Impact of FDG-PET findings on decisions regarding patient management strategies: a multicenter trial in patients with lung cancer and other types of cancer

Prognostic Value of the Metabolic Response on Serial 18F-FDG PET/CT in Pancreatic Cancer

Background/Aims

The prognostic value of serial 18F-fluorodeoxyglucose positron emission tomography/ computed tomography (18F-FDG PET/CT) for patients with borderline resectable or locally advanced pancreatic cancer who undergo conversion surgery or continue chemotherapy without surgery has not been well-established.

Methods

A retrospective analysis of patients with pancreatic ductal adenocarcinoma was conducted at Seoul National University Bundang Hospital between March 2013 and February 2022. Patients underwent PET/CT at baseline and subsequent radiologic evaluations following chemotherapy. Changes in the maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), metabolic tumor volume, and total lesion glycolysis were analyzed. Based on their treatment regimens, patients were stratified into the conversion surgery group or nonconversion surgery group. Survival outcomes and various clinical factors were assessed.

Results

Among 121 patients, 52 underwent conversion surgery, and 69 continued to receive chemotherapy without surgery. A significant reduction in the SUVmax was correlated with prolonged recurrence-free survival and overall survival in the conversion surgery group. Confirmation of a pathologic response indicated a significant association between reductions in the SUVmax and positive outcomes. Reductions in the metabolic tumor volume and total lesion glycolysis were associated with improved progression-free survival and overall survival in the nonconversion surgery group.

Conclusions

Serial PET/CT scans demonstrated prognostic value in pancreatic ductal adenocarcinoma patients, revealing distinct correlations in the conversion surgery group and nonconversion surgery group.

The Prognostic Value of Positron Emission Tomography/Computed Tomography in Clinical Stage I Lung Cancer Patients: A Propensity-Match Analysis

Background: The application of positron emission tomography/computed tomography (PET/CT) helps provide accurate clinical staging for lung cancer patients. However, the effects and trends in early-stage lung cancer remain unclear. The aim of this study was to compare differences between clinical stage I lung cancer patients who received PET/CT for staging and those who did not. Methods: Data were obtained from the Taiwan Society of Cancer Registry. There were 6587 clinical stage I lung cancer patients between 2009 and 2014 analyzed in this study. We compared the characteristics of the PET/CT and no PET/CT groups. After propensity score matching, it resulted in both groups having 2649 patients. We measured the overall survival rates of all clinical stage I lung cancer patients and the overall survival rates of patients with PET/CT and without PET/CT. Results: The 1-, 3-, and 5-year survival rates of all clinical stage I lung cancer patients were 97.2%, 88.2%, and 79.0%, respectively. Patients with a larger tumor size tended to receive PET/CT for staging (stage Ib: 38.25% vs. 27.82%, p < 0.0001) and a larger resection (lobectomy: 74.62% vs. 66.61%, p < 0.0001). The 5-year survival rates were 79.8% in the PET/CT group and 78.2% in the no PET/CT group after propensity score matching (p = 0.6528). Conclusions: For clinical stage I lung cancer in Taiwan, patients with larger tumor sizes tend to have PET/CT for staging. Although PET/CT provided more precise clinical staging, these patients still received larger resections and had more pathological migration. However, there was no overall survival rate benefit after PET/CT.

How [18F]FDG-PET/CT Affects the Management of Patients with Differentiated Thyroid Carcinoma in Clinical Routines

PURPOSE

To investigate the impact of [18F]FDG-PET/CT on the management of differentiated thyroid carcinoma (DTC) in routine clinical settings.

MATERIAL AND METHODS

In total, 98 patients (55 females, age 56 ± 18 years) with histologically confirmed thyroid cancer, including all types of DTC and poorly differentiated thyroid cancer (PDTC, n = 7), underwent [18F]FDG-PET/CT for staging or recurrence diagnostics performed using a state-of-the art clinical scanner (Biograph mCT, Siemens Healthineers) with a standardized examination protocol. The impact of PET/CT on clinical decision making was prospectively evaluated using standardized questionnaires completed by the referring physicians before and after PET/CT. Patient outcome was analyzed for OS drawn from patient records.

RESULTS

Referring physicians were unable to establish a treatment plan for 81% of patients with thyroid cancer in the absence of PET/CT. The use of PET/CT had a notable influence on patient management, leading to the development of a well-defined treatment plan for 92% of patients. Moreover, after PET/CT a change in pre-PET/CT-intended treatments occurred in 32% of cases, and further invasive diagnostic could be waived in 7% of cases. [18F]FDG-PET/CT revealed a tumor detection rate of 68% (local tumor: 19%, lymph node metastases: 40%, distant metastases: 42%). HTg levels, when stimulated via TSH, were considerably higher in patients with metastases detected on PET/CT, compared to those without metastatic findings (p = 0.02). OS was significantly worse in patients with PDTC (p = 0.002) compared to follicular thyroid cancer (FTC) and PTC or even in patients with distant metastases at first diagnosis (p = 0.03).

CONCLUSIONS

This prospective registry study confirms that [18F]FDG-PET/CT used in a routine clinical setting has a very important impact on the management of patients with thyroid cancer by initiating treatments and reducing the uses of additional imaging and invasive tests.

Reproducibility of the principal component analysis (PCA)-based data-driven respiratory gating on texture features in non-small cell lung cancer patients with 18 F-FDG PET/CT

OBJECTIVE

Texture analysis is one of the lung cancer countermeasures in the field of radiomics. Even though image quality affects texture features, the reproducibility of principal component analysis (PCA)-based data-driven respiratory gating (DDG) on texture features remains poorly understood. Hence, this study aimed to clarify the reproducibility of PCA-based DDG on texture features in non-small cell lung cancer (NSCLC) patients with ¹⁸ F-Fluorodeoxyglucose (¹⁸ F-FDG) Positron emission tomography/computed tomography (PET/CT).

METHODS

Twenty patients with NSCLC who underwent ¹⁸ F-FDG PET/CT in routine clinical practice were retrospectively analyzed. Each patient's PET data were reconstructed in two PET groups of no gating (NG-PET) and PCA-based DDG gating (DDG-PET). Forty-six image features were analyzed using LIFEx software. Reproducibility was evaluated using Lin's concordance correlation coefficient ( ρ c ${\rho _c}$ ) and percentage difference (%Diff). Non-reproducibility was defined as having unacceptable strength ( ρ c $({\rho _c}$  < 0.8) and a %Diff of >10%. NG-PET and DDG-PET were compared using the Wilcoxon signed-rank test.

RESULTS

A total of 3/46 (6.5%) image features had unacceptable strength, and 9/46 (19.6%) image features had a %Diff of >10%. Significant differences between the NG-PET and DDG-PET groups were confirmed in only 4/46 (8.7%) of the high %Diff image features.

CONCLUSION

Although the DDG application affected several texture features, most image features had adequate reproducibility. PCA-based DDG-PET can be routinely used as interchangeable images for texture feature extraction from NSCLC patients.

Lack of Adherence to Guideline-Based Imaging Before Subsequent Radiation in Patients with Non-Small Cell Lung Cancer: Impact on Patient Outcomes

Lung cancer is the leading cause of cancer death within the United States, yet prior studies have shown a lack of adherence to imaging and treatment guidelines in patients with lung cancer. This study evaluated the use of ¹⁸F-FDG PET/CT imaging before subsequent radiation therapy (RT) in patients with non-small cell lung cancer (NSCLC), as recommended by National Comprehensive Cancer Network guidelines, and whether the use of this imaging modality impacts cancer-specific survival. Methods: This was a retrospective study of the National Cancer Institute's Surveillance, Epidemiology, and End Results program of Medicare-linked data in patients with NSCLC. Hazard ratios and 95% CIs for overall and cancer-specific survival were estimated for patients diagnosed between 2006 and 2015 who underwent either ¹⁸F-FDG PET/CT-based or CT-based imaging before subsequent RT. Results: Significant improvement in cancer-specific survival was found in patients who underwent ¹⁸F-FDG PET/CT imaging before subsequent RT, compared with those who underwent CT (hazard ratio, 1.43 [95% CI, 1.32-1.55; P < 0.0001]). Although the National Comprehensive Cancer Network recommends ¹⁸F-FDG PET/CT before subsequent RT, 43.6% of patients were imaged with CT alone. Conclusion: Many patients with NSCLC are not being imaged according to national guidelines before subsequent RT, and this omission is associated with a lower cancer-specific survival.

18-Fluoride fluorodeoxyglucose positron emission tomography is impactful in newly diagnosed pancreatic adenocarcinoma

BACKGROUND

Adenocarcinoma of the pancreas has a dismal prognosis. Surgical resection increases survival but is reliant on accurate detection and staging of disease. In overseas studies, ¹⁸ F-FDG positron emission tomography (PET) has been shown to have high diagnostic accuracy and staging utility, but local data remain sparse, in part because the technique has hitherto been unfunded via the Medicare benefits schedule. Although Commonwealth funding for rare tumours (including of the pancreas) has been recently approved to commence in late 2022, the proposed item descriptor wording implies that PET should lead to a significant change in management. Accordingly, the aims of this study are to characterize PET findings in newly diagnosed pancreatic adenocarcinoma using standard parameters, such as the SUV_max , and assess the proportion of cases in which PET altered initial management planning.

METHODS

We analysed the PET findings of these cancers (presence and degree of metabolic activity in the primary lesion, as well as within malignant nodal and metastatic lesions) and compared the pre- and post-PET management plans of the referring specialists.

RESULTS

Of 51 patients we found that (a) increasing SUV_max of the primary lesion correlated with an increase in disease stage (r-value = 0.335; P-value = 0.016), and (b) PET contributed to a significant change in management in 35% of patients.

CONCLUSION

In newly diagnosed pancreatic adenocarcinoma, parameters in PET correlate with disease stage and the overall findings contribute to a significant management change in about 35% of patients.

[68Ga]FAPI-PET/CT for radiation therapy planning in biliary tract, pancreatic ductal adeno-, and adenoidcystic carcinomas

Biliary-tract-carcinomas (BTC), pancreatic-ductal-adenocarcinomas (PDAC) and adenoidcystic-carcinomas (AC) have in common that they are traditionally treated with large clinical-target-volumes (CTV). The aim of this study is to examine the impact of pretreatment-[⁶⁸Ga]FAPI-PET/CT on target-volume-definition and posttreatment-[⁶⁸Ga]FAPI-PET/CT-response-assessment for BTC-, PDAC- and AC-patients referred to radiation-therapy. All consecutive BTC-, PDAC-, and AC-patients who received pretreatment-[⁶⁸Ga]FAPI-PET/CT±[¹⁸F]FDG-PET/CT were included from 01.01.2020 to 01.03.2022. MTV and SUV_max were separately generated based on [⁶⁸Ga]FAPI- and [¹⁸F]FDG-PET/CT-images. A [⁶⁸Ga]FAPI- and [¹⁸F]FDG-based-CTV was defined. Treatment-plans were compared. Treatment-response was reassessed by a second [⁶⁸Ga]FAPI-PET/CT and [¹⁸F]FDG-PET/CT after treatment-completion. Intermodality comparison of lesion-to-background-ratios [SUV_{max_lesion}/SUV_{mean_background}] for individual timepoints t₁ and t₂ revealed significant higher values for [⁶⁸Ga]FAPI compared to [¹⁸F]FDG (t₁, p = 0.008; t₂, p = 0.005). Intermodality comparison of radiation-therapy-plans showed that [⁶⁸Ga]FAPI-based planning resulted in D100% = 97.2% and V95% = 98.8% for the [¹⁸F]FDG-MTV. [¹⁸F]FDG-based-planning resulted in D100% = 35.9% and V95% = 78.1% for [⁶⁸Ga]FAPI-MTV. [¹⁸F]FDG-based-planning resulted only in 2 patients in V95% > 95% for [⁶⁸Ga]FAPI-MTV, and in 1 patient in D100% > 97% for [⁶⁸Ga]FAPI-MTV. GTV-coverage in terms of V95% was 76.4% by [¹⁸F]FDG-based-planning and 99.5% by [⁶⁸Ga]FAPI-based-planning. Pretreatment [⁶⁸Ga]FAPI-PET/CT enhances radiation-treatment-planning in this particular group of patients. While perilesional and tumoral follow-up [¹⁸F]FDG-uptake behaved uniformly, perilesional and tumoral reaction may differ in follow-up [⁶⁸Ga]FAPI-imaging. Complementary [⁶⁸Ga]FAPI- and [¹⁸F]FDG-imaging enhance treatment-response-assessment.

Joint EANM/SNMMI/ESTRO practice recommendations for the use of 2-[18F]FDG PET/CT external beam radiation treatment planning in lung cancer V1.0

PURPOSE

2-[18F]FDG PET/CT is of utmost importance for radiation treatment (RT) planning and response monitoring in lung cancer patients, in both non-small and small cell lung cancer (NSCLC and SCLC). This topic has been addressed in guidelines composed by experts within the field of radiation oncology. However, up to present, there is no procedural guideline on this subject, with involvement of the nuclear medicine societies.

METHODS

A literature review was performed, followed by a discussion between a multidisciplinary team of experts in the different fields involved in the RT planning of lung cancer, in order to guide clinical management. The project was led by experts of the two nuclear medicine societies (EANM and SNMMI) and radiation oncology (ESTRO).

RESULTS AND CONCLUSION

This guideline results from a joint and dynamic collaboration between the relevant disciplines for this topic. It provides a worldwide, state of the art, and multidisciplinary guide to 2-[18F]FDG PET/CT RT planning in NSCLC and SCLC. These practical recommendations describe applicable updates for existing clinical practices, highlight potential flaws, and provide solutions to overcome these as well. Finally, the recent developments considered for future application are also reviewed.

Impact of Follow-up 18F-FDG PET on the Management in Patients With Lung Cancer: A Meta-analysis

PURPOSE

The incidence of lung cancer has increased steadily. We meta-analyzed to assess the impact of 18F-FDG PET on the management of lung cancer to detect recurrence/metastasis.

MATERIALS AND METHODS

We performed systematic searches of Medline and Embase databases for English-language publications. All published studies regarding the impact of PET on the management of patients with lung cancer in detection of recurrence/metastasis were searched. The proportion of management change (%) defined as the percentage of patients who changed management after FDG PET to patients who had FDG PET was calculated. The data from each study were analyzed using MedCalc Statistical Software version 14.12.0 (MedCalc Software, Ostend, Belgium).

RESULTS

Eight studies including 523 patients were eligible for inclusion in the study. The impact of 18F-FDG PET for the purpose of detecting recurrence/metastasis in patients with lung cancer was evaluated using management change rates, which were ranged from 28.6% to 79.2% with a pooled effect of 61.4% (95% confidence interval, 49.5%-72.7%; I2 = 85.7%). In a subgroup analysis, impact of 18F-FDG PET was evaluated in studies of patients with non-small cell lung cancer with indication of abnormal findings of conventional imaging, elevated tumor markers, and clinical symptoms with the pooled rate of management change of 62.2% (95% confidence interval, 44.2%-78.5%; I2 = 88.0%).

CONCLUSIONS

We have highlighted that 18F-FDG PET has a major impact on the management of patients with recurrent lung cancer. These findings suggest that 18F-FDG PET should be performed in patients with lung cancer, especially in cases involving equivocal or suspicious recurrence/metastasis on conventional imaging, elevated tumor markers, or clinical symptoms during follow-up.

The importance of anatomical localization of non-small cell lung carcinoma in predicting mediastinal lymph node metastasis

Bronchopulmonary segmental location of non-small lung carcinomas is closely related to metastatic lymph node foci in the mediastinum. Our aim was to investigate the relationship between the anatomical locations of pulmonary masses on the bronchopulmonary segmental base and metastatic lymph node regions in non-small cell lung cancer using preoperative 18F-FDG PET/CT images. Ninety patients newly diagnosed with non-small cell lung carcinoma and referred to PET/CT imaging for staging were included in the study. Tumoral masses that could be evaluated visually and mediastinal node metastases were identified in 18F-FDG PET/CT images, then the relationship between them was investigated statistically. The diagnostic power of 18F-FDG PET/CT of mediastinal nodes was also revealed. Seventy-four males (82.2%) and sixteen females (17.8%) were enrolled in the study. Half of the patients were diagnosed as adenocarcinoma (50%). Investigation of the tumor location and mediastinal metastatic nodes revealed a statistically significant relationship between the apicoposterior segment of the left superior lobe and the left upper and lower paratracheal, subaortic, paraaortic, and left hilar regions according to the IASLC map. The sensitivity, specificity and accuracy of 18F-FDG PET/CT in the mediastinal nodes were 69.2%, 66.6%, and 68%, respectively. There was no statistically significant relationship between tumor location and 8th TNM Stage. Anatomical locations of non-small cell lung carcinomas can affect the disease stage and prognosis because of their tendency to metastasize to some mediastinal regions. However, this relationship needs to be investigated in larger study groups.

[Investigation of the Administration Accuracy of an Auto Infusion Device in 18F-FDG PET]

PURPOSE

The administration accuracy of the automated infusion device for the positron emission radiopharmaceutical affects to calculation of the standardized uptake value (SUV) in ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET examination. The purpose of this study was to investigate the administration error in the clinical use of an automated infusion device for quantitative management in PET examination.

METHODS

We assumed clinical use of the automated infusion device and investigated two types of administration errors. First, for investigating the administration error over time in a day (error_day), a total of 13 infusion works were performed every 30 minutes. Second, for investigating the long period administration error (error_period), the infusion work was performed once before clinical use of an automated infusion device. The dispensed radioactivity was set to 150 MBq. The administration error was calculated using output values from the automated infusion device and measured values from the dose calibrator.

RESULTS

The administration error_day was 0.9±1.3%, and the maximum error was 2.7%. The administration error_period was 1.1±2.0%, and the maximum error was 5.9%.

CONCLUSION

We investigated the administration error of the automated infusion device. We confirmed the approximately 1% administration error and high-accuracy injection in an automated-device method.

Ethnic Disparities in Imaging Utilization at Diagnosis of Non-Small Cell Lung Cancer

BACKGROUND

Prior research demonstrated statistically significant racial disparities related to lung cancer treatment and outcomes. We examined differences in initial imaging and survival between blacks, Hispanics, and non-Hispanic whites.

METHODS

The linked Surveillance, Epidemiology, and End Results-Medicare database between 2007 and 2015 was used to compare initial imaging modality for patients with lung cancer. Participants included 28 881 non-Hispanic whites, 3123 black, and 1907 Hispanics, patients age 66 years and older who were enrolled in Medicare fee-for-service and diagnosed with lung cancer. The primary outcome was comparison of positron emission tomography (PET) imaging with computerized tomography (CT) imaging use between groups. A secondary outcome was 12-month cancer-specific survival. Information on stage, treatment, and treatment facility was included in the analysis. Chi-square test and logistic regression were used to evaluate factors associated with imaging use. Kaplan-Meier method and Cox proportional hazards regression were used to calculate adjusted hazard ratios and survival. All statistical tests were two-sided.

RESULTS

After adjusting for demographic, community, and facility characteristics, blacks were less likely to undergo PET or CT imaging at diagnosis compared with non-Hispanic whites odds ratio (OR) = 0.54 (95% confidence interval [CI] = 0.50 to 0.59; P < .001). Hispanics were also less likely to receive PET with CT imaging (OR = 0.72, 95% CI = 0.65 to 0.81; P < .001). PET with CT was associated with improved survival (HR = 0.61, 95% CI = 0.57 to 0.65; P < .001).

CONCLUSIONS

Blacks and Hispanics are less likely to undergo guideline-recommended PET with CT imaging at diagnosis of lung cancer, which may partially explain differences in survival. Awareness of this issue will allow for future interventions aimed at reducing this disparity.

Thoracic positron emission tomography: 18F-fluorodeoxyglucose and beyond

Ongoing technologic and therapeutic advancements in medicine are now testing the limits of conventional anatomic imaging techniques. The ability to image physiology, rather than simply anatomy, is critical in the management of multiple disease processes, especially in oncology. Nuclear medicine has assumed a leading role in detecting, diagnosing, staging and assessing treatment response of various pathologic entities, and appears well positioned to do so into the future. When combined with computed tomography (CT) or magnetic resonance imaging (MRI), positron emission tomography (PET) has become the sine quo non technique of evaluating most solid tumors especially in the thorax. PET/CT serves as a key imaging modality in the initial evaluation of pulmonary nodules, often obviating the need for more invasive testing. PET/CT is essential to staging and restaging in bronchogenic carcinoma and offers key physiologic information with regard to treatment response. A more recent development, PET/MRI, shows promise in several specific lung cancer applications as well. Additional recent advancements in the field have allowed PET to expand beyond imaging with ¹⁸F-flurodeoxyglucose (FDG) alone, now with the ability to specifically image certain types of cell surface receptors. In the thorax this predominantly includes ⁶⁸Ga-DOTATATE which targets the somatostatin receptors abundantly expressed in neuroendocrine tumors, including bronchial carcinoid. This receptor targeted imaging technique permits targeting these tumors with therapeutic analogues such as ¹⁷⁷Lu labeled DOTATATE. Overall, the proper utilization of PET in the thorax has the ability to directly impact and improve patient care.

Recent and Current Advances in FDG-PET Imaging within the Field of Clinical Oncology in NSCLC: A Review of the Literature

Lung cancer is the leading cause of cancer-related deaths around the world, the most common type of which is non-small-cell lung cancer (NSCLC). Computed tomography (CT) is required for patients with NSCLC, but often involves diagnostic issues and large intra- and interobserver variability. The anatomic data obtained using CT can be supplemented by the metabolic data obtained using fluorodeoxyglucose F 18 (FDG) positron emission tomography (PET); therefore, the use of FDG-PET/CT for staging NSCLC is recommended, as it provides more accuracy than either modality alone. Furthermore, FDG-PET/magnetic resonance imaging (MRI) provides useful information on metabolic activity and tumor cellularity, and has become increasingly popular. A number of studies have described FDG-PET/MRI as having a high diagnostic performance in NSCLC staging. Therefore, multidimensional functional imaging using FDG-PET/MRI is promising for evaluating the activity of the intratumoral environment. Radiomics is the quantitative extraction of imaging features from medical scans. The chief advantages of FDG-PET/CT radiomics are the ability to capture information beyond the capabilities of the human eye, non-invasiveness, the (virtually) real-time response, and full-field analysis of the lesion. This review summarizes the recent advances in FDG-PET imaging within the field of clinical oncology in NSCLC, with a focus on surgery and prognostication, and investigates the site-specific strengths and limitations of FDG-PET/CT. Overall, the goal of treatment for NSCLC is to provide the best opportunity for long-term survival; therefore, FDG-PET/CT is expected to play an increasingly important role in deciding the appropriate treatment for such patients.

Predictive and Prognostic Role of Metabolic Response in Patients With Stage III NSCLC Treated With Neoadjuvant Chemotherapy

INTRODUCTION

The purpose of this study was to assess the predictive and prognostic role of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) in candidates with stage III non-small-cell lung cancer (NSCLC) to neoadjuvant chemotherapy.

PATIENTS AND METHODS

Sixty-six patients with stage III NSCLC treated with induction chemotherapy from March 2013 to December 2017 were retrospectively identified. Response assessment were evaluated according to the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 and European Organisation for Research and Treatment of Cancer (EORTC) criteria. 18F-FDG PET/CT metabolic parameters were analyzed as absolute values as well as percentage changes (Δ) between 2 consecutive scans, for primary tumor (T) and for regional lymph nodes (N). All clinical variables and metabolic parameters were compared with treatment response and correlated with progression-free survival (PFS) and overall survival (OS), based on a median follow-up of 9.4 months.

RESULTS

Post-induction therapy standardized uptake value (SUV)max_T, SUVmean_T, metabolic tumor volume (MTV_T), and total lesion glycolysis of the tumor (TLG_T) varied significantly between responders and non-responders (6.6 vs. 13.8; P = .001; 4.2 vs. 8.1; P < .001; 6 vs. 17.9; P = .002; and 24.1 vs. 136.3; P < .001, respectively). Likewise, percentage changes (Δ_T) were significantly different between the 2 groups (P < .001). Along with primary tumor, also post-SUVmax_N, post-SUVmean_N, and post-TLG_N (P = .024, P = .015, and P = .024, respectively), as well as all percentage changes (Δ_N) were different between responders and non-responders. RECIST 1.1 and EORTC response classifications were discordant in 27 patients (40.9%; κ = 0.265; P = .003). On multivariate analysis, post-TLG_N was an independent predictor for both PFS and OS, whereas RECIST 1.1 was a predictor only for OS.

CONCLUSIONS

Several metabolic parameters may differentiate responders from non-responders following neoadjuvant chemotherapy in stage III NSCLC. As compared with RECIST 1.1, EORTC seems to be more appropriate for evaluation therapeutic response. Finally, post-TLG_N has significant prognostic information.

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.

Practice-based evidence for the clinical benefit of PET/CT-results of the first oncologic PET/CT registry in Germany

PURPOSE

The purpose of this study was to evaluate the impact of PET/CT on clinical management of cancer patients based on a prospective data registry. The study was developed to inform consultations with public health insurances on PET/CT coverage.

METHODS

We evaluated a prospective patient cohort having a clinically indicated PET/CT at a single German University Center from April 2013 to August 2016. The registry collected questionnaire data from requesting physicians on intended patient management before and after PET/CT. A total of 4,504 patients with 5,939 PET/CT examinations were enrolled in the registry, resulting in evaluable data from 3,724 patients receiving 4,754 scans. The impact of PET/CT on patient management was assessed across 22 tumor types, for different indications (diagnosis, staging, suspected recurrence) and different categories of management including treatment (curative or palliative) and non-treatment (watchful waiting, additional imaging, invasive tests).

RESULTS

The most frequent PET/CT indication was tumor staging (59.7%). Melanoma, lung cancer, lymphoma, neuroendocrine tumor and prostate cancer accounted for 70% of cases. Overall, the use of PET/CT resulted in a 37.1% change of clinical management (95% CI, 35.7-38.5), most frequently (30.6%) from an intended non-treatment strategy before PET/CT to active treatment after PET/CT. The frequency of changes ranged from 28.3% for head and neck cancers up to 46.0% for melanomas. The impact of PET/CT was greatest in reducing demands for additional imaging which decreased from 66.1% before PET/CT to 6.1% after PET/CT. Pre-PET/CT planned invasive tests could be avoided in 72.7% of cases. The treatment goal changed after PET/CT in 21.7% of cases, in twice as many cases from curative to palliative therapy than vice versa.

CONCLUSIONS

The data of this large prospective registry confirm that physicians often change their intended management on the basis of PET/CT by initiating treatment and reducing additional imaging as well as invasive tests. This applies to various cancer types and indications.

Variations in positron emission tomography-computed tomography findings for patients receiving neoadjuvant and non-neoadjuvant therapy for non-small cell lung cancer

BACKGROUND

The aims of this study were to predict locoregional lymph node (LN) metastases using positron emission tomography-computed tomography (PET-CT) and investigate variations in PET-CT findings for patients receiving neoadjuvant (NT) and non-neoadjuvant (non-NT) for non-small cell lung cancer (NSCLC).

METHODS

Data from 578 consecutive patients from January 2010 to December 2015 who met this study inclusion criteria were retrospectively reviewed. All patients underwent curative and complete resections for NSCLC in a Korean hospital. We analyzed the associations between maximum standard uptake value (SUVmax) and pathological stage, compared disease-free survival (DFS) and overall survival (OS), investigated relationships among SUVmax values, evaluated LN status and compared pathologically negative and positive LNs by SUVmax, and assessed the influence of neoadjuvant therapy on SUVmax. All LNs were analyzed separately for N1 and N2.

RESULTS

(I) For non-NT, we found significantly positive associations between pathological stage and SUVmax (tumor, N1 LN, and N2 LN, all P<0.001). For NT, we found positive correlations between pathological stage and tumor and N2 LN SUVmax, except for N1 LN (tumor P=0.005, N1 LN P=0.981, N2 LN P=0.045); (II) for non-NT, the low SUVmax group had higher DFS and OS than the high SUVmax group (DFS: tumor SUVmax P<0.001, N1 LN SUVmax P=0.002, N2 LN SUVmax P=0.027; OS: tumor SUVmax P<0.001, N1 LN SUVmax P=0.006, N2 LN SUVmax P=0.006). For NT, the low SUVmax group had nonsignificantly higher DFS and OS than the high SUVmax group. When age, sex, and SUVmax were equal, pathological stages were significantly higher for NT than non-NT (P<0.001). Non-NT had significantly higher DFS (P=0.001) and OS (P=0.024) than NT; (III) for non-NT, tumor, N1 LN, and N2 SUVmax were positively associated (all P<0.001). For NT, tumor and N2 SUVmax (P<0.001), and N1 and N2 SUVmax (P=0.025) correlated positively; tumor and N1 LN SUVmax did not (P=0.911); (IV) for non-NT, there was significant cutoff values for prediction of LN metastases using both tumor and LN SUVmax (N1 LN: tumor SUVmax cutoff 5.95, sensitivity 66.3%, specificity 66.0%, area =0.748, P<0.001; N1 LN SUVmax cutoff 2.05, sensitivity 57.83%, specificity 66.43%, area =0.676, P<0.001) (N2 LN: tumor SUVmax cutoff 5.95, sensitivity 63.04%, specificity 63.95%, area =0.726, P<0.001; N2 LN SUVmax cutoff 2.05, sensitivity 65.22%, specificity 69.96%, area =0.678, P<0.001). For NT, no SUVmax values significantly predicted LN metastases; () Pathologically malignant and benign LN SUVmax after neoadjuvant therapy were not different (N1 LN P=0.570, N2 LN P=0.105). For non-NT, pathologically malignant LN SUVmax was significantly higher than pathologically benign LN SUVmax (N1 LN P<0.001, N2 LN P=0.001).

CONCLUSIONS

This study showed variations in PET-CT findings for NT and non-NT, which should be verified for evaluation and management, especially for surgery planning. SUV max is not a reliable predictor of lymphatic involvement after neoadjuvant therapy in patients with NSCLC. Surgery should not be withheld or delayed based on lack of knowledge about variations in PET-CT findings, which must be interpreted in conjunction with other conditions. Further studies on interpretation of PET-CT findings, especially for NT, are needed for better management and prognosis.

18F-FDG PET/CT for the Diagnosis of Malignant and Infectious Complications After Solid Organ Transplantation

PURPOSE

Infection and malignancy represent two common complications after solid organ transplantation, which are often characterized by poorly specific clinical symptomatology. Herein, we have evaluated the role of ¹⁸F-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography/computed tomography (PET/CT) in this clinical setting.

METHODS

Fifty-eight consecutive patients who underwent FDG PET/CT after kidney, lung or heart transplantation were included in this retrospective analysis. Twelve patients underwent FDG PET/CT to strengthen or confirm a diagnostic suspicion of malignancies. The remaining 46 patients presented with unexplained inflammatory syndrome, fever of unknown origin (FUO), CMV or EBV seroconversion during post-transplant follow-up without conclusive conventional imaging. FDG PET/CT results were compared to histology or to the finding obtained during a clinical/imaging follow-up period of at least 6 months after PET/CT study.

RESULTS

Positive FDG PET/CT results were obtained in 18 (31 %) patients. In the remaining 40 (69 %) cases, FDG PET/CT was negative, showing exclusively a physiological radiotracer distribution. On the basis of a patient-based analysis, FDG PET/CT's sensitivity, specificity, PPV and NPV were respectively 78 %, 90 %, 78 % and 90 %, with a global accuracy of 86 %. FDG PET/CT was true positive in 14 patients with bacterial pneumonias (n = 4), pulmonary fungal infection (n = 1), histoplasmosis (n = 1), cutaneous abscess (n = 1), inflammatory disorder (sacroiliitis) (n = 1), lymphoma (n = 3) and NSCLC (n = 3). On the other hand, FDG PET/CT failed to detect lung bronchoalveolar adenocarcinoma, septicemia, endocarditis and graft-versus-host disease (GVHD), respectively, in four patients. FDG PET/CT contributed to adjusting the patient therapeutic strategy in 40 % of cases.

CONCLUSIONS

FDG PET/CT emerges as a valuable technique to manage complications in the post-transplantation period. FDG PET/CT should be considered in patients with severe unexplained inflammatory syndrome or FUO and inconclusive conventional imaging or to discriminate active from silent lesions previously detected by conventional imaging particularly when malignancy is suspected.