Abstract
Objective: To investigate the correlation between hypothyroidism and serum creatine kinase (CK) levels in patients with differentiated thyroid cancer (DTC) during radioactive iodine (131I) therapy following total thyroidectomy.
Methods: This prospective study enrolled 170 DTC patients (50 males and 120 females) with a mean age of 39.41±9.45 years, who were treated at the First Affiliated Hospital of Zhengzhou University from January 2023 to June 2023. Thyroid-related hormones and serum CK levels were measured at two time points: one month postoperatively (before 131I therapy) and seven months postoperatively (before 131I therapy follow-up), both under hypothyroid conditions. Paired t-tests (two-tailed) were used to compare changes in serum biomarkers between the two time points within the same patients, and Pearson correlation analysis (correlation coefficient r) was employed to assess the relationship between thyroid-related hormones and serum CK levels.
Results: At one month postoperatively (before 131I therapy), the mean serum CK level in hypothyroid DTC patients was 160.22±130.95 U/L, with mean FT3, FT4, and TSH levels of 2.89±0.60 pmol/L, 1.87±130.98 pmol/L, and 135.99±68.23 mIU/L, respectively. At seven months postoperatively (before 131I therapy follow-up), the mean serum CK level increased to 253.80 ±429.10 U/L, while mean FT3, FT4, and TSH levels were 3.29±0.58 pmol/L, 1.84±422.61 pmol/L, and 109.87±53.02 mIU/L, respectively. A significant difference was observed in serum CK levels between one month and seven months postoperatively (t = -2.94, p = 0.004). Pearson correlation analysis revealed a negative correlation between FT3 and serum CK levels at both one month (r = -0.196, p = 0.01) and seven months (r = -0.153, p = 0.047) postoperatively.
Conclusion: The elevation of serum CK levels in DTC patients after total thyroidectomy is primarily attributed to hypothyroidism rather than surgical trauma, with FT3 being a key contributing factor. These findings highlight the importance of closely monitoring thyroid function and CK levels in postoperative DTC patients to optimize clinical management strategies.