Relationship between primary lesion FDG uptake and clinical stage at PET–CT for non-small cell lung cancer patients: An observation

Machine learning for differentiating lung squamous cell cancer from adenocarcinoma using Clinical-Metabolic characteristics and 18F-FDG PET/CT radiomics

Noninvasive differentiation between the squamous cell carcinoma (SCC) and adenocarcinoma (ADC) subtypes of non-small cell lung cancer (NSCLC) could benefit patients who are unsuitable for invasive diagnostic procedures. Therefore, this study evaluates the predictive performance of a PET/CT-based radiomics model. It aims to distinguish between the histological subtypes of lung adenocarcinoma and squamous cell carcinoma, employing four different machine learning techniques. A total of 255 Non-Small Cell Lung Cancer (NSCLC) patients were retrospectively analyzed and randomly divided into the training (n = 177) and validation (n = 78) sets, respectively. Radiomics features were extracted, and the Least Absolute Shrinkage and Selection Operator (LASSO) method was employed for feature selection. Subsequently, models were constructed using four distinct machine learning techniques, with the top-performing algorithm determined by evaluating metrics such as accuracy, sensitivity, specificity, and the area under the curve (AUC). The efficacy of the various models was appraised and compared using the DeLong test. A nomogram was developed based on the model with the best predictive efficiency and clinical utility, and it was validated using calibration curves. Results indicated that the logistic regression classifier had better predictive power in the validation cohort of the radiomic model. The combined model (AUC 0.870) exhibited superior predictive power compared to the clinical model (AUC 0.848) and the radiomics model (AUC 0.774). In this study, we discovered that the combined model, refined by the logistic regression classifier, exhibited the most effective performance in classifying the histological subtypes of NSCLC.

Preoperative PET-SUVmax and volume based PET parameters of the primary tumor fail to predict nodal upstaging in early-stage lung cancer

OBJECTIVES

Accurate nodal staging is of utmost importance in patients with lung cancer. FDG-PET/CT imaging is now part of the routine staging. Despite thorough preoperative staging nodal upstaging still occurs in early-stage lung cancer. However, the predictive value of preoperative PET metrics of the primary tumor on nodal upstaging remains to be unexplored. Our aim was to assess the association of these preoperative PET-parameters with nodal upstaging in histologically confirmed lung adenocarcinoma and squamous cell carcinoma.

METHODS

From January 2016 to November 2018, 500 patients with pT1-T2/cN0 lung cancer received an anatomical resection with curative intent. 171 patients with adenocarcinoma and squamous cell carcinoma and available PET-CTs were retrospectively included. We analyzed the the association of nodal upstaging with preoperative PET-SUVmax and metabolic PET metrics including total lesion glycolysis (TLG) and metabolic tumor volume (MTV) with different defined thresholds.

RESULTS

High values of preoperative PET-SUVmax of the primary tumor were associated with squamous cell carcinoma (p < 0.0001) and with larger tumors (p < 0.0001). Increased preoperative C-reactive protein levels (<1mg/dL) correlated significantly with high preoperative PET-SUVmax values (p < 0.0001). No significant relationship between PET-SUVmax and lactate dehydrogenase activity (p = 0.6818), white blood cell count (p = 0.7681), gender (p = 0.1115) or age (p = 0.9284) was observed. Nodal upstaging rate was 14.0 % with 8.8 % N1 and 5.3 % N2 upstaging. Tumor size (p = 0.0468) and number of removed lymph nodes (p = 0.0461) were significant predictors of nodal upstaging but no significant association was found with histology or PET parameters. Of note, increased MTV - regardless of the threshold - tended to associate with nodal upstaging.

CONCLUSION

Early-stage lung cancer patients with squamous histology and T2 tumors presented increased preoperative PET-SUVmax values. Nevertheless, beyond tumor size and number of removed lymph nodes neither SUVmax nor metabolic PET parameters MTV and TLG were significant predictors of nodal upstaging.

The role of artificial intelligence based on PET/CT radiomics in NSCLC: Disease management, opportunities, and challenges

Objectives

Lung cancer has been widely characterized through radiomics and artificial intelligence (AI). This review aims to summarize the published studies of AI based on positron emission tomography/computed tomography (PET/CT) radiomics in non-small-cell lung cancer (NSCLC).

Materials and methods

A comprehensive search of literature published between 2012 and 2022 was conducted on the PubMed database. There were no language or publication status restrictions on the search. About 127 articles in the search results were screened and gradually excluded according to the exclusion criteria. Finally, this review included 39 articles for analysis.

Results

Classification is conducted according to purposes and several studies were identified at each stage of disease:1) Cancer detection (n=8), 2) histology and stage of cancer (n=11), 3) metastases (n=6), 4) genotype (n=6), 5) treatment outcome and survival (n=8). There is a wide range of heterogeneity among studies due to differences in patient sources, evaluation criteria and workflow of radiomics. On the whole, most models show diagnostic performance comparable to or even better than experts, and the common problems are repeatability and clinical transformability.

Conclusion

AI-based PET/CT Radiomics play potential roles in NSCLC clinical management. However, there is still a long way to go before being translated into clinical application. Large-scale, multi-center, prospective research is the direction of future efforts, while we need to face the risk of repeatability of radiomics features and the limitation of access to large databases.

Relationships between SUVmax of lung adenocarcinoma and different T stages, histological grades and pathological subtypes: a retrospective cohort study in China

OBJECTIVES

Cancer cell has aberrant metabolism. The purpose of this study aimed to investigate relationships between maximum standard uptake value (SUVmax）of ¹⁸fluoro-2-deoxy-d-glucose and T stages, histological grades and pathological subtypes of lung adenocarcinoma.

DESIGN

Retrospective cohort study, employing the Kruskal-Wallis, Bonferroni-Dunn and Mann-Whitney tests to compare SUVmax of different T stages, histological grades and pathological subtypes of lung adenocarcinoma.

SETTING

The outpatients who had aberrant positron emission tomography/CT (PET/CT) images in chest were enrolled this study from August 2016 to November 2018 in Shanghai, China.

PARTICIPANT

Initial 11 270 patients with suspected lung cancer who underwent PET/CT examinations were surveyed. A total of 1454 patients who were diagnosed as lung adenocarcinoma by pathologist were included in this project.

PRIMARY OUTCOME MEASURES

SUVmax value at different tumour-node-metastasis stages of lung adenocarcinoma before surgery.

RESULTS

The mean SUVmax of patients with lung adenocarcinoma was significantly elevated with the increase in T stages. There were significant evident differences in SUVmax among T1a-T1c (p<0.05). However, after the staging of patients was more than T1 stage, SUVmax of T2a, T2b, T2 visceral pleural invasion, T3 and T4 had not dramatic changes. SUVmax value of lung adenocarcinoma in the same T stage group was the highest in patients with the high grade of malignancy and solid-predominant invasive adenocarcinoma.

CONCLUSIONS

SUVmax value was significantly associated with T stages, grades of malignancy and pathological subtypes of lung adenocarcinoma.

Investigating the Clinico-Molecular and Immunological Evolution of Lung Adenocarcinoma Using Pseudotime Analysis

Introduction

As the molecular features of lung adenocarcinoma (LUAD) have been evaluated as a cross-sectional study, the course of tumor characteristics has not been modeled. The temporal evolution of the tumor immune microenvironment (TIME), as well as the clinico-molecular features of LUAD, could provide a precise strategy for immunotherapy and surrogate biomarkers for the course of LUAD.

Methods

A pseudotime trajectory was constructed in patients with LUAD from the Cancer Genome Atlas and non-small cell lung cancer radiogenomics datasets. Correlation analyses were performed between clinical features and pseudotime. Genes associated with pseudotime were selected, and gene ontology analysis was performed. F-18 fluorodeoxyglucose positron emission tomography images of subjects were collected, and imaging parameters, including standardized uptake value (SUV), were obtained. Correlation analyses were performed between imaging parameters and pseudotime. Correlation analyses were performed between the enrichment scores of various immune cell types and pseudotime. In addition, correlation analyses were performed between the expression of PD-L1, tumor mutation burden, and pseudotime.

Results

Pseudotime trajectories of LUAD corresponded to clinical stages. Molecular profiles related to cell division and natural killer cell activity were changed along the pseudotime. The maximal SUV of LUAD tumors showed a positive correlation with pseudotime. Type 1 helper T (Th1) cells showed a positive correlation, whereas M2 macrophages showed a negative correlation with pseudotime. PD-L1 expression showed a negative correlation, whereas tumor mutation burden showed a positive correlation with pseudotime.

Conclusion

The estimated pseudotime associated with the stage suggested that it could reflect the clinico-molecular evolution of LUAD. Specific immune cell types in the TIME as well as cell division and glucose metabolism were dynamically changed according to the progression of the pseudotime. As a molecular progression of LUAD, different cellular targets should be considered for immunotherapy.

Maximum Standardized Uptake Value on Positron Emission Tomography is Associated With More Advanced Disease and High-risk Features in Lung Adenocarcinoma

¹⁸F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG-PET/CT) has been widely used for preoperative staging of lung adenocarcinomas. The aim of this study was to determine whether a high maximum standardized uptake value (SUVmax) could correlate with pathological characteristics in those patients. We retrospectively reviewed patients with clinical stage 0-IA lung adenocarcinoma who underwent preoperative ¹⁸F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography followed by curative anatomical resection. To identify more advanced disease and high-risk features, representing visceral pleural involvement, pulmonary metastasis, lymph node involvement, and lymphovascular involvement in resected surgical specimens, univariate and multivariate logistic regression analyses were performed. The optimal cutoff point for the SUVmax was determined by receiver operating characteristic analysis. In 2 groups divided according to the cutoff point, the disease-free survivals were calculated and compared using the Kaplan-Meier method and the log-rank test. More advanced disease and high-risk features were identified in 55 (18.9%) of the 291 patients. SUVmax was significantly correlated with more advanced disease and high-risk features, as did the consolidation/tumor ratio on computed tomography. Only 2 (1.2%) of the 169 patients with a SUVmax <3.20 showed more advanced disease and high-risk features, compared with 43.4% of patients with a SUVmax ≥3.20. The disease-free survival was significantly higher in patients with a SUVmax <3.20 than in those with a SUVmax ≥3.20 (P = 0.002). A high SUVmax correlates with more advanced disease and high-risk features in patients with clinical stage 0-IA lung adenocarcinoma. The SUVmax should be considered when deciding treatment strategy in early-stage lung adenocarcinoma.

Narrative review of optimal prognostic radiological tools using computed tomography for T1N0-staged non-small cell lung cancer

Various radiological tools can predict the prognosis of non-small cell lung cancer (NSCLC). In this study, we evaluated the prognostic effect of different radiological tools such as whole tumor size (WTS), consolidation size (CS), consolidation tumor ratio (CTR), tumor disappearance ratio (TDR), mediastinal diameter (MD), and ground glass opacity (GGO) using high-resolution computed tomography (HRCT). We reviewed recent retrospective studies on the predictive effect of these radiological tools on disease-free survival (DFS) and overall survival (OS) in patients with T1N0-staged NSCLC. We searched PubMed and the British Library databases for the English literature published from January 2010 to December 2020 and generated a total of 32 publications (NSCLC, n=16; adenocarcinoma, n=16). The TNM classification version 7 was used in 18 studies, and version 8 in 14 studies. The evaluated radiological parameters were WTS, CS including T category, CTR, TDR, MD, presence of GGO, GGO ratio, and pure GGO. This review suggested that CS, MD, and the presence of GGO are optimal prognostic radiological tools for cT1N0-Staged NSCLC. CTR or TDR for part solid nodules (PSNs) is not a well-accepted prognostic factor. Further investigations are required to differentiate between benign scars and malignant components on HRCT and evaluate the prognosis of PSNs (1< CS ≤2 cm) with large WTS in the future.

18F-FDG PET/CT in lung adenosquamous carcinoma and its correlation with clinicopathological features and prognosis

OBJECTIVE

Lung adenosquamous carcinoma (ASC) is a rare histological subtype of non-small cell lung cancer (NSCLC). Due to its rarity, the studies about ¹⁸F-FDG PET/CT in this kind of pulmonary tumor were quite limited. Thus, this study investigated ¹⁸F-FDG PET/CT findings in ASC and its correlation with clinicopathological features and clinical outcomes.

METHODS

Preoperative ¹⁸F-FDG PET/CT findings and parameters of maximum standard uptake value (SUV_max), metabolic tumor volume and total lesion glycolysis of primary lesion (MTV-P, TLG-P), combination of primary lesion and metastases (MTV-C, TLG-C), and clinicopathological features were retrospectively investigated in patients with ASC. Moreover, progression-free survival (PFS) was also analyzed.

RESULTS

All 41 patients (25 men; 16 women; age: 60 ± 7 years) had single ASC with the mean diameter of 33 ± 14 mm. Six lesions were located centrally and 35 peripherally. Serum tumor markers were abnormally increased sporadically. Twenty-two cases were at TNM stage I, 9 at II, and 10 at III. The primary tumors were FDG-avid in all cases, with the average SUV_max of 11.5 ± 6.0. SUV_max was significantly associated with tumor location, size, and TNM stage (P < 0.05). Forty-one lesions were subgrouped into 23 AC-predominant and 18 SCC-predominant lesions, and significant differences were observed for age, tumor size, and SUV_max in two groups (P < 0.05). The median PFS of 41 cases was 19 months, and 12-month and 24-month PFS rates were 72.1% and 36.1%, respectively. SUV_max, MTV-P, and TLG-C were significantly associated with PFS (P < 0.05).

CONCLUSIONS

ASC of the lung displayed high SUV_max on ¹⁸F-FDG PET/CT, which was associated with tumor location, size, TNM stage, and predominant histologic component. Moreover, metabolic parameters of ¹⁸F-FDG PET/CT were independent prognostic factors of this rare lung malignancy.

Role of FDG PET/CT in the Eighth Edition of TNM Staging of Non-Small Cell Lung Cancer

Lung cancer is the leading cause of cancer-related mortality in the United States, and accurate staging plays a vital role in determining prognosis and treatment. The recently revised eighth edition of the TNM staging system for lung cancer defines new T and M descriptors and updates stage groupings on the basis of substantial differences in survival. There are new T descriptors that are based on the findings at histopathologic examination, and T descriptors are reassigned on the basis of tumor size and extent. No changes were made to the N descriptors in the eighth edition of the TNM staging of lung cancer, because the four N categories that are based on the location of the diseased nodes can be used to consistently predict prognosis. The eighth edition includes a new M1b descriptor for patients with a single extrathoracic metastatic lesion in a single organ (M1b), because they have better survival and different treatment options, compared with those with multiple extrathoracic lesions (M1c). Examination with fluorine 18 fluorodeoxyglucose (FDG) PET/CT is the standard of care and is an integral part of the clinical staging of patients with lung cancer. To provide the treating physicians with accurate staging information, radiologists and nuclear medicine physicians should be aware of the updated classification system and should be cognizant of the site-specific strengths and limitations of FDG PET/CT. In this article, the eighth edition of the TNM staging system is reviewed, as well as the role of FDG PET/CT in the staging of non-small cell lung carcinoma. ^©RSNA, 2018.

Correlation study on 18F-FDG PET/CT metabolic characteristics of primary lesion with clinical stage in lung cancer

BACKGROUND

¹⁸F-FDG PET/CT metabolic characteristics provide the crucial biologic and molecular information for tumors. To explore the relationships between ¹⁸F-FDG PET/CT derived parameters such as maximum standardized uptake value (SUV<inf>max</inf>), metabolic tumor volume (MTV), total lesion glycolysis (TLG) of primary tumor and clinical stage in different histopathologic subtypes of lung cancer.

METHODS

A total of 97 newly diagnosed lung cancer patients (69 males, 28 females; average age 65.1 years) with pathologically proven were retrospectively analyzed, who had undergone ¹⁸F-FDG PET/CT scan before treatment from September 2016 to November 2017. SUV<inf>max</inf>, MTV and TLG of primary tumor were measured. Clinical stage was mainly determined by ¹⁸F-FDG PET/CT, in conjunction with conventional imaging and endoscopic biopsy. Mann-Whitney U test, χ² test, Spearman correlation test and ROC curve analysis were used for statistical analysis.

RESULTS

There were 53 adenocarcinomas (AC), 28 squamous carcinomas (SCC), 13 small cell carcinomas (SCLC), one adenosquamous carcinoma, one mucoepidermoid carcinoma, and one sarcomatoid carcinoma in 97 patients. Both AC and SCLC revealed more cases in stage IV than in stage I-III (P<0.01). There was no significant difference in four stages of SCC (P>0.05). Metabolic parameters of SCC were higher than AC including SUV<inf>max</inf>, MTV and TLG (P<0.01). SCLC showed a higher value than AC in TLG (P<0.05). No significant differences were found between AC and SCLC in SUV<inf>max</inf> and MTV, also between SCC and SCLC in SUV<inf>max</inf>, MTV and TLG (P>0.05). MTV and TLG except SUV<inf>max</inf> were positively correlated with stage in AC (P≤0.001). Only MTV showed a positive correlation with stage in SCC (P<0.05). Whereas there were no definitive relationships between metabolic parameters and stage in SCLC (P>0.05). AC with a higher MTV (MTV≥5.965 cm³) indicated a significantly higher rate of distant metastasis than those with a lower MTV (77.5% (31/40) vs. 30.8% (4/13), χ²=9.553, P<0.01), as well as AC with a higher TLG (TLG≥46.922) than those with a lower TLG (88.5% (23/26) vs. 44.4% (12/27), χ²=11.422, P<0.01).

CONCLUSIONS

Histopathologic subtypes have a significant influence on the relationships between MTV/TLG not SUV<inf>max</inf> of primary foci and stage in lung cancer. Primary MTV/TLG is related to clinical stage closely in AC, and a higher MTV/TLG results in a higher risk of distant metastasis.

Contribution of ¹⁸Fluorodeoxyglucose positron emission tomography uptake and TTF-1 expression in the evaluation of the EGFR mutation in patients with lung adenocarcinoma

AIM

The aim of this study is to evaluate the diagnostic value of PET-CT scan for the prediction of EGFR mutation status and the contribution of TTF-1 expression to PET-CT scan.

METHODS

We retrospectively studied 218 cases with a diagnosis of pulmonary adenocarcinoma between 2012-2014 which underwent EGFR analysis, TTF-1 and PET-CT before treatment.

RESULTS

The EGFR mutation was present in 28.9% (n= 63) of cases. TTF-1 positivity was 66.9% (n= 105). Standardized uptake value (SUV max) was 16.7 ± 6.8 in EGFR mutant type, 13.8 ± 7.6 in cases having no EGFR mutations. According to our evaluations, high SUVmax is positively correlated with EGFR mutation status. TTF-1 expression in multivariate analysis strengthens the accuracy of detecting an EGFR mutation.

CONCLUSION

PET-CT FDG uptake may, together with TTF-1 expression, help diagnosis in lung adenocarcinoma cases when evaluating for EGFR mutation status.

Evaluation of locoregional invasiveness of small-sized non-small cell lung cancers by enhanced dual-energy computed tomography

Background

To investigate the correlation between iodine-related attenuation of dual-energy computed tomography (DE-CT) and the histopathological invasiveness of surgically resected primary non-small cell lung cancers (NSCLCs) ≤ 3 cm in diameter.

Methods

We selected 63 consecutive NSCLC lesions from 60 patients (32 males, 28 females; age range, 39–85 years; mean age, 68 years). After injection of iodinated contrast media, arterial phases were scanned using 140-kVp and 80-kVp tube voltages. Three-dimensional iodine-related attenuation (3D-IRA) of primary tumors at the arterial phase was computed using “lung nodule” application software. The corrected 3D-IRA normalized to the patient’s body weight and contrast medium concentration was then calculated. Single-factor analysis of variance (ANOVA) was used for comparison among tumor differentiation grade groups. Univariate and multivariate logistic regression analysis was used for the correlation between locoregional invasive tumor and clinical factors.

Results

Resected tumors were histopathologically classified into well-differentiated (G1; n = 24), moderately-differentiated (G2; n = 28), and poorly-differentiated (G3; n = 11) groups by degree of tumor differentiation. The mean ± standard deviation of the 3D-IRA was 56.1 ± 22.6 HU in G1 tumours, 48.5 ± 23.9 HU in G2 tumours, and 28.4 ± 15.8 HU in G3 tumours; significant differences were observed between groups by ANOVA. (p = 0.005). Univariate logistic analysis showed that the 3D-IRA and corrected 3D-IRAs were significantly correlated with locoregional invasive tumors (p = 0.002 and p < 0.001, respectively). Multivariate logistic analysis revealed that only the corrected 3D-IRA was significantly correlated with tumor invasiveness (p = 0.003), while gender, clinical size, and solid/subsolid type were not (p = 0.950, p = 0.057 and p = 0.456, respectively).

Conclusions

The 3D-IRA of small-sized NSCLCs was significantly associated with and invasiveness. Low 3D-IRA tumors tended to have greater invasiveness than high 3D-IRA tumors.

Association between histopathological subtype, 18F-fluorodeoxyglucose uptake and epidermal growth factor receptor mutations in lung adenocarcinoma

The aim of the present study was to investigate the association between histopathological subtypes, epidermal growth factor receptor (EGFR) mutations and ¹⁸F-fluorodeoxyglucose (FDG) uptake in patients with lung adenocarcinoma (ADC). The cases of 97 patients with lung ADC who underwent ¹⁸F-FDG positron emission tomography-computed tomography prior to surgical resection were retrospectively reviewed. The patients were stratified according to the International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society (IASLC/ATS/ERS) classification, and graded using a histopathological scoring system. EGFR mutations were identified. Clinicopathological characteristics associated with EGFR mutation status were evaluated using univariate and multivariate analyses. EGFR mutation was identified in 45.4% of the patients and was associated with gender, smoking history, maximum standardized uptake value (SUVmax) and histopathological score. ADC patients with a low SUVmax were more likely to exhibit EGFR mutations compared with patients with a high SUVmax (P=0.018). Patients with a lower histopathological score possessed a significantly lower SUVmax compared with patients with a higher score (P<0.001). Furthermore, the histopathological score and smoking history of the patients were identified to be independent predictors for EGFR mutations, according to multivariate logistic regression analysis. In conclusion, SUVmax and EGFR mutations were associated with lung ADC patients stratified according to the IASLC/ATS/ERS classification. Overall, SUVmax has the potential to be a useful marker in stratifying pre-operative patients with lung ADC and identifying EGFR mutations.

Correlation between FDG-PET/CT findings and solid type non-small cell cancer prognostic factors: are there differences between adenocarcinoma and squamous cell carcinoma?

OBJECTIVES

The maximum standardized uptake value (SUVmax) of FDG-PET/CT is commonly used as an indicator to evaluate the invasiveness and prognosis of non-small-cell lung cancers (NSCLC). We investigated the correlation between SUVmax and tumor invasiveness or postoperative recurrence of solid type NSCLC and compared squamous cell carcinoma (SCC)/adenosquamous carcinoma (ASC) to adenocarcinoma (AC).

METHODS

A retrospective review of preoperative PET/CT, thin-section CT, and postoperative pathological records obtained over a 5-year period was conducted. Solid type NSCLC tumors on thin-section CT with confirmed diagnosis from surgical resection (diameter ≤3 cm) were included. Multivariate logistic regression was used to evaluate the correlation between tumor characteristics and pathological prognostic factors or postoperative recurrence.

RESULTS

150 patients (111 males, 39 females; mean age 67 years; 106 cases of AC, 36 cases of SCC, and 8 cases of ASC) were included. SUVmax was significantly correlated with pleural involvement (p = 0.047), lymphatic permeation (p = 0.003), lymph node metastasis (p = 0.027), and tumor invasiveness (p < 0.001). Receiver operating characteristic analysis indicated an optimal SUVmax threshold of 5.0 for tumor invasiveness. Histopathological type was significantly correlated with pleural involvement (p = 0.042), but not with other types of invasiveness. Twenty-nine patients experienced postoperative recurrence. SUVmax was significantly correlated with tumor recurrence (p = 0.004), but size and histopathological type were not (p = 0.502 and p = 0.351, respectively).

CONCLUSION

SUVmax of the primary lesion in solid type NSCLC was significantly correlated with tumor invasiveness and postoperative recurrence. No differences in tumor invasiveness were observed between solid type AC and SCC/ASC. However, in solid type AC, SUVmax of the primary lesion was more significantly correlated with recurrence.

Evaluation of the factors affecting the maximum standardized uptake value of metastatic lymph nodes in different histological types of non-small cell lung cancer on PET-CT

Background

To evaluate the factors affecting the maximum standardized uptake value (SUVmax) of metastatic lymph nodes in different histological types of non-small cell lung cancer (NSCLC) on integrated positron emission tomography and computed tomography (PET-CT).

Methods

This was a retrospective, single-institution review of 122 patients with pathologically proven NSCLC who had PET-CT scanning at the same center. Lymph node metastases were pathologically confirmed in tissue specimens from surgical patients. Statistical evaluation of PET-CT results was performed on a per-nodal-station basis.

Results

The tumor SUVmax of squamous cell carcinoma (SCC) (11.0 ± 4.1) was higher than that of adenocarcinoma (AC) (7.4 ± 4.4) (P < 0.01), however, the SUVmax of the metastatic lymph nodes did not differ between the SCC (4.6 ± 3.1) and AC groups(3.6 ± 2.5) (P = 0.221). The SUVmax of metastatic lymph nodes was positively correlated with lymph node size but not with the primary tumor SUVmax, primary tumor size, tumor location and tumor differentiation. The frequency of a SUVmax of lymph nodes ≥2.5 was 44%, 80%,100% in SCC group and 39%, 59%, 90% in AC group when the short-axis diameter of metastatic lymph node was <10 mm, 10–15 mm, and > 15 mm, respectively. The low sensitivity for metastatic lymph nodes on PET-CT was increased when the SUVmax cut-off for malignancy was considered to be above the normal background compared with that when the SUVmax cut-off was above 2.5.

Conclusions

There was no difference in the SUVmax of metastatic lymph nodes in the SCC and AC groups. The SUVmax of metastatic lymph nodes was positively correlated with metastatic lymph node size. There was a high false negative rate if lymph nodes with a short-axis diameter less than 10 mm and a extremely low false negative rate if lymph nodes with a short-axis diameter higher than 15 mm. Although an increased sensitivity may be achieved by decreasing the SUVmax cut-off, invasive staging may still be required for negative lymph nodes due to the lower sensitivity of PET-CT in both SCC and AC.

Medical management of lung cancer: Experience in China

Lung cancer is the leading cause of death from cancer worldwide, as well as in China. A multidisciplinary treatment strategy for lung cancer, which includes medical and radiation oncology, surgery, and pathology is used in clinical practice in China. Chinese lung cancer patients are treated according to different pathologic and genetic types of the disease. For those with active epidermal growth factor receptor (EGFR) mutation, EGFR tyrosine kinase inhibitors (EGFR-TKIs) are used in first-, second- or third-line and maintenance treatment of non-small cell lung cancer (NSCLC). For patients with anaplastic lymphoma kinase (ALK) gene rearrangement, Crizotinib is a promising treatment in advanced NSCLC patients. A platinum-based regimen remains the mainstay of first-line systemic therapy for advanced NSCLC patients who are negative for EGFR mutation or ALK gene rearrangement. For patients with non-squamous NSCLC, Pemetrexed plus Cisplatin is recommended in first-line systemic therapy. An Endostatin combination with chemotherapy is used in first- and second-line advanced NSCLC patients. S-1 presents a new option of chemotherapy in advanced NSCLC cases. Cisplatin-based doublet chemotherapy is commonly used in NSCLC patients after surgery as adjuvant therapy. EGFR-TKIs are now being assessed in the adjuvant setting. The standard first-line chemotherapy regimen of small cell lung cancer (SCLC) is platinum with Etoposide (PE). Amrubicin provides similar survival compared with the PE regimen with an acceptable toxicity profile in extensive stage SCLC patients. Supportive care, such as traditional Chinese medicine and pegylated filgrastim, play an important role in improving patients' quality of life.

Prediction of pathologic prognostic factors in patients with lung adenocarcinomas: comparison of thin-section computed tomography and positron emission tomography/computed tomography

Background

The ratio of the maximum diameter of consolidation to the maximum tumor diameter (C/T ratio) on thin-section computed tomography (TSCT) and the maximum standardized uptake value (SUVmax) on ¹⁸ F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) are often used as preoperative independent variables to evaluate the invasiveness of lung adenocarcinoma. We investigated the associations between these independent variables and pathologic invasiveness in pulmonary adenocarcinomas.

Methods

We selected patients with peripheral lung adenocarcinomas, definitively diagnosed by surgical resection, with diameters of ≤ 30 mm over a 4-year period ending in December 2010. The association between 3 independent variables (tumor size, SUVmax, and C/T ratio) and pathologic prognostic factors was evaluated using logistic analysis.

Results

We evaluated a total of 163 primary lung adenocarcinomas in 148 patients (93 males and 55 females; age range: 34 to 84 years). Using multivariate logistic regression analysis, SUVmax and the C/T ratio were significantly associated with tumor invasiveness (odds ratio [OR] = 1.227; p = 0.025 and OR = 1.019; p = 0.008, respectively). Tumor size was not associated with invasiveness (OR = 1.003; p = 0.925). For solid type adenocarcinomas, only SUVmax was significantly associated with invasiveness (OR = 1.558; p = 0.003). For subsolid type adenocarcinomas, only the C/T ratio was significantly associated with invasiveness (OR = 1.030; p = 0.009).

Conclusions

Both the C/T ratio and the SUVmax are significantly correlated with pathologic invasiveness in patients with small lung adenocarcinomas, while there was a difference between the 2 evaluations. Solid type adenocarcinomas with SUVmax values of ≥ 4.4 and subsolid type adenocarcinomas with C/T ratio ≥ 53% were so highly invasive.

Non-FDG-avid primary papillary thyroid carcinoma may not differ from FDG-avid papillary thyroid carcinoma

BACKGROUND

FDG (2-[(18)F]Fluoro-2-D-deoxyglucose-positron emission tomography (PET)/computed tomography (CT), which can detect a change in glucose metabolism in cancer cells, has been introduced as a diagnostic and prognostic tool in papillary thyroid carcinoma (PTC). However, differences in the clinicopathological and biological characteristics between primary PTCs with FDG uptake and those without FDG uptake are not well established.

METHODS

A total of 188 patients with PTC who had preoperative PET/CT scans were enrolled to compare the differences of clinicopathological parameters between FDG-avid (F-PTC; n = 150) and non-FDG-avid tumors (FN-PTC; n = 38). Immunohistochemical staining for glucose transporter (GLUT)-1 and hypoxia-inducible factor-1 alpha (HIF-1α) was performed.

RESULTS

FN-PTCs were smaller; had a lower incidence of lymphatic invasion, vascular invasion, multifocality, and central lymph node metastasis; and had a lower maximum standardized uptake value than F-PTCs. After exclusion of high-risk patients for recurrence, FN-PTCs remained smaller (p < 0.001) and had less lymphatic invasion (p = 0.061). Among tumors larger than the spatial resolution of the PET/CT scan, macrocalcification was more frequent in FN-PTC than in F-PTC (p = 0.043). While FN-PTC and F-PTC showed no difference in GLUT-1 expression (50% vs. 75%, p = 0.363), FN-PTC showed lower HIF-1α immunoreactivity than F-PTC (25.0% vs. 75.0%, p = 0.032).

CONCLUSION

Tumor size and macrocalcification are clinicopathological differences between FN-PTC and F-PTC. Biologically, HIF-1α may be responsible for increased FDG uptake in PTC.

Relationship between primary lesion metabolic parameters and clinical stage in lung cancer

OBJECTIVES

The relation of PET-derived parameters as maximum standardized uptake value (SUVmax), total lesion glycolysis (TLG), metabolic tumor volume (MTV) with clinical stage in lung cancer and correlation of SUVmax of primary tumor and that of metastatic lesion was studied in lung cancer patients.

MATERIALS AND METHODS

Patients with lung cancer who were referred for FDG PET/CT were included in the study.

RESULTS

PET/CT scans and pathology reports of 168 patients were assessed. A total of 146 (86.9%) of these patients had a diagnosis of non-small cell lung cancer (NSCLC) and 22 (13.1%) had small cell lung cancer (SCLC). Metabolic parameters such as SUVmax, TLG and MTV showed significant differences in all the stages in NSCLC patients (p<0.001). However, after tumors sizes <25 mm were excluded, no significant differences in SUVmax between stages were observed. No significant differences were found between these metabolic parameters and limited or extended disease SCLC. Tumor diameter correlated with primary tumor SUVmax and significant correlations between primary lesion SUVmax and metastatic lesion SUVmax were found.

CONCLUSIONS

Although differences were found regarding indices between stages of NSCLC cases, SUVmax differences between stages seem to be caused by underestimation of SUVmax in small lesions. Other glucose metabolism indexes such as MTV and TLG show promising results in terms of prognostic stratification. Future studies are needed for better understanding of their contribution to clinical cases.

The correlation of SUVmax with pathological characteristics of primary tumor and the value of Tumor/ Lymph node SUVmax ratio for predicting metastasis to lymph nodes in resected NSCLC patients

Background

We aimed to investigate the correlation of maximum standardized uptake value (SUVmax) with pathological characteristics of primary tumor and to determine a Tumor/ Lymph node (T/LN) SUVmax ratio predicting metastasis to lymph nodes in NSCLC patients.

Methods

Eighty-one NSCLC patients who had PET/CT examination at initial staging and subsequently underwent surgical resection were retrospectively evaluated. There were 100 PET/CT positive mediastinal or hilar lymph node stations. Pathological characteristics of the tumor such as largest tumor diameter, tumor histology, differentiation, number of mitosis, degree of stromal inflammation, necrosis; etiology of PET/CT positive lymph node stations; SUVmax of primary tumor and positive lymph node stations were recorded. A T/LN SUVmax ratio was calculated for each lymph node station.

Results

SUVmax of the primary tumor was positively correlated with the largest tumor diameter (p = 0.001, r = 0.374), number of mitosis (p < 0.001, r = 0.405), and postoperative pathological stage (p = 0.007, r = 0.298). Patients with squamous cell carcinoma had a statistically significant higher mean SUVmax, number of mitosis and advanced N stages compared to adenocarcinoma. The etiology of 100 PET/CT positive lymph node stations were metastasis in 14, anthracosis in 40, reactive in 39, granulomatous in 4, and silicosis in 3 patients. A T/LN SUVmax ratio of 5 or lower was suggestive for a malignant lymph node with a sensitivity of 92.8% and specificity of 47%.

Conclusions

SUVmax of a primary tumor is related to certain pathological characteristics, such as largest diameter, histology, and number of mitosis. A T/LN SUVmax ratio lower than 5 predicts the metastasis to lymph nodes with a high sensitivity.

Diagnostic accuracy of lymph node metastasis depends on metabolic activity of the primary lesion in thoracic squamous esophageal cancer

The metabolic activity of the primary tumor is an important variable in (18)F-FDG PET interpretation for presurgical staging, because this activity is likely to affect the possibility of detection of malignant involvement in lymph nodes (LNs). The purpose of this study was to reevaluate the diagnostic accuracy of (18)F-FDG PET/CT for the presurgical staging of esophageal squamous cell carcinoma (SCC) in correlation with the (18)F-FDG avidity of the primary lesions.

METHODS

One hundred fifty-six patients (mean age ± SD, 61.4 ± 8.0 y) underwent (18)F-FDG PET/CT before surgical esophagectomy and LN dissection. LN metastasis was identified using the fusion of PET and CT images with increased (18)F-FDG uptake greater than the background activity of the adjacent structures. The results of the patients' (18)F-FDG PET/CT examinations for LN involvement were compared with the histopathologic results to investigate the diagnostic accuracy of (18)F-FDG PET/CT for tumor staging. In addition, we examined the correlation between the diagnostic accuracy of (18)F-FDG PET/CT for LN involvement and the (18)F-FDG avidity of the primary lesions, to investigate the effect of tumor aggressiveness on the diagnosis of LN metastasis.

RESULTS

The diagnostic accuracy of (18)F-FDG PET/CT for LN metastasis showed a low sensitivity, ranging from 29.3% to 53.3%, whereas the specificity was higher than 89.8% in regional thoracic nodes and in remote areas of the cervical and abdominal regions. The (18)F-FDG uptake of the primary lesions positively correlated with that of the metastatic LNs in the thoracic field (R = 0.52, P < 0.05). As a result, our receiver-operating-characteristic analyses demonstrated an area under the curve value of 0.73, with the optimal cutoff value at a maximum standardized uptake value of 3.3 in patients with mid to high (18)F-FDG avidity in the primary lesions (maximum standardized uptake value ≥ 5).

CONCLUSION

This study showed that the avidity of the primary esophageal SCCs affected the detectability of lymph nodal metastases. If primary lesions of esophageal SCC present with a low (18)F-FDG uptake, PET/CT may have a limited role for initial staging because of low sensitivity to detect lymph node metastases.

Non-small cell lung cancer evaluated with quantitative contrast-enhanced CT and PET-CT: net enhancement and standardized uptake values are related to tumour size and histology

Background

Personalized cancer therapy remains a challenge. In this context, we attempted to identify correlations between tumour angiogenesis, tumour metabolism and tumour cell type. To this aim, we used single=phase multidetector computed tomography (MDCT) and hybrid positron emission tomography-computed tomography (PET/CT) to determine whether net enhancement and standardized uptake value (SUVmax) were correlated with tumour size and cytology in patients affected by non-small cell lung cancer (NSCLC).

Material/Methods

Our study included 38 patients (30 men, 8 women, mean age 70) with a NSCLC measuring between 3 cm and 7 cm, using a 16-slice multidetector CT (Brilliance Philips) and with PET-CT (Biograph 16 Siemens Medical Solutions). The following lesion parameters were evaluated: maximum diameter, medium density before contrast injection (CT_pre), medium density after contrast injection (CT_{post average}), density in the most enhanced part of the lesion after contrast (CT_{post max}), net enhancement, SUVmax, age, and cytology. Correlation coefficient and p-value were computed for each pair of variables. In addition, correlations were computed for each pair of variables, and for all combinations of tumour types. We focused on subsets of data with more than 10 observations, and with correlation r>0.500 and p<0.05.

Results

A weak correlation (r=0.32; p=0.048) was found between SUVmax and tumour size; the correlation was stronger for masses larger than 31 mm (r=0.4515; p=0.0268). No other correlations were found among the variables examined.

Conclusions

Our data may have prognostic significance, and could lead to more appropriate surgical treatment and better treatment outcome.

Relationship between (18)F-fluorodeoxyglucose uptake in primary lesions and clinicopathological characteristics of esophageal squamous cell carcinoma patients

The aim of this study, was to investigate the relationship between ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) uptake in primary tumors and the clinicopathological characteristics of esophageal squamous cell carcinoma (ESCC) patients. Patients with histopathologically diagnosed ESCC who had received a pre-therapeutic ¹⁸F-FDG positron emission tomography-computed tomography (PET-CT) scan were enrolled in the study. The maximum standardized uptake value (SUVmax) and the length of the primary tumor were measured by PET-CT. The clinical tumor-node-metastasis (TNM) stage was determined mainly by PET-CT images according to the American Joint Committee on Cancer (AJCC) staging system, 2002. A significant difference was observed in SUVmax between the length and T stage of the primary tumor (P=0.000 and P=0.017, respectively), but not in the grade of tumor differentiation (P=0.383), clinical stage (P=0.583), N staging (P=0.387), M staging (P=0.886), patient age (P= 0.752) or gender (P=0.233). There was a significant positive correlation between the SUVmax and the length of the tumor (r=0.456, P=0.000) and the depth of invasion of the primary tumor (r=0.257, P=0.006). After controlling for length, no statistically significant correlation was found between T stage and SUVmax (r=0.074, P=0.537). In conclusion, these findings suggest that tumor length influences FDG uptake in ESCC tumors, and that the T stage of the primary tumor is not significantly correlated with the SUVmax after controlling for length. However, we did not find a significant correlation between the SUVmax and primary tumor differentiation and clinical stage. These data provide important information for the management of ESCC.

Evaluation of integrated positron emission tomography and computed tomography accuracy in detecting lymph node metastasis in patients with adenocarcinoma vs squamous cell carcinoma

OBJECTIVES

The aim of our study was to analyze the specificity and sensitivity of integrated positron emission tomography and computed tomography (PET/CT) in detecting nodal metastasis according to histology (adenocarcinoma vs squamous cell carcinoma), and to identify the factors related to false-negative findings.

METHODS

A retrospective, single-institution review of 353 consecutive patients with suspected or pathologically proven, potentially resectable non-small-cell lung cancer (NSCLC) who had integrated PET/CT scanning at the same centre. Lymph node staging was pathologically confirmed on tissue specimens obtained at mediastinoscopy and/or thoracotomy. Statistical evaluation of PET/CT results was performed on a per-patient and per-nodal-station basis.

RESULTS

A total of 2286 nodal stations (1643 mediastinal, 333 hilar and 310 intrapulmonary) were evaluated. Adenocarcinoma was the final diagnosis in 244 patients and squamous carcinoma in 109 patients. Nodes were positive for malignancy in 80 (32.8%) of 244 patients with adenocarcinoma (N1 = 31; N2 = 48 and N3 = 1) and in 32 (29.3%) of 109 with squamous carcinoma (N1 = 21 and N2 = 11). PET/CT in the adenocarcinoma group had a sensitivity, specificity and accuracy of 53.8, 91.5 and 79.1%, and in the squamous cell group, of 87.5, 81.8 and 83.5%, respectively in a per-patient analysis. In the analysis for N2 disease on a per-patient basis, the sensitivity, specificity and accuracy were 38.8, 97.4, and 85.7% for the adenocarcinoma group and 81.8, 91.8 and 90.8% in the squamous cell group. In the adenocarcinoma group, the mean diameter of false-negative lymph nodes was 7 mm (standard deviation [SD] ± 2.5 mm) compared with the diameter of true-positive lymph nodes of 12.5 (SD ± 4 mm; P < 0.00001). In the squamous cell group, the mean diameter of false-negative lymph nodes was 7.4 mm (SD ± 2.8 mm) compared with the diameter of true-positive lymph nodes of 14.7 (SD ± 6 mm; P < 0.005). In the adenocarcinoma group, false-negative lymph nodes were statistically correlated with the presence of vascular invasion and in the squamous cell group only with the maximum standardized uptake value (SUV(max)) < 5.4.

CONCLUSIONS

The sensitivity of PET/CT in detecting nodal metastasis in patients with adenocarcinoma is too low to avoid any further invasive staging procedure. Ultrasound-guided needle biopsy or mediastinoscopy is still necessary in staging patients undergoing lung resection for adenocarcinoma.

Multimodality FDG PET/CT appearance of pulmonary tuberculoma mimicking lung cancer and pathologic correlation in a tuberculosis-endemic country

OBJECTIVES

Differentiation between pulmonary tuberculoma and malignancy by preoperative diagnostic imaging sometimes proves difficult. The purpose of this study is to investigate variable manifestations of pulmonary tuberculoma mimicking lung cancer on fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) image and pathologic correlation.

PATIENTS AND METHODS

Twenty-five patients with a high suspicion of malignancy and histopathologically diagnosed as pulmonary tuberculoma were included. Their FDG PET/CT images, clinical data, and pathologic findings were investigated.

RESULTS

There were 18 men and seven women. The mean age was 52 ± 8.8 years. The maximal diameter of pulmonary tuberculoma ranged from 1.7 to 4.2 cm. CT scan revealed that abnormal signs associated with malignancy such as spicular radiation, notching, and pleural indentation also frequently manifested in tuberculoma. During early imaging, positive FDG uptake was identified in 21 patients (84%), intermediate uptake in 3 patients (12%) and negative uptake in 1 patient (4%). During delayed imaging, 16 patients (64%) showed persistent elevated FDG accumulation and 8 patients (32%) experienced a slight drop of FDG accumulation. Pathologically active tuberculoma showed significantly higher FDG radioactivity during both early and delayed imaging than inactive lesion (P < 0.05). Lymphadenopathy with positive FDG uptake was identified in nine patients (36%).

CONCLUSION

Pulmonary tuberculomas mimicking lung cancer, most of which were pathologically active lesions, commonly displayed abnormal appearances in CT scan and an increase in FDG uptake, similar to changes seen on malignancy. Coexistent lymphadenopathy made differential diagnosis even more complicated. These results suggested that positive FDG PET/CT findings should be interpreted with caution in tuberculosis-endemic regions.