A systematic review of neoadjuvant targeted therapy in locally advanced thyroid cancer

Abstract

Abstract Introduction Locally advanced thyroid cancer refers to thyroid cancer that invades important structures of the neck, with poor prognosis. Neoadjuvant targeted therapy has the potential to increase the R0/1 resection rate in locally advanced thyroid cancer and improve the outcome in these patients. Methods We conducted a systematic review of studies that reported neoadjuvant targeted therapy in locally advanced thyroid cancer. Individual patient data was extracted from eligible studies. Objective response rate (ORR) and R0/1 resection rate were calculated. Results Sixteen studies and 32 patients were included into analysis, including 18 differentiated thyroid cancer (DTC), 3 medullary thyroid cancer (MTC), 8 anaplastic thyroid cancer (ATC) and 3 poor-differentiated thyroid cancer (PDTC). Most patients were stage T4a (53.1%) and T4b (28.1%). 81.3% patients had regional lymph node metastasis and 37.5% had distant metastasis. RET mutated MTC and BRAF mutated ATC were treated with selective RET inhibitor and selective BRAF/MEK inhibitors. Other treatment regimens were multitarget tyrosine kinase inhibitors (mTKIs). The average duration of treatment was 4.3 months (SD = 4.1). The overall ORR was 78.1% (95%CI: 60.0%–90.7%), and the R0/1 resection rate for the intention to treat population was 78.1% (95%CI: 60.0%–90.7%). With a median follow-up time of 12.1 months, 1 DTC patient and 3 ATC patients died of the disease. Conclusions Neoadjuvant targeted therapy was a new treatment option for locally advanced thyroid cancer and might improve the R0/1 resection rate in selective cases. However, more clinical trials with longer follow-up time are awaited to confirm the clinical benefit of neoadjuvant targeted treatment.