Which factors affect treatment success/prognosis in thyroid cancers with pulmonary metastases and what is/how should be the effective cumulative cure/dose as a current approach; a retrospective study.

Abstract

Objective: Our primary objective in this study was to analyse clinical-prognostic factors, to evaluate their effects on response to radioactive iodine therapy (RAIT) and survival in pulmonary metastatic differantiated thyroid cancer. Another aim was to evaluate the treatment cycles/doses to achieve effective treatment at the end of the follow-up.

Methods: 68 patients with pulmonary metastatic differentiated thyroid cancer who met all inclusion criteria were included. Clinical-pathological features and imaging findings of patients were collected and analysed retrospectively.

Results: Advanced age (p 0.037, OR 1.045), > 2 cm primary tumor (p: 0.009, OR 8), macronodular pulmonary metastases (p: 0.024, OR 3.7) and non-RAI-avidity (p: 0.045, OR 4.5) were independent factors associated with non-response to RAIT. When cumulative RAIT responses in the first 3 cycles were compared, no significant change was observed until the 3rd cycle (up to a cumulative dose of 21.27 GBq). That is, excluding patients who achieved an excellent response in ≤ 2 cycles, it would be appropriate to administer at least 3 cycles (21.27 GBq) to achieve an indeterminate response, which constitutes another pillar of the good prognostic group.

Conclusion: Collectively, it would be appropriate to consider that response and survival to RAIT decrease in advanced age and in the presence of macronodular pulmonary metastases. In addition to this, it was concluded that at least 3 cycles of RAIT (21.27 GBq) may be appropriate in the determination of treatment-resistant cases, in other words, in the determination of cases in which biochemical-structural incomplete response can be obtained during follow-up.