Positron emission tomography 18F-fluorodeoxyglucose uptake and prognosis in patients with surgically treated, stage I non-small cell lung cancer: a systematic review

Pretreatment and Posttreatment Tumor Metabolic Activity Assessed by FDG-PET/CT as Predictors of Tumor Recurrence and Survival Outcomes in Early-Stage Non-Small Cell Lung Cancer Treated With Stereotactic Body Radiation Therapy

Purpose

Stereotactic body radiation therapy (SBRT) is considered the standard of care for medically inoperable early-stage non-small cell lung cancer. There is mixed evidence on the prognostic significance of tumor metabolic activity assessed by positron emission tomography combined with computed tomography (PET/CT) using F-18 fluorodeoxyglucose (FDG). The objectives of this study were to evaluate the maximum standardized uptake value (SUVmax) pretreatment and at 3 and 6 months after SBRT for prediction of tumor control and survival outcomes.

Methods and Materials

Consecutive patients from a single institution with T12N0M0 non-small cell lung cancer receiving primary treatment with SBRT with pretreatment FDG-PET/CT (n = 163) and follow-up FDG-PET/CT at 3 or 6 months (n = 71) were included. Receiver operator characteristic analysis was performed to dichotomize variables for Kaplan-Meier survival analysis. Multivariate analysis was performed with Cox proportional hazards regression.

Results

Median follow-up was 19 months. For the whole cohort, 1-year and 2-year local control, progression-free survival (PFS), and overall survival (OS) were 95.0% and 80.3%, 87.1% and 75.4%, and 67.0% and 49.6% respectively. The following pre-SBRT SUVmax cutoffs were significant: SUV > 4.0 for distant failure-free survival (adjusted hazard ratio [aHR], 3.33, P = .006), >12.3 for PFS (aHR, 2.80, P = .011), and >12.6 for OS (aHR, 3.00, P = .003). SUVmax decreases of at least 45% at 3 months (aHR, 0.15, P = .018), and 53% at 6 months (aHR, 0.12, P = .046) were associated with improved local failure-free survival.

Conclusions

Pre-SBRT SUVmax cutoffs can predict distant failure, PFS, and OS. At both 3 and 6 months after SBRT, cutoffs for percentage change in SUVmax can potentially stratify risk of local recurrence.

Clinical features and prognosis of advanced intra- and extra-pulmonary neuroendocrine carcinomas

Objective

We examined the clinical features and prognosis of advanced intra- and extra-pulmonary neuroendocrine carcinomas (NECs) to offer additional guidance for the clinical treatment of small-cell lung cancer (SCLC), which is a type of advanced intrapulmonary NEC (IPNECs).

Materials and Methods

The clinical data and survival of 123 patients with advanced IPNECs and extrapulmonary NECs (EPNECs) were obtained. We retrospectively examined the corresponding clinical diagnosis and treatment and investigated the significant factors influencing the survival prognosis of patients with NECs.

Results

There were 90 cases of IPNECs (including 81 cases of SCLC), and 33 cases of EPNECs. The median overall survival (OS) of IPNECs was significantly longer than that of the EPNECs in the gastrointestinal tract and in the other regions (P < 0.05). The median OS of patients with other IPNECs was longer than that of patients with SCLC (P > 0.05). Multivariate analysis demonstrated that age, liver metastasis, number of cycles of first-line chemotherapy, and chest radiotherapy were risk factors influencing OS in patients with NECs (P < 0.05).

Conclusions

The survival of IPNECs was significantly longer than that of EPNECs in the gastrointestinal tract and other regions. Nevertheless, patients with advanced NECs who were older and had liver metastases had a poorer prognosis. Multidisciplinary treatments including multicycle chemotherapy and a combination of chemotherapy and radiotherapy should function significantly in extending the survival of NECs.

Correlation of preoperative PET/computer tomography 18F-fluorodeoxyglucose uptake (maximum standardized uptake value) with prognosis in patients with operated lung cancer

PURPOSE

The aim of this study was to investigate the correlation of preoperative 18F-fluorodeoxyglucose PET/computed tomography maximum standardized uptake value (SUVmax) in operated non-small cell lung cancer (NSCLC) cases with other prognostic parameters and survival.

PATIENTS AND METHODS

NSCLC patients treated by surgical resection were imaged with PET within 60 days before surgery.

RESULTS

Overall, 525 cases consecutive patients were retrospectively reviewed. The median value of SUVmax in a total of 525 cases was 12.1, and the mean was 13.3 ± 7.13. Logistic regression analysis performed to identify the variables that have an impact on SUVmax revealed that histology [hazard ratio (HR: 1.893; 95% CI; P = 0.001) and T status (HR: 8.991; 95% CI; P = 0.000) are correlated with SUVmax. Kaplan-Meier analysis revealed a mean survival of 73.7 ± 1.95 months and a median survival of 85.6 ± 6.03 months. In the group with an SUVmax value of less than 10, the mean survival was 81.9 ± 3.02 months (76.0-87.8), and in the group with SUVmax greater than 10.1, the mean survival was 68.6 ± 2.4 months (63.9-73.3) (P = 0.000). In the multivariate analysis, SUVmax, age, tumor histology, lymph node metastasis, comorbid diseases and complete/incomplete status of the resection were identified as the factors predictive of prognosis.

CONCLUSION

It is seen that preoperative SUVmax is a parameter with prognostic significance at least as much as histopathology, age, complete/incomplete status of resection and lymph node involvement.

Is the size of the lepidic component negligible when measuring the size of the tumor to determine the stage of lung adenocarcinoma?

Background

After applying the 8th edition of the TNM staging system, the invasive component size, not total tumor size, began to be used as a T descriptor for the stage. The aim of this study was to evaluate whether the size of the lepidic component can be negligible when using only the invasive component size as the T descriptor.

Methods

From 2010 to 2018, 613 consecutive patients were diagnosed as having stage IA lung adenocarcinoma and underwent anatomical lobectomy at a tertiary hospital. Pathologic specimens and medical records were reviewed retrospectively. Statistical analyses were conducted to find out whether the recurrence of stage IA lung adenocarcinoma was more affected by total tumor size (including lepidic component size) or invasive component size.

Results

The 5-year recurrence-free survival (RFS) rates of stage 0, stage IA1, stage IA2, and stage IA3 were 100%, 98.4%, 89.1%, and 81.7%, respectively. In multivariate analysis, total tumor size was not a risk factor for recurrence, whereas invasive component size was a significant risk factor for recurrence (Hazard ratio =1.658, P=0.043). In subgroup analysis, 5-year RFS rates of large lung adenocarcinoma (total tumor size >3 cm) and others (total tumor size ≤3 cm) in the same invasive component size group (stage IA2 and stage IA3) were not statistically different.

Conclusions

Invasive component size was a risk factor for recurrence of stage IA lung adenocarcinoma, while total tumor size was not a risk factor. Therefore, it seems to be appropriate to ignore the size of the lepidic component.

A PET/CT volumetric parameter predicts prognosis of non-small cell lung cancer treated using preoperative chemoradiotherapy and surgery: A retrospective case series study

The purpose of the present study was to clarify whether positron emission tomography/computed tomography (PET/CT) volumetric parameters were prognostic predictors of non-small cell lung cancer (NSCLC) treatment in patients who had undergone preoperative concurrent chemoradiotherapy (CCRT) and surgery. In the present study, retrospectively surveyed the data of patients with NSCLC who underwent preoperative CCRT and surgery at Okayama University Hospital (Okayama, Japan) between April 2006 and March 2018. The maximum standardized uptake value (SUV_max) and volumetric parameters, including metabolic tumor volume (MTV) and total lesion glycolysis (TLG), were calculated using PET/CT and the percentage decrease (Δ) in each parameter value post-CCRT. The SUV_max threshold for defining MTV was set at 2.5. Furthermore, the association between survival and PET parameter values was analyzed. A total of 52 patients were included in the present study. The median follow-up period was 50.65 months. In univariate analysis, ΔTLG was identified to be a significant predictor of progression-free survival (PFS; P=0.03). The 5-year PFS rates were 48.6 and 76.6% for patients with low ΔTLG and high ΔTLG, respectively. High ΔTLG was indicative of a higher overall survival rate (P=0.08). The present results suggest that ΔTLG calculated using PET/CT is a prognostic predictor of NSCLC treated using preoperative CCRT and surgery, and may help physicians determine treatment strategies.

Prognostic role of positron emission tomography and computed tomography parameters in stage I lung adenocarcinoma

Background

According to the current pathological classification, lung adenocarcinoma includes histological subtypes with significantly different prognoses, which may require specific surgical approaches. The aim of the study was to assess the role of CT and PET parameters in stratifying patients with stage I adenocarcinoma according to prognosis.

Patients and methods

Fifty-eight patients with pathological stage I lung adenocarcinoma who underwent surgical treatment were retrospectively reviewed. Adenocarcinoma in situ and minimally-invasive adenocarcinoma were grouped as non-invasive adenocarcinoma. Other histotypes were referred as invasive adenocarcinoma. CT scan assessed parameters were: ground glass opacity (GGO) ratio, tumour disappearance rate (TDR) and consolidation diameter. The prognostic role of the following PET parameters was also assessed: standardized uptake value (SUV) max, SUVindex (SUVmax to liver SUVratio), metabolic tumour volume (MTV), total lesion glycolysis (TLG).

Results

Seven patients had a non-invasive adenocarcinoma and 51 an invasive adenocarcinoma. Five-year disease-free survival (DFS) and cancer-specific survival (CSS) for non-invasive and invasive adenocarcinoma were 100% and 100%, 70% and 91%, respectively. Univariate analysis showed a significant difference in SUVmax, SUVindex, GGO ratio and TDR ratio values between non-invasive and invasive adenocarcinoma groups. Optimal SUVmax, SUVindex, GGO ratio and TDR cut-off ratios to predict invasive tumours were 2.6, 0.9, 40% and 56%, respectively. TLG, SUVmax, SUVindex significantly correlated with cancer specific survival.

Conclusions

CT and PET scan parameters may differentiate between non-invasive and invasive stage I adenocarcinomas. If these data are confirmed in larger series, surgical strategy may be selected on the basis of preoperative imaging.

Use of a prognostic risk score that aggregates the FDG-PET/CT SUVmax, tumor size, and histologic group for predicting the prognosis of pStage I lung adenocarcinoma

BACKGROUND

pStage I includes clinicopathologically diverse groups. This study aimed to identify the prognostic factors for pStage I lung adenocarcinoma.

METHODS

We retrospectively reviewed 208 patients with pStage I adenocarcinomas who underwent curative resection in our institute between 2006 and 2013. The maximum standardized uptake value (SUVmax) on [F18]-fluoro-deoxy-D-glucose positron emission tomography-computed tomography (PET/CT) was evaluated. Adenocarcinomas were categorized into the following histologic groups: group 0 (minimally invasive adenocarcinoma and lepidic predominant adenocarcinoma), group 1 (papillary predominant adenocarcinoma), and group 2 (acinar predominant adenocarcinoma and all the remaining subtypes). We assessed the relationship between disease-free survival (DFS) and clinicopathological factors.

RESULTS

Multivariate analysis of DFS demonstrated that SUVmax > 3.0 (p < 0.001), total tumor size > 20 mm (p = 0.016), and histologic groups (p < 0.05) were independent prognostic factors. The prognostic risk score (PRS) was calculated using the following equation: PRS = SUVmax (≤ 3.0: 0 point, > 3.0: 2 points) + total tumor size (≤ 20 mm: 0 point, > 20 mm: 1 point) + histologic group (group 0: 0 point, group 1: 1 point, group 2: 2 points). Patients were divided into the following three risk groups: low-risk (PRS 0-2 points, n = 136), intermediate-risk (PRS 3-4 points, n = 49), and high-risk groups (PRS 5 points, n = 13). The 5-year DFS rates were 93.2%, 50.6%, and 30.8% for the low-, intermediate-, and high-risk groups, respectively (p < 0.001).

CONCLUSIONS

The PRS aggregating the FDG-PET/CT SUVmax, total tumor size, and histologic group predicts the prognosis of pStage I lung adenocarcinoma.

Prognostic value of [18F]FDG PET/CT parameters in surgically resected primary lung adenocarcinoma: a single-center experience

OBJECTIVE

To evaluate the prognostic role of maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) measured by FDG-positron emission tomography (PET)/computed tomography (CT) in patients with primary lung adenocarcinoma undergoing surgical resection.

METHODS

All consecutive patients undergoing curative surgery for primary lung adenocarcinoma at the Thoracic Surgery Unit of the University Hospital of Parma between January 2009 and December 2014 were retrospectively analyzed. The cutoff point of each continuous PET parameter was determined through receiver operating characteristic curve and Youden index, using overall survival (OS) as the classification status. Univariate and multivariate Cox proportional hazards models were applied to evaluate the association between OS and potential prognostic variables, including SUVmax, MTV, and TLG.

RESULTS

A total of 193 patients were considered eligible for this study. The mean 5-year OS rate was 70.5 ± 3.5%. Acinar and lepidic patterns were more frequently associated with absent or low (<2.5) SUVmax values [18F]FDG uptake. At univariate analysis, male sex, advanced stage, micropapillary and solid pattern, lymphatic, blood vessels and pleural invasion, high SUVmax, MTV, and TLG were significantly associated with poorer OS. Multivariate analyses revealed that only sex, stage, and TLG were independent factors for OS, with male sex, stage 3+4, and high TLG value (p = 0.041) significantly associated with poorer OS.

CONCLUSIONS

In this study, [18F]FDG PET/CT parameters SUVmax, MTV, and TLG were prognostic factors in patients with surgically resected lung adenocarcinoma, able to predict OS and helping to further stratify these patients into prognostic subsets. Elevated TLG was also an independent predictor for shorter OS.

Correlation between expression of Ki-67 and MSCT signs in different types of lung adenocarcinoma

To investigate the correlation between the proliferating cell nuclear antigen Ki-67 and the multislice computed tomography (MSCT) signs in different subtypes of lung adenocarcinoma.Ninety-five patients with lung adenocarcinoma confirmed by surgical pathology and treated between January 2017 and December 2017 were included. MSCT was performed before the operation, and the characteristics of the high-resolution CT (HRCT) signs of the lesions were compared with the Ki-67 immunohistochemistry results.The levels of Ki-67 in the 95 lung adenocarcinoma specimens were positively correlated with the malignancy of lung adenocarcinoma. Spearman correlation coefficient was 0.615. The expression of Ki-67 was positively correlated with the nodules' diameter, density, and lobulated sign, with Spearman correlation coefficients of 0.58, 0.554, and 0.436. There was no significant correlation with spiculation and pleural retraction, with correlation coefficients of 0.319/0.381.These findings suggest that the MSCT signs of different types of lung adenocarcinoma might be associated with the expression of Ki-67. Without replacing biopsy, the imaging features of pulmonary nodules could be comprehensively analyzed to evaluate the proliferation potential of preoperative nodules, but additional studies are needed for confirmation.

New insight on the correlation of metabolic status on 18F-FDG PET/CT with immune marker expression in patients with non-small cell lung cancer

BACKGROUND

Metabolic information obtained through ¹⁸F-flurodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) is used to evaluate malignancy by calculating the glucose uptake rate, and these parameters play important roles in determining the prognosis of non-small cell lung cancer (NSCLC). The expression of immune-related markers in tumor tissue reflects the immune status in the tumor microenvironment. However, there is lack of reports on the association between metabolic variables and intra-tumor immune markers. Herein, we investigate the correlation between metabolic status on ¹⁸F-FDG PET/CT and intra-tumor immunomarkers' expression in NSCLC patients.

METHODS

From April 2008 to August 2014, 763 patients were enrolled in the analysis to investigate the role of maximum standardized uptake value (SUVmax) in lung cancer. One hundred twenty-two tumor specimens were analyzed by immunohistochemistry (IHC) to intra-tumor immune cells and programmed death protein ligand 1(PD-L1) expression on tumor cells. The correlation between metabolic variables and the expression of tissue immune markers were analyzed.

RESULTS

SUVmax values have significant variations in different epidermal growth factor receptor (EGFR) statuses (wild type vs mutant type), high/low neutrophil-to-lymphocyte ratio (NLR) groups, and high/low platelets-to-lymphocyte ratio (PLR) groups (p < 0.001, p < 0.001, p = 0.003, respectively). SUVmax was an independent prognostic factor in lung cancer patients (p = 0.013). IHC demonstrated a statistically significant correlation between SUVmax and the expression of CD8 tumor-infiltrating lymphocytes (p = 0.015), CD163 tumor-associated macrophages (TAMs) (p = 0.003), and Foxp3-regulatory T cells (Tregs) (p = 0.004), as well as PD-1 and PD-L1 (p = 0.003 and p = 0.012, respectively). With respect to patient outcomes, disease stage, BMI, SUVmax, metabolic tumor volume (MTV), TLG (tumor lesion glycolysis), CD163-TAMs, CD11c-dendritic cells (DCs), PD-L1, and Tregs showed a statistically significant correlation with progression-free survival (PFS) (p < 0.001, 0.023, < 0.001, 0.007, 0.005, 0.004, 0.008, 0.048, and 0.014, respectively), and disease stage, SUVmax, MTV, TLG, CD163-TAMs, CD11c-DCs, and PD-L1 showed a statistically significant correlation with overall survival (OS) (p < 0.001, < 0.001, 0.014, 0.012, < 0.001, 0.001, and < 0.001, respectively).

CONCLUSION

This study revealed an association between metabolic variable and immune cell expression in the tumor microenvironment and suggests that SUVmax on ¹⁸F-FDG PET/CT could be a potential predictor for selecting candidates for immunotherapy.

Potential Prognostic Role of 18F-FDG PET/CT in Invasive Epithelial Ovarian Cancer Relapse. A Preliminary Study

Epithelial ovarian cancer (EOC) is the most lethal gynecological malignancy, with relapse occurring in about 70% of advanced cases with poor prognosis. Fluorine-18-2-fluoro-2-deoxy-d-glucose PET/CT (¹⁸F-FDGPET/CT) is the most specific radiological imaging used to assess recurrence. Some intensity-based and volume-based PET parameters, maximum standardized uptake values (SUV_max), metabolic tumor volume (MTV) and total lesion glycolysis (TLG), are indicated to have a correlation with treatment response. The aim of our study is to correlate these parameters with post relapse survival (PRS) and overall survival (OS) in Epithelial Ovarian Cancer (EOC) relapse. The study included 50 patients affected by EOC relapse who underwent ¹⁸F-FDGPET/CT before surgery. All imaging was reviewed and SUV_max, MTV and TLG were calculated and correlated to PRS and OS. PRS and OS were obtained from the first relapse and from the first diagnosis to the last follow up or death, respectively. SUV_max, MTV and TLG were tested in a univariate logistic regression analysis, only SUV_max demonstrated to be significantly associated to PRS and OS (p = 0.005 and p = 0.024 respectively). Multivariate analysis confirmed the results. We found a cut-off of SUV_max of 13 that defined worse or better survival (p = 0.003). In the first relapse of EOC, SUV_max is correlated to PRS and OS, and when SUV_max is greater than 13, it is an unfavorable prognostic factor.

18F-fluorodeoxyglucose positron emission tomography/computed tomography in the evaluation of clinically node-negative non-small cell lung cancer

One in four non-small cell lung cancer (NSCLC) patients are diagnosed at an early-stage. Following the results of the National Lung Screening Trial that demonstrated a survival benefit for low-dose computed tomography screening in high-risk patients, the incidence of early-stage NSCLC is expected to increase. Use of 18F-fluorodeoxyglucose positron emission tomography/computed tomography during initial diagnosis of these early-stage lesions has been increasing. Traditionally, positron emission tomography/computed tomography scans have been utilized for mediastinal nodal staging and to rule out distant metastases in suspected early-stage NSCLC. In clinically node-negative NSCLC, the use of sublobar resection and selective lymph node dissection has been increasing as a therapeutic option. The higher rate of locoregional recurrences after limited resection and the significant incidence of occult lymph node metastases underscores the need to further stratify clinically node-negative NSCLC in order to select patients for limited resection versus lobectomy with complete mediastinal lymph node dissection. In this report, we review the published data, and discuss the significance and potential role of 18F-fluorodeoxyglucose positron emission tomography/computed tomography evaluation for clinically node-negative NSCLC. Consequently, the literature review demonstrates that maximum standardized uptake value is a predictive factor for occult nodal metastasis with an accuracy of 55-77%. In addition, maximum standardized uptake value is a predictor for worse overall, as well as disease-free, survival.

Metabolic positron emission tomography parameters predict failure patterns in early non-small-cell lung cancer treated with stereotactic body radiation therapy: a single institution experience

Objective

The prognostic value of metabolic parameters using 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) has not been established for early non-small cell lung cancer (NSCLC). Accordingly, the authors investigated the prognostic value of metabolic parameters in terms of failure patterns in patients with early NSCLC who underwent stereotactic body radiation therapy (SBRT).

Methods

Data from 35 patients with Stage I NSCLC who underwent SBRT using CyberKnife and received pretreatment FDG PET/CT between 2008 and 2016 were retrospectively reviewed. Maximum standardized uptake value (SUVmax), metabolic tumor volume, and total lesion glycolysis were measured. The significance of these parameters with regard to failure patterns was assessed.

Results

The median follow-up was 23 months for all patients and 34 months for living patients. Ten patients experienced recurrence: three local failures, five regional failures (RF), and eight distant failures (DF). Three-year local, regional and distant control rates were 96.7%, 86.4% and 71.1%, respectively. High SUVmax (<9 vs. ≥9) was an independent predictive factor associated with increased RF (P = 0.027) and DF (P = 0.008). Furthermore, SUVmax was indicative of both progression-free (P = 0.015) and overall (P = 0.034) survival.

Conclusions

High SUVmax was a significant metabolic parameter associated with increased RF and DF in patients with early NSCLC who received SBRT, having a high propensity for dissemination. These results suggest that adjuvant treatment in conjunction with SBRT may be considered in patients with early NSCLC and high SUVmax.

Effect of PET/CT standardized uptake values on complete response to treatment before definitive chemoradiotherapy in stage III non-small cell lung cancer

PURPOSE

The standard treatment for patients with stage III non-small cell lung cancer (NSCLC), unsuitable for resection and with good performance, is definitive radiotherapy with cisplatin-based chemotherapy. Our aim is to evaluate the effect of the maximum value of standardized uptake values (SUVmax) of the primary tumor in positron emission tomography-computed tomography (PET/CT) before treatment on complete response (CR) and overall survival.

METHODS

The data of 73 stage III NSCLC patients treated with concurrent definitive chemoradiotherapy (CRT) between 2008 and 2017 and had PET/CT staging in the pretreatment period were evaluated. ROC curve analysis was performed to determine the ideal cut-off value of pretreatment SUVmax to predict CR.

RESULTS

Median age was 58 years (range 27-83 years) and 66 patients were male (90.4%). Median follow-up time was 18 months (range 3-98 months); median survival was 23 months. 1-year overall survival (OS) rate and 5-year OS rate were 72 and 19%, respectively. Median progression-free survival (PFS) was 9 months; 1-year PFS rate and 5-year PFS rate were 38 and 19%, respectively. The ideal cut-off value of pretreatment SUVmax that predicted the complete response of CRT was 12 in the ROC analysis [AUC 0.699 (0.550-0.833)/P < 0.01] with a sensitivity of 83%, and specificity of 55%. In patients with SUVmax < 12, CR rate was 60%, while, in patients with SUV ≥ 12, it was only 19% (P = 0.002). Median OS was 26 months in patients with pretreatment SUVmax < 12, and 21 months in patients with SUVmax ≥ 12 (HR = 2.93; 95% CI 17.24-28.75; P = 0.087). CR rate of the whole patient population was 26%, and it was the only factor that showed a significant benefit on survival in both univariate and multivariate analyses.

CONCLUSION

Pretreatment SUVmax of the primary tumor in PET/CT may predict CR in stage III NSCLC patients who were treated with definitive CRT. Having clinical CR is the only positive predictive factor for prolonged survival.

The value of different 18F-FDG PET/CT baseline parameters in risk stratification of stage I surgical NSCLC patients

OBJECTIVE

Administration of postoperative chemotherapy to patients with completely resected stage I NSCLC is still a matter of debate. The aim of the present study was to evaluate the value of different baseline ¹⁸F-FDG PET parameters in identifying surgical stage I NSCLC patients who are at high risk of recurrence, and thus are indicated for further postoperative treatment.

METHODS

This is a retrospective study, which included 49 patients (28 males, 21 females) with the median age of 69 years (range 28-84), who had pathologically proven stage I NSCLC. All patients underwent ¹⁸F-FDG PET/CT at baseline followed by complete surgical resection of the tumor (R0). Baseline SUV_max, MTV and TLG were measured. Patients' follow-up records were retrospectively reviewed, and DFS (disease-free survival) was assessed. For each parameter, the most accurate cut-off value for the prediction of recurrence was calculated using the ROC curve analysis and the Youden index. DFS was evaluated for patients above and below the calculated cut-off value using the Kaplan-Meier method and the difference in survival between the two groups was estimated using the log-rank test.

RESULTS

Median observation time of the patients after surgery was 28.7 months (range 3.5-58.8 months). 9 patients developed recurrence. The calculated cut-off values for SUV_max, MTV and TLG were 6, 6.6 and 33.6, respectively. Using these cut-offs, the observed sensitivity for SUV_max, MTV and TLG for prediction of recurrence was 100%, 89% and 89%, respectively, while the observed specificity was 43%, 73% and 65%, respectively. The difference in survival between patients below and above the cut-off value was statistically significant in all three studied parameters. The highest AUC was observed for MTV (AUC = 0.825, p = 0.003), followed by TLG (AUC = 0.789, p = 0.007), and lastly SUV_max (AUC = 0.719, p = 0.041). ROC curve analysis showed that volumetric parameters had better predictive performance than SUV_max as regards recurrence.

CONCLUSION

PET-derived parameters at baseline were predictive of recurrence in stage I surgical NSCLC patients. Moreover, the metabolic volume of the tumor was the most significant parameter for this purpose among the studied indices.

Pretreatment 18F-Fluorodeoxyglucose Positron Emission Tomography Standardized Uptake Values and Tumor Size in Medically Inoperable Nonsmall Cell Lung Cancer Is Prognostic of Overall 2-Year Survival After Stereotactic Body Radiation Therapy

OBJECTIVE

The aim of this study was to determine prognostic value of tumor size and metabolic activity on survival for patients with early stage nonsmall cell lung cancer receiving stereotactic body radiation therapy.

METHODS

We retrospectively evaluated the patients who underwent positron emission tomography-computed tomography scan before stereotactic body radiation therapy treatment. Tumor diameter, tumor volume, maximum standardized uptake value (SUVmax), standardized uptake value (SUV) average, and SUV volume were obtained. Cox regression analyses were performed to determine the associations between tumor characteristics and survival.

RESULTS

The patients with large tumors and high SUVmax have worse survival than patients with small tumors and low SUVmax (hazard ratio [HR] = 3.47, P = 0.007). Patients with small tumors and high SUVmax (HR = 1.80; P = 0.24) and large tumors and low SUVmax (HR = 1.55; P = 0.43) had increased risk of death compared with patients with small tumors and low SUVmax.

CONCLUSIONS

Both increased tumor size and metabolic activity are associated with increased risk of death. Combining size and metabolic activity together is superior for predicting 2-year survival and identifying patients for whom survival is statistically worse.

Prediction of EGFR and KRAS mutation in non-small cell lung cancer using quantitative 18F FDG-PET/CT metrics

This study investigated the relationship between epidermal growth factor receptor (EGFR) and Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations in non-small-cell lung cancer (NSCLC) and quantitative FDG-PET/CT parameters including tumor heterogeneity. 131 patients with NSCLC underwent staging FDG-PET/CT followed by tumor resection and histopathological analysis that included testing for the EGFR and KRAS gene mutations. Patient and lesion characteristics, including smoking habits and FDG uptake parameters, were correlated to each gene mutation. Never-smoker (P < 0.001) or low pack-year smoking history (p = 0.002) and female gender (p = 0.047) were predictive factors for the presence of the EGFR mutations. Being a current or former smoker was a predictive factor for the KRAS mutations (p = 0.018). The maximum standardized uptake value (SUV_max) of FDG uptake in lung lesions was a predictive factor of the EGFR mutations (p = 0.029), while metabolic tumor volume and total lesion glycolysis were not predictive. Amongst several tumor heterogeneity metrics included in our analysis, inverse coefficient of variation (1/COV) was a predictive factor (p < 0.02) of EGFR mutations status, independent of metabolic tumor diameter. Multivariate analysis showed that being a never-smoker was the most significant factor (p < 0.001) for the EGFR mutations in lung cancer overall. The tumor heterogeneity metric 1/COV and SUV_max were both predictive for the EGFR mutations in NSCLC in a univariate analysis. Overall, smoking status was the most significant factor for the presence of the EGFR and KRAS mutations in lung cancer.

Maximum standardized uptake value on FDG-PET predicts survival in stage I non-small cell lung cancer following carbon ion radiotherapy

The present study (University Hospital Medical Information Network study no. UMIN000003797) aimed to evaluate whether the maximum standardized uptake value (SUV_max) of pretreatment ¹⁸F-fluorodeoxyglucose-positron emission tomography (FDG-PET) is prognostic factor for stage I non-small cell lung cancer (NSCLC) treated with carbon ion radiotherapy (C-ion RT). Patients treated between June 2010 and June 2013 at Gunma University Heavy Ion Medical Center (Maebashi, Japan) on a prospective protocol were included in the present study. Patients with T1a-b and T2a NSCLC were treated with C-ion RT at a dose of 52.8 Gy [relative biological effectiveness (RBE)] and 60.0 Gy (RBE), respectively, in four fractions. Prior to treatment, all patients underwent FDG-PET, in which the SUV_max of primary tumors was evaluated. Local control, progression-free survival (PFS), and overall survival (OS) were calculated. A total of 45 patients were analyzed and the median follow-up period was 28.9 months. The 2-year local control, PFS and OS rates for all patients were 93, 78 and 89%, respectively. The mean SUV_max of primary tumors was 5.5, and patients were divided into higher (≥5.5) and lower (<5.5) SUV_max groups. The 2-year PFS rates were 61 and 89% for the higher and lower SUV_max groups, respectively (P=0.01), and the 2-year OS rates for the higher and lower SUV_max groups were 76 and 96%, respectively (P=0.01). The higher SUV_max group exhibited a significantly worse PFS and OS compared with the lower SUV_max group; however, the SUV_max was not associated with the local control rate. In total, 2 patients (4%) experienced grade 2 or 3 radiation pneumonitis, with their symptoms improved through conservative treatment. No patients experienced any grade 4 or 5 toxicities. The results of the present study indicate that pretreatment SUV_max is a prognostic indicator for outcomes in patients with stage I NSCLC treated with C-ion RT.

Role of CT and PET Imaging in Predicting Tumor Recurrence and Survival in Patients with Lung Adenocarcinoma: A Comparison with the International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society Classification of Lung Adenocarcinoma

INTRODUCTION

Recently, a new lung adenocarcinoma classification scheme was published. The prognostic value of this new classification has not been elaborated together with the value of imaging biomarkers including computed tomography (CT) and positron emission tomography (PET).

METHODS

We reviewed pathologic specimens and imaging characteristics of primary tumors from 723 consecutive patients who underwent surgical resection for lung adenocarcinoma. On pathology, the predominant histologic subtype and pattern group were quantified. Tumor-shadow disappearance ratio (TDR) on CT and maximum standardized uptake value (SUVmax) on PET were assessed. The relationships between those variables and survival (overall survival [OS] and disease-free survival) were analyzed by using Kaplan-Meier curves and Cox regression analyses.

RESULTS

The median follow-up period was 3.8 years. There were 137 patients (19%) with recurrence and 167 patients (23%) with metastasis after surgical resection. Among 723 patients, 35 patients (4.8%) had adenocarcinoma in situ, 34 patients (4.7%) had minimally invasive adenocarcinoma, 125 patients (17.3%) had lepidic predominant, 314 patients (43.4%) had acinar predominant, 65 patients (9.0%) had papillary predominant, 23 patients (3.2%) had micropapillary predominant, 113 patients (15.6%) had solid predominant, and 14 patients (1.9%) had variant adenocarcinomas. OS and disease-free survival rates were significantly different according to TDR on CT and SUVmax on PET, predominant subtypes, and pattern groups. On multivariate analysis, the SUVmax (p < 0.001), TDR (p = 0.038), and pattern group (p = 0.015) were independent predictors of OS.

CONCLUSIONS

TDR on CT, SUVmax on PET, and the new histologic classification schemes appear to be promising parameters for the prognostic stratification of patients with lung adenocarcinomas, allowing for the triage of patients who necessitate further staging workup and adjuvant therapy.

FDG Uptake on Positron Emission Tomography Correlates with Survival and Time to Recurrence in Patients with Stage I Non-Small-Cell Lung Cancer

INTRODUCTION

Patients with stage I non-small-cell lung cancer (NSCLC) have a wide variation in outcomes, most likely because there are undetected metastases at presentation. We retrospectively reviewed patients with early stage lung cancer to determine if FDG uptake of the primary tumor as measured on positron emission tomography (PET) at the time of diagnosis was associated with overall survival (OS) or time to recurrence (TTR).

METHODS

We reviewed the Tumor Registry at our institution and identified 336 consecutive patients diagnosed with stage I NSCLC over a 5-year period who underwent an FDG-PET/computed tomography within 90 days before surgery. Kaplan-Meier curves were used to describe the survival and TTR experience within subgroups defined by PET maximum standardized uptake value (SUVmax). Cox proportional hazards model was used to assess the impact of PET SUVmax as a continuous variable on OS and TTR. Logistic regression was used to analyze the effect of SUVmax on dichotomized outcomes.

RESULTS

Three hundred thirty-six consecutive patients (176 women and 160 men) with stage I NSCLC were retrospectively reviewed. Mean SUVmax was 9.2 ± 6.9 (range 0.6-30.3). The hazard or risk of dying and recurrence increased significantly as SUVmax increased (p = 0.0008 and 0.024, respectively).

CONCLUSIONS

Preoperative FDG uptake in the primary tumor in patients with stage I disease is associated with OS and TTR. This may be useful in identifying early stage patients who may benefit from more aggressive therapy after surgical resection.

ERK and AKT phosphorylation status in lung cancer and emphysema using nanocapillary isoelectric focusing

BACKGROUND

Emphysema is an independent risk factor for the development of lung cancer in smokers. Activation of oncogenic signalling proteins AKT and ERK by phosphorylation has an established role in the development of lung cancer and has also been implicated in the pathogenesis of emphysema. The aim of this study was to compare the protein level and phosphorylation status of AKT and ERK in paired lung cancer and emphysema tissue using a highly sensitive phosphoprotein analysis approach.

METHODS

An antibody-based, nanocapillary isoelectric focusing (cIEF) assay was used to determine the relative quantities and phosphorylation status of AKT and ERK in tumour and matched lung tissue from patients, with or without evidence of emphysema, undergoing curative resection for non-small cell lung cancer.

RESULTS

20 patients with adenocarcinoma (n=9) or squamous cell carcinoma (n=11) of the lung were included (mean age 67.3 years (SD 7.5, range 47-80 years)), 12 were men and all were current (n=10) or former smokers (n=10). Paired macroscopically normal lung tissue was either histologically normal (n=7) or showed emphysema (n=13). Total and phosphorylated AKT levels were fourfold (p=0.0001) and fivefold (p=0.001) higher in tumour compared with matched lung, respectively. There was no correlation with tumour histology, stage or differentiation; however, total AKT signal in tumour was significantly correlated with fluorodeoxyglucose avidity on positron emission tomography-CT scan (r=0.53, p=0.035). Total ERK was not differentially expressed, but doubly phosphorylated (activated) ERK was threefold higher in emphysema (23.5%, SD 9.2) than either matched tumour (8.8%, SD 8.6) or normal lung tissue (8.3%, SD 9.0) and correlated with the histological severity of emphysema (p=0.005).

CONCLUSIONS

cIEF offers opportunities for quantifying subtle shifts in the phosphorylation status of oncoproteins in nanogram amounts of lung tissue. ERK activation is a feature of emphysema.

Prognostic Value of 18F-FDG PET/CT in Surgical Non-Small Cell Lung Cancer: A Meta-Analysis

Background

The identification of surgical non-small cell lung cancer (NSCLC) patients with poor prognosis is a priority in clinical oncology because of their high 5-year mortality. This meta-analysis explored the prognostic value of maximal standardized uptake value (SUV_max), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) on disease-free survival (DFS) and overall survival (OS) in surgical NSCLC patients.

Materials and Methods

MEDLINE, EMBASE and Cochrane Libraries were systematically searched until August 1, 2015. Prospective or retrospective studies that evaluated the prognostic roles of preoperative 18F-FDG PET/CT with complete DFS and OS data in surgical NSCLC patients were included. The impact of SUV_max, MTV or TLG on survival was measured using hazard ratios (HR). Sub-group analyses were performed based on disease stage, pathological classification, surgery only and cut-off values.

Results

Thirty-six studies comprised of 5807 patients were included. The combined HRs for DFS were 2.74 (95%CI 2.33–3.24, unadjusted) and 2.43 (95%CI: 1.76–3.36, adjusted) for SUV_max, 2.27 (95%CI 1.77–2.90, unadjusted) and 2.49 (95%CI 1.23–5.04, adjusted) for MTV, and 2.46 (95%CI 1.91–3.17, unadjusted) and 2.97 (95%CI 1.68–5.28, adjusted) for TLG. The pooled HRs for OS were 2.54 (95%CI 1.86–3.49, unadjusted) and 1.52 (95%CI 1.16–2.00, adjusted) for SUV_max, 2.07 (95%CI 1.16–3.69, unadjusted) and 1.91 (95%CI 1.13–3.22, adjusted) for MTV, and 2.47 (95%CI 1.38–4.43, unadjusted) and 1.94 (95%CI 1.12–3.33, adjusted) for TLG. Begg’s test detected publication bias, the trim and fill procedure was performed, and similar HRs were obtained. The prognostic role of SUV_max, MTV and TLG remained similar in the sub-group analyses.

Conclusions

High values of SUV_max, MTV and TLG predicted a higher risk of recurrence or death in patients with surgical NSCLC. We suggest the use of FDG PET/CT to select patients who are at high risk of disease recurrence or death and may benefit from aggressive treatments.

Targeting the de novo biosynthesis of thymidylate for the development of a PET probe for pancreatic cancer imaging

The development of cancer-specific probes for imaging by positron emission tomography (PET) is gaining impetus in cancer research and clinical oncology. One of the hallmarks of most cancer cells is incessant DNA replication, which requires the continuous synthesis of nucleotides. Thymidylate synthase (TSase) is unique in this context because it is the only enzyme in humans that is responsible for the de novo biosynthesis of the DNA building block 2'-deoxy-thymidylate (dTMP). TSase catalyzes the reductive methylation of 2'-deoxy-uridylate (dUMP) to dTMP using (R)-N(5),N(10)-methylene-5,6,7,8-tetrahydrofolate (MTHF) as a cofactor. Not surprisingly, several human cancers overexpress TSase, which makes it a common target for chemotherapy (e.g., 5-fluorouracil). We envisioned that [(11)C]-MTHF might be a PET probe that could specifically label cancerous cells. Using stable radiotracer [(14)C]-MTHF, we had initially found increased uptake by breast and colon cancer cell lines. In the current study, we examined the uptake of this radiotracer in human pancreatic cancer cell lines MIAPaCa-2 and PANC-1 and found predominant radiolabeling of cancerous versus normal pancreatic cells. Furthermore, uptake of the radiotracer is dependent on the intracellular level of the folate pool, cell cycle phase, expression of folate receptors on the cell membrane, and cotreatment with the common chemotherapeutic drug methotrexate (MTX, which blocks the biosynthesis of endogenous MTHF). These results point toward [(11)C]-MTHF being used as PET probe with broad specificity and being able to control its signal through MTX co-administration.

Clinical significance of Ki-67 and p53 expression in curatively resected non-small cell lung cancer

The aim of this study is to explore the association of Ki-67 and p53 expression with prognosis in non-small cell lung cancer (NSCLC) patients who underwent curative resection. We retrospectively identified 116 consecutive patients with stages I-III NSCLC who underwent curative resection at a single center from January 2007 to December 2012. Ki-67 and p53 expression was assessed by immunohistochemistry. Data on clinicopathologic features and survival were collected retrospectively. Ki-67 expression in 109 samples and p53 expression in 115 patients were analyzed. According to the results, 108 patients (99 %) showed at least some expression of Ki-67. The median Ki-67 expression level was 30 %. Positive p53 expression was observed in 91 (79 %) patients. Higher Ki-67 expression (>40 %) was significantly more frequent in male (26 vs. 4 % in female, p=0.002), ever-smoker (31 vs. 10 % in never-smoker, p=0.024), and non-adenocarcinoma (30 vs. 11 % of adenocarcinoma, p=0.012) patients. In univariable analysis, median disease-free survival (DFS) was shorter with higher Ki-67 expression (16.1 vs. 61.9 months in those with lower Ki-67 expression, p=0.005), and p53 expression did not show an association with DFS. Among 42 patients with stage I NSCLC who did not receive adjuvant chemotherapy, DFS was significantly worse in patients with higher Ki-67 expression (2-year DFS rate 57 vs. 88 %, p=0.018). In a Cox regression model, higher Ki-67 expression (>40 %) was a significant independent prognostic factor associated with poorer DFS (HR 2.9, 95 % CI 1.3-6.2) along with TNM stage and age. Higher Ki-67 expression (>40 %) showed an independent association with shorter DFS in NSCLC patients who underwent curative resection.

Pretreatment [18F]-fluoro-2-deoxy-glucose positron emission tomography maximum standardized uptake value as predictor of distant metastasis in early-stage non-small cell lung cancer treated with definitive radiation therapy: rethinking the role of positron emission tomography in personalizing treatment based on risk status

PURPOSE

The aim of this study was to determine whether the preradiation maximum standardized uptake value (SUVmax) of the primary tumor for [(18)F]-fluoro-2-deoxy-glucose positron emission tomography (FDG-PET) has a prognostic significance in patients with Stage T1 or T2N0 non-small cell lung cancer (NSCLC) treated with curative radiation therapy, whether conventional or stereotactic body radiation therapy (SBRT).

METHODS AND MATERIALS

Between January 2007 and December 2011, a total of 163 patients (180 tumors) with medically inoperable histologically proven Stage T1 or T2N0 NSCLC and treated with radiation therapy (both conventional and SBRT) were entered in a research ethics board approved database. All patients received pretreatment FDG-PET / computed tomography (CT) at 1 institution with consistent acquisition technique. The medical records and radiologic images of these patients were analyzed.

RESULTS

The overall survival at 2 years and 3 years for the whole group was 76% and 67%, respectively. The mean and median SUVmax were 8.1 and 7, respectively. Progression-free survival at 2 years with SUVmax <7 was better than that of the patients with tumor SUVmax ≥7 (67% vs 51%; P=.0096). Tumors with SUVmax ≥7 were associated with a worse regional recurrence-free survival and distant metastasis-free survival. In the multivariate analysis, SUVmax ≥7 was an independent prognostic factor for distant metastasis-free survival.

CONCLUSION

In early-stage NSCLC managed with radiation alone, patients with SUVmax ≥7 on FDG-PET / CT scan have poorer outcomes and high risk of progression, possibly because of aggressive biology. There is a potential role for adjuvant therapies for these high-risk patients with intent to improve outcomes.

New positron emission tomography derived parameters as predictive factors for recurrence in resected stage I non-small cell lung cancer

BACKGROUND

The recurrence rate for stage I non-small cell lung cancer is high, with 20-40% of patients that relapse after surgery. The aim of this study was to evaluate new F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) derived parameters, such as standardized uptake value index (SUVindex), metabolic tumor volume (MTV) and total lesion glycolysis (TLG), as predictive factors for recurrence in resected stage I non-small cell lung cancer.

METHODS

We retrospectively reviewed 99 resected stage I non-small cell lung cancer patients that were grouped by SUVindex, TLG and MTV above or below their median value. Disease free survival was evaluated as primary end point.

RESULTS

The 5-year overall survival and the 5-year disease free survival rates were 62% and 73%, respectively. The median SUVindex, MTL and TLG were 2.73, 2.95 and 9.61, respectively. Patients with low SUVindex, MTV and TLG were more likely to have smaller tumors (p ≤ 0.001). Univariate analysis demonstrated that SUVindex (p = 0.027), MTV (p = 0.014) and TLG (p = 0.006) were significantly related to recurrence showing a better predictive performance than SUVmax (p = 0.031). The 5-year disease free survival rates in patients with low and high SUVindex, MTV and TLG were 84% and 59%, 86% and 62% and 88% and 60%, respectively. The multivariate analysis showed that only TLG was an independent prognostic factor (p = 0.014) with a hazard ratio of 4.782.

CONCLUSION

Of the three PET-derived parameters evaluated, TLG seems to be the most accurate in stratifying surgically treated stage I non-small cell lung cancer patients according to their risk of recurrence.

Principal component analysis based feature extraction approach to identify circulating microRNA biomarkers

The discovery and characterization of blood-based disease biomarkers are clinically important because blood collection is easy and involves relatively little stress for the patient. However, blood generally reflects not only targeted diseases, but also the whole body status of patients. Thus, the selection of biomarkers may be difficult. In this study, we considered miRNAs as biomarker candidates for several reasons. First, since miRNAs were discovered relatively recently, they have not yet been tested extensively. Second, since the number of miRNAs is relatively limited, selection is expected to be easy. Third, since they are known to play critical roles in a wide range of biological processes, their expression may be disease specific. We applied a newly proposed method to select combinations of miRNAs that discriminate between healthy controls and each of 14 diseases that include 5 cancers. A new feature selection method is based on principal component analysis. Namely this method does not require knowledge of whether each sample was derived from a disease patient or a healthy control. Using this method, we found that hsa-miR-425, hsa-miR-15b, hsa-miR-185, hsa-miR-92a, hsa-miR-140-3p, hsa-miR-320a, hsa-miR-486-5p, hsa-miR-16, hsa-miR-191, hsa-miR-106b, hsa-miR-19b, and hsa-miR-30d were potential biomarkers; combinations of 10 of these miRNAs allowed us to discriminate each disease included in this study from healthy controls. These 12 miRNAs are significantly up- or downregulated in most cancers and other diseases, albeit in a cancer- or disease-specific combinatory manner. Therefore, these 12 miRNAs were also previously reported to be cancer- and disease-related miRNAs. Many disease-specific KEGG pathways were also significantly enriched by target genes of up−/downregulated miRNAs within several combinations of 10 miRNAs among these 12 miRNAs. We also selected miRNAs that could discriminate one disease from another or from healthy controls. These miRNAs were found to be largely overlapped with miRNAs that discriminate each disease from healthy controls.

Sunlight may increase the FDG uptake value in primary tumors of patients with non-small cell lung cancer

Currently, positron emission tomography with computerized tomography (PET-CT) is the most sensitive technique for detecting extracranial metastases in non-small cell lung cancer (NSCLC). It has been reported that there is a correlation between the maximal standardized uptake value (SUV(max)) of primary tumors and prognosis in patients with NSCLC. The effect of sunlight exposure on PET-CT SUV(max) value is not known. Therefore, we aimed to evaluate the effect of sunlight exposure on PET-CT SUV(max) value in patients with NSCLC. A total of 290 patients with NSCLC from two different regions of Turkey (Kayseri, n=168 and Adana, n=122) that have different climate and sunlight exposure intensity, were included in the study. Age, gender, histology of cancer, cancer stage, smoking status, comorbidity and SUV(max) of the primary tumor area at the time of staging were evaluated as prognostic factors. In the multivariate analysis, we detected that the region was the only independent factor affecting SUV(max) (P=0.019). We identified that warmer climate and more sunlight exposure significantly increases the SUV(max) value of the primary tumor area in patients with NSCLC. Further studies are warranted to clarify the issue.

Metabolic and metastatic characteristics of ALK-rearranged lung adenocarcinoma on FDG PET/CT

INTRODUCTION

ALK rearrangement in lung cancer has been identified as a novel molecular target in lung adenocarcinoma. In this study, we evaluated metabolic and metastatic features of lung adenocarcinoma by using FDG PET/CT, with regard to specific genotypes of ALK and EGFR mutation.

METHODS

Patients with lung adenocarcinoma initially diagnosed and examined with FDG PET/CT and molecular genotyping with biopsy specimen, from September 2009 to September 2011, were selected retrospectively. ALK fluorescence in situ hybridization and EGFR mutations were tested. Maximum standardized uptake value (SUVmax) and metastatic characteristics on FDG PET/CT were analyzed with regard to ALK and EGFR status.

RESULTS

Of the 331 lung adenocarcinoma patients, 18 were ALK positive (ALK(+)), 156 were EGFR mutation positive (EGFR(+)), and 157 were wild type (WT) for both ALK and EGFR mutation. The ALK(+) tumor showed significantly higher SUVmax and more common metastasis to lymph nodes and distant organs than those of other genotypes in overall patients (P<0.01). In a subgroup analysis of advanced stage (stage IIIb and IV), ALK(+) lung cancer showed significantly higher SUVmax (P<0.05) than EGFR(+) tumors. In another subgroup analysis of size matched groups, ALK(+) tumors showed significant difference in SUVmax, lymph node and distant metastasis (P<0.01), particularly in the moderate-sized tumors (1.5-3cm).

CONCLUSION

ALK-rearranged lung adenocarcinoma represents higher glucose metabolism and more rapid metastasis to lymph nodes or distant sites compared with those with EGFR mutation and wild type, which suggests more aggressive features of ALK rearrangement.

Utilisation of search filters in systematic reviews of prognosis questions

BACKGROUND

Search filters are designed to increase efficiency of information retrieval and can be particularly useful in limiting the large numbers of articles retrieved for systematic reviews (SRs). Existing published prognosis search filters (or hedges) have lower sensitivity and precision values than their therapy counterparts.

OBJECTIVES

Taking into account the relatively poor performance of prognosis filters, this study seeks to identify which methods of limiting search results to prognostic studies are most often used by SR teams.

METHODS

One hundred and three SRs of prognostic studies published in 2009 and indexed in MEDLINE were retrieved. Each review's search strategy was reviewed and prognosis-related search terms were extracted.

RESULTS

Forty-seven of 103 studies used prognosis-related terms to limit the search. Six SRs of 103 did not specify their search terms, and the remaining 50 SRs used content terms only (no terms related to methodology or prognosis). Of the 47 strategies using prognosis-related terms, only six used a published filter. Many SRs used few or poorly selected prognosis-related search terms which are unlikely to provide the sensitivity generally sought for SRs.

CONCLUSIONS

Published prognosis search filters are used in only a small minority of prognosis SRs.

The use and misuse of positron emission tomography in lung cancer evaluation

This article discusses the potential benefits and limitations of positron emission tomography (PET) for characterizing lung nodules, staging the mediastinum, identifying occult distant metastasis, determining prognosis and treatment response, guiding plans for radiation therapy, restaging during and after treatment, and selecting targets for tissue sampling. The key findings from the medical literature are presented regarding the capabilities and fallibilities of PET in lung cancer evaluation, including characterization of pulmonary nodules and staging in patients with known or suspected non-small-cell lung cancer. The discussion is limited to PET imaging with fluorodeoxyglucose.

Changes of positron emission tomography in newborn infants at different gestational ages, and neonatal hypoxic-ischemic encephalopathy

Cerebral glucose metabolism was measured by (18)F-fluorodeoxyglucose position emission tomography in infants at different gestational ages and with neonatal hypoxic-ischemic encephalopathy. Thirty-six preterm and term infants at different gestational ages without brain injury were divided into four subgroups: ≤32 weeks (n = 4), 33-34 weeks (n = 5), 35-36 weeks (n = 12), and ≥37 weeks (n = 15). Twenty-four newborn infants with hypoxic-ischemic encephalopathy were divided into three subgroups: mild (n = 13), moderate (n = 7), and severe (n = 4). Cerebral glucose metabolism manifested a trend toward increase, and the structure of cranial (18)F-fluorodeoxyglucose positron emission tomography images became clear with increased gestational age, especially at ≥37 weeks. Uptakes of (18)F-fluorodeoxyglucose in the ≥37-week group were significantly higher than in the ≤32-week group (P < 0.01). Cerebral glucose metabolism changed significantly in neonatal hypoxic-ischemic encephalopathy, and was either unbalanced bilaterally or relatively low at all sites. Moreover, uptakes of (18)F-fluorodeoxyglucose were significantly lower in severe than in mild and medium hypoxic-ischemic encephalopathy (P < 0.05). Cerebral glucose metabolism, as measured by (18)F-fluorodeoxyglucose positron emission tomography, may prove useful for estimating brain development and injury in newborn infants, and its clinical values need further investigation.

Novel positron emission tomography tracer distinguishes normal from cancerous cells

Development of tumor-specific probes for imaging by positron emission tomography has broad implications in clinical oncology, such as diagnosis, staging, and monitoring therapeutic responses in patients, as well as in biomedical research. Thymidylate synthase (TSase)-based de novo biosynthesis of DNA is an important target for drug development. Increased DNA replication in proliferating cancerous cells requires TSase activity, which catalyzes the reductive methylation of dUMP to dTMP using (R)-N(5),N(10)-methylene-5,6,7,8-tetrahydrofolate (MTHF) as a cofactor. In principle, radiolabeled MTHF can be used as a substrate for this reaction to identify rapidly dividing cells. In this proof-of-principle study, actively growing (log phase) breast cancer (MCF7, MDA-MB-231, and hTERT-HME1), normal breast (human mammary epithelial and MCF10A), colon cancer (HT-29), and normal colon (FHC) cells were incubated with [(14)C]MTHF in culture medium from 30 min to 2 h, and uptake of radiotracer was measured. Cancerous cell lines incorporated significantly more radioactivity than their normal counterparts. The uptake of radioactively labeled MTHF depended upon a combination of cell doubling time, folate receptor status, S phase percentage, and TSase expression in the cells. These findings suggest that the recently synthesized [(11)C]MTHF may serve as a new positron emission tomography tracer for cancer imaging.