The characteristics and course of pure papillary
carcinoma and follicular variant of papillary carcinoma are similar
(July 2003)
The background of
the study. There are two major subtypes of papillary carcinoma
of the thyroid, so-called pure papillary carcinoma and follicular
variant of papillary carcinoma. The latter has been recognized with
increasing frequency in recent years, but whether its biology is
similar to that of pure papillary carcinoma is not clear. In this
retrospective study, the characteristics and outcome of patients
with the two subtypes were compared.
How the study was done. The study
subjects were 243 patients with papillary carcinoma treated at a
single oncology center in Israel between 1972 and 1990. Sections
of all tumors were reviewed by several pathologists. The tumor was
classified as a pure papillary carcinoma if it was composed of papillae
lined by cells with nuclei that were enlarged and overlapped one
another, and the nuclei had a thick nuclear membrane, small nucleoli
next to the nuclear membrane, intranuclear grooves, and intranuclear
inclusions. The tumor was classified as a follicular variant of
papillary carcinoma if it was composed primarily of follicles (80
percent or more) and the nuclei of the cells had at least two of
the features of papillary carcinoma. All patients had undergone
total or near-total thyroidectomy, and 226 patients in whom postoperative
imaging revealed uptake of radioactive iodine (I-131) received a
therapeutic dose of I-131; later treatment varied according to the
presence and site of recurrence.
The results of the study. There
were 143 patients (59 percent) with pure papillary carcinoma and
100 patients (41 percent) with follicular variant of papillary carcinoma.
There were no differences in the characteristics of the patients,
the size of the tumors, or the frequency of multifocal tumors in
the two groups. The median follow-up was 138 months (range, 48 to
288). The overall 21-year survival rates were, respectively, 82
percent in the patients with pure papillary carcinoma and 86 percent
in the patients with the follicular variant of papillary carcinoma.
Among several prognostic factors, only age was a determinant of
poor outcome in either group, but there was no difference between
groups.
The conclusions of the study. Patients
with pure papillary carcinoma and follicular variant of papillary
carcinoma do not differ in age, sex, or extent of tumor at the time
of diagnosis, nor is their prognosis different.
The original article. Zidan J, Karen
D, Stein M, Rosenblatt E, Basher W, Kuten A. Pure versus follicular
variant of papillary thyroid carcinoma: clinical features, prognostic
factors, treatment, and survival. Cancer 2003;97:1181-5.
|
