<i>BRAF</i> V600E Status Sharply Differentiates Lymph Node Metastasis-associated Mortality Risk in Papillary Thyroid Cancer
Yubing Tao, Fei Wang, Xiaopei Shen, Guangwu Zhu, Rengyun Liu, David Viola, Rossella Elisei, Efisio Puxeddu, Laura Fugazzola, Carla Colombo, Barbara Jarząb, Agnieszka Czarniecka, Alfred K. Lam, Caterina Mian, Federica Vianello, Linwah Yip, Garcilaso Riesco‐Eizaguirre, Pilar Santisteban, Christine J. O’Neill, Mark Sywak, Roderick Clifton‐Bligh, Běla Bendlová, Vlasta Sýkorová, Shihua Zhao, Yangang Wang, Mingzhao Xing
Abstract
CONTEXT: How lymph node metastasis (LNM)-associated mortality risk is affected by BRAF V600E in papillary thyroid cancer (PTC) remains undefined. OBJECTIVE: To study whether BRAF V600E affected LNM-associated mortality in PTC. DESIGN, SETTING, AND PARTICIPANTS: We retrospectively analyzed the effect of LNM on PTC-specific mortality with respect to BRAF status in 2638 patients (2015 females and 623 males) from 11 centers in 6 countries, with median age of 46 [interquartile range (IQR) 35-58] years and median follow-up time of 58 (IQR 26-107) months. RESULTS: Overall, LNM showed a modest mortality risk in wild-type BRAF patients but a strong one in BRAF V600E patients. In conventional PTC (CPTC), LNM showed no increased mortality risk in wild-type BRAF patients but a robustly increased one in BRAF V600E patients; mortality rates were 2/659 (0.3%) vs 4/321 (1.2%) in non-LNM vs LNM patients (P = 0.094) with wild-type BRAF, corresponding to a hazard ratio (HR) (95% CI) of 4.37 (0.80-23.89), which remained insignificant at 3.32 (0.52-21.14) after multivariate adjustment. In BRAF V600E CPTC, morality rates were 7/515 (1.4%) vs 28/363 (7.7%) in non-LNM vs LNM patients (P < 0.001), corresponding to an HR of 4.90 (2.12-11.29) or, after multivariate adjustment, 5.76 (2.19-15.11). Adjusted mortality HR of coexisting LNM and BRAF V600E vs absence of both was 27.39 (5.15-145.80), with Kaplan-Meier analyses showing a similar synergism. CONCLUSIONS: LNM-associated mortality risk is sharply differentiated by the BRAF status in PTC; in CPTC, LNM showed no increased mortality risk with wild-type BRAF but a robust one with BRAF mutation. These results have strong clinical relevance.