“At present, few studies examining the correlation between the outcome of differentiated thyroid cancer (DTC) and pregnancy have been published,” explained senior author Fabio Orlandi, MD, Associate Professor of Endocrinology, University of Turin, Italy. “Most of these studies concluded that pregnancy is not a determining condition for prognosis of DTC, neither in terms of mortality nor in terms of overall survival. Conversely, our study is in agreement with a paper published in 2010 by Vannucchi et al, in which the authors report a significant increase of persistence/recurrence of DTC in pregnant patients compared with nonpregnant women. The retrospective design of both studies represents the main limitation of the findings,” Dr. Orlandi said.
“Currently, even if an increasing awareness of the impact of pregnancy on DTC outcome is established, the significance of the findings is not strong enough to warrant modification of the 2011 American Thyroid Association guidelines for the management of thyroid cancer during pregnancy,” Dr. Orlandi said. “In other words, a thyroid nodule with cytology indicating papillary carcinoma discovered early in pregnancy should be monitored sonographically. Neck ultrasounds should be performed during each trimester to assess for rapid tumor growth or lymph node metastases, which indicate the need for surgery during pregnancy. In this case, the operation should be performed in the second trimester. For other women, surgery could be deferred until after delivery,” Dr. Orlandi said.
The retrospective study included medical records from 340 women (age <45 years) with DTC who were treated and followed for at least 1 year at a single hospital between 2001 and 2011.
Women diagnosed with DTC during pregnancy or within 2 years after were significantly more likely to experience tumor persistence/recurrence (10.5%) compared with women diagnosed at least 2 years after delivery (4.7%) or before pregnancy or nulliparous women (1.3%; P=0.023). No significant differences were found in other clinical parameters; immunohistochemical expression of estrogen receptor a (ERa), ERb, progesterone receptor, and aromatase; gene expression of NIS (SLC5A5); or the prevalence of BRAFV600E mutations.
The poorer outcome in women diagnosed with DTC during pregnancy could not be attributed to a more advanced staging at diagnosis or more aggressive phenotype as the three groups of women had similar clinical and morphological parameters.
“Perspective studies are strongly needed to evaluate whether the higher rate of persistent/recurrent disease could affect quality of life or mortality rate in a long-term follow-up study,” Dr. Orlandi concluded.
More Careful Followup Is Needed
The study finding “leads us to pay more attention on the follow-up of DTC discovered during pregnancy or shortly after,” commented Sebastiano Filetti, MD, Professor of Internal Medicine, Department of Internal Medicine, University of Sapienza, Rome, Italy.
“A different approach for the follow-up of women with DTC diagnosed during pregnancy is not yet established in international guidelines,” Dr. Filetti said. “In my opinion, these patients deserve a more careful follow-up in order to detect early signs of a more aggressive disease, as suggested by the authors,” he noted.
“At present, the available data disclose a higher percentage of biochemical or clinical disease, but we don’t know whether this could affect the morbidity/mortality rate of the patients on long-term follow-up,” Dr. Filetti concluded, adding that perspective, multicenter studies are needed to gain a better understanding of this association.
Messuti I, Corvisieri S, Bardesono F, et al. Impact of pregnancy on prognosis of differentiated thyroid cancer: clinical and molecular features. Eur J Endocrinol. 2014;170(5):659-666.