Epidemiology and Biostatistics

Positron emission tomography (PET) utilizing fluorine-18 fluorodeoxyglucose (FDG) has been used in the evaluation of non-small cell lung cancer (NSCLC). Recently its use in the staging of small cell lung cancer (SCLC) has been reported. However, the prognostic value of FDG-PET imaging in SCLC has not been studied. We performed a retrospective analysis to assess this, with the following hypotheses: (1) PET-positive patients would have a less favorable prognosis than PET-negative patients and (2) a high standardized uptake value (SUV) would be associated with a poor prognosis. Retrospective review of a mixed population of treated and untreated patients imaged between 1995 and 2000 was performed. Results of 62 scans in 46 patients were analyzed. There were 8 untreated and 38 treated patients. Findings were correlated with pathology, computed tomography/magnetic resonance imaging and clinical data. The sensitivity of PET scanning was 100% with pathological correlation. The prognostic value of a positive PET study was determined. Overall survival in PET-positive cases was significantly worse than that in PET-negative cases (P=0.0108). Correlation of SUVmax with survival showed a significant negative correlation (P=0.0021). In the eight untreated patients, scans were strongly positive and in all cases the scan results concurred with the final clinical stage assigned on the basis of conventional methods. We conclude that FDG-PET imaging provides prognostic information in treated patients. A positive study and a high SUVmax are significantly associated with poor survival. Additionally, FDG-PET may be helpful in staging and follow-up.

The standardized uptake value (SUV) is the most commonly used parameter to quantify the intensity of radiotracer uptake in tumors. Previous studies suggested that measurements of 18 F-FDG accumulation in tissue might be affected by the image reconstruction method, but the clinical relevance of these findings has not been assessed. Methods: Phantom studies were performed and clinical whole-body 18 F-FDG PET images of 85 cancer patients were analyzed. All images were reconstructed using either filtered backprojection (FBP) with measured attenuation correction (MAC) or iterative reconstruction (IR) with segmented attenuation correction (SAC). In a subset of 15 patients, images were reconstructed using all 4 combinations of IRϩSAC, IRϩMAC, FBPϩSAC, and FBPϩMAC. For phantom studies, a sphere containing 18 F-FDG was placed in a waterfilled cylinder and the activity concentration of that sphere was measured in FBP and IR reconstructed images using all 4 combinations. Clinical studies were displayed simultaneously and identical regions of interest (ROIs, 50 pixels) were placed in liver, urinary bladder, and tumor tissue in both image sets. SUV max (maximal counts per pixel in ROI) and SUV avg (average counts per pixel) were measured. Results: In phantom studies, measurements from FBP images underestimated the true activity concentration to a greater degree than those from IR images (20% vs. 5% underestimation). In patient studies, SUV derived from FBP images were consistently lower than those from IR images in both normal and tumor tissue: Tumor SUV max with IRϩSAC was 9.6 Ϯ 4.5, with IRϩMAC it was 7.7 Ϯ 3.5, with FBPϩMAC it was 6.9 Ϯ 3.0, and with FBPϩSAC it was 8.6 Ϯ 4.1 (all P Ͻ 0.01 vs. IRϩSAC). Compared with IRϩSAC, SUV from FBPϩMAC images were 25%-30% lower. Similar discrepancies were noted for liver and bladder. Discrepancies between measurements became more apparent with increasing 18 F-FDG concentration in tissue. Conclusion: SUV measurements in whole-body PET studies are affected by the applied methods for both image reconstruction and attenuation correction. This should be considered when serial PET studies are done in cancer patients. Moreover, if SUV is used for tissue characterization, different cutoff values should be applied, de-pending on the chosen method for image reconstruction and attenuation correction.

Context/Objective: Approximately 15% of thyroid cancer patients develop subsequent metastases. The clinical course of patients with metastatic thyroid carcinoma is highly variable. We hypothesized that the metabolic activity of metastatic lesions, as defined by retention of 2-[ 18 F] fluoro-2-deoxyglucose (FDG), would correlate with prognosis.

Computed tomography and magnetic resonance imaging often fail to predict resectability in patients with malignant pleural mesothelioma. Small studies suggest that fluorodeoxyglucose-positron emission tomography may improve staging. We analyzed our experience to determine more definitively the potential utility of fluorodeoxyglucose-positron emission tomography.Patients with malignant pleural mesothelioma who underwent fluorodeoxyglucose-positron emission tomography scanning were identified from an institutional database. All patients fasted and received a minimum of 10 mCi of F-18-fluorodeoxyglucose. Whole-body emission studies were acquired, followed by whole-body transmission studies, allowing iterative reconstruction. Blinded review of positron emission tomography scans was performed for clinical staging, which was then correlated with surgical and pathologic findings. Sensitivity and specificity were determined for tumor and nodal status.From 1998 to 2002, 63 patients underwent positron emission tomography scans, 60 preoperatively and 3 to assess disease recurrence after surgery. Increased fluorodeoxyglucose uptake was seen in all but 1 tumor, which was very early stage (IA). Positron emission tomography findings yielded sensitivities of only 19% and 11% for tumor and nodal status, respectively. However, a high standard uptake value in the primary tumor correlated with the presence of N2 disease. Positron emission tomography correctly identified supraclavicular N3 or M1 disease in 6 patients.Positron emission tomography does not identify the local extent of tumor or mediastinal nodal metastases reliably but detects extrathoracic metastases, thereby obviating inappropriate thoracotomy. Further studies of the association between tumor standard uptake value and the presence of N2 disease are warranted.

Background Preoperative identifi cation of tumour type could have important implications for the choice of treatment for renal cancers. Antibody cG250 reacts against carbonic anhydrase-IX, which is over-expressed in clear-cell renal carcinomas. We aimed to assess whether iodine-124-labelled antibody chimeric G250 ( 124 I-cG250) PET predicts clearcell renal carcinoma, the most common and aggressive renal tumour.

Background With increasing frequency, breast cancer patients and clinicians are questioning the need for completion axillary lymph node dissection (ALND) in the setting of a positive sentinel lymph node (SLN). We previously developed a nomogram to estimate the likelihood of residual disease in the axilla after a positive SLN biopsy result. In this study, we compared the predictions of clinical experts with those generated by the nomogram and evaluated the ability of the nomogram to change clinicians’ behavior. Methods Pathologic features of the primary tumor and SLN metastases of 33 patients who underwent completion ALND were presented to 17 breast cancer specialists. Their predictions for each patient were recorded and compared with results from our nomogram. Subsequently, clinicians were presented with clinical information for eight patients and asked whether they would perform a completion ALND before and after being presented with the nomogram prediction. Results The predictive model achieved an area under the receiver operating characteristic curve of .72 when applied to the test data set of 33 patients. In comparison, the clinicians as a group were associated with an area under the receiver operating characteristic curve of .54 (P Conclusions Our predictive model seemed to substantially outperform clinical experts. Despite this, clinicians were unlikely to change their surgical plan based on nomogram results. It seems that most clinicians can improve their predictive ability by using the nomogram to predict the likelihood of additional non-SLN metastases in a woman with a positive SLN biopsy result.

BACKGROUNDBecause the recovery of erectile function and the avoidance of positive surgical margins are important but competing outcomes, the decision to preserve or resect a neurovascular bundle (NVB) during radical prostatectomy (RP) should be based on the most accurate information concerning the location and extent of the tumor. In the current study, the authors determined the incremental value of endorectal magnetic resonance imaging (eMRI) in making this decision.Because the recovery of erectile function and the avoidance of positive surgical margins are important but competing outcomes, the decision to preserve or resect a neurovascular bundle (NVB) during radical prostatectomy (RP) should be based on the most accurate information concerning the location and extent of the tumor. In the current study, the authors determined the incremental value of endorectal magnetic resonance imaging (eMRI) in making this decision.METHODSeMRI was performed in 135 patients preoperatively. For each NVB, tumor extension to the NVB and the need for NVB resection was judged by a surgeon on a scale from 1 (definite preservation) to 5 (definite resection) before and after reviewing eMRI with a radiologist. Histopathologic findings were used as the standard of reference. The value of eMRI was assessed using binormal receiver operating characteristic (ROC) analysis adjusted for multiple observations per patient, and a mixed effects ordinal regression model was used for risk stratification.eMRI was performed in 135 patients preoperatively. For each NVB, tumor extension to the NVB and the need for NVB resection was judged by a surgeon on a scale from 1 (definite preservation) to 5 (definite resection) before and after reviewing eMRI with a radiologist. Histopathologic findings were used as the standard of reference. The value of eMRI was assessed using binormal receiver operating characteristic (ROC) analysis adjusted for multiple observations per patient, and a mixed effects ordinal regression model was used for risk stratification.RESULTSHistopathologic examination determined that NVB resection was warranted in 44 of 270 NVBs (16%) because of posterolateral extracapsular extension (n = 29), positive surgical margins (n = 7), or both (n = 8). The areas under the ROC curves (AUC) were 0.741 for pre-MRI and 0.832 for post-MRI surgical planning (P < 0.01). MRI findings suggested altering the surgical plan in 39% of NVBs (106 of 270 NVBs). When the surgeon judged that the NVB resection was definitely not necessary (165 NVBs), MRI confirmed that decision in 138 NVBs (84%); the concordant decision was correct in 96% of the cases (133 of 138 NVBs). In 36 high-risk patients (≥ 75% probability of extracapsular extension), MRI findings changed the surgical plan for 28 NVBs (78%); the change was found to be appropriate in 26 cases (93%).Histopathologic examination determined that NVB resection was warranted in 44 of 270 NVBs (16%) because of posterolateral extracapsular extension (n = 29), positive surgical margins (n = 7), or both (n = 8). The areas under the ROC curves (AUC) were 0.741 for pre-MRI and 0.832 for post-MRI surgical planning (P < 0.01). MRI findings suggested altering the surgical plan in 39% of NVBs (106 of 270 NVBs). When the surgeon judged that the NVB resection was definitely not necessary (165 NVBs), MRI confirmed that decision in 138 NVBs (84%); the concordant decision was correct in 96% of the cases (133 of 138 NVBs). In 36 high-risk patients (≥ 75% probability of extracapsular extension), MRI findings changed the surgical plan for 28 NVBs (78%); the change was found to be appropriate in 26 cases (93%).CONCLUSIONSMRI was found to significantly improve the surgeon's decision to preserve or resect the NVB during radical prostatectomy. Cancer 2004. © 2004 American Cancer Society.MRI was found to significantly improve the surgeon's decision to preserve or resect the NVB during radical prostatectomy. Cancer 2004. © 2004 American Cancer Society.

Purpose: We reported a nomogram and subsequently a corrected version for predicting the probability of positive biopsy in men with 1 or more prior negative biopsies. In this study we assessed the validity of this nomogram when applied to an external dataset.

Background:Patients with potentially resectable hepatobiliary malignancy are frequently found to have unresectable tumors at laparotomy. We prospectively evaluated staging laparoscopy in patients with resectable disease on preoperative imaging. Methods:Staging laparoscopy was performed on 410 patients with potentially resectable hepatobiliary malignancy. The preoperative likelihood of resectability was recorded. Data on preoperative imaging, operative findings, and hospital course were analyzed. Results:Laparoscopic inspection was complete in 291 (73%) patients. In total, 153 patients (38%) had unresectable disease, 84 of whom were identified laparoscopically, increasing resectability from 62% to 78%. On multivariate analysis, a complete examination, preoperative likelihood of resection, and primary diagnosis were significant predictors of identifying unresectable disease at laparoscopy. The highest yield was for biliary cancers, and the lowest was for metastatic colorectal cancer. In patients with unresectable disease identified at laparoscopy, the mean hospital stay was 3 days, and postoperative morbidity was 9%, compared with 8 days and 27%, respectively, in patients found to have unresectable disease at laparotomy. Conclusions:Laparoscopy spared one in five patients a laparotomy while reducing hospital stay and morbidity. Targeting laparoscopy to patients at high risk for unresectable disease requires consideration of disease-specific factors; however, the surgeons’ preoperative impression of resectability is also important.

Fatty liver disease may interfere with liver regeneration and is postulated to result in an adverse outcome for patients subjected to partial hepatectomy. This study examines the impact of steatosis on outcome following hepatic resection for neoplasms. All patients with fatty livers (n = 325) who underwent hepatectomy between December 1991 and September 2001 were identified from a prospective database. Slides were reviewed and steatosis was quantified as follows:

Resection of colorectal liver metastases (CLM) in selected patients has evolved as the standard of care during the last 20 years. In the absence of prospective randomized clinical trials, a survival benefit has been deduced relative to historical controls based on actuarial data. There is now sufficient follow-up on a significant number of patients to address the curative intent of resecting CLM.

Purpose: Gastrointestinal stromal tumors (GISTs) are specific KIT expressing and KIT-signaling driven mesenchymal tumors of the human digestive tract, many of which have KIT-activating mutations. Previous studies have found a relatively homogeneous gene expression profile in GIST, as compared with other histological types of sarcomas. Transcriptional heterogeneity within clinically or molecularly defined subsets of GISTs has not been previously reported. We tested the hypothesis that the gene expression profile in GISTs might be related to KIT genotype and possibly to other clinicopathological factors.