The association between BRAF^V600E mutation and lymph node metastasis of papillary thyroid cancer and its effect on stimulated thyroglobulin radioactive iodine

Objective: To evaluate the association between BRAF^V600E mutation and the lymph node metastasis (LNM) of papillary thyroid cancer (PTC). The effect of BRAF^V600E mutation on stimulated thyroglobulin (s-Tg) after radioactive iodine (RAI) remnant ablation treatment was also evaluated. Methods: The clinicopathological data of 2647 PTC patients (599 males; 2048 females; age range: 8-84 (45.00 ± 11.70) years) who underwent near total or total thyroidectomy at Henan Cancer Hospital Affiliated to Zhengzhou University, from January 2013 to December 2018 were retrospectively collected and analyzed. The BRAF^V600E status of the primary tumor was then identified. The patients were subsequently divided into the BRAF^V600E mutation group (2230 cases) and the BRAF^V600E wild group (417 cases), and differences in age, gender, tumor size, and lymph node metastasis between these two groups were analyzed. A total of 86 PTC patients (males 28; females 58; age range: 13-77 (42.72 ± 15.69) years) who had received two RAI treatments were filtered from the groups and evaluated further in terms of differences in s-Tg level. The basic data of the two groups were compared via the chisquared, two independent samples Student's t, and Mann-Whitney U rank-sum tests. Paired t test was used to evaluate the relationship between s-Tg and BRAF^V600E mutation. Results: The overall prevalence of BRAF^V600E mutation in this study was 84.2% (2230/2647). The mean age and proportion of LNM were significantly higher in the mutation group than in the non-mutation group [(45.29 ± 11.51) years vs. (43.43 ± 12.53) years, t = 5.28, P = 0.022; 48.39% vs. 41.97%, X² = 5.81, P = 0.016]. Among the 86 PTC patients who received RAI two RAI treatments, s-Tg levels were slightly higher in the mutation group [(61.16 ± 90.95) ng/mL vs. (18.56 ± 37.77) ng/mL, Z = -2.41, P = 0.003], while significantly sharp decreased of s-Tg in wild group [(-1.61 ± 37.18) ng/mL vs. (-24.00 ± 30.00) ng/mL, t = -2.81, P = 0.006] undergoing the first RAI remnant ablation. High s-Tg levels were present in the mutation group after the initial treatment. Conclusion: PTC patients with the BRAF^V600E mutation are at higher risk of developing LNM in PTC and show poor improvement in biochemical indicators after initial treatment. (authors)