Serum progastrin-releasing peptide levels followed by whole-body positron emission tomography detects early recurrence of small-cell lung cancer

: A 65-year-old male smoker with severe COPD was diagnosed with limited-stage small-cell lung cancer. After receiving cisplatin/irinotecan, serum progastrin-releasing peptide (ProGRP) levels decreased to within the reference values and the lesions were markedly reduced in size. A whole-body 18F-fluorodeoxyglucose PET (FDG-PET) scan confirmed complete remission. During follow up, serum ProGRP levels increased, and a whole-body FDG-PET scan detected recurrence at the hilar lymph node that had been negative on CT. Complete remission was again achieved with second-line chemotherapy (cisplatin/etoposide) and local irradiation to the hilar lymph node. Monitoring serum ProGRP levels, followed by whole-body FDG-PET when indicated, may improve the clinical management of patients with small-cell lung cancer after initial complete remission.