Page 1 of 8
British Journal of Healthcare and Medical Research - Vol. 10, No. 1
Publication Date: February 25, 2023
DOI:10.14738/jbemi.101.14049.
Fernandes, U., Guidi, G., Martins, D., Vieira, B., Leal, C., Marques, R., Santos, C., Gaspar, J., & Pinto-de-Sousa, J. (2023).
Micropapillary Thyroid Carcinoma: Not So Harmless as it Seems. A 5-Year Follow-Up Cohort Retrospective Study. British Journal
of Healthcare and Medical Research, Vol - 10(1). 217-224.
Services for Science and Education – United Kingdom
Micropapillary Thyroid Carcinoma: Not So Harmless as it Seems.
A 5-Year Follow-Up Cohort Retrospective Study
Urânia Fernandes
https://orcid.org/0000-0001-7741-877X
General Surgery Department, Hospital Centre Hospitalar de Trás-os-Montes e Alto Douro
(CHTAMAD), Clinical Academic Centre Trás-os-Montes e Alto Douro (CACTMAD); Vila Real,
Portugal
Gonçalo Guidi
https://orcid.org/0000-0003-3564-1468
General Surgery Department, Hospital Centre Hospitalar de Trás-os-Montes e Alto Douro
(CHTAMAD), Clinical Academic Centre Trás-os-Montes e Alto Douro (CACTMAD); Vila Real,
Portugal
Daniela Martins
https://orcid.org/0000-0003-3189-4599
General Surgery Department, Hospital Centre Hospitalar de Trás-os-Montes e Alto Douro
(CHTAMAD), Clinical Academic Centre Trás-os-Montes e Alto Douro (CACTMAD); Vila Real,
Portugal
Bruno Vieira
https://orcid.org/0000-0001-9705-6489
General Surgery Department, Hospital Centre Hospitalar de Trás-os-Montes e Alto Douro
(CHTAMAD), Clinical Academic Centre Trás-os-Montes e Alto Douro (CACTMAD); Vila Real,
Portugal
Clara Leal
https://orcid.org/0000-0003-2387-5144
General Surgery Department, Hospital Centre Hospitalar de Trás-os-Montes e Alto Douro
(CHTAMAD), Clinical Academic Centre Trás-os-Montes e Alto Douro (CACTMAD); Vila Real,
Portugal
Rita Marques
https://orcid.org/0000-0002-7267-6443
General Surgery Department, Hospital Centre Hospitalar de Trás-os-Montes e Alto Douro
(CHTAMAD), Clinical Academic Centre Trás-os-Montes e Alto Douro (CACTMAD); Vila Real,
Portugal
Carlos Santos
General Surgery Department, Hospital Centre Hospitalar de Trás-os-Montes e Alto Douro
(CHTAMAD), Clinical Academic Centre Trás-os-Montes e Alto Douro (CACTMAD); Vila Real,
Portugal
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218
British Journal of Healthcare and Medical Research (BJHMR) Vol 10, Issue 1, February - 2023
Services for Science and Education – United Kingdom
João Gaspar
General Surgery Department, Hospital Centre Hospitalar de Trás-os-Montes e Alto Douro
(CHTAMAD), Clinical Academic Centre Trás-os-Montes e Alto Douro (CACTMAD); Vila Real,
Portugal
João Pinto-de-Sousa
https://orcid.org/0000-0001-6634-9756
General Surgery Department, Hospital Centre Hospitalar de Trás-os-Montes e Alto Douro
(CHTAMAD), Clinical Academic Centre Trás-os-Montes e Alto Douro (CACTMAD); Vila Real,
Portugal
ABSTRACT
Introduction: Differentiated thyroid cancer is becoming increasingly prevalent
mostly due to the increasing incidence of micropapillary carcinoma. For low-risk
tumors, hemithyroidectomy does not reduce survival and may be associated with
higher local recurrence. This study aimed to compare Micropapillary versus
Papillary thyroid carcinomas regarding overall survival and disease-free survival.
Methods: A retrospective, unicentric, cohort study was carried between 2012 and
2016. Consecutive cases with (micro)papillary thyroid carcinoma were enrolled
and divided in microcarcinoma group and control group. Exclusion criteria were
loss to follow-up, previous thyroid surgery and non-operative treatment. A
comparison of several clinical and pathological parameters, recurrence rate and
cumulative survival was performed between groups. Results: Patients with
micropapillary carcinomas were younger and frequently asymptomatic. 6.5% of
these carcinomas presented a benign cytology (Bethesda II) in this study. 18.9% of
these patients were submitted to hemithyroidectomy but 71.4% were thereafter
totalized. Micropapillary carcinomas presented higher rate of multifocality but
similar lymph node invasion rate, lymph node dissection rate and adjuvant iodine
therapy. Patients with micropapillary carcinomas presented less advanced staging
but similar recurrence rate and time to recurrence; moreover, higher stage was
only related with (older) age of presentation. Conclusions: In this study
micropapillary carcinomas presented better staging but similar recurrence rate
comparing with papillary carcinomas. Moreover, most of these patients were
submitted to totalization. These results question if hemithyroidectomy is still a
good option for micropapillary carcinomas and if this staging system is adequate.
Larger studies with longer follow-up are needed to confirm or refute these results.
Keywords: thyroid neoplasms, thryroidectomy, surgical oncology
INTRODUCTION
Although plateauing, incidence rates of thyroid cancer (TC) have increased in Europe in the last
thirty years, while mortality showed negative trends.[1] The rising incidence rates are mainly
due to the increased diagnosis of papillary thyroid cancers (PTCs), particularly micropapillary
thyroid cancers (mPTCs).[2-4] These are defined as PTCs less than 10 millimeters and are
associated with an excellent prognosis and long term survival rate above 96%.[4, 5] This
overdiagnosis results invariably in overtreatment. For low-risk tumors, hemithyroidectomy
has proven not to reduce survival but it may be associated with a higher local recurrence. Even
though, support is growing for more conservative, risk-tailored strategies for TC management
(including watchful waiting).[2, 4, 6] However, the risk factors such as multifocality,
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219
Fernandes, U., Guidi, G., Martins, D., Vieira, B., Leal, C., Marques, R., Santos, C., Gaspar, J., & Pinto-de-Sousa, J. (2023). Micropapillary Thyroid
Carcinoma: Not So Harmless as it Seems. A 5-Year Follow-Up Cohort Retrospective Study. British Journal of Healthcare and Medical Research, Vol -
10(1). 217-224.
URL: http://dx.doi.org/10.14738/jbemi.101.14049
extrathyroidal extension, and lymphovascular invasion, contributing to higher recurrence risk,
are not infrequent in mPTCs.[7] This study aimed to compare patients with mPTCs vs. PTCs
regarding overall survival and disease-free survival, and identify clinical and pathological risk
factors for prognosis.
METHODS
A retrospective, unicentric, cohort study was carried between 2012 and 2016. All consecutive
patients with (micro)papillary thyroid carcinoma was enrolled and divided in two groups:
microcarcinoma group (<10 millimeters) and control group ( 10 millimeters). Exclusion
criteria were loss to follow-up, previous thyroid surgery and non-operative treatment. Primary
endpoints were to compare overall survival and disease-free survival between groups.
Secondary endpoints were to assess which variables were associated to higher stages and
recurrence rate. In this study aggressive histology was defined as tall cell, hobnail variant,
columnar cell carcinoma, squamous differentiation, diffuse sclerosing variant or
solid/trabecular variant. The risk of recurrence was catalogued as high in the presence of
previous radiation exposure, family history of thyroid cancer, posterior location (near
recurrent nerve, esophagus or trachea), aggressive histology, multifocality or extrathyroidal
extension, according to ESMO Guidelines.[2] Tumour stage was catalogued by the eighth edition
of the Union for International Cancer Control (UICC) Tumour, Node and Metastasis (TNM)
classification.
Statistical analysis was performed using SPSS 26 (International Business Machines
Corporation). Continuous variables were presented as mean ± SD, whereas qualitative data
were presented as number and percentage. Categorical variables were presented as the
number of patients and its corresponding proportion with respect to the group under study.
Patient characteristics were compared with Mann Whitney tests for continuous variables and
Chi-square or Fisher’s exact tests for categorical variables. Overall cumulative survival and
disease-free survival were obtained by the Kaplan-Meyer method and compared by log rank
test. Significance was assumed whenever p values were less than 0.05. This work has been
performed in accordance with the ethical standards laid down in the Declaration of Helsinki.
Approval of ethical commission of our hospital was dismissed because it was an observational
study that granted confidentiality of data.
RESULTS
Patient’s Demographics
Records of 93 patients (37 mPTCs and 56 PTCs) were analyzed (table 1). Yearly distribution of
cases was 7.4 and 11.2 cases for mPTCs and PTCs, respectively. There were only 5 male patients,
2 in mPTC and 3 in PTC group (5.4 vs. 6.9%, p=1). Patients in mPTC group were significantly
older (45.4 vs. 54.3 years, p=0.003) and had significantly smaller nodules (11 7 vs. 23 11
millimeters; p=0.000). There were no differences regarding family history (0 vs. 3.5%) of TC,
radiation exposure (0 vs. 1.8%) and symptomatic clinical presentation (p=0.148) between
groups. The most frequent clinical presentations were asymptomatic thyroid nodule (70.3 vs.
55.4%), goiter (10.8 vs. 17.9%), dysphagia (8.1 vs. 7.2%), globus sensation (0 vs. 8.9%), lymph
node (5.4 vs. 0%) and dysphonia (2.7 vs. 3.6%). Diagnosis was incidental following
thyroidectomy for presumably benign thyroid lesions in 6 cases (5.4 vs. 7.1%, p=0.739).
Hemithyroidectomy (lobectomy and isthmusectomy) was performed in 18.9% of patients with