Surgical treatment and postoperative foll owup of patients wi th papillary thyroid carcinoma after the Сhornobyl accident (accordi ng to hospital register data)

Abstract

Papillary thyroid carcinoma (PTC) is recognized as the main
type of post-Chornobyl radiogenic thyroid cancer, the study of which
is the focus of attention of numerous scientific institutions around the
world. In Ukraine, the main center in this field was been and remains
the SI «V.P. Komissarenko Institute of Endocrinology and Metabolism
of the National Academy of Medical Sciences of Ukraine» (IEM).
Objective. Based on data from the IEM hospital registry, to analyze
demographic data, surgical treatment tactics, and long-term follow-
up results for Ukrainian residents of various ages with PTC who
underwent surgery at the IEM after the Chornobyl accident over a
30-year period. Material and methods. The study included all available
cases of primary surgery for PTC during the period 1990-2019,
diagnosed in persons born before January 1,1987, which to one degree
or another could have been exposed to radiation as a result of
the Chornobyl accident in the postnatal or prenatal periods (7,247 patients).
Two groups of patients were analyzed: those who were under
18 years of age at the time of the Chornobyl accident constituted a
group at increased risk of developing radiogenic PTC (group «0-18»,
3,610 cases) and those who were 19 years of age and older at the time
of the accident, who constituted a group at lower risk according to
radiation medicine standards (group «Others», 3,637 cases). Observation
period: from 1990 (the beginning of a probable increase in the
incidence of thyroid cancer in Ukraine after the Chornobyl accident)
to 2019 (achieving a sufficient period of postoperative follow-up of patients).
To analyze the dynamics of changes in indicators over time, the

entire period 1990 to 2019 was divided into 10 periods of 3 years each.
Results. The percentage of men in the «0-18» group was statistically
significantly higher at the beginning of the study (37.7% vs. 17.4% in
the «Others» group) and gradually decreased until 2008, after which it
was about 18% in both groups. In the «0-18» patient group, compared
to the «Others» group, there was also a significantly higher incidence
of regional lymph node involvement (N1) during 1990-2007. In subsequent
years, the advantage of the N1 percentage in the «0-18» group
remained statistically significant compared to the «Others» group, but
within the «0-18» group itself, the frequency of regional metastases
decreased significantly from 66.2% in 1990-1992 to 28.0% during 2008-
2019. The percentage of patients with PTC from the six most affected
northern regions of Ukraine did not undergo statistically significant
changes between the groups of those who were <18 or ≥19 years of
age in 1986, but tended to decrease from more than 70% in the early
years of the study to approximately 40-50% in 2017-2019. The dynamics
of the frequency of chronic thyroiditis (CT) was quite variable: until
2008, signs of CT were less frequently detected in the «0-18» group,
and in 2011-2019, on the contrary, more frequently than in the «Others
» group. A gradual increase in the percentage of thyroidectomies
occurred from 1990 to 1998 in both the «0-18» group and the «Others»
group, with a statistically significant of the first advantage. From 1999
to 2007, the percentage of thyroidectomies no longer had a statistically
significant difference between the groups, and from 2008 to 2019, the
percentage of thyroidectomies in the «0-18» group became lower than
in the «Others» group (p<0.001). Conclusions. The lower frequency of
recurrences (repeat operations) in the «0-18» group compared to the
«Others» group, determined over a 30-year observation period, suggests
a more favorable prognosis in the treatment of patients from the
high-risk group for the development of radiogenic PTC.