Potential use of FDG-PET scan after induction chemotherapy in surgically staged IIIa-N2 non-small-cell lung cancer: a prospective pilot study. The Leuven Lung Cancer Group

Revalidation of PET/computed tomography criteria (Hopkins criteria) for the assessment of therapeutic response in lung cancer patients: inter-reader reliability, accuracy and survival outcomes

BACKGROUND/AIM

Systematic reporting using qualitative evaluation of PET/computed tomography (CT) results has been demonstrated to be very accurate and reproducible in posttherapy assessment of lung cancer (so-called Hopkins criteria). Our aim was to test, in a different cohort of patients, the Hopkins criteria for assessment of therapeutic response in lung cancer and to compare the results with those obtained using a semi-quantitative evaluation of uptake.

METHODS

This is a retrospective study. A total of 85 patients with known lung cancer who underwent fluorine-18 fluorodeoxyglucose PET/CT assessment within 24 weeks (mean 7.9 weeks) of completion of treatment were included. Treatments included surgical resection, chemotherapy, radiation therapy, immunotherapy or combinations thereof. PET/CT interpretation was done by two nuclear medicine physicians, and discrepancies were resolved by a third interpreter. Studies were scored both according to the Hopkins criteria using qualitative assessment of tracer uptake for the primary tumour, locoregional disease in the mediastinum and distant metastatic sites and by applying the same five-point score using a semi-quantitative measure, maximum standardized uptake value. Overall scores of 1, 2 and 3 were considered negative for residual disease, while scores of 4 and 5 were considered positive. Patients were followed up for a median of 18.5 months (range 2-139 months). Kaplan-Meier plots with a Mantel-Cox log-rank test were performed, considering death as the endpoint. Inter-reader variability was assessed using percent agreement and kappa statistics.

RESULTS

The Cohen κ coefficient analysis showed substantial agreement between the two interpreters on the five-point Hopkins criteria scoring, with a κ of 0.73. There was almost perfect agreement between the interpreters with respect to classification as positive or negative according to the Hopkins criteria, with a κ of 0.89. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of the Hopkins criteria were 88.5% [95% confidence interval (CI) 80.6-96.5%), 79.2% (95% CI 63.2-95.1%), 91.5% (95% CI 84.4-98.6%), 73.1% (95% CI 61.8-84.4%) and 85.9% (95% CI 78.5-93.3%), respectively. There was almost perfect agreement between the qualitative and semi-quantitative scoring with a κ of 0.87, with sensitivity, specificity, positive predictive value, negative predictive value and accuracy of the semi-quantitative Hopkin's criteria of 86.9% (95% CI 78.4-95.4%), 79.2% (95% CI 62.9-95.4%), 91.4% (95% CI 84.2-98.6%), 70.4% (95% CI 58.6-82.1%) and 84.7% (95% CI 80.8-92.4%), respectively.

CONCLUSION

The use of Hopkins criteria for posttherapy assessment in patients with lung cancer represents an easy and reproducible method with substantial to almost perfect interobserver agreement and high positive predictive value and accuracy; moreover, it is easily understood by referring physicians. Additionally, there was no significant difference when applying a semi-quantitative measure to the same five-point score.

Prognostic value of 18F-FDG PET parameters in patients with locally advanced non-small cell lung cancer treated with induction chemotherapy

AIM

To investigate predictive and prognostic role of metabolic parameters using [¹⁸ F]-2-fluoro-2-deoxy-D-glucose positron emission tomography (¹⁸ F-FDG PET) in patients with locally advanced non-small cell lung cancer (NSCLC) treated with docetaxel-platinum induction chemotherapy (IC).

METHODS

Medical records of 31 patients with pre- and post-IC ¹⁸ F-FDG PET were reviewed. Using ¹⁸ F-FDG PET, metabolic parameters, including metabolic tumor response, adjusted peak standardized uptake values using lean body mass at baseline (pre-SUL_peak ) and after IC (post-SUL_peak ), and percentage change of pre- and post-SUL_peak (ΔSUL_peak ), were assessed.

RESULTS

Response rate (RR) was 71%, with a metabolic RR of 83.9%. Nineteen (61.3%) patients underwent surgery, R0 resection was achieved for 17 (89.5%) patients. Median relapse-free survival (RFS) and overall survival (OS) were 8.9 months (95% CI: 4.5-12.1) and 24.1 months (95% CI: 17.1-34.1), respectively. Post-SUL_peak  < 2 was identified as a favorable prognostic factor for RFS (hazard ratio [HR]: 0.12; P = .004), while ΔSUL_peak ≥60% and R0 resection were found as positive prognostic factors for OS (HR: 0.09 and 0.13; P = .011 and P = .042, respectively). Using a receiver operating characteristics curve, post-SUL_peak  > 1.4 could predict recurrence with a sensitivity of 84% and a specificity of 100%.

CONCLUSION

In patients with locally advanced NSCLC receiving IC, post-SUL_peak and ΔSUL_peak showed clinical significance for survival outcome.

Changes in Glucose Metabolism during and after Radiotherapy in Non-Small Cell Lung Cancer

Aims and background

Evaluation of the metabolic response to radiotherapy in non-small cell lung cancer patients is commonly performed about three months after the end of radiotherapy. The aim of the present study was to assess with positron emission tomography/computed tomography (PET/CT) and [18F]fluorodeoxyglucose changes in glucose metabolism during and after radiotherapy in non-small cell lung cancer patients.

Methods and study design

In 6 patients, PET/CT scans with [18F]fluorodeoxyglucose were performed before (PET0), during (PET1; at a median of 14 days before the end of radiotherapy) and after the end of radiotherapy (PET2 and PET3, at a median of 28 and 93 days, respectively). The metabolic response was scored according to visual and semiquantitative criteria.

Results

Standardize maximum uptake at PET1 (7.9 ± 4.8), PET2 (5.1 ± 4.1) and PET3 (2.7 ± 3.1) were all significantly (P <0.05; ANOVA repeated measures) lower than at PET0 (16.1 ± 10.1). Standardized maximum uptake at PET1 was significantly higher than at both PET2 and PET3. There were no significant differences in SUVmax between PET2 and PET3. PET3 identified 4 complete and 2 partial metabolic responses, whereas PET1 identified 6 partial metabolic responses. Radiotherapy-induced increased [18F]fluorodeoxyglucose uptake could be visually distinguished from tumor uptake based on PET/CT integration and was less frequent at PET1 (n = 2) than at PET3 (n = 6).

Conclusions

In non-small cell lung cancer, radiotherapy induces a progressive decrease in glucose metabolism that is greater 3 months after the end of treatment but can be detected during the treatment itself. Glucose avid, radiotherapy-induced inflammation is more evident after the end of radiotherapy than during radiotherapy and does not preclude the interpretation of [18F]fluorodeoxyglucose images, particularly when using PET/CT.

PET Scan Contribution in Chest Tumor Management: A Systematic Review for Thoracic Surgeons

Aims and background

In the 90s, the introduction of positron emission tomography (PET) represented a milestone in the staging of thoracic tumors. In the last 10 years, PET scan has been widely adopted in thoracic oncology, showing high accuracy in diagnosis and staging and with promising issues in defining prognosis. The aim of this systematic review was to focus on the results and pitfalls of PET scan use in the modern management of chest tumors.

Methods and study design.

The literature search was performed on May 2010 in PubMed, Embase, and Cochrane according to PRISMA protocol. The search was restricted to publications in English, using in the same string the word “PET” with 9 different chest tumors; results were then filtered by eliminating technical articles, focusing only on papers in which surgery was considered as a potential diagnostic or therapeutic tool. From 6600 papers initially selected, 99 manuscripts were fully analyzed.

Results

Glucose uptake is a metabolic marker useful in the diagnosis and staging of chest tumors. In lung cancer screening, standard uptake value is helpful in defining the risk of malignancy of isolated pulmonary nodules. The addition of PET scan to conventional staging increases detection of nodal and distant metastases in lung cancer, esophageal cancer and malignant mesothelioma. In thymoma, a close relationship between standard uptake value, histology, and Masaoka stage has been advocated. This link between glucose uptake and prognosis suggests that PET translates biological tumor behavior into clinically detectable findings.

Conclusions

PET scan has a crucial role in thoracic oncology due to its impact on diagnosis, staging and prognosis. PET scan expresses the biological behavior of tumors, opening interesting perspectives in chest tumor management and improving detection and stage grouping in lung cancer. It anticipates the diagnosis in long-incubating diseases such as mesothelioma and increases biological knowledge of rare diseases, such as thymoma and other mediastinal tumors.

The role of PET/CT as a prognosticator and outcome predictor in lung cancer

Positron emission tomography/computed tomography (PET/CT) is an important imaging tool for management of lung cancer and can be utilized in diagnosis, staging, restaging, treatment planning and evaluating treatment response. In the past decade PET/CT has proven to be beneficial for the prediction of prognosis and outcome. PET findings before and after treatment, the quantitative PET parameters such as standardized uptake value (SUV), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) as well as delayed PET/CT imaging can be used to determine patient prognosis and outcome. Other tracers such as hypoxia and proliferation marker tracers may be used for prognostication. The prognostic factors derived from PET/CT imaging help early development of risk-adapted treatment strategies, which provides cost-effective treatment and leads to improved patient management. Here, we discuss findings of studies related to application of PET/CT in lung cancer as well as some technical updates on quantitative PET/CT in lung cancer.

Inter-observer agreement improves with PERCIST 1.0 as opposed to qualitative evaluation in non-small cell lung cancer patients evaluated with F-18-FDG PET/CT early in the course of chemo-radiotherapy

Background

The purpose of this study is to determine whether a qualitative approach or a semi-quantitative approach provides the most robust method for early response evaluation with 2′-deoxy-2′-[¹⁸F]fluoro-d-glucose (F-18-FDG) positron emission tomography combined with whole body computed tomography (PET/CT) in non-small cell lung cancer (NSCLC).

In this study eight Nuclear Medicine consultants analyzed F-18-FDG PET/CT scans from 35 patients with locally advanced NSCLC. Scans were performed at baseline and after 2 cycles of chemotherapy. Each observer used two different methods for evaluation: (1) PET response criteria in solid tumors (PERCIST) 1.0 and (2) a qualitative approach. Both methods allocate patients into one of four response categories (complete and partial metabolic response (CMR and PMR) and stable and progressive metabolic disease (SMD and PMD)). The inter-observer agreement was evaluated using Fleiss’ kappa for multiple raters, Cohens kappa for comparison of the two methods, and intraclass correlation coefficients (ICC) for comparison of lean body mass corrected standardized uptake value (SUL) peak measurements.

Results

The agreement between observers when determining the percentage change in SULpeak was “almost perfect”, with ICC = 0.959. There was a strong agreement among observers allocating patients to the different response categories with a Fleiss kappa of 0.76 (0.71–0.81). In 22 of the 35 patients, complete agreement was observed with PERCIST 1.0. The agreement was lower when using the qualitative method, moderate, having a Fleiss kappa of 0.60 (0.55–0.64). Complete agreement was achieved in only 10 of the 35 patients. The difference between the two methods was statistically significant (p < 0.005) (chi-squared).

Comparing the two methods for each individual observer showed Cohen’s kappa values ranging from 0.64 to 0.79, translating into a strong agreement between the two methods.

Conclusions

PERCIST 1.0 provides a higher overall agreement between observers than the qualitative approach in categorizing early treatment response in NSCLC patients. The inter-observer agreement is in fact strong when using PERCIST 1.0 even when the level of instruction is purposely kept to a minimum in order to mimic the everyday situation. The variability is largely owing to the subjective elements of the method.

Electronic supplementary material

The online version of this article (doi:10.1186/s13550-016-0223-6) contains supplementary material, which is available to authorized users.

Comparison of WHO, RECIST 1.1, EORTC, and PERCIST criteria in the evaluation of treatment response in malignant solid tumors

AIM

To compare response assessment according to the WHO, RECIST 1.1, EORTC, and PERCIST criteria in patients diagnosed with malignant solid tumors and who had received cytotoxic chemotherapy to establish the strength of agreement between each criterion.

MATERIALS AND METHODS

Sixty patients with malignant solid tumors were included in this retrospective study. The baseline and the sequential follow-up fluorine-18-fluorodeoxyglucose PET/computed tomography (CT) of each patient were evaluated according to the WHO, RECIST 1.1, EORTC, and PERCIST criteria. PET/CT images were used for both metabolic and anatomic evaluation. The concurrent diagnostic CT and MRI images (performed within 1 week of PET/CT) were also utilized when needed. The results were compared using the κ-statistics.

RESULTS

The response and progression rates according to the WHO criteria were 37 and 38%, respectively. The same ratios were also found for RECIST 1.1 (κ=1). The response and progression rates according to the EORTC criteria were 47 and 40%, respectively. When PERCIST criteria were used, one patient with progressive disease was upgraded to stable disease (κ=0.976). As we found the same results with WHO and RECIST 1.1 criteria, we used WHO criteria to compare the anatomic and metabolic criteria. When we compared the WHO and EORTC criteria, there was an agreement in 80% of the patients (κ=0.711). With WHO and PERCIST criteria, there was an agreement in 81.6% of the patients (κ=0.736).

CONCLUSION

Significant agreement was detected when the WHO, RECIST 1.1, EORTC, and PERCIST criteria were compared both within as well as between each other.

Mechanism and non-mechanism based imaging biomarkers for assessing biological response to treatment in non-small cell lung cancer

Therapeutic options in locally advanced non-small cell lung cancer (NSCLC) have expanded in the past decade to include a palate of targeted interventions such as high dose targeted thermal ablations, radiotherapy and growing platform of antibody and small molecule therapies and immunotherapies. Although these therapies have varied mechanisms of action, they often induce changes in tumour architecture and microenvironment such that response is not always accompanied by early reduction in tumour mass, and evaluation by criteria other than size is needed to report more effectively on response. Functional imaging techniques, which probe the tumour and its microenvironment through novel positron emission tomography and magnetic resonance imaging techniques, offer more detailed insights into and quantitation of tumour response than is available on anatomical imaging alone. Use of these biomarkers, or other rational combinations as readouts of pathological response in NSCLC have potential to provide more accurate predictors of treatment outcomes. In this article, the robustness of the more commonly available positron emission tomography and magnetic resonance imaging biomarker indices is examined and the evidence for their application in NSCLC is reviewed.

Adaptive Neoadjuvant Chemotherapy Guided by (18)F-FDG PET in Resectable Non-Small Cell Lung Cancers: The NEOSCAN Trial

INTRODUCTION

Although perioperative chemotherapy improves survival in patients with resectable lung cancers, systemic recurrence remains common. Neoadjuvant chemotherapy permits response assessment and an opportunity to switch treatment regimens. Response measured by fludeoxyglucose ((18)F-FDG) positron emission tomography (PET) correlates with clinical outcomes better than computed tomography (CT) does. This trial assessed PET-measured response rate to alternative chemotherapy in patients with a suboptimal PET response after two cycles of neoadjuvant chemotherapy.

METHODS

This phase II study enrolled patients with resectable stage IB-IIIA lung cancers (primary tumor ≥ 2 cm and peak standard uptake value [SUVpeak] ≥ 4.5). Patients had a pretreatment (18)F-FDG PET/CT scan before two cycles of cisplatin (or carboplatin) plus gemcitabine (squamous cell carcinoma) or pemetrexed (adenocarcinoma) and then a repeat PET/CT scan. If SUVpeak in the primary tumor decreased by at least 35%, patients continued the initial chemotherapy. Individuals with less than a 35% PET response were switched to vinorelbine plus docetaxel. Postoperative radiotherapy was recommended to all patients with positive N2 nodes. A Simon's optimal two-stage design was used to evaluate the primary end point of a PET Response in Solid Tumors-defined response rate to vinorelbine plus docetaxel in previously nonresponding patients.

RESULTS

Forty patients were enrolled. Fifteen patients (38% [95% confidence interval: 38-53]) had less than a 35% decrease in SUVpeak, and 13 received vinorelbine plus docetaxel. The study met its primary end point with 10 of 15 PET metabolic responses to alternate therapy (67%). Chemotherapy toxicities never precluded surgical exploration.

CONCLUSIONS

Utilizing (18)F-FDG PET/CT to assess response and change preoperative chemotherapy in nonresponding patients can improve radiographic measures of response. This adaptive approach can also be used to test new drugs, attempting to optimize perioperative chemotherapy to achieve better long-term outcomes.

Interpretation and Prognostic Value of Positron Emission Tomography-Computed Tomography After Induction Chemotherapy With or Without Radiation in IIIA-N2 Non-small Cell Lung Cancer Patients Who Receive Curative Surgery

We evaluate the correlation of clinical staging on positron emission tomography-computed tomography (PET-CT) and pathologic staging and the prognostic value of PET-CT after induction chemotherapy in patients with locally advanced nonsmall cell lung cancer (NSCLC). We analyzed 42 cases of clinical stage IIIA-N2 NSCLC who receive 2 to 4 cycles of preoperative chemotherapy with or without radiation followed by curative resection. The maximum standard uptake value (SUVmax) of the suspected lesion on PET-CT was recorded. PET-CT findings after induction chemotherapy were compared with those of initial PET-CT and pathology after surgery. The accuracy of PET-CT in restaging of the primary tumor after induction chemotherapy was 50.0%. Eighteen (42.8%) of 42 patients were underestimated ycT stage, and 3 (7.1%) of 42 patients was overestimated ycT stage by PET-CT scan. The accuracy of PET-CT in restaging of the nodal disease was 71.4%. Six (14.3%) of 42 patients were underestimated ycN stage, and 6 (14.3%) of 42 patients were overestimated ycN stage as compared with pathologic staging. The 2-year overall survival (OS) and relapse-free survival (RFS) rate were 68.5% and 40.9%, respectively. Complete responders (ycT0N0M0) on PET-CT after induction chemotherapy had a significantly longer RFS time than did incomplete responders (28.3 vs 9.1 months, P = 0.021). Complete response on PET-CT after induction chemotherapy with or without radiation was a good prognosticator for RFS in stage IIIA-N2 NSCLC patients who received surgery. However, response evaluation on PET-CT after induction chemotherapy should be interpreted with caution due to its unacceptable accuracy.

Computerized PET/CT image analysis in the evaluation of tumour response to therapy

Current cancer therapy strategy is mostly population based, however, there are large differences in tumour response among patients. It is therefore important for treating physicians to know individual tumour response. In recent years, many studies proposed the use of computerized positron emission tomography/CT image analysis in the evaluation of tumour response. Results showed that computerized analysis overcame some major limitations of current qualitative and semiquantitative analysis and led to improved accuracy. In this review, we summarize these studies in four steps of the analysis: image registration, tumour segmentation, image feature extraction and response evaluation. Future works are proposed and challenges described.

Predictive factors for survival in stage IIIA N2 NSCLC patients treated with neoadjuvant CCRT followed by surgery

PURPOSE

To assess the impact of imaging, surgical, histopathologic and patient-related factors on the risks of recurrence and overall survival (OS) in stage IIIA-N2 non-small cell lung cancer (NSCLC) patients undergoing definitive resection after neoadjuvant concurrent chemoradiotherapy (CCRT).

METHODS

We retrospectively examined 104 consecutive patients with stage IIIA-N2 NSCLC who received neoadjuvant CCRT followed by surgery between 2008 and 2011. While reviewing the clinical and surgical data, we also assessed histopathologic and imaging (CT and PET/CT) factors. Disease-free survival (DFS) and OS were estimated with predictors for recurrence and survival.

RESULTS

The 3-year OS for patients with and without recurrence was 37.1 and 63.3 %, respectively (p < 0.001). Size decrease of target lesion(s) ≥36 % on post-neoadjuvant CCRT CT (p = 0.048) and viable tumor size on surgical specimen <9.4 mm (p = 0.035) were related to longer OS. Regarding shorter DFS, tumor size on post-neoadjuvant CCRT CT (p = 0.046), SUV(max) of the primary tumor (p = 0.011), male gender (p = 0.023), total tumor size on surgical specimen (p = 0.041) and viable tumor size on surgical specimen (p = 0.043) were the significant predictors.

CONCLUSIONS

OS is prolonged with greater extent of size decrease of target lesion(s) on post-neoadjuvant CCRT CT and smaller viable tumor size on surgical specimen. Larger tumor size on post-neoadjuvant CCRT CT, higher SUV(max), male gender, larger total tumor size and larger viable tumor size on surgical specimen may herald the higher probability of recurrence and the necessity of more attention.

Positron Emission Tomography (PET) in Oncology

Since its introduction in the early nineties as a promising functional imaging technique in the management of neoplastic disorders, FDG-PET, and subsequently FDG-PET/CT, has become a cornerstone in several oncologic procedures such as tumor staging and restaging, treatment efficacy assessment during or after treatment end and radiotherapy planning. Moreover, the continuous technological progress of image generation and the introduction of sophisticated software to use PET scan as a biomarker paved the way to calculate new prognostic markers such as the metabolic tumor volume (MTV) and the total amount of tumor glycolysis (TLG). FDG-PET/CT proved more sensitive than contrast-enhanced CT scan in staging of several type of lymphoma or in detecting widespread tumor dissemination in several solid cancers, such as breast, lung, colon, ovary and head and neck carcinoma. As a consequence the stage of patients was upgraded, with a change of treatment in 10%-15% of them. One of the most evident advantages of FDG-PET was its ability to detect, very early during treatment, significant changes in glucose metabolism or even complete shutoff of the neoplastic cell metabolism as a surrogate of tumor chemosensitivity assessment. This could enable clinicians to detect much earlier the effectiveness of a given antineoplastic treatment, as compared to the traditional radiological detection of tumor shrinkage, which usually takes time and occurs much later.

Positron emission tomography/computerized tomography in lung cancer

Positron emission tomography (PET) using 2-(18F)-flouro-2-deoxy-D-glucose (FDG) has emerged as a useful tool in the clinical work-up of lung cancer. This review article provides an overview of applications of PET in diagnosis, staging, treatment response evaluation, radiotherapy planning, recurrence assessment and prognostication of lung cancer.

(18)F-FDG-PET/CT in assessing response to neoadjuvant chemoradiotherapy for potentially resectable locally advanced esophageal cancer

PURPOSE

To correlate metabolic response to neoadjuvant chemoradiotherapy (NACR) on FDG-PET/CT using PERCIST-based criteria to pathologic and clinical response, and survival in patients with locally advanced esophageal cancer (LAEC).

MATERIALS AND METHODS

Forty-five patients with LAEC underwent PET/CT at baseline and after NACR. Tumors were evaluated using PERCIST (PET response criteria in solid tumors)-based criteria including SUL, SUL tumor/liver ratio, % change in SUL. These parameters were compared to pathology regression grade (PRG), clinical response (including residual or new disease beyond the surgical specimen), and overall survival.

RESULTS

On surgical pathology, there was complete or near-complete regression of tumor in 51.1 %, partial response in 42.2 %, and lack regression in 4.4 %. One patient (2.2 %) had progression of disease on imaging and did not undergo surgical resection. None of the baseline PET parameters had significant correlation to pathology regression grade or clinical response. On follow-up, a positive correlation was found between post-therapy SUL ratio, %∆ SUL and %∆ SUL ratio and clinical response (p = 0.025, 0.035, 0.030, respectively). A weak correlation was found between post-therapy SUL ratio to PRG (p = 0.049). A strong correlation was found between the metabolic response score and PRG (p = 0.002) as well as between metabolic response and clinical response (p < 0.001).

CONCLUSION

PERCIST-based metabolic response assessment to NACR in LAEC may correlate with clinical outcome and survival.

18F-FDG PET early response evaluation of locally advanced non-small cell lung cancer treated with concomitant chemoradiotherapy

The potential of (18)F-FDG PET changes was evaluated for prediction of response to concomitant chemoradiotherapy in patients with locally advanced non-small cell lung cancer (NSCLC).

METHODS

For 28 patients, (18)F-FDG PET was performed before treatment, at the end of the second week of treatment, and at 2 wk and 3 mo after the completion of treatment. Standardized uptake value (SUV), maximum SUV, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were obtained. Early metabolic changes were defined as fractional change (ΔTLG) when (18)F-FDG PET at the end of the second week was compared with pretreatment (18)F-FDG PET. In-treatment metabolic changes, as measured by serial (18)F-FDG PET, were correlated with standard criteria of response evaluation of solid tumors by means of CT imaging (Response Evaluation Criteria In Solid Tumors 1.1). Parameters were analyzed for stratification in progression-free survival (PFS).

RESULTS

When compared with early metabolic nonresponders, a ΔTLG decrease of 38% or more was associated with a significantly longer PFS (1-y PFS 80% vs. 36%, P = 0.02). Pretreatment TLG was found to be a prognostic factor for PFS.

CONCLUSION

The degree of change in TLG was predictive for response to concomitant chemoradiotherapy as early as the end of the second week into treatment for patients with locally advanced NSCLC. Pretreatment TLG was prognostic for PFS.

Positron emission tomography-computed tomography in the management of lung cancer: An update

This communication presents an update on the current role of positron emission tomography-computed tomography (PET-CT) in the various clinical decision-making steps in lung carcinoma. The modality has been reported to be useful in characterizing solitary pulmonary nodules, improving lung cancer staging, especially for the detection of nodal and metastatic site involvement, guiding therapy, monitoring treatment response, and predicting outcome in non-small cell lung carcinoma (NSCLC). Its role has been more extensively evaluated in NSCLC than small cell lung carcinoma (SCLC). Limitations in FDG PET-CT are encountered in cases of tumor histotypes characterized by low glucose uptake (mucinous forms, bronchioalveolar carcinoma, neuroendocrine tumors), in the assessment of brain metastases (high physiologic 18F-FDG uptake in the brain) and in cases presenting with associated inflammation. The future potentials of newer PET tracers beyond FDG are enumerated. An evolving area is PET-guided assessment of targeted therapy (e.g., EGFR and EGFR tyrosine kinase overexpression) in tumors which have significant potential for drug development.

Early response to chemotherapy in patients with non-small-cell lung cancer assessed by [18F]-fluoro-deoxy-D-glucose positron emission tomography and computed tomography

BACKGROUND

This study aimed to demonstrate that patients who exhibit a tumor metabolic response to first-line chemotherapy seen on FDG-PET and computed tomography (CT) would survive longer than those who did not show such a response, comparing this evaluation with the morphologic response seen on CT.

PATIENTS AND METHODS

Images were acquired in 22 consecutive patients with advanced non-small-cell lung cancer (NSCLC) randomized to receive carboplatin/paclitaxel/sorafenib or placebo. FDG-PET was performed within 4 weeks before (PET1) and 2 weeks after starting treatment (PET2). Similarly, CT (CT1) was performed at baseline and then every 2 cycles (6 weeks) during treatment (CT2). Responders and nonresponders were identified with FDG-PET, and metabolic response was then compared with morphologic changes detected by spiral CT.

RESULTS

Twenty-one of 22 patients completed this study. In terms of progression-free survival (PFS) (45 vs. 22.2 weeks) and overall survival (OS) (77 vs. 47.7 weeks), we observed a trend that was not statistically significant for patients whose response after 2 weeks of treatment was seen on FDG-PET (P = .22 for PFS; P = .15 for OS).

CONCLUSION

Patients with advanced NSCLC who had a positive outcome, as evidenced by prolonged survival, were those who showed a tumor metabolic response seen on FDG-PET.

Targeting insulin inhibition as a metabolic therapy in advanced cancer: a pilot safety and feasibility dietary trial in 10 patients

OBJECTIVE

Most aggressive cancers demonstrate a positive positron emission tomographic (PET) result using ¹⁸F-2-fluoro-2-deoxyglucose (FDG), reflecting a glycolytic phenotype. Inhibiting insulin secretion provides a method, consistent with published mechanisms, for limiting cancer growth.

METHODS

Eligible patients with advanced incurable cancers had a positive PET result, an Eastern Cooperative Oncology Group performance status of 0 to 2, normal organ function without diabetes or recent weight loss, and a body mass index of at least 20 kg/m². Insulin inhibition, effected by a supervised carbohydrate dietary restriction (5% of total kilocalories), was monitored for macronutrient intake, body weight, serum electrolytes, β-hydroxybutyrate, insulin, and insulin-like growth factors-1 and -2. An FDG-PET scan was obtained at study entry and exit.

RESULTS

Ten subjects completed 26 to 28 d of the study diet without associated unsafe adverse effects. Mean caloric intake decreased 35 ± 6% versus baseline, and weight decreased by a median of 4% (range 0.0-6.1%). In nine patients with prior rapid disease progression, five with stable disease or partial remission on PET scan after the diet exhibited a three-fold higher dietary ketosis than those with continued progressive disease (n = 4, P = 0.018). Caloric intake (P = 0.65) and weight loss (P = 0.45) did not differ in those with stable disease or partial remission versus progressive disease. Ketosis was associated inversely with serum insulin levels (P = 0.03).

CONCLUSION

Preliminary data demonstrate that an insulin-inhibiting diet is safe and feasible in selected patients with advanced cancer. The extent of ketosis, but not calorie deficit or weight loss, correlated with stable disease or partial remission. Further study is needed to assess insulin inhibition as complementary to standard cytotoxic and endocrine therapies.

[Positron emission tomography with 18F-FDG and cancer response to chemotherapy]

INTRODUCTION

Few data are available about the predictive value of FDG-PET-CT in the evaluation of the response to chemotherapy of patients with advanced NSCLC and its impact on subsequent survival.

METHODS

A retrospective study of patients with advanced NSCLC who underwent a FDG-PET-CT before treatment and after three cycles of first-line chemotherapy. Morphological and metabolic responses were assessed respectively using RECIST/OMS and EORTC criteria. The relation between response and survival was analysed through Cox regression models.

RESULTS

Fifty-nine patients were included in the study (stage IIIA/IIIB/IV: 9/11/39). Median survival was 40 weeks (44 deaths observed). The evaluation of treatment response (morphological or metabolic, taken alone or combined) in terms of survival failed to identify any difference between responders and patients with stable disease. Only patients with progressive disease had a significantly shorter survival. The negative predictive value of the metabolic response for the morphological response is 0.90 and that of metabolic progression for morphological progression is 0.98.

CONCLUSION

Only progressive disease differs significantly from other types of response with a more sensitive and earlier detection by PET-CT.

Prediction of residual metabolic activity after treatment in NSCLC patients

PURPOSE

Metabolic response assessment is often used as a surrogate of local failure and survival. Early identification of patients with residual metabolic activity is essential as this enables selection of patients who could potentially benefit from additional therapy. We report on the development of a pre-treatment prediction model for metabolic response using patient, tumor and treatment factors.

METHODS

One hundred and one patients with inoperable NSCLC (stage I-IV), treated with 3D conformal radical (chemo)-radiotherapy were retrospectively included in this study. All patients received a pre and post-radiotherapy fluorodeoxyglucose positron emission tomography-computed tomography FDG-PET-CT scan. The electronic medical record system and the medical patient charts were reviewed to obtain demographic, clinical, tumor and treatment data. Primary outcome measure was examined using a metabolic response assessment on a post-radiotherapy FDG-PET-CT scan. Radiotherapy was delivered in fractions of 1.8 Gy, twice a day, with a median prescribed dose of 60 Gy.

RESULTS

Overall survival was worse in patients with residual metabolic active areas compared with the patients with a complete metabolic response (p=0.0001). In univariate analysis, three variables were significantly associated with residual disease: larger primary gross tumor volume (GTV(primary), p=0.002), higher pre-treatment maximum standardized uptake value (SUV(max), p=0.0005) in the primary tumor and shorter overall treatment time (OTT, p=0.046). A multivariate model including GTV(primary), SUV(max), equivalent radiation dose at 2 Gy corrected for time (EQD(2, T)) and OTT yielded an area under the curve assessed by the leave-one-out cross validation of 0.71 (95% CI, 0.65-0.76).

CONCLUSION

Our results confirmed the validity of metabolic response assessment as a surrogate of survival. We developed a multivariate model that is able to identify patients at risk of residual disease. These patients may benefit from an individualized and more adequate therapeutic approach, thereby improving local control and survival.

Dual-time-point F-18 FDG PET/CT for evaluation of intrathoracic lymph nodes in patients with non-small cell lung cancer

PURPOSE

The aim of this study was to evaluate the diagnostic capacity of F-18 fluorodeoxyglucose dual-time-point (DTP) positron emission tomography (PET)/computed tomography (CT) for intrathoracic lymph node (LN) metastases in patients with nonsmall cell lung cancer (NSCLC).

MATERIALS AND METHODS

Thirty-four patients had DTP PET/CT, with 60 minutes and 2-hour scans (n=19, NSCLC; n=15, benign pulmonary disease). LN diagnoses were confirmed by surgery or clinical follow-up (n=14, metastatic LNs; n=45, nonmetastatic LNs; n=39, inflammatory LNs).

RESULTS

The maximum standardized uptake value (SUVmax) in the metastatic group was significantly higher than those in the nonmetastatic and inflammatory groups on both early- and delayed-phase imaging (each P<0.0001). The retention index (RI) of SUVmax (RI-SUVmax) in the metastatic group was significantly higher than in the nonmetastatic (P=0.0008) and inflammatory groups (P=0.0074). No significant difference was found between SUVmax values of the nonmetastatic and inflammatory groups on early- (P=0.6461) or delayed-phase (P=0.6913), or between RI-SUVmax values of the nonmetastatic and inflammatory groups (P=0.5717). For early-phase SUVmax, the cut-off value for highest accuracy with metastatic LNs was 3.61, yielding a sensitivity of 86.67% and a specificity of 88.00%. For delayed-phase SUVmax, the cut-off value was 4.00, yielding a sensitivity of 91.6% and specificity of 92.9%. For RI-SUVmax, the cut-off value was 20.91%, yielding a sensitivity of 73.6% and specificity of 75.9%.

CONCLUSIONS

DTP PET/CT with a semiquantitative technique may improve diagnostic capacity for nodal staging of NSCLC.

From RECIST to PERCIST: Evolving Considerations for PET response criteria in solid tumors

The purpose of this article is to review the status and limitations of anatomic tumor response metrics including the World Health Organization (WHO) criteria, the Response Evaluation Criteria in Solid Tumors (RECIST), and RECIST 1.1. This article also reviews qualitative and quantitative approaches to metabolic tumor response assessment with (18)F-FDG PET and proposes a draft framework for PET Response Criteria in Solid Tumors (PERCIST), version 1.0.

METHODS

PubMed searches, including searches for the terms RECIST, positron, WHO, FDG, cancer (including specific types), treatment response, region of interest, and derivative references, were performed. Abstracts and articles judged most relevant to the goals of this report were reviewed with emphasis on limitations and strengths of the anatomic and PET approaches to treatment response assessment. On the basis of these data and the authors' experience, draft criteria were formulated for PET tumor response to treatment.

RESULTS

Approximately 3,000 potentially relevant references were screened. Anatomic imaging alone using standard WHO, RECIST, and RECIST 1.1 criteria is widely applied but still has limitations in response assessments. For example, despite effective treatment, changes in tumor size can be minimal in tumors such as lymphomas, sarcoma, hepatomas, mesothelioma, and gastrointestinal stromal tumor. CT tumor density, contrast enhancement, or MRI characteristics appear more informative than size but are not yet routinely applied. RECIST criteria may show progression of tumor more slowly than WHO criteria. RECIST 1.1 criteria (assessing a maximum of 5 tumor foci, vs. 10 in RECIST) result in a higher complete response rate than the original RECIST criteria, at least in lymph nodes. Variability appears greater in assessing progression than in assessing response. Qualitative and quantitative approaches to (18)F-FDG PET response assessment have been applied and require a consistent PET methodology to allow quantitative assessments. Statistically significant changes in tumor standardized uptake value (SUV) occur in careful test-retest studies of high-SUV tumors, with a change of 20% in SUV of a region 1 cm or larger in diameter; however, medically relevant beneficial changes are often associated with a 30% or greater decline. The more extensive the therapy, the greater the decline in SUV with most effective treatments. Important components of the proposed PERCIST criteria include assessing normal reference tissue values in a 3-cm-diameter region of interest in the liver, using a consistent PET protocol, using a fixed small region of interest about 1 cm(3) in volume (1.2-cm diameter) in the most active region of metabolically active tumors to minimize statistical variability, assessing tumor size, treating SUV lean measurements in the 1 (up to 5 optional) most metabolically active tumor focus as a continuous variable, requiring a 30% decline in SUV for "response," and deferring to RECIST 1.1 in cases that do not have (18)F-FDG avidity or are technically unsuitable. Criteria to define progression of tumor-absent new lesions are uncertain but are proposed.

CONCLUSION

Anatomic imaging alone using standard WHO, RECIST, and RECIST 1.1 criteria have limitations, particularly in assessing the activity of newer cancer therapies that stabilize disease, whereas (18)F-FDG PET appears particularly valuable in such cases. The proposed PERCIST 1.0 criteria should serve as a starting point for use in clinical trials and in structured quantitative clinical reporting. Undoubtedly, subsequent revisions and enhancements will be required as validation studies are undertaken in varying diseases and treatments.

Positron emission tomography in lung cancer

Recent advances in positron emission tomography (PET) with 2-deoxy-2-fluoro [F-18]-D: -glucose (FDG) has enabled not only the diagnosis and staging of lung cancer but also the prediction of its malignancy grade. However, FDG-PET has been known to have several pitfalls for imaging of lung cancer. For the effective clinical use of FDG-PET in lung cancer, we reviewed the pitfalls of using FDG-PET in the diagnosis of pulmonary nodules, semiquantitative analysis of FDG-uptake, N-staging, prediction of tumor aggressiveness, prognostic significance, and prediction of pathological response after chemoradiotherapy.

Computed Tomography Response, But Not Positron Emission Tomography Scan Response, Predicts Survival After Neoadjuvant Chemotherapy for Resectable Non–Small-Cell Lung Cancer

Purpose

Tumor response is considered a surrogate marker of survival. We investigated whether tumor response based on computed tomography (CT) scan or whole-body [18F]fluorodeoxyglucose positron emission tomography (PET) scan after neoadjuvant chemotherapy for resectable non–small-cell lung cancer (NSCLC) is prognostic of survival.

Patients and Methods

Two consecutive phase II clinical trials were jointly analyzed. Patients underwent CT and PET scans before and after completion of neoadjuvant chemotherapy, followed by surgery.

Results

Eighty-nine patients were included. Patients with a partial or complete response based on Response Evaluation Criteria in Solid Tumors categories (n = 33) had a better overall survival than those with stable or progressive disease (n = 56; median survival time, not reached v 36 months, respectively; P = .04). Of all patients, those with response in the highest quartile had 1- and 2-year survival rates of 100% and 81%, respectively, compared with 77% and 61%, respectively, among patients in the lowest quartile. However, on the basis of visual analysis of PET scan, patients with a metabolic response (n = 28) had no significant difference in survival compared with patients without response (n = 61; median survival time, 35.6 months v not reached, respectively; P = .94). In addition, on the basis of a semiquantitative analysis of PET scan, using at least 30% reduction in tumor metabolism as a response (n = 59), we also found no significant difference in survival among those with or without response.

Conclusion

Among patients with resectable NSCLC treated with neoadjuvant chemotherapy, we found no evidence that tumor response by PET scan after chemotherapy is prognostic of survival; however, response by CT scan was associated with better survival.

[Usefulness of positron emission tomography-computed tomography in respiratory medicine]

The introduction of positron emission tomography (PET) into the management of neoplastic disease in respiratory patients signified an important change from classic algorithms based exclusively on anatomic information obtained through computed tomography (CT). Non-small cell lung cancer and solitary pulmonary nodule were the 2 diseases in which metabolic PET imaging offered the highest diagnostic yield, as has been evident since the inclusion of this technology among the services available within the Spanish national health service. However, a number of limitations were encountered in relation to the lack of anatomic definition in PET imaging, as had been described in the literature. The appearance in 2001 of hybrid PET-CT devices has not only helped remedy those defects, but has also made it possible to combine anatomic and metabolic information in a single image, making this hybrid technology the most valuable tool in the current diagnostic arsenal.

Prognostic stratification of stage IIIA-N2 non-small-cell lung cancer after induction chemotherapy: a model based on the combination of morphometric-pathologic response in mediastinal nodes and primary tumor response on serial 18-fluoro-2-deoxy-glucose positron emission tomography

PURPOSE

Surgical resection in patients with stage IIIA-N2 non-small-cell lung cancer (NSCLC) is usually reserved for patients with mediastinal downstaging after induction chemotherapy (IC). However, clinical restaging is often inaccurate, and there are insufficient data to conclude that all patients with persistent mediastinal disease will not benefit from surgery, or that all patients with mediastinal clearance benefit from surgery. We created a data-based restaging strategy combining morphometric tissue analysis of mediastinal lymph nodes (LNs) and 18-fluoro-2-deoxy-glucose positron emission tomography (FDG-PET) response monitoring in the primary tumor.

PATIENTS AND METHODS

Baseline and repeat FDG-PET after IC, as well as complete resection specimens of both mediastinal LNs and primary tumor, were available in 30 patients. Histologic response grading was performed by means of conventional morphometric procedures. Mediastinal response grading combined with the percentage decrease of maximum standardized uptake value (SUV(max)) on the primary tumor was correlated with survival.

RESULTS

Patients with persistent major mediastinal LN involvement have a 5-year overall survival rate of 0%. The 5-year overall survival rate for patients with cleared or persistent minor mediastinal LN involvement was significantly higher in patients with a more than 60% decrease in SUV(max) on the primary tumor as compared with patients with a less than 60% decrease in SUV(max) (62% v 13%; log-rank P = .002).

CONCLUSION

These data may suggest that (1) persistent mediastinal disease after IC does not always exclude favorable outcome after surgery; (2) serial FDG-PET may select surgical candidates among patients with mediastinal downstaging or persistent minor disease; (3) persistent major mediastinal disease has a poor prognosis and such patients should not be considered for surgery.

Predictive and prognostic value of FDG-PET

The predictive and prognostic value of fluorodeoxyglucose (FDG)-positron emission tomography (PET) in non-small-cell lung carcinoma, colorectal carcinoma and lymphoma is discussed. The degree of FDG uptake is of prognostic value at initial presentation, after induction treatment prior to resection and in the case of relapse of non-small cell lung cancer (NSCLC). In locally advanced and advanced stages of NSCLC, FDG-PET has been shown to be predictive for clinical outcome at an early stage of treatment. In colorectal carcinoma, limited studies are available on the prognostic value of FDG-PET, however, the technique appears to have great potential in monitoring the success of local ablative therapies soon after intervention and in the prediction and evaluation of response to radiotherapy, systemic therapy, and combinations thereof. The prognostic value of end-of treatment FDG-PET for FDG-avid lymphomas has been established, and the next step is to define how to use this information to optimize patient outcome. In Hodgkin's lymphoma, FDG-PET has a high negative predictive value, however, histological confirmation of positive findings should be sought where possible. For non-Hodgkin's lymphoma, the opposite applies. The newly published standardized guidelines for interpretation formulates specific criteria for visual interpretation and for defining PET positivity in the liver, spleen, lung, bone marrow and small residual lesions. The introduction of these guidelines should reduce variability among studies. Interim PET offers a reliable method for early prediction of long-term remission, however it should only be performed in prospective randomized controlled trials. Many of the diagnostic and management questions considered in this review are relevant to other tumour types. Further research in this field is of great importance, since it may lead to a change in the therapeutic concept of cancer. The preliminary findings call for systematic inclusion of FDG-PET in therapeutic trials to adequately position FDG-PET in treatment time lines.

Predictive and prognostic value of FDG-PET in nonsmall-cell lung cancer: a systematic review

For several years, molecular imaging with (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) has become part of the standard of care in presurgical staging of patients with nonsmall-cell lung cancer (NSCLC), focusing on the detection of malignant lesions at early stages, early detection of recurrence, and metastatic spread. Currently, there is an increasing interest in the role of FDG-PET beyond staging, such as the evaluation of biological characteristics of the tumor and prediction of prognosis in the context of treatment stratification and the early assessment of tumor response to therapy. In this systematic review, the literature on the value of the evolving applications of FDG-PET as a marker for prediction (ie, therapy response monitoring) and prognosis in NSCLC is addressed, divided in sections on the predictive value of FDG-PET in locally advanced and advanced disease, the prognostic value of FDG-PET at diagnosis, after induction treatment, and in recurrent disease. Furthermore, the background and recommendations for the application of FDG-PET for these indications will be discussed.

Integrated FDG-PET/CT does not make invasive staging of the intrathoracic lymph nodes in non-small cell lung cancer redundant: a prospective study

BACKGROUND

Staging of non-small cell lung cancer (NSCLC) is important for determining choice of treatment and prognosis. The accuracy of FDG-PET scans for staging of lymph nodes is too low to replace invasive nodal staging. It is unknown whether the accuracy of integrated FDG-PET/CT scanning makes invasive staging redundant.

METHODS

In a prospective study, the mediastinal and/or hilar lymph nodes in patients with proven NSCLC were investigated with integrated FDG-PET/CT scanning. Pathological confirmation of all suspect lymph nodes was obtained to calculate the accuracy of the fusion images. In addition, the use of the standardised uptake value (SUV) in the staging of intrathoracic lymph nodes was analysed.

RESULTS

105 intrathoracic lymph node stations from 52 patients with NSCLC were characterised. The prevalence of malignancy in the lymph nodes was 36%. The sensitivity of the integrated FDG-PET/CT scan to detect malignant lymph nodes was 84% and its specificity was 85% (positive likelihood ratio 5.64, negative likelihood ratio 0.19). SUV(max), SUV(mean) and the SUV(max)/SUV(liver) ratio were all significantly higher in malignant than in benign lymph nodes. The area under the receiver operating curve did not differ between these three quantitative variables, but the highest accuracy was found with the SUV(max)/SUV(liver) ratio. At a cut-off value of 1.5 for the SUV(max)/SUV(liver )ratio, the sensitivity and specificity to detect malignant lymph node invasion were 82% and 93%, respectively.

CONCLUSION

The accuracy of integrated FDG-PET/CT scanning is too low to replace invasive intrathoracic lymph node staging in patients with NSCLC. The visual interpretation of the fusion images of the integrated FDG-PET/CT scan can be replaced by the quantitative variable SUV(max)/SUV(liver) without loss of accuracy for intrathoracic lymph node staging.

Treatment of Non-small Cell Lung Cancer-Stage IIIA

STUDY OBJECTIVES

Stage IIIA non-small cell lung cancer represents a relatively heterogeneous group of patients with metastatic disease to the ipsilateral mediastinal (N2) lymph nodes and also includes T3N1 patients. Presentations of disease range from apparently resectable tumors with occult microscopic nodal metastases to unresectable, bulky multistation nodal disease. This review explores the published clinical trials to make treatment recommendations in this controversial subset of lung cancer.

DESIGN, SETTING, AND PARTICIPANTS

Systematic searches were made of MEDLINE, HealthStar, and Cochrane Library databases up to May 2006, focusing primarily on randomized trials, with inclusion of selected metaanalyses, practice guidelines, and reviews. Study designs and results are summarized in evidence tables.

MEASUREMENT AND RESULTS

The evidence derived from the literature now appears to support routine adjuvant chemotherapy after complete resection of stage IIIA lung cancer encountered unexpectedly at surgery. However, using neoadjuvant therapy followed by surgery for known stage IIIA lung cancer as a routine therapeutic option is not supported by current published randomized trials. Combination chemoradiotherapy, especially delivered concurrently, is still the preferred treatment for prospectively recognized stage IIIA lung cancer with all degrees of mediastinal lymph node involvement. Current and future trials may modify these recommendations.

CONCLUSIONS

Multimodality therapy of some type appears to be preferable in all subsets of stage IIIA patients. However, because of the relative lack of consistent randomized trial data in this subset, the following evidence-based treatment guidelines lack compelling evidence in most scenarios.

Positron emission tomography in nonsmall cell lung cancer

PURPOSE OF REVIEW

[(8)F]2-Fluoro-2-deoxy-glucose positron emission tomography is an important functional imaging technique for the diagnosis, staging and follow-up of patients with nonsmall cell lung cancer. We review recent developments with the emphasis on impact of positron emission tomography in early diagnosis, staging, restaging and prognosis of nonsmall cell lung cancer.

RECENT FINDINGS

Data on the use and interpretation of positron emission tomography became available for small pulmonary nodules. We should abandon the 'magic' standardized uptake value threshold of 2.5 and rather make a visual assessment in this setting. The high negative predictive value of positron emission tomography in mediastinal staging was confirmed in a large prospective study. Tissue confirmation of all qualitative or quantitative suspicious mediastinal lymph nodes at positron emission tomography remains required. Minimally invasive techniques such as endobronchial ultrasound-guided transbronchial needle aspiration seem promising in this setting with sensitivities up to 90%. Recent data also point at integrated positron emission tomography/computed tomography as a tool for response assessment of mediastinal nodes and, more interestingly, of the primary tumor. Positron emission tomography has the potential to predict survival based on baseline positron emission tomography stage and standardized uptake value, visual [(18)F]2-fluoro-2-deoxy-glucose uptake at the time of suspected recurrence, and change in [(18)F]2-fluoro-2-deoxy-glucose uptake after neoadjuvant therapy.

SUMMARY

Refinements in diagnosis and staging, as well as newer applications such as guidance of endoscopy and assessment of treatment, are described.

Staging of Lung Cancer

Imaging techniques play a vital role in the diagnosis, staging, and follow-up of patients who have lung cancer. For this purpose, PET has become an important adjunct to conventional imaging techniques such as chest radiography, CT, ultrasonography, and MR imaging. The ability of PET to differentiate the metabolic properties of tissues allows more accurate assessment of undetermined lung lesions, mediastinal lymph nodes, or extrathoracic abnormalities, tumor response after induction treatment, and detection of disease recurrence.