Secondary Cancer Induction: Lifetime Attributable Risk Estimates Following Radioiodine Therapy Among Thyroid Cancer Female Survivors in Saudi Arabia

Radiation-induced second solid cancer (RISSC) is one of the critical late side effects of radiotherapy treatment of first cancer. The mechanism of second cancer incidence is not fully known yet. However, many elements contribute to the development of RISSC such as age at exposure, effective dose to the organ and surrounding tissues, treatment modalities and family history of cancer. The aim of this study is to provide long-term forecasts of second cancer prevalence among thyroid cancer female survivors in Saudi Arabia. The long-term harm resulting from radiation exposure or lifetime attributable risk (LAR) of RISSC after a radiation treatment of thyroid cancer was determined, between the age at exposure and up to 90 years, in a cohort of female cancer survivors whose age at treatment was in the range 15 to 76 years. Risk estimates varied significantly with age at exposure and effective organ dose. The results of the study clearly indicate a direct positive correlation between the patient's age at exposure and the induction of a thyroid secondary cancer. The chance of developing thyroid second cancer after radiotherapy is highest in those exposed as children. Furthermore, the radiation dose directly affects the emergence of secondary cancers.