Background: Although pathologic stage I lung cancers generally have a favorable prognosis, approximately 20% of patients experience recurrence after surgery. Therefore, a method of selecting patients who need adjuvant therapy is necessary. The goal of this study was to evaluate the significance of positron emission tomography (PET)/computed tomography (CT) results after lung cancer surgery and to identify the predictive factors for recurrence in cases of pathologic stage I lung cancer.
Methods: From January 2004 to December 2008, 356 patients with lung cancer underwent surgery at our institution. Of these, 282 patients received F-18 fluorodeoxyglucose PET/CT, and the maximum standardized uptake value (max SUV) was measured. There were 201 patients with pathologic stages IA and IB evaluated. The associations between disease-free survival (DFS) and the following clinicopathological factors were analyzed: age, gender, smoking history, carcinoembryonic antigen level, tumor size, max SUV values, histology, and lymphovascular and pleural invasion.
Results: The 4-year DFS rate was 86.3%. Multivariate analysis revealed lymphovascular invasion (LVI; p < 0.01) and max SUV ≥4.7 (p < 0.01) to be independent predictive factors. Patients with a max SUV more than 4.7 had a significantly high risk of recurrence. DFS of patients with high max SUVs and LVI (n = 18) was significantly reduced compared with other patients (n = 183, p < 0.01).
Conclusions: The PET-CT results significantly correlated with recurrence in pathologic stage I lung cancers. Patients with high max SUVs and LVI were more likely to have recurrence and should be candidates for adjuvant chemotherapy.