Thyroid Cancer. Not Always Mr Nice Guy. (#344)
Hospital Introduction The incidence of thyroid cancer is increasing. For the majority treatment with surgery and radioactive Iodine [ I 131]results in high cure rates and a normal survival experience. A minority however die of their disease. This presentation discusses those who do badly and attempts to provide indications for the use of external radiotherapy and newer drugs. Materials and Methods Patients presenting to the Royal Brisbane Thyroid Cancer Clinic from 1980 to 2012 were reviewed. 4158 patients were seen and 244 died of thyroid cancer. Good prognosis tumours included papillary and follicular histology and T-Stage 1, 2 and 3. Results On multivariant analysis the factors predicting a poor disease specific survival are: Age hazard ratio 1.05(p<0.001). T-Stage only T4 makes any significant difference with a hazard ratio of 5.05(p <0.001), N Stage hazard ratio is 1.33(p=0.05), M Stage has a hazard ratio of 3.25 (p<0.001). Histology : medullary tumours have a hazard ratio of 3.4(p<0.001) and anaplastic tumours have a hazard ratio of 11.27(p<0.001). The use of external beam radiation is associated with a poor prognosis but this is due to selection bias. Discussion External beam radiotherapy needs to be high dose in the order of 60Gy and the late effects may be quite considerable and therefore management with surgery and I 131is preferred. The groups benefiting from external radiation are those with poorly differentiated or anaplastic histology, widespread invasion of vital structures such as trachea and oesophagus, medullary cancers and patients who have failed to take up I 131.New drugs such as lenvatenib and vandetinib have shown high response rates but are not routinely available in Australia. Anaplastic carcinoma remains resistant to all forms of therapy.