Pregnancy Does not Affect the Prognoses of Differentiated Thyroid Cancer Patients With Lung Metastases.

Context: Pregnancy-related hormones may stimulate thyroid cancer growth, but whether pregnancy affects the prognoses of patients with lung metastases from differentiated thyroid cancer (DTC-LM) after surgery and radioiodine therapy is unclear.
Objective: To assess the impact of pregnancy on DTC-LM through the comparison of prognoses between female patients with DTC-LM who did and did not become pregnant after surgery and radioiodine therapy.
Methods: We retrospectively analyzed the records of 124 female patients aged 16 to 35 years who underwent surgery and radioiodine therapy for DTC-LM. These patients were divided into pregnancy group (n = 37) and nonpregnancy group (n = 87) according to whether they became pregnant after surgery and radioiodine therapy, regardless of whether they had a pregnant history before treatment.
Results: The 5- and 10-year progression-free survival rates were 94.52% and 63.22% in pregnancy group versus 89.82% and 58.13% in nonpregnancy group. The 5- and 10-year cumulative overall survival rates of pregnancy group were 97.30% and 85.77% versus 93.50% and 81.95% in nonpregnancy group (all P > 0.05). The median time of follow-up in the pregnancy and nonpregnancy groups was 82 months (25-136 months) and 68 months (13-133 months), respectively. Non-radioiodine-avid LM and primary tumors needing repeated resection were independent predictors of poor progression-free survival for patients in pregnancy group.
Conclusion: Pregnancy does not affect the prognoses of patients with DTC-LM after surgery and radioiodine therapy. Non-radioiodine-avid LM and repeated primary tumor surgeries are independent risk factors for poor prognoses of pregnant patients.
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