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MTE18 - PET-CT for Staging, Judging Response to Therapy, Restaging (ID 62)
- Event: WCLC 2013
- Type: Meet the Expert (ticketed session)
- Track: Imaging, Staging & Screening
- Presentations: 1
MTE18.1 - PET-CT for Staging, Judging Response to Therapy, Restaging (ID 615)
07:00 - 08:00 | Author(s): J. Erasmus
Staging: Positron emission tomography (PET) using the radiopharmaceutical, 18F-2-deoxy-D-glucose (FDG), a D-glucose analog, is useful in the detection of nodal (N) and extrathoracic metastases (M1b) in patients with non-small cell lung (NSCLC). FDG-PET has a higher sensitivity (83%) and specificity (92%) than CT in the detection of nodal metastases. However, a commonly encountered dilemma occurs when nodal imaging is discordant i.e. in patients with NSCLC and small nodes on CT and a positive PET, the predicted post-test probability of N2 malignancy is 62% and when the nodes are >16-mm and the PET is negative, the post-test probability of N2 malignancy is 21%. When the findings are concordant (enlarged nodes on CT and positive PET) the post-test probability of N2 malignancy is 90%. Accordingly, FDG-PET is usually used to direct invasive nodal staging. Metastatic disease (additional nodule/s in the contralateral lung, pleural nodules, malignant pleural or pericardial effusion (M1a) and extrathoracic metastasis (M1b)) are common in patients with NSCLC at presentation. Whole-body FDG-PET imaging improves the accuracy of staging and has a higher sensitivity and specificity than CT in detecting extrathoracic metastases although many solitary FDG-avid extrathoracic lesions are unrelated to the NSCLC. The American College of Surgeons Oncology Trial reports PET sensitivity, specificity, positive predictive value and negative predictive values of 83%, 90%, 36% and 99%, respectively for M1 disease. Importantly, whole-body PET imaging is useful in the detection of occult extrathoracic metastases in patients considered resectable by standard imaging and clinical evaluation and prevents inappropriate resection in up to 20% of these patients. Response: PET is being evaluated in the assessment of therapeutic response and may allow an early and sensitive assessment of the effectiveness of anticancer chemotherapy as FDG uptake is not only a function of proliferative activity but is also related to viable tumor cell number. FDG-PET/CT can predict early response to therapy in patients with stage IIIB-IV NSCLC who receive standard chemotherapy or molecular-targeted therapy. Early metabolic response (after one cycle of systemic therapy) has a significant correlation with best overall response. FDG-PET has also been reported to be useful in the assessment of therapy response and preoperative re-evaluation after neoadjuvant radio-chemotherapy in stage III non-small cell lung cancer. Additionally, in patients with advanced NSCLC, FDG-PET can potentially be useful in identifying a subgroup of patients that would benefit from maintenance treatment after completion of first-line chemotherapy. Furthermore, FDG-PET can be useful in the assessment of early response during radiotherapy with respect to overall survival in patients with NSCLC. While FDG-PET/CT assessment may be useful in the prediction of early treatment response, progression-free survival and overall survival in NSCLC, the response to therapy and survival is multifactorial with stage at presentation, performance status and genomic patterns influencing outcome. It is not certain whether FDG-PET in patients with NSCLC will provide reliable and routinely applicable clinical information in terms of therapeutic response. Restaging: In patients with recurrent malignancy after attempted curative treatment of NSCLC, repeat resection, salvage chemotherapy, or radiotherapy are therapeutic options. FDG-PET can detect local recurrence of tumor after definitive treatment with surgery, chemotherapy, or radiotherapy before conventional imaging and has been reported to have a sensitivity of 98-100% and specificity of 62-92%. In one recent prospective study of patients with NSCLC who had undergone surgical resection, PET was able to detect tumor recurrence (sensitivity 93%, specificity 89%, and accuracy 92%) and predict which patients would benefit most from surgical retreatment. Additionally, in patients with NSCLC treated with radical radiotherapy, FDG-PET performed a median of 70 after completion of radical radiotherapy was useful in the assessment of therapeutic response.
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P1.07 - Poster Session 1 - Surgery (ID 184)
- Event: WCLC 2013
- Type: Poster Session
- Track: Surgery
- Presentations: 1
- Coordinates: 10/28/2013, 09:30 - 16:30, Exhibit Hall, Ground Level
P1.07-010 - Preoperative Flourodeoxyglucose-Positron Emission Tomography Scan with Positive N1 Disease Does Not Predict Worse Survival in Pathologic Stage II Patients (ID 1070)
09:30 - 16:30 | Author(s): J. Erasmus
The rate of fluorodeoxyglucose uptake measured as standardized uptake value (SUV) on positron emission tomography (PET) of the primary tumor has been correlated with tumor aggressiveness and poor survival in patients with lung cancer. A retrospective review of patients with lung cancer who were treated with surgical resection at MD Anderson Cancer Center (MDACC) was performed to determine if the pre-operative SUV uptake of N1 disease has any prognostic significance in patients with pathologic stage II lung cancer.
We reviewed all patients who underwent surgical resection for lung cancer at MDACC from 1998 to 2011. We evaluated non-small cell lung cancer patients who had at least a lobectomy at MDACC as first mode of surgical therapy who had pathologic stage T1-2 and N1 disease and pre-operative PET-CT scan. We determined the clinicopathologic characteristics of patients who had PET-positive N1 disease and compared them to patients who had PET-negative N1 disease. We also performed Kaplan Meier analysis to determine the survival between the two groups.
Among patients who underwent surgical resection for lung cancer at MDACC during this time period, 120 patients met the inclusion criteria for the study. There were 100 stage IIA or T1aN1, T1bN1 or T2aN1 and 20 stage IIB or T2bN1 patients in the study. There were 62 patients (50% of the patients) who had a primary tumor in the periphery of the lung and 58 patients (50% of the patients) who had a primary tumor in the central portion of the lung. Within this group of 120 patients, only 29 patients (24% of the patients) had PET-positive N1 disease. Only 16 out of 58 patients (28%) in the central group and only 13 out of 62 patients (21%) in the peripheral group had PET-positive N1 disease. There was no clinical or pathological difference between the patients who had PET-positive N1 disease and PET-negative N1 disease. The average maxSUV of the primary tumor was 13 ± 10.7 and average maxSUV of the PET-positive N1 disease was 6.3 ± 4.1. Kaplan Meier analysis showed that there was no significant difference in survival between the patients who had PET-positive N1 disease and PET-negative N1 disease.
Among patients with pathologic stage II non-small cell lung cancer, preoperative PET scan was very poor at predicting positive pathologic N1 disease. Since it is difficult to predict pN1 disease, operative patients with clinical stage I non-small cell lung cancer should have surgical resection oppose to ablative therapy. Moreover, SUV uptake of N1 disease in patients with pathologic stage II lung cancer did not predict worse survival in pathologic stage II patients. Thus, patients with cN1 disease should undergo surgical resection after appropriate mediastinal staging.