Can positron emission tomography be used as a staging tool for small-cell lung cancer?

Positron emission tomography (PET) is widely used for the staging evaluation of non-small-cell lung cancer; however, its use in small-cell lung cancer (SCLC) remains investigational.

We did a retrospective study of 137 patients to evaluate the role of PET in SCLC. Fifty-one of 137 patients had computed tomography (CT) and PET scans during initial evaluation of a lung mass.

All 51 patients had PET-positive results for malignancy (100% sensitivity). In 40 of 51 cases (78%), the PET staging correlated with that on CT. Two of 51 patients (4%) had disease that was accurately upstaged by PET. Positron emission tomography accurately downstaged disease in 6 of 51 patients (12%). Positron emission tomography detected additional sites of disease in 13 of 42 patients (32%). Of the 13 additional sites of disease, PET detected supraclavicular nodes in 4 of 13 patients (30%) and bone lesions in 4 of 13 patients (30%). The sensitivity to detect brain lesions was 5 of 11 patients (45%) in this series. In this series, the PET results from 8 of 51 patients (16%) resulted in a change in disease management. Because of PET results, 6 of 51 patients (12%) who otherwise would not have been treated, were treated with radiation.

Positron emission tomography is potentially useful for accurate initial staging of SCLC and can ensure that a patient's disease is not overstaged by CT scan, which might result in denied potentially curative treatment for limited-stage SCLC. It can identify the occult adrenal metastasis and metastasis to supraclavicular lymph nodes that are missed by CT; however, brain lesions are difficult to assess by PET.