Efficacy of external beam radiotherapy and targeted therapy with vandenanib in patients with inoperable and progressive medullary thyroid cancer

The study objective is to evaluate modern-era radiotherapy (external beam radiotherapy, EBRT) and target therapy (TT) outcomes for advanced medullary thyroid cancer (MTC).

Materials and methods. Seventy eight consecutive patients with stage IV MTC were evaluated. All of them with relapsing locally advanced or metastatic MTC, 16 had clinically relevant mediastinal involvement, and 59 had distant metastasis; 26 patients received conformal EBRT or intensity-modulated radiotherapy in monomode, 16 patients – conformal EBRT with simultaneous TT with vandenanib, 36 patients – TT in monomode. Median EBRT dose was 60 Gy.

Results. Kaplan–Meier estimates of the median overall survival rate was 14 months for radiotherapy in monomode, 48 months – for conformal EBRT + simultaneous TT with vandenanib, 50 months – for TT in monomode. EBRT and TT allows for significantly shorter periods (median 3.8 weeks), to relieve the symptoms of compression-mediated organs and structures of the neck and mediastinum than in the TT (median 10.2 weeks) (p <0.001).

Conclusion. EBRT and TT provided durable locoregional disease control with limited morbidity.

1. RECIST. Version 1.1 Update. Available at: http://irrecist.com/recist/recist-inpractice/01.html.

2. Каприн А. Д., Галкин В. Н., Жаворонков Л. П. и др. Синтез фундаментальных и прикладных исследований – основа обеспечения высокого уровня научных результатов и внедрения их в медицинскую практику. Радиация и риск 2017;26(2):26–40. [Kaprin A. D., Galkin V. N., Zhavoronkov L. P. et al. Synthesis of basic and applied research is the basis of obtaining high-quality findings and translating them into clinical practice. Radiatsiya i risk = Radiation and Risk 2017;26(2):26–40. (In Russ.)].

3. Schwartz D. L., Rana V., Shaw S. et al. Postoperative radiotherapy for advanced medullary thyroid cancer – local disease control in the modern era. Head Neck 2008;30(7):883–8. DOI: 10.1002/hed. 20791. PMID: 18213725.

4. Terezakis S. A., Lee K. S., Ghossein R. A. et al. Role of external beam radiotherapy in patients with advanced or recurrent nonanaplastic thyroid cancer: Memorial Sloan-kettering Cancer Center experience. Int J Radiat Oncol Biol Phys 2009;73(3):795–801. DOI: 10.1016/j.ijrobp.2008.05.012. PMID: 18676097.

5. Trimboli P., Castellana M., Virili C. et al. Efficacy of vandetanib in treating locally advanced or metastatic medullary thyroid carcinoma according to RECIST criteria: a systematic review and metaanalysis. Front Endocrinol (Lausanne) 2018;9:224. DOI: 10.3389/fendo.2018.00224. PMID: 29774010.

6. Cooper M. R., Yi S. Y., Alghamdi W. et al. Vandetanib for the treatment of medullary thyroid carcinoma. Ann Pharmacother 2014;48(3):387–94. DOI: 10.1177/1060028013512791. PMID: 24259657.

7. Wells S. A. Jr, Gosnell J. E., Gagel R. F. et al. Vandetanib for the treatment of patients with locally advanced or metastatic hereditary medullary thyroid cancer. J Clin Oncol. 2010;28(5):767–72. DOI: 10.1200/JCO.2009.23.6604. PMID: 20065189.