Optimal Timing of Surgery for Differentiated Thyroid Cancer in Pregnant Women

Diagnostic and Treatment Considerations for Thyroid Cancer in Women of Reproductive Age and the Perinatal Period

Thyroid cancer is one of the most common cancers diagnosed in women of reproductive age and during pregnancy. This leads to important questions about thyroid cancer prognosis and treatment, but also fertility and risk for adverse obstetric and/or fetal and neonatal outcomes. The benefits of thyroid cancer treatment should be weighed against its harms, as various options may adversely impact maternal and fetal health. In the current review, the authors focus on perinatal-specific clinical considerations related to the care of patients with thyroid cancer.

Thyroid Disease in Pregnancy: A Descriptive Review of Guidelines

Importance

Thyroid disorders represent one of the most frequent complications of pregnancy associated with adverse obstetric, fetal, and neonatal outcomes, especially in case of delayed diagnosis and suboptimal management.

Objective

The aim of this study was to review and compare the recommendations of the most recently published guidelines on the diagnosis and management of these common conditions.

Evidence Acquisition

A descriptive review of guidelines from the Endocrine Society, the European Thyroid Association, the Royal Australian and New Zealand College of Obstetricians and Gynecologists, the American Thyroid Association, and the American College of Obstetricians and Gynecologists on thyroid disease in pregnancy was carried out.

Results

There is an overall consensus regarding the diagnosis of overt and subclinical hypothyroidism and hyperthyroidism in pregnancy using the pregnancy-specific reference ranges and the definition of postpartum thyroiditis. The reviewed guidelines unanimously discourage universal screening for thyroid function abnormalities before and during pregnancy and support targeted screening of high-risk patients by measuring serum thyroid-stimulating hormone levels. Moreover, they all highlight the need of treating overt hypothyroidism and hyperthyroidism, not only during pregnancy, but also before conception, suggesting similar management policies and treatment targets. There is also agreement regarding the management of gestational transient hyperthyroidism with hyperemesis gravidarum, suspected fetal thyrotoxicosis, postpartum thyroiditis, and thyroid malignancy. Scanning or treating with radioactive iodine is contraindicated during pregnancy and breastfeeding. On the other hand, there is controversy on the management of subclinical thyroid disease, thyroid function surveillance protocols, and iodine nutrition recommendations. Of note, the American College of Obstetricians and Gynecologists makes some specific recommendations on the treatment of thyroid storm and thyrotoxic heart failure in pregnant women, whereas the American Thyroid Association makes a special reference to the management of women with thyroid cancer.

Conclusions

As the disorders of the thyroid gland affect a significant proportion of pregnant women, it is of paramount importance to develop uniform international evidence-based protocols for their accurate diagnosis and optimal management, in order to safely guide clinical practice and eventually improve perinatal outcomes.

Time to Surgery and Thyroid Cancer Survival in the United States

BACKGROUND

Longer time to surgery worsens survival in multiple malignancies, including lung, colorectal, and breast cancers, but limited data exist for well-differentiated thyroid cancer. We sought to investigate the impact of time to surgery on overall survival in patients with papillary thyroid cancer.

METHODS

In a retrospective cohort study of the National Cancer Database, we used Cox proportional hazard models to investigate overall survival as a function of time between diagnosis and surgery for adults with papillary thyroid cancer, adjusting for demographic, patient, and cancer-related variables. Time to surgery was investigated both as a continuous variable and as intervals of 0-90 days, 90-180 days, and > 180 days. Subgroup analyses were conducted by T stage.

RESULTS

Overall, 103,812 adults with papillary thyroid cancer were included from 2004 to 2016. Median follow-up was 55.2 months (interquartile range 28.4-89.5). Increasing time to surgery was associated with increased mortality: delaying by 91-180 days increased the risk by 30% (adjusted hazard ratio [aHR] 1.30, 95% CI 1.19-1.43) and delaying by over 180 days increased the risk by 94% (aHR 1.94, 95% CI 1.68-2.24). Five-year overall survival was 95.7% for 0-90 days, 93.0% for 91-180 days, and 87.9% for over 180 days. On subgroup analysis, increasing delay was associated with worse overall survival for T1, T2, and T3 tumors, but not T4 tumors.

CONCLUSIONS

Increasing time to surgery in papillary thyroid cancer is associated with reduced overall survival. Further research is necessary to assess the impact of surgical delay on disease-specific survival.

Thyroid nodules and cancer during pregnancy, post-partum and preconception planning: Addressing the uncertainties and challenges

Thyroid nodules and thyroid cancer have become increasingly common worldwide. When discovered during pregnancy, they pose unique diagnostic and therapeutic challenges for both the treating physician and the patient. The benefits of treatment should be carefully weighed against risks that may adversely impact maternal and fetal health. In this review, we present current knowledge and controversies surrounding the management of thyroid nodules and thyroid cancer in pregnancy, in the post-partum period and during preconception planning.

Pregnancy outcomes after thyroid cancer

Background Thyroid cancer is one of the most common cancers in women of reproductive age. Our purpose was to evaluate the association between thyroid cancer and maternal and neonatal outcomes of pregnancy. Methods We conducted a retrospective cohort study using the Healthcare Cost and Utilization Project, Nationwide Inpatient Sample (HCUP-NIS) database from the US. A cohort consisting of women who delivered between 1999 and 2014 was created. Multivariate logistic regression, controlling for baseline maternal characteristics, was used to compare pregnancy complications and neonatal outcomes of pregnant women with thyroid cancer [International Classification of Diseases, ninth edition (ICD-9) code 193] diagnosed before or during pregnancy with those of the obstetric population without thyroid cancer. Results The study included 14,513,587 pregnant women, of which 581 women had a diagnosis of thyroid cancer (4/100,000). During the observation period, there was an upward trend in the prevalence of thyroid cancer among pregnant women, though not statistically significant (P = 0.147). Women with thyroid cancer were more likely to be Caucasian, belong to a higher income quartile, have private insurance, to be discharged from an urban teaching hospital and to have pre-gestational hypertension. Women with thyroid cancer had a greater chance of delivering vaginally, requiring transfusion of blood and developing venous thromboembolism (VTE). Neonates of mothers with thyroid cancer were not found to be at increased risk for the adverse neonatal outcomes examined, specifically, congenital malformations, intrauterine growth restriction, fetal death and preterm labor. Conclusion Pregnancies complicated by thyroid cancer have higher incidences of VTE and need for transfusions, with comparable overall newborn outcomes.

Pregnancy as a risk factor for thyroid cancer progression

PURPOSE OF REVIEW

The current review evaluates the impact of pregnancy on women with thyroid cancer in three different clinical situations: those with newly diagnosed differentiated thyroid cancer (DTC), those under active surveillance for papillary thyroid microcarcinomas (PMCs), and those with previously treated DTC.

RECENT FINDINGS

Recent pregnancy is not associated with high-risk pathological features of DTC. In women with known PMCs under active surveillance, pregnancy does not increase the risk of disease progression. Thus, deferring surgery for newly diagnosed DTC or known PMCs until after delivery is safe for both mother and the unborn child. If a woman with previously treated DTC is planning pregnancy, response-to-therapy status is an excellent guide for predicting pregnancy-associated disease progression or recurrence.

SUMMARY

Clinical studies consistently show that pregnancy is not associated with significant disease progression in newly diagnosed thyroid cancer, PMCs under active surveillance, or previously treated DTC.

Pregnancy in papillary thyroid cancer survivors

OBJECTIVE

To evaluate “papillary thyroid carcinoma-pregnancy” interaction among cancer survivors.

MATERIAL AND METHODS

The clinical records of 8 pregnant women who received treatment for papillary thyroid cancer before their pregnancy were evaluated. Clinical features, pregnancy/perinatal outcomes and high-risk factors were compared with 45 controls who were randomly assigned from the institutional perinatal medicine database.

RESULTS

Patients in the cancer group were older than the control group (34.3 vs 29.8 years). The cesarean section rate was higher (62.5% vs 33.3%) and the APGAR scores at the 1^st and 5^th minutes were lower in the cancer group.

CONCLUSION

Management of pregnancies with papillary thyroid cancer treatment and follow-up requires a multidisciplinary approach with careful antenatal care and perinatal surveillance. Patients who have received papillary thyroid cancer treatment can safely undergo pregnancy.

Maternal and obstetrical outcome in 35 cases of well-differentiated thyroid carcinoma during pregnancy

OBJECTIVES/HYPOTHESIS

Thyroid cancer, with 6% to 10% of cancer diagnoses, is one of the most common malignancies during pregnancy. Its treatment poses a risk for the pregnancy, as the thyroid gland plays a crucial role in the evolution of pregnancy. The aim of this study is to evaluate treatment of primary well-differentiated thyroid carcinoma during pregnancy and fetal and maternal outcomes.

STUDY DESIGN

This is an international cohort study.

METHODS

Primary thyroid cancer patients were identified from the database of the International Network on Cancer, Infertility, and Pregnancy registration study. Data on histopathological characteristics, diagnostic and therapeutic interventions, outcome (obstetrical, neonatal, and maternal) and maternal follow-up were analyzed.

RESULTS

Thirty-five patients with well-differentiated thyroid carcinoma were eligible. All 35 patients underwent surgery, 29 (83%) of which during pregnancy. Procedures during pregnancy were mainly total thyroidectomies (n = 24). The median number of days between diagnosis and surgical treatment was different between the groups with surgery during and after pregnancy (27 vs. 139 days, P < .001). Both maternal and neonatal outcomes were uncomplicated, regardless of gestational age during surgery.

CONCLUSIONS

Well-differentiated thyroid carcinoma diagnosed during pregnancy has a favorable outcome for both mother and child. Surgical management during pregnancy has no negative impact on the pregnancy regardless of the trimester at the time of surgery. However, the potential negative effects of thyroid surgery early in pregnancy demand management of these patients in an experienced multidisciplinary team to provide the best possible care for these patients and their unborn babies.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:1493-1500, 2018.

Thyroid papillary cancer-related pregnancy: a case report

Differentiated thyroid cancer is the second-most frequent tumor among those tumors diagnosed during pregnancy after breast cancer; it also is the most common endocrine malignancy. Pregnancy-associated cancer was defined as a malignancy detected during pregnancy or within 2 years of delivery, but most of the patients with pregnancy-associated cancer were recognized in the postpartum period. The best time for surgery is unclear. Its management is a challenge for both doctors and patients. Enlargement of the thyroid gland in pregnancy is usually a physiological change related to pregnancy, but even if it is rare, it can be due to thyroid malignancy. We report a case of 31-year-old female diagnosed with thyroid papillary cancer during pregnancy with no symptoms except for a lump on her neck. For this reason, the examination of the thyroid gland and the examination of neck lymph nodes should be routinely performed on all pregnant women.

2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum

BACKGROUND

Thyroid disease in pregnancy is a common clinical problem. Since the guidelines for the management of these disorders by the American Thyroid Association (ATA) were first published in 2011, significant clinical and scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, researchers, and health policy makers on published evidence relating to the diagnosis and management of thyroid disease in women during pregnancy, preconception, and the postpartum period.

METHODS

The specific clinical questions addressed in these guidelines were based on prior versions of the guidelines, stakeholder input, and input of task force members. Task force panel members were educated on knowledge synthesis methods, including electronic database searching, review and selection of relevant citations, and critical appraisal of selected studies. Published English language articles were eligible for inclusion. The American College of Physicians Guideline Grading System was used for critical appraisal of evidence and grading strength of recommendations. The guideline task force had complete editorial independence from the ATA. Competing interests of guideline task force members were regularly updated, managed, and communicated to the ATA and task force members.

RESULTS

The revised guidelines for the management of thyroid disease in pregnancy include recommendations regarding the interpretation of thyroid function tests in pregnancy, iodine nutrition, thyroid autoantibodies and pregnancy complications, thyroid considerations in infertile women, hypothyroidism in pregnancy, thyrotoxicosis in pregnancy, thyroid nodules and cancer in pregnant women, fetal and neonatal considerations, thyroid disease and lactation, screening for thyroid dysfunction in pregnancy, and directions for future research.

CONCLUSIONS

We have developed evidence-based recommendations to inform clinical decision-making in the management of thyroid disease in pregnant and postpartum women. While all care must be individualized, such recommendations provide, in our opinion, optimal care paradigms for patients with these disorders.

Thyroid nodule update on diagnosis and management

Thyroid nodules are common. The clinical importance of thyroid nodules is related to excluding malignancy (4.0 to 6.5% of all thyroid nodules), evaluate their functional status and assess for the presence of pressure symptoms. Incidental thyroid nodules are being diagnosed with increasing frequency in the recent years with the use of newer and highly sensitive imaging techniques. The high prevalence of thyroid nodules necessitates that the clinicians use evidence-based approaches for their assessment and management. New molecular tests have been developed to help with evaluation of malignancy in thyroid nodules. This review addresses advances in thyroid nodule evaluation, and their management considering the current guidelines and supporting evidence.

A review on thyroid cancer during pregnancy: Multitasking is required

Thyroid cancer is the second most common cancer diagnosed during pregnancy after breast cancer. The goal of management is to control malignancy and prevent maternal and fetal complications as a result of maternal hypothyroidism. The role of female sex hormones as an etiologic factor was investigated, with no clear association. Pregnancy can cause an increase in size of a previously existed thyroid nodule through the structural similarity between TSH and BHCG, and the normally expressed estrogen receptors on thyroid gland cells. Effect of pregnancy on development and prognosis of differentiated thyroid malignancies (papillary and follicular) has also been studied. The prognosis of thyroid cancer is not worse in patients diagnosed during pregnancy or those who got pregnant after curative treatment. Termination of pregnancy is not indicated at all, surgery can be delayed till after delivery except in rapidly growing aggressive tumors. While radioactive iodine ablation is absolutely contra-indicated, the new systemic therapies are not well studied during pregnancy. However, almost all these new agents are classified as FDA category C or D and are better to be avoided. The effect of pregnancy on other types of thyroid cancer (medullary and anaplastic thyroid tumors) is not well studied because of very low incidence with pregnancy. The endocrinological management of thyroid cancer during pregnancy is of utmost importance. The hypothyroidism after total thyroidectomy can cause fetal hypothyroidism. Therefore, the management of thyroid cancer related to pregnancy needs a multidisciplinary team.