[Chest X ray: routine indication in the follow-up of differentiated thyroid cancer?]

This retrospective study sought to elucidate whether routine chest x-ray is still useful for detection of pulmonary metastases in low risk patients despite the high sensitivity of the tumor marker thyroglobulin.

The hospital files of 609 patients with well-differentiated thyroid cancer were analysed. Pulmonary formation of metastases was diagnosed in 50 patients. The thyroglobulin value at the time of diagnosis was compared with the chest x-ray findings and, if present, additional diagnostic information such as Iodine-131 whole body scintigraphy (WBS) and thorax CT.

The sensitivity of the chest x-ray to detect pulmonary metastases was at 52% lower than that of WBS (64%), thorax CT (82%) and thyroglobulin during suppression therapy (86%). Among the patients with papillary carcinoma stage I and II (UICC 1987), only 1 patient developed pulmonary metastases during follow up. In this low risk group of patients, detection of lung metastases exclusively by chest x-ray, without elevation of thyroglobulin level is extremely rare (calculated probability 1/4000) and associated with considerable costs.

Routine, life long chest x-ray in low risk patients without a suspected recurrence (e.g. positive thyroglobulin) needs to be reconsidered.