Purpose: To prospectively study the capacity of positron emission tomography (PET) and computed tomography (CT) to determine response soon after radical radiotherapy or chemoradiotherapy and, thereby, predict survival. PET is known to provide a more accurate estimate of true extent of disease than CT when used to stage non–small-cell lung cancer (NSCLC). Patients and Methods: Seventy-three patients with NSCLC underwent [¹⁸F]fluorodeoxyglucose PET and CT scans before and after radical radiotherapy (n = 10) or chemoradiotherapy (n = 63). Follow-up PET scans were performed at a median of 70 days after radiotherapy. The median PET-CT interval was 1 day. Each patient had determinations of response to therapy made with PET and CT, categorized as complete response, partial response, no response, progressive disease, or nonassessable. Responses were correlated with subsequent survival. Results: Median survival after follow-up PET was 24 months. There was poor agreement between PET and CT responses (weighted kappa = 0.35), which were identical in only 40% of patients. There were significantly more complete responders on PET (n = 34) than CT (n = 10), whereas fewer patients were judged to be nonresponders (12 patients on PET v 20 on CT) or nonassessable (zero patients on PET v six on CT) by PET. Both CT and PET responses were individually significantly associated with survival duration; but on multifactor analysis that included the known prognostic factors of CT response, performance status, weight loss, and stage, only PET response was significantly associated with survival duration (P < .0001). Conclusion: In NSCLC, a single, early, posttreatment PET scan is a better predictor of survival than CT response, stage, or pretreatment performance status.

Hypofractionated stereotactic body radiotherapy (SBRT) is an emerging noninvasive technique for the treatment of oligometastatic cancer. The use of small numbers of large doses, should in theory, achieve high rates of local control. The aim of this literature review is to critically assess the use of SBRT for the treatment of pulmonary metastases as judged by its effect on local control, survival, and toxicity. A systematic literature search was performed. Both single fraction stereotactic radiosurgery (SRS) and hypofractionated radiotherapy (SBRT) were considered individually. Thirteen institutions reported results regarding SBRT and seven institutions regarding SRS (a total of 29 publications). Outcomes, techniques, radiobiology, and the scientific rigor of the reported studies were analyzed. A wide range of techniques, doses, and dose fractionation schedules were found. Three hundred thirty-four patients with 564 targets were reported in the SBRT series. The 2-year weighted local control was 77.9%. The corresponding 2-year weighted overall survival was 53.7%, with a 4% rate of grade 3 or higher radiation toxicities. One hundred fifty-four patients with 174 targets were treated in the SRS series. The 2-year weighted local control was 78.6%. The corresponding weighted 2-year overall survival was 50.3%, with 2.6% rate of grade 3 or higher toxicities. There was insufficient evidence to recommend a consensus view for optimal tumor parameters, dose fractionation, and technical delivery of treatment. This indicates the need for further prospective studies. However, high local control rates that could potentially lead to a survival benefit justifies the consideration of stereotactic radiotherapy for patients with limited pulmonary oligometastases.

PURPOSE: To prospectively study the impact of ¹⁸F fluorodeoxyglucose (FDG) positron emission tomography (PET) on clinical management of patients with non–small-cell lung cancer (NSCLC). PATIENTS AND METHODS: One hundred five consecutive patients with NSCLC undergoing ¹⁸F FDG PET were analyzed. Before PET, referring physicians recorded scan indication, conventional clinical stage, and proposed treatment plan. PET scan results were reported in conjunction with available clinical and imaging data, including results of computed tomography (CT). Subsequent management and appropriateness of PET-induced changes were assessed by follow-up for at least 6 months or until the patient’s death. RESULTS: Indications for PET were primary staging (n = 59), restaging (n = 34), and suspected malignancy subsequently proven to be NSCLC (n = 12). In 27 (26%) of 105 of cases, PET results led to a change from curative to palliative therapy by upstaging disease extent. Validity of the PET result was established in all but one case. PET appropriately downstaged 10 of 16 patients initially planned for palliative therapy, allowing either potentially curative treatment (four patients) or no treatment (six patients). PET influenced the radiation delivery in 22 (65%) of 34 patients who subsequently received radical radiotherapy. Twelve patients considered probably inoperable on conventional imaging studies were downstaged by PET and underwent potentially curative surgery. PET missed only one primary tumor (5-mm scar carcinoma). CT and PET understaged three of 20 surgical patients (two with N1 lesions < 5 mm and one with unrecognized atrial involvement), and PET missed one small intrapulmonary metastasis apparent on CT. No pathological N2 disease was missed on PET. CONCLUSION: FDG PET scanning changed or influenced management decisions in 70 patients (67%) with NSCLC. Patients were frequently spared unnecessary treatment, and management was more appropriately targeted.