Bone scanning in lung cancer: Evidence is not sufficient to justify routine bone scanning

EDITOR—Hetzel et al claim that patients with lung cancer may be undergoing “futile” surgery owing to incomplete preoperative staging.1 Their high incidence of bone metastases may be explained by the unusually high proportion of small cell lung cancer (30%). For potentially resectable early stage tumours, metastases are unlikely without clinical signs.2 Were the bone metastases in the field scanned by staging computed tomography and, if so, were they detected? Without TNM (tumour, node, and metastases) staging for the study population the authors cannot claim that a positive bone scan would have altered clinical management.

Positron emission tomography may be preferable to isotope bone scanning if concern exists about occult skeletal metastases in patients with potentially operable lung cancer. Studies have shown that positron emission tomography improves the detection rate of occult distant metastases, including bony lesions, compared with standard methods of staging3 and is cost effective in preventing futile operations.4

The gold standard used by Hetzel et al is magnetic resonance imaging of the vertebral column and patients' subsequent clinical course. However, they do not mention the length of clinical follow up. A previous pilot study showed that magnetic resonance imaging may have a role in detecting occult metastases in patients with potentially resectable cancer, but with a false positive rate.5 Hetzel et al do not comment on the accuracy of magnetic resonance imaging or what happened to cases with discrepant results on magnetic resonance imaging and bone scanning.

This paper does not provide sufficient evidence to recommend the routine use of bone scans in the staging of lung cancer.