 2007 Feb;14(2):730-8. Epub 2006 Nov 11.
BACKGROUND:
Papillary thyroid carcinoma (PTC) and follicular thyroid carcinoma
(FTC) are two distinct histological types of thyroid carcinoma but
have often been studied and staged as a collective group, known as
differentiated thyroid carcinoma (DTC). However, this may not be an
optimal approach to cancer staging. METHODS: A total of 760 patients
with DTC, comprising 589 (77.5%) with PTC and 171 with (22.5%) FTC,
being managed at our institution from 1961 to 2001 were
retrospectively reviewed. Their clinicopathological features,
treatment modalities received, and postoperative outcome were
analyzed. Both univariate and multivariate analyses were performed to
identify prognostic factors related to cancer-specific survival (CSS)
for PTC and FTC. RESULTS: There were statistically significant
differences between PTC and FTC in terms of age >/=50 years at
diagnosis (P = .040), tumor size (P < .001), lymph node metastases (P
< .001), distant metastases (P < .001), extrathyroidal extension (P <
.001), multifocality (P = .002), capsular invasion (P < .001), extent
of thyroid resection (P < .001), radioiodine ablation (P < .001), and
external-beam irradiation (P = .003). Although PTC and FTC had similar
10-year and 15-year CSS (P = .846), each possessed its own set of
independent prognostic factors for CSS. Age at diagnosis and
completeness of resection were independent prognostic factors in both
PTC and FTC. CONCLUSIONS: There were marked differences in
clinicopathologic features, treatment, and prognostic factors between
the two histologic types of DTC. Different staging systems should be
evaluated and validated for PTC and FTC individually in the future.
Follicular thyroid
carcinoma: the role of histology and staging systems in predicting
survival.
Ann Surg. 2005 Nov;242(5):708-15.
OBJECTIVE: To
evaluate the risk factors including tumor histomorphology for survival
specific to follicular thyroid carcinoma (FTC) and to apply commonly
employed staging systems in predicting survival for patients with FTC.
SUMMARY BACKGROUND DATA: FTC is usually analyzed collectively with
papillary thyroid carcinoma (PTC) in risk group analysis. Risk factors
and risk group analysis are important in the management of patients
with FTC, although current published therapeutic guidelines call for
total thyroidectomy followed by radioactive iodine (I) ablation for
all FTC patients. METHODS: Over a 40-year period, 156 patients
surgically treated for FTC with an average follow-up of 14.4 years
were retrospectively studied after histologic reclassification
according to the type and degree of invasiveness of the tumor.
Potential risk factors for survival were calculated using multivariate
analysis, and the prognostic accuracy of AMES risk group
stratification, UICC/AJCC pTNM staging, Degroot classification, and
MACIS scoring schemes in predicting survival was compared. RESULTS:
Seventeen (11%) patients had distant metastases at presentation, and
bilateral thyroid resection was performed for 131 (84%) patients.
Seventeen (11%) patients died of recurrent or metastatic disease. The
overall and cancer-specific survival (CSS) rates at 10 years were 79%
and 88%, respectively. None of the patients with minimally invasive (n
= 49) or angioinvasive (n = 23) carcinomas died compared with 17 of 84
patients with widely invasive carcinomas (P = 0.0007). Using the Cox
proportional hazards model, old age, the presence of distant
metastases, and incomplete tumor excision were independent prognostic
factors for survival. For patients who underwent curative treatment,
old age and widely invasive carcinoma were risk factors for poor
survival. All staging systems studied accurately predicted CSS, and
the pTNM UICC/AJCC staging system yielded the best prognostic
information. CONCLUSIONS: Commonly adopted staging systems can be
applied specifically to patients with FTC. The distinction of FTC in
minimally invasive and widely invasive carcinoma based on the extent
of invasiveness rather than vascular invasion is important in
identifying low-risk FTC patients for a more conservative management.
Follicular thyroid
carcinoma: histology and prognosis.
Cancer. 2004 Mar 15;100(6):1123-9.
BACKGROUND:
Follicular thyroid carcinoma (FTC) is the second most common thyroid
malignancy after papillary thyroid carcinoma. The authors studied the
clinical course of 132 patients with FTC to determine whether there
was a direct relation between the histologic degree of invasion, tumor
recurrence, and patient survival. METHODS: The 132 patients in the
study population underwent 182 thyroid carcinoma-related operations,
and their mean follow-up was 7.5 years (median:,6 years; range, 0-39
years). The following criteria were used to define malignant
follicular neoplasms: 1) minimally invasive, tumor invasion through
the entire thickness of the tumor capsule; 2) moderately invasive,
tumor with angioinvasion (with or without capsular invasion); and 3)
widely invasive, broad area or areas of transcapsular invasion of
thyroid and extrathyroidal tissue. Forty-five of 119 patients (37.8%)
presented with minimally invasive FTC (capsular invasion only), 50
patients (42%) presented with moderately invasive FTC (angioinvasion
with or without capsular invasion), and 24 patients (20%) presented
with widely invasive FTC. At presentation, 12 patients (9%) had
distant metastases, and 8 patients (6%) had lymph node metastases.
RESULTS: Excluding 12 patients who presented with distant metastases,
21 patients (16%) developed recurrent metastases 6 months after their
initial treatment. Among 45 patients with capsular invasion only, 6
patients (13%) developed recurrent or persistent disease, and 5
patients (11%) died. Of the 50 patients who had angioinvasion with or
without capsular invasion, 10 patients (20%) developed recurrent or
persistent disease, and 7 patients (14%) died. Patients who had
angioinvasion with or without capsular invasion had a less favorable
prognosis compared with patients who had capsular invasion only (P <
0.0001). Among patients who had widely invasive FTC, 9 of 24 patients
(38%) developed recurrent disease, and 8 patients (33%) died; in
addition, 7 of the other 24 patients (29%) had persistent disease and
died. The overall death rate for patients with widely invasive FTC was
62%. Patients with persistent disease had a poorer prognosis compared
with patients who had recurrent disease (P < 0.0001). Twenty-eight
patients (21%) in the entire group died of FTC. CONCLUSIONS: In the
current retrospective investigation, the authors demonstrate that
patients with minimally invasive FTC (capsular invasion only) had a
slightly better survival rate at 5 years (98%) compared with patients
who had angioinvasion with or without capsular invasion (80%) and had
better survival compared with patients who had widely invasive FTC
(38%). Other (but not all) reports in the literature support the
findings that FTC with angioinvasion is more aggressive than FTC with
only capsular invasion yet is less aggressive than widely invasive
FTC. The authors conclude that FTC no longer should be classified as
either minimally invasive or widely invasive; rather, they recommend
classifying FTC as minimally invasive, moderately invasive, or widely
invasive, because prognosis varies according to these groupings.
A clinicopathologic
study of minimally invasive follicular carcinoma of the thyroid gland
with a review of the English literature.
Cancer.2001 Feb 1;91(3):505-24
BACKGROUND:
The criteria for minimally invasive (low grade) follicular carcinoma
of the thyroid (MI) remain controversial, often resulting in
unnecessary treatment. METHODS: The records of 130 patients with
minimally invasive (MI) follicular thyroid carcinoma were retrieved
from the files of the Endocrine Tumor Registry of the Armed Forces
Institute of Pathology. RESULTS: Ninety-five patients were confirmed
to have MI based on the authors' criteria of small-to-medium vessel
invasion, capsular invasion of up to full thickness, no parenchymal
tumor extension, and no tumor necrosis (patients with oxyphilic tumors
were excluded). The remaining 35 patients had tumors that were
reclassified as "not low grade" based on large vessel invasion,
extension into parenchyma, and tumor necrosis (oxyphilic cases
excluded). The MI patients included 67 women and 28 men, ages 20-95
years (average, 42.0 years). Nearly all patients presented with a
thyroid mass (n = 90 patients). The mean tumor size was 2.8 cm.
Histologic features examined for tumor classification included
cellularity, capsule nature, capsular invasion, vascular invasion,
extension into parenchyma, cytoplasmic oxyphilia, mitotic activity,
and necrosis. All patients were treated with surgical excision.
Adjuvant radioactive iodine therapy was performed in 24 patients. Five
patients developed recurrent disease: four were alive or had died
without evidence of disease after additional treatment (mean, 18.1
years), and one patient died with disease (MI tumor) at 15.1 years.
All of the remaining patients were disease free (mean follow-up, 16.5
years). CONCLUSIONS: There are reproducible histologic criteria to
diagnose patients with MI follicular carcinoma. The overall excellent
long term prognosis and a good patient outcome suggests that no
additional surgery is necessary.
Prognosis and
prognostic factors of follicular carcinoma in Japan: importance of
postoperative pathological examination.
World J
Surg. 2007 Jul;31(7):1417-24.
BACKGROUND:
Follicular carcinoma is known to show a worse prognosis than papillary
carcinoma because of distant metastasis in higher incidence. However,
few studies have been published regarding the prognosis of follicular
carcinoma patients in Japan, which prompted us to investigate this
issue. METHODS: We examined the prognosis and whether and how various
clinicopathological features have affected disease-free survival (DFS)
and cause-specific survival (CSS) of 334 patients who underwent
initial surgery for follicular carcinoma. RESULTS: In 18 patients
(5.4%), curative surgery could not be achieved because of distant
metastasis at surgery in 17 patients and local extension in 1 patient.
For 316 patients who underwent curative surgery, 5-year and 10-year
DFS rates were 88.4% and 75.3%, respectively. Poorly differentiated
carcinoma and widely invasive carcinoma, together with some
conventional prognostic factors, predicted poorer DFS of patients. On
multivariate analysis, poorly differentiated carcinoma was an
independent prognostic factor for DFS. The 5-year and 10-year CSS
rates for these 334 patients were 96.4% and 90.4%, respectively.
Curative surgery and poorly differentiated carcinoma were recognized
as independent prognostic factors. CONCLUSIONS: We can hypothesize
that follicular carcinoma in Japan is generally a nonaggressive
disease with a good prognosis. However, because poorly differentiated
or widely invasive carcinomas showed a worse prognosis, postoperative
pathological examination is important in predicting patient prognosis.
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