Screening for thyroid cancer in survivors of childhood and young adult cancer treated with neck radiation.

BACKGROUND

The optimal method of screening for thyroid cancer in survivors of childhood and young adult cancer exposed to neck radiation remains controversial. Outcome data for a physical exam-based screening approach are lacking.

METHODS

We conducted a retrospective review of adult survivors of childhood and young adult cancer with a history of neck radiation followed in the Adult Long-Term Follow-Up Clinic at Memorial Sloan Kettering between November 2005 and August 2014. Eligible patients underwent a physical exam of the thyroid and were followed for at least 1 year afterwards. Ineligible patients were those with prior diagnosis of benign or malignant thyroid nodules.

RESULTS

During a median follow-up of 3.1 years (range 0-9.4 years), 106 ultrasounds and 2277 physical exams were performed among 585 patients. Forty survivors had an abnormal thyroid physical exam median of 21 years from radiotherapy; 50% of those with an abnormal exam were survivors of Hodgkin lymphoma, 60% had radiation at ages 10-19, and 53% were female. Ultimately, 24 underwent fine needle aspiration (FNA). Surgery revealed papillary carcinoma in seven survivors; six are currently free of disease and one with active disease is undergoing watchful waiting. Among those with one or more annual visits, representing 1732 person-years of follow-up, no cases of thyroid cancer were diagnosed within a year of normal physical exam.

CONCLUSIONS

These findings support the application of annual physical exam without routine ultrasound for thyroid cancer screening among survivors with a history of neck radiation.

IMPLICATIONS FOR CANCER SURVIVORS

Survivors with a history of neck radiation may not require routine thyroid ultrasound for thyroid cancer screening. Among adult survivors of childhood and young adult cancer with a history of radiation therapy to the neck, annual physical exam is an acceptable thyroid cancer screening strategy.