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Revista Peruana de Ginecología y Obstetricia

versión On-line ISSN 2304-5132

Rev. peru. ginecol. obstet. vol.67 no.1 Lima ene./mar 2021

http://dx.doi.org/10.31403/rpgo.v67i2304 

Special Articles

Management of thyroid cancer during pregnancy

Eduardo Reyna-Villasmil1 

1. Doctor in Clinical Medicine, Specialist in gynecology and obstetrics, Obstetrics and Gynecology Service, Central Hospital "Dr. Urquinaona , Maracaibo, Zulia State, Venezuela

ABSTRACT

Pregnancy is a favorable condition for the formation and growth of thyroid cancer, since the iodine balance can be negative in addition to increasing the production of hormones with thyroid stimulating activity. Most of the cancers found during pregnancy are differentiated thyroid cancers with an excellent prognosis. Those cases diagnosed during the first trimester can be removed by surgery. Thyroidectomy can be safely performed in the second trimester of pregnancy or delayed to the postpartum period, depending on gestational age. The patient should receive levothyroxine at a dose sufficient to keep serum thyroid-stimulating hormone levels low. Serum thyroglobulin is a valuable noninvasive method for evaluating the effects of this treatment. The purpose of this review is to establish the management of thyroid cancer during pregnancy.

Key words: Thyroid cancer; Pregnancy complications, neoplastic

Introduction

The number of new cases of thyroid cancer, according to the National Cancer Institute, is 13.9 per 100,000 people per year, and its 5-year survival rate is 98.1%1. In recent decades, the incidence of thyroid cancer, mainly those smaller than 2 centimeters in diameter, has increased. This trend does not apply to other types of thyroid cancer (follicular, medullary, or anaplastic)2. The increase in frequency can be explained by the better diagnostic tools available at present. However, risk factors for thyroid cancer include exposure to ionizing radiation and iodine deficiency. The negative effect of ionization is greater the younger the age of the exposed patients. After Chernobyl events in 1986, incidence of benign and malignant thyroid tumors increased 80 times in children born in vicinity of the power plant3.

Thyroid cancer like other thyroid diseases is 3 times more common in women than in men. It can occur in women of any age, but the risk is at its highest at a younger age compared to men and with a clear prevalence during reproductive age (more than a third of diagnosed cases),

which would indicate a possible effect of sex hormones on pathogenesis4,5. Cohort studies show that late menarche and prolonged menstrual cycles of more than 30 days increase the risk of papillary cancer6-8. On the other hand, 1% -2% of patients with thyroid cancer have germline mutations of RET gene9. People with type 2 multiple endocrine neoplasia have a risk greater than 95% of developing thyroid cancer.

The aim of this review is to establish the management of cervical cancer during pregnancy.

Methodology of the Information search

Between July and January 2019, electronic databases of biomedical scientific literature (UP-ToDATE, OVIDSP, ScienceDirect, SciELO and PUBMED) were examined to investigate eligible articles in the last 30 years (1989 -2019), with the search terms: "Thyroid cancer", "Pregnancy", "Malignant thyroid neoplasms", "Diagnosis" and "treatment". Articles in English and Spanish of studies carried out in humans were included, subsequently carrying out an analysis of the different aspects of diagnosis, treatment and management of neoplastic lesions of the thyroid gland in pregnant women.

Diagnosis

During pregnancy, thyroid gland increases 30% of its volume. The thyroid stimulating hormone (TSH) levels first decrease and then return to normal. These changes lead to an increase in circulating concentration of human chorionic gonadotropin (hCG) and estrogens. hCG stimulates TSH receptors and thus increases the activity of the thyroid gland. The effect of estrogens on the thyroid gland is twofold: indirect, by increasing the concentration of thyroxine-binding globulin, and direct, through estrogen receptors (ERs) found in thyroid cells10. These intracellular nuclear receptors (alpha and beta) are present in both healthy and neoplastic cells. Estradiol, by binding to ER alpha, increases cell proliferation, while beta receptors inhibit this effect and induce apoptosis11,12. Research suggests a relationship between the expression of the estrogen receptor and the onset of the disease13-15.

Pregnancy-related thyroid cancer is diagnosed during pregnancy or within a year after delivery16. Pregnancy does not adversely affect overall survival17,18. Data on relapses and mortality associated with disease progression during pregnancy are not conclusive19,20. Pregnancy causes an increase in size of the micropapillary carcinoma foci20.

Thyroid nodular lesions are quite common during pregnancy: they appear de novo or existing lesions increase in size21. In areas with mild to moderate iodine deficiency, the incidence of thyroid nodules during pregnancy ranges from 3% to 21%22-24. In pregnant women, thyroid nodules have similar diagnostic criteria to non-pregnant patients, with the exception of images with radioactive agents. It is necessary to determine the serum concentrations of TSH, free thyroxine and evaluate the structure of the gland by ultrasound. Indications for fine needle biopsy do not differ from those in the general population25,26. Retrospective studies report that 12% -43% of neoplastic lesions are based on existing benign lesions27-30.

Another question is the possible impact of pregnancy on the course of the disease, its prognosis and the risk of recurrence in patients previously treated for thyroid cancer. Risk of recurrence is low in women without residual tumor sites and low thyroglobulin concentrations31,32. Pregnancy does not change the course of differentiated thyroid cancer33. Women diagnosed with thyroid carcinoma during pregnancy should be closely followed to detect persistent or recurrent disease and monitor for possible complications31-34. Patients with elevated thyroglobulin or persistent disease should be evaluated by ultrasound at least once each trimester and their thyroglobulin concentrations should be determined35.

If irregular and hypoechoic margins, increased internal vascularization, presence of lymphadenopathy and / or microcalcifications are observed during the physical examination and ultrasound, it is necessary to perform a fine needle biopsy and subsequent cytological examination, using the Bethesda classification as the gold standard. The procedure must be repeated in case of an inconclusive result36,37. Due to the free absorption of radioactive elements by the fetal thyroid gland and the possible induction of thyroid cancer in the offspring, the use of radiolabeled iodine (I131) is contraindicated in pregnant women. Alternatives are Technetium 99 or Iodine 12338.

Treatment

Thyroid cancer is not an indication for termination of pregnancy15. Subtotal or total thyroidectomy is the primary treatment for these cases. Before the diagnosis of follicular cancer, it is necessary to consider surgery during pregnancy. In cases of differentiated tumor, it is advisable to postpone surgery until after delivery. If treatment is postponed, ultrasound checks are required every trimester. If tumor size does not change, treatment should be established to keep TSH values between 0.1 - 1.5 mIU / L26,35.

In cases of rapid tumor growth in early pregnancy, presence of lymph node metastases, signs of histological malignancy or symptoms of compression, surgery may be performed in second trimester of pregnancy, as it is safe for both mother and fetus.27,35. Surgery during pregnancy is associated with a higher risk of postoperative complications39. In retrospective studies in pregnant women undergoing thyroidectomy, surgical (11% compared to 4%) and endocrine (16% compared to 8%) complications were greater in pregnant women compared to non-pregnant women40. Endocrine complications include: maternal hypoparathyroidism, hypocalcemia, and recurrent laryngeal nerve damage. Surgical complications depend on the experience of the surgeon. Due to the increased risk of preterm delivery and alterations in fetal well-being during the procedure, diagnosis during the second trimester should lead to a delay in surgery until the postpartum period36,41,42.

In most patients, complementary therapy after surgery is treatment with I131(43, which reduces the risk of recurrence and distant metastasis. This can only be done after delivery and breastfeeding15. Exposure of the fetus to I131 causes hypothyroidism, cognitive impairment, and mental retardation42. If postpartum treatment is necessary, breastfeeding should be completed 6 to 8 weeks prior to treatment44. This recommendation is due to the increased activity of iodine in glandular tissue subjected to the effects of estrogen, leading to accumulation of radiolabeled iodine in the breast. Dopamine agonists are helpful in lowering prolactin levels and shortening the time to start treatment45. There is no evidence that this treatment affects fertility46. It is desirable to maintain an interval of 6 to 12 months after completing the treatment to conceive, which allows achieving remission and maintaining adequate replacement therapy34,46.

Levothyroxine can be administered for a variety of indications: treatment when surgery is postponed, replacement after thyroidectomy, or treatment for persistent disease. The suppressive dose maintains TSH concentration at 0.1 -1 mIU / L. It should be indicated as soon as possible after confirmation of pregnancy diagnosis, then every month until mid-pregnancy and at least once between 26 and 32 weeks35. After surgery, levothyroxine replacement during pregnancy is necessary due to the risk of fetal hypothyroidism. Doses should be modified due to the 20-30% increase in the needs of the growing fetus. The switch should be made when TSH concentrations exceed 0.5 mIU / L, which can occur early in pregnancy46. The simultaneous supplementation of iron and / or calcium affects the absorption of levothyroxine36,47.

Suppression doses in persistent or residual neoplastic disease should ensure that TSH concentrations are kept below 0.1 mIU / L. Most studies establish that the target value in pregnant women should be less than 0.5 mIU / L. For high-risk patients, doses that achieve TSH suppression are recommended, as is done outside of pregnancy48. Radioactive iodine-resistant thyroid cancer can be treated with tyrosine kinase inhibitors. However, these drugs are contraindicated in pregnancy, as they are classified in category D according to the US Food and Drug Administration47,49

Conclusions

Thyroid cancer is often found in young women. The association between pregnancy and thyroid cancer is not uncommon, since 10% of thyroid cancer cases that occur during reproductive age are diagnosed during pregnancy or in puerperium. Most of the cancers found during pregnancy are differentiated thyroid cancers with an excellent prognosis and disease-free survival in pregnant women does not differ compared to nonpregnant women of similar age and stage.

The main objectives of the management of pregnant women with thyroid cancer are: to achieve an adequate balance of thyroid hormones necessary for the normal maturation of the fetal central nervous system and to maintain optimal hormonal concentrations that prevent the recurrence or spread of the disease. Those cases diagnosed early in pregnancy can be treated with surgery, safely in the second trimester. Cases diagnosed in the second and third trimesters should be treated in puerperium. There are no data to support the termination of pregnancy in these patients.

REFERENCES

1. Aschebrook-Kilfoy B, Grogan RH, Ward MH, Kaplan E, Devesa SS. Follicular thyroid cancer incidence patterns in the United States, 1980-2009. Thyroid. 2013;23(8):1015-21. doi: 10.1089/thy.2012.0356 [ Links ]

2. Veiga LH, Neta G, Aschebrook-Kilfoy B, Ron E, Devesa SS. Thyroid cancer incidence patterns in Sao Paulo, Brazil, and the U.S. SEER program, 1997-2008. Thyroid. 2013;23(6):748-57. doi: 10.1089/thy.2012.0532 [ Links ]

3. Farahati J, Demidchik EP, Biko J, Reiners C. Inverse association between age at the time of radiation exposure and extent of disease in cases of radiation-induced childhood thyroid carcinoma in Belarus. Cancer. 2000;88(6):1470-6. [ Links ]

4. Weeks KS, Kahl AR, Lynch CF, Charlton ME. Racial/ethnic differences in thyroid cancer incidence in the United States, 2007-2014. Cancer. 2018;124(7):1483-91. doi: 10.1002/cncr.31229 [ Links ]

5. Smith LH, Danielsen B, Allen ME, Cress R. Cancer associated with obstetric delivery: results of linkage with the California cancer registry. Am J Obstet Gynecol. 2003;189(4):1128-35. [ Links ]

6. Wang P, Lv L, Qi F, Qiu F. Increased risk of papillary thyroid cancer related to hormonal factors in women. Tumour Biol. 2015;36(7):5127-32. doi: 10.1007/s13277-015-3165-0 [ Links ]

7. Shin S, Sawada N, Saito E, Yamaji T, Iwasaki M, Shimazu T, et al. Menstrual and reproductive factors in the risk of thyroid cancer in Japanese women: the Japan Public Health Center-Based Prospective Study. Eur J Cancer Prev. 2018;27(4):361-9. doi: 10.1097/CEJ.0000000000000338 [ Links ]

8. Zhou YQ, Zhou Z, Qian MF, Gong T, Wang JD. Association of thyroid carcinoma with pregnancy: A meta-analysis. Mol Clin Oncol. 2015;3(2):341-6. DOI: 10.3892/mco.2014.472 [ Links ]

9. Vigneri R, Malandrino P, Vigneri P. The changing epidemiology of thyroid cancer: why is incidence increasing? Curr Opin Oncol. 2015;27(1):1-7. doi: 10.1097/CCO.0000000000000148 [ Links ]

10. Derwahl M, Nicula D. Estrogen and its role in thyroid cancer. Endocr Relat Cancer. 2014;21(5):T273-83. doi: 10.1530/ERC-14-0053 [ Links ]

11. Huang Y, Dong W, Li J, Zhang H, Shan Z, Teng W. Differential expression patterns and clinical significance of estrogen receptor-a and ß in papillary thyroid carcinoma. BMC Cancer. 2014;14:383. doi: 10.1186/1471-2407-14-383 [ Links ]

12. Dong WW, Li J, Li J, Zhang P, Wang ZH, Sun W, et al. Reduced expression of oestrogen receptor-ß is associated with tumour invasion and metastasis in oestrogen receptor-a-negative human papillary thyroid carcinoma. Int J Exp Pathol. 2018;99(1):15-21. doi: 10.1111/iep.12266 [ Links ]

13. Tafani M, De Santis E, Coppola L, Perrone GA, Carnevale I, Russo A, et al. Bridging hypoxia, inflammation and estrogen receptors in thyroid cancer progression. Biomed Pharmacother. 2014;68(1):1-5. doi: 10.1016/j.biopha.2013.10.013 [ Links ]

14. Zahid M, Goldner W, Beseler CL, Rogan EG, Cavalieri EL. Unbalanced estrogen metabolism in thyroid cancer. Int J Cancer. 2013;133(11):2642-9. doi: 10.1002/ijc.28275 [ Links ]

15. Vannucchi G, Perrino M, Rossi S, Colombo C, Vicentini L, Dazzi D, et al. Clinical and molecular features of differentiated thyroid cancer diagnosed during pregnancy. Eur J Endocrinol. 2010;162(1):145-51. doi: 10.1530/EJE-09-0761 [ Links ]

16. Messuti I, Corvisieri S, Bardesono F, Rapa I, Giorcelli J, Pellerito R, et al. Impact of pregnancy on prognosis of differentiated thyroid cancer: clinical and molecular features. Eur J Endocrinol. 2014;170(5):659-66. doi: 10.1530/EJE-13-0903 [ Links ]

17. Yasmeen S, Cress R, Romano PS, Xing G, Berger-Chen S, Danielsen B, et al. Thyroid cancer in pregnancy. Int J Gynaecol Obstet. 2005;91(1):15-20. [ Links ]

18. Aschebrook-Kilfoy B, Ward MH, Sabra MM, Devesa SS. Thyroid cancer incidence patterns in the United States by histologic type, 1992-2006. Thyroid. 2011;21(2):125-34. doi: 10.1089/thy.2010.0021 [ Links ]

19. Yu SS, Bischoff LA. Thyroid Cancer in Pregnancy. Semin Reprod Med. 2016;34(6):351-5. DOI: 10.1055/s-0036-1593484 [ Links ]

20. Shindo H, Amino N, Ito Y, Kihara M, Kobayashi K, Miya A, et al. Papillary thyroid microcarcinoma might progress during pregnancy. Thyroid. 2014;24(5):840-4. doi: 10.1089/thy.2013.0527 [ Links ]

21. Kung AW, Chau MT, Lao TT, Tam SC, Low LC. The effect of pregnancy on thyroid nodule formation. J Clin Endocrinol Metab. 2002;87(3):1010-4. [ Links ]

22. Sahin SB, Ogullar S, Ural UM, Ilkkilic K, Metin Y, Ayaz T. Alterations of thyroid volume and nodular size during and after pregnancy in a severe iodine-deficient area. Clin Endocrinol (Oxf). 2014;81(5):762-8. doi: 10.1111/cen.12490 [ Links ]

23. Glinoer D, Soto MF, Bourdoux P, Lejeune B, Delange F, Lemone M, et al. Pregnancy in patients with mild thyroid abnormalities: maternal and neonatal repercussions. J Clin Endocrinol Metab. 1991;73(2):421-7. [ Links ]

24. Karger S, Schötz S, Stumvoll M, Berger F, Führer D. Impact of pregnancy on prevalence of goitre and nodular thyroid disease in women living in a region of borderline sufficient iodine supply. Horm Metab Res. 2010;42(2):137-42. doi: 10.1055/s-0029-1241861 [ Links ]

25. Mitchell AL, Gandhi A, Scott-Coombes D, Perros P. Management of thyroid cancer: United Kingdom National Multidisciplinary Guidelines. J Laryngol Otol. 2016;130(S2):S150-S160. DOI: 10.1017/S0022215116000578 [ Links ]

26. Alexander EK, Pearce EN, Brent GA, Brown RS, Chen H, Dosiou C, et al. 2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum. Thyroid. 2017;27(3):315-89. doi: 10.1089/thy.2016.0457 [ Links ]

27. Angell TE, Alexander EK. Thyroid nodules and thyroid cancer in the pregnant woman. Endocrinol Metab Clin North Am. 2019;48(3):557-67. DOI: 10.1016/j.ecl.2019.05.003 [ Links ]

28. Dabelic N, Matesa N, Matesa-Anic D, Kusic Z. Malignancy risk assessment in adenomatoid nodules and suspicious follicular lesions of the thyroid obtained by fine needle aspiration cytology. Coll Antropol. 2010;34(2):349-54. PMID: 20698101 [ Links ]

29. Rosen IB, Walfish PG, Nikore V. Pregnancy and surgical thyroid disease. Surgery. 1985;98(6):1135-40. [ Links ]

30. Smith LH, Danielsen B, Allen ME, Cress R. Cancer associated with obstetric delivery: results of linkage with the California cancer registry. Am J Obstet Gynecol. 2003;189(4):1128-35. [ Links ]

31. Rosario PW, Mineiro Filho AF, Lacerda RX, dos Santos DA, Calsolari MR. The value of diagnostic whole-body scanning and serum thyroglobulin in the presence of elevated serum thyrotropin during follow-up of anti-thyroglobulin antibody- positive patients with differentiated thyroid carcinoma who appeared to be free of disease after total thyroidectomy and radioactive iodine ablation. Thyroid. 2012;22(2):113- 6. doi: 10.1089/thy.2011.0020 [ Links ]

32. Hirsch D, Levy S, Tsvetov G, Weinstein R, Lifshitz A, Singer J, et al. Impact of pregnancy on outcome and prognosis of survivors of papillary thyroid cancer. Thyroid. 2010;20(10):1179-85. doi: 10.1089/thy.2010.0081 [ Links ]

33. Budak A, Gulhan I, Aldemir OS, Ileri A, Tekin E, Ozeren M. Lack of influence of pregnancy on the prognosis of survivors of thyroid cancer. Asian Pac J Cancer Prev. 2013;14(11):6941-3. [ Links ]

34. Chen PV, Osborne R, Ahn E, Avitia S, Juillard G. Adjuvant external-beam radiotherapy in patients with high-risk well-differentiated thyroid cancer. Ear Nose Throat J. 2009;88(7):E01. [ Links ]

35. Parkes IL, Schenker JG, Shufaro Y. Thyroid disorders during pregnancy. Gynecol Endocrinol. 2012;28(12):993-8. doi: 10.3109/09513590.2012.692001 [ Links ]

36. Delshad H, Amouzegar A, Mehran L, Azizi F. Comparison of two guidelines on management of thyroid nodules and thyroid cancer during pregnancy. Arch Iran Med. 2014;17(10):670-3. doi: 0141710/AIM.006 [ Links ]

37. Akalra B, Sawhney K, Kalra S. Management of thyroid disorders in pregnancy: Recommendations made simple. J Pak Med Assoc. 2017;67(9):1452-5. PMID: 28924295 [ Links ]

38. Helewa M, Lévesque P, Provencher D, Lea RH, Rosolowich V, Shapiro HM, et al. Breast cancer, pregnancy, and breastfeeding. J Obstet Gynaecol Can. 2002;24(2):164-80. [ Links ]

39. Papini E, Negro R, Pinchera A, Guglielmi R, Baroli A, Beck-Peccoz P, et al. Thyroid nodule and differentiated thyroid cancer management in pregnancy. An Italian Association of Clinical Endocrinologists (AME) and Italian Thyroid Association (AIT) Joint Statement for Clinical Practice. J Endocrinol Invest. 2010;33(8):579-86. doi: 10.3275/7172 [ Links ]

40. Kuy S, Roman SA, Desai R, Sosa JA. Outcomes following thyroid and parathyroid surgery in pregnant women. Arch Surg. 2009;144(5):399-406; discussion 406. doi: 10.1001/ archsurg.2009.48 [ Links ]

41. Chong KM, Tsai YL, Chuang J, Hwang JL, Chen KT. Thyroid cancer in pregnancy: a report of 3 cases. J Reprod Med. 2007;52(5):416-8. [ Links ]

42. Wémeau JL, Do Cao C. Thyroid nodule, cancer and pregnancy. Ann Endocrinol (Paris). 2002;63(5):438-42. [ Links ]

43. Durante C, Haddy N, Baudin E, Leboulleux S, Hartl D, Travagli JP, et al. Long-term outcome of 444 patients with distant metastases from papillary and follicular thyroid carcinoma: benefits and limits of radioiodine therapy. J Clin Endocrinol Metab. 2006;91(8):2892-9. [ Links ]

44. Modesti C, Aceto P, Masini L, Lombardi CP, Bellantone R, Sollazzi L. Approach to thyroid carcinoma in pregnancy. Updates Surg. 2017;69(2):261-5. doi: 10.1007/s13304-017-0476-2 [ Links ]

45. Greenlee C, Burmeister LA, Butler RS, Edinboro CH, Morrison SM, Milas M, et al. Current safety practices relating to I-131 administration for diseases of the thyroid: a survey of physicians and allied practitioners. Thyroid. 2011;21(2):151- 60. doi: 10.1089/thy.2010.0090 [ Links ]

46. Galofré JC, Riesco-Eizaguirre G, Alvarez-Escolá C; Grupo de Trabajo de Cáncer de Tiroides de la Sociedad Española de Endocrinología y Nutrición. Clinical guidelines for management of thyroid nodule and cancer during pregnancy. Endocrinol Nutr. 2014;61(3):130-8. doi: 10.1016/j.endonu. 2013.08.003 [ Links ]

47. Papini E, Negro R, Pinchera A, Guglielmi R, Baroli A, Beck-Peccoz P, et al. Thyroid nodule and differentiated thyroid cancer management in pregnancy. An Italian Association of Clinical Endocrinologists (AME) and Italian Thyroid Association (AIT) Joint Statement for Clinical Practice. J Endocrinol Invest. 2010;33(8):579-86. doi: 10.3275/7172 [ Links ]

48. Toloza FJK, Singh Ospina NM, Rodriguez-Gutierrez R, O'Keeffe DT, Brito JP, Montori VM, et al. Practice Variation in the Care of Subclinical Hypothyroidism During Pregnancy: A National Survey of Physicians in the United States. J Endocr Soc. 2019;3(10):1892-906. doi: 10.1210/js.2019-00196 [ Links ]

49. Pacini F, Castagna MG, Brilli L, Pentheroudakis G; ESMO Guidelines Working Group. Thyroid cancer: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Ann Oncol. 2012;23 Suppl 7:vii110-9. doi: 10.1093/annonc/mds230. [ Links ]

The author states the following:

Financing. The author certifies that he has not received financial support, equipment, personnel or in-kind support from individuals, public and/or private institutions for the study

Cite as: Reyna-Villasmil E. Management of thyroid cancer during pregnancy. Rev Peru Ginecol Obstet. 2021;67(1). DOI: https://doi. org/10.31403/rpgo.v67i2304

Received: February 14, 2020; Accepted: November 03, 2020

Corresponding author: Dr. Eduardo Reyna-Villasmil , Hospital Central "Dr. Urquinaona" Final Av. El Milagro, Maracaibo, Estado Zulia, Venezuela • 58162605233 sippenbauch@gmail.com

Acknowledgment of authorship: The author declares that he has made contributions to the idea, study design, data collection, analysis and interpretation of data, critical review of the intellectual content and final approval of the manuscript that he is sending

Conflict of interests. The author declares no conflict of interest

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