Preliminary study of 131I adjuvant therapy in BRAF V600E mutant patients with non-distant metastatic papillary thyroid cancer / 中华核医学与分子影像杂志

ABSTRACT

Objective:To evaluate 131I adjuvant therapy in B-Raf proto-oncogene, serine/threonine kinase (BRAF) V600E mutant patients with non-distant metastatic papillary thyroid cancer (PTC). Methods:From January 2008 to January 2019, a total of 181 PTC patients (65 males, 116 females, age (38.9±11.8) years) with non-distant metastases from Peking Union Medical College Hospital were retrospectively enrolled. All patients received only one time 131I therapy with complete clinicopathological information, data of follow-up (median time 63 months) and assessment of response to therapy. Patients were divided into mutant and wild type group in terms of BRAF V600E status or ablation group (1.1 GBq) and adjuvant therapy group (3.7-5.5 GBq) in terms of different 131I dosage. Clinicopathological features and the response to therapy were compared between different groups by using independent-sample t test, Mann-Whitney U test and χ2 test. Results:The levels of preablative stimulated thyroglobulin (ps-Tg) in the BRAF V600E mutant type group ( n=150) was significantly higher than that in the wild type group ( n=31; 6.32(0.90, 8.70) vs 3.92(0.40, 4.40) μg/L; z=-2.413, P=0.016), however, there were no significant differences in other clinicopathological characteristics (including age, sex, tumor size, multifocality, capsule invasion and N staging) between the two groups ( t=-0.663, z=-1.151, χ2 values 0.003-1.491, all P>0.05) and the therapeutic response was also not different between the two groups( χ2=1.094, P=0.778). Of 81 patients who received 131I adjuvant therapy, the ps-Tg level of BRAF V600E mutant type group ( n=69) was higher than that of the wild type group( n=12; 8.70(1.30, 11.80) vs 3.40(0.30, 4.50) μg/L; z=-2.194, P=0.028), while the therapeutic response was not different between the two groups ( χ2=1.792, P=0.617). Compared with BRAF V600E mutant patients received 131I ablation ( n=81), BRAF V600E mutant patients received 131I adjuvant therapy ( n=69) had larger tumors (1.52(0.95, 2.00) vs 1.21(0.60, 1.50) cm; z=-2.728, P=0.006), more advanced N staging ( χ2=11.460, P=0.003) and higher ps-Tg level (8.70(1.30, 11.80) vs 4.34(0.50, 5.30) μg/L; z=-3.314, P=0.001), but the therapeutic response was not different between the two groups ( χ2=6.478, P=0.091). Conclusion:131I adjuvant therapy may improve the longer-term response to therapy in BRAF V600E mutant PTC patients with lager tumors, more advanced N staging and higher ps-Tg level.