Background:Papillary thyroid cancer (PTC) is the second most common malignancy during pregnancy, accounting for 6%-10% of all cancers diagnosed during pregnancy. Given their excellent prognosis, studies have demonstrated that postponing surgery for PTC until postpartum or at earliest, in the second trimester of pregnancy, does not affect tumor recurrence or mortality. During this period, the changes to the behavior of PTC is relatively unknown.
Objective: The goal of this study is to evaluate the natural progression of papillary thyroid cancer during pregnancy as well as the long-term outcomes in this specific population.
Methods: A single institution retrospective chart review was undertaken from January 2008 to December 2017 at a major cancer center. 7 patients diagnosed with papillary thyroid cancer just prior to or during pregnancy were identified. Tumor growth was monitored with serial ultrasound during pregnancy. Postoperative outcomes were collected.
Results: 7 patients were found to have papillary thyroid cancer, confirmed with final pathology after surgery. 6 (71%) were identified during the first trimester, while 1 (14%) patients were identified one month prior to pregnancy. The initial sizes based on ultrasound ranged from 0.4 - 4.0 cm (median=2.1 cm). Final ultrasound size prior to surgery ranged from 0.8-5.5 cm (median=2.4 cm). Nodule growth based upon imaging was noted in 4/7 of the patients, ranging from 0.4-2.2 cm from time of diagnosis to prior to surgery. 2 patients had a decrease in nodule size during their pregnancy. Lymphadenopathy was present on imaging in 2 (29%) patients, and none of the patients developed further lymphadenopathy as evidenced by ultrasound on the day of surgery. One (14%) patient had an increase in T stage, while two (29%) had a decrease in their T stage. There were no changes to overall staging. Median interval from time of diagnosis to surgery was 11.5 months. Surgical treatments included Total Thyroidectomy with Central neck dissection (3/7, 43%), Total Thyroidectomy with Central and Right Lateral Neck dissection (1/7, 14%), Total Thyroidectomy alone (1/7, 14%), and Right Lobectomy (2/7, 29%). None of the patients had vocal cord paralysis postoperatively. Three (43%) patients received postoperative radioactive iodine treatment, and none had further evidence of residual disease or recurrence. Postoperative thyroglobulin levels in 6 patients (1 unavailable) confirmed undetectable levels.
Conclusions: Papillary thyroid cancer in pregnancy exhibits slow growth patterns during pregnancy. No patients had significant progression of disease throughout their pregnancy. No patient had evidence of disease or recurrence after treatment was completed. This series suggests that it is safe to delay surgery until after pregnancy in patients with papillary thyroid cancer, even among those with central and lateral neck disease.