Can FDG-PET reduce the need for mediastinoscopy in potentially resectable nonsmall cell lung cancer?

Utility of PET-CT in non-small cell lung cancer clinical stage IB-IIA according to AJCC 8th edition staging system: an alternative to invasive mediastinal staging?

Objective

Mediastinal nodal staging in lung cancer is essential to determine treatment strategy and prognosis. There are controversies as to whether a mediastinal negative result in PET-CT may spare the invasive staging of the mediastinum. The main endpoint is to evaluate the negative predictive value (NPV) of PET-CT in non-small cell lung cancer (NSCLC) clinical stage IB-IIA without clinical nodal involvement. The secondary endpoint is to evaluate the prevalence of mediastinal and hilar nodal affection in this population.

Methods

We performed an observational descriptive study from January 2010 to January 2020, including 76 patients with clinical stage IB-IIA, who underwent pulmonary resection with systematic nodal sampling (pre-determined lymph node stations based on tumour location) for primary NSCLC. Clinically, nodal involvement was defined as any lymph node greater than 1 cm in the short axis on a CT or with metabolic uptake greater than 2.5 SUV on PET-CT. The prevalence of nodal metastases was recorded.

Results

Fifty six patients had clinical stage IB and 20 had clinical stage IIA. Mean tumour size was 3.74 ± 0.5 cm. Lobectomy was the resection procedure most frequently performed. Of the 76 patients with clinical N0 by PET-CT who underwent surgical resection, 10 (13.1%) were upstaged to pN1 and none were upstaged to pN2. NPV of PET-CT for overall nodal metastasis was 87% (95% CI: 0.79-0.94). NPV of PET-CT for N2 metastasis was 100%.

Conclusion

PET-CT might be an alternative to invasive mediastinal staging in patients with NSCLC clinical stage IB-IIA who are surgical candidates. Further prospective multi-institutional studies are necessary to verify the external validity of our study.

Mediastinal lymph node staging for lung cancer

Mediastinal lymph node staging is crucial in deciding the treatment strategy for lung carcinoma. The diagnosis rate of computed tomography is not high; however, it is a standard examination. Although the contrast computed tomography is necessary for an accurate diagnosis, images from the positron emission tomography are excellent, and these two technologies are independent and complementary. Positron emission tomography has a disadvantage of false positives and false negatives, but it should also be used in cases where lymph node diameters are 1 cm or more. However, image-based diagnostic methods are not an alternative to histological examination. The results of a transbronchial needle biopsy are extremely dependent on the inspection method, the diagnostic ability of the physician, and the staging of the case. The transesophageal ultrasound endoscope is useful for reaching parts inaccessible by a mediastinoscope. Although its employment requires technical training, it is becoming popular as a minimally invasive method of obtaining cell and the tissue samples. A thoracoscopic biopsy is considered as a last resort for mediastinal lymph node diagnosis. Carefully-chosen invasive procedures are necessary to diagnose swollen lymph nodes. Although mediastinoscopy is still considered as the gold standard, most procedures will be replaced by a comparatively minimally invasive method in the future.

Thoracoscopic lobectomy after induction therapy-a paradigm shift?

Video-assisted thoracoscopic approaches (or VATS) have gained significant momentum in the management of locally advanced NSCLC in the current era. Accrual of experiences and concurrent improvements in instrumentation and video technology have further enhanced its role in patients with stage IIIA (N2) non-small cell lung cancer (NSCLC). However, substantial controversy exists around the notion of mediastinal staging and restaging after induction therapy, the utility of induction chemotherapy versus chemoradiation for N2 disease, and subsequent role of video-assisted thoracoscopic surgery (VATS) lobectomy following induction therapy. This perspective will closely examine these issues in the context of existing guidelines and contemporary studies.

Indications for invasive mediastinal staging in patients with early non-small cell lung cancer staged with PET-CT

PURPOSE/OBJECTIVE(S)

Appropriate use of invasive mediastinal staging in patients with clinically node-negative NSCLC staged by PET-CT is critical in selecting patients for curative-intent therapy such as surgery or SBRT, but little data exists to guide this decision-making. We examined a large population of patients with clinical stage I NSCLC referred for mediastinoscopy or EBUS to find risk factors for occult N2 lymph nodes and determine which patients benefit from invasive staging.

MATERIALS/METHODS

We identified consecutive clinical T1-2N0 NSCLC patients being evaluated for curative-intent therapy between 2011 and 2015. None had evidence of nodal disease by PET-CT; the endpoint was pathologic confirmation of occult N2 disease by EBUS or mediastinoscopy. Tumor size, location, histology, SUV_max, and radiographic appearance were evaluated as determinants of occult N2 disease. Two group comparisons of continuous variables were done with independent t-tests and categorical variables were compared with χ² or Fisher's exact test.

RESULTS

In 284 patients with PET-CT-staged clinical T1-2N0 disease, the prevalence of occult N2 metastases was 7.0%. The negative predictive value of PET-CT was 92.9% and the negative predictive value of mediastinoscopy/EBUS was 96.3%. T2 tumors were more likely to have occult N2 disease than T1 tumors (11.8% v 3.6% p=0.009). Pure solid tumors had greater involvement of N2 nodes than tumors with any ground glass component (12.6% v 3.1%, p<0.001). 17.5% of central tumor cases were found to have occult N2 metastases while 4.4% of patients with peripheral tumors (P<0.001). 33.3% of patients with solid central T2 tumors had occult N2 metastases whereas 2.0% of patients with peripheral T2 tumors with a ground glass component, 1.2% of patients with peripheral T1 tumors with a ground glass component and 3.6% of patients with peripheral T1 solid tumors had N2 metastases.

CONCLUSIONS

Invasive mediastinal staging should be strongly encouraged in central tumors and solid T2 tumors because the risk of occult nodal involvement is greater than 10% in these cohorts. However, for patients with peripheral T1 tumors or peripheral T2 tumors with a significant ground glass component, the yield of invasive staging after a negative PET-CT is very low and invasive staging may not be warranted.

Pre- and postoperative care for stage I-III NSCLC: Which quality of care indicators are evidence-based?

Identification of evidenced-based Quality of Care (QoC) indicators for lung cancer care is essential to quality improvement. The aim of this review was to identify evidence-based quality indicators for the pre- and postoperative care of stage I-III Non Small Cell Lung Cancer (NSCLC) provided by the lung physician. To obtain these indicators, a search in PubMed, Embase and the Cochrane library database was performed. English literature published between 1980 and 2012 was included and search terms regarding 'lung neoplasms', 'quality of care', 'pathology', 'diagnostic methods', 'preoperative and postoperative treatment' were used. The potential indicators were categorized as structure, process or outcome measures and the indicators supported by literature with high evidence level were selected. Five QoC indicators were identified. The use of the positron emission tomography-computed tomography (PET-CT) results in more accurate mediastinal staging compared to the CT scan. Endoscopic Ultrasound-Fine Needle Aspiration and Endobronchial Ultrasound-Fine Needle Aspiration are sensitive diagnostic tools for mediastinal staging and reduce futile thoracotomies. Pathological conformation of lung cancer can best be obtained by a combination of cytological and histological diagnostics used during bronchoscopy. For patients with clinical stage III NSCLC, preoperative multimodality treatment (i.e. preoperative chemoradiation) results in superior survival and increased mediastinal downstaging compared to single modality treatment (i.e. preoperative chemotherapy or radiotherapy). After surgery, the addition of chemotherapy results in a significant survival benefit for patients with pathological stage II and III NSCLC. These five QoC indicators can be used for benchmarking and ultimately quality improvement of lung cancer care.

Use of Positron Emission Tomography/Computed Tomography in Radiation Treatment Planning for Lung Cancer

Radiotherapy (RT) plays an important role in the treatment of lung cancer. Accurate diagnosis and staging are crucial in the delivery of RT with curative intent. Target miss can be prevented by accurate determination of tumor contours during RT planning. Currently, tumor contours are determined manually by computed tomography (CT) during RT planning. This method leads to differences in delineation of tumor volume between users. Given the change in RT tools and methods due to rapidly developing technology, it is now more significant to accurately delineate the tumor tissue. F18 fluorodeoxyglucose positron emission tomography/CT (F18 FDG PET/CT) has been established as an accurate method in correctly staging and detecting tumor dissemination in lung cancer. Since it provides both anatomic and biologic information, F18 FDG PET decreases inter-user variability in tumor delineation. For instance, tumor volumes may be decreased as atelectasis and malignant tissue can be more accurately differentiated, as well as better evaluation of benign and malignant lymph nodes given the difference in FDG uptake. Using F18 FDG PET/CT, the radiation dose can be escalated without serious adverse effects in lung cancer. In this study, we evaluated the contribution of F18 FDG PET/CT for RT planning in lung cancer.

Abnormal FDG Uptake in the Pericardial Adipose Tissue Mimicking Malignancy

Focal mediastinal F-18 FDG uptake may be from potential adenopathy requiring biopsy confirmation or benign active brown adipose tissue to be left untouched. Knowledge of this potential pitfall and precise localization with fusion PET/CT are important in preventing misinterpretation as malignancy. Our case report is important in the aspect that CT was not able to confirm the uptake as benign finding, which led to invasive biopsy and biopsy confirmed it to be a benign brown adipose tissue.

Accuracy of positron emission tomography in identifying hilar (N1) lymph node involvement in non-small cell lung cancer: Implications for stereotactic body radiation therapy

PURPOSE

To assess the efficacy of preoperative positron emission tomography (PET) to stage the ipsilateral hilum in resected non-small cell lung cancer (NSCLC).

METHODS AND MATERIALS

All patients who underwent surgery for NSCLC between 1995 and 2008 were evaluated. Patients who underwent preoperative PET imaging at our institution and had hilar nodal sampling were included. Those whose primary tumors extended to the hilum or who received preoperative chemotherapy or radiation therapy were excluded. All PET studies were interpreted by an attending nuclear medicine radiologist and were scored as positive or negative in the hilum or peribronchial area based on visual analysis alone. A 2-sided Fisher exact test compared patient subgroups.

RESULTS

During the time interval, 1558 patients underwent surgery for NSCLC, of whom 484 were eligible for this analysis. The ipsilateral hilum was positive on preoperative PET in 107 patients. The median number of N1 lymph nodes sampled was 4 (range, 1-31). Positive ipsilateral N1 lymph nodes were identified pathologically in 91 patients (19%). Among the 91 patients with involved N1 lymph nodes, 40 were PET positive resulting in a sensitivity of 44%. Among 393 patients without pathologic involvement of hilar lymph nodes, 326 were PET negative resulting in a specificity of 83%. The positive predictive and negative predictive values were 37% and 86%, respectively.

CONCLUSIONS

Positron emission tomography appears to have limitations in staging the ipsilateral hilar lymph nodes. Invasive sampling is appropriate if treatment would differ based on the nodal status.

Neural networks for nodal staging of non-small cell lung cancer with FDG PET and CT: importance of combining uptake values and sizes of nodes and primary tumor

PURPOSE

To evaluate the effect of adding lymph node size to three previously explored artificial neural network (ANN) input parameters (primary tumor maximum standardized uptake value or tumor uptake, tumor size, and nodal uptake at N1, N2, and N3 stations) in the structure of the ANN. The goal was to allow the resulting ANN structure to relate lymph node uptake for size to primary tumor uptake for size in the determination of the status of nodes as human readers do.

MATERIALS AND METHODS

This prospective study was approved by the institutional review board, and informed consent was obtained from all participants. The authors developed a back-propagation ANN with one hidden layer and eight processing units. The data set used to train the network included node and tumor size and uptake from 133 patients with non-small cell lung cancer with surgically proved N status. Statistical analysis was performed with the paired t test.

RESULTS

The ANN correctly predicted the N stage in 99.2% of cases, compared with 72.4% for the expert reader (P < .001). In categorization of N0 and N1 versus N2 and N3 disease, the ANN performed with 99.2% accuracy versus 92.2% for the expert reader (P < .001).

CONCLUSION

The ANN is 99.2% accurate in predicting surgical-pathologic nodal status with use of four fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT)-derived parameters. Malignant and benign inflammatory lymph nodes have overlapping appearances at FDG PET/CT but can be differentiated by ANNs when the crucial input of node size is used.

Mediastinoscopy: trends and practice patterns in the United States

OBJECTIVES

Historically, mediastinoscopy has been the gold standard for the staging of lung cancer. A practice gap exists as the result of a variation in knowledge concerning current trends and practice patterns of mediastinoscopy usage. In addition, there are regional variations in practice-based learning and patient care. Lessons learned during surgeries performed on patients with lung cancer and other advances such as positron emission tomography and endobronchial ultrasound could be universally applied to improve surgeons' management of patient care. The purpose of this study was to assess contemporary practices in the staging of lung cancer.

METHODS

We queried the Society of Thoracic Surgeons National Database for data regarding mediastinoscopy usage, yield, and variation, both by year and region.

RESULTS

Cases with mediastinoscopy, as a percentage of all cases performed in the database, have significantly decreased from 14.6% in 2006 to 11.4% in 2010 (P < 0.001). The 5-year median rate of mediastinoscopy in lung cancer patients at 163 centers was 15.3% (interquartile range 5.2%-31.7%), indicating significant variation among centers. The overall median center rate also decreased over time from 21.4% (2006) to 10.0% (2010).

CONCLUSIONS

With advances in minimally invasive procedures and imaging, mediastinoscopy usage has declined significantly. Our findings are likely to be relevant to both clinical practice and practice guidelines.

Methods for staging non-small cell lung cancer: Diagnosis and management of lung cancer, 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines

BACKGROUND

Correctly staging lung cancer is important because the treatment options and prognosis differ significantly by stage. Several noninvasive imaging studies and invasive tests are available. Understanding the accuracy, advantages, and disadvantages of the available methods for staging non-small cell lung cancer is critical to decision-making.

METHODS

Test accuracies for the available staging studies were updated from the second iteration of the American College of Chest Physicians Lung Cancer Guidelines. Systematic searches of the MEDLINE database were performed up to June 2012 with the inclusion of selected meta-analyses, practice guidelines, and reviews. Study designs and results are summarized in evidence tables.

RESULTS

The sensitivity and specificity of CT scanning for identifying mediastinal lymph node metastasis were approximately 55% and 81%, respectively, confirming that CT scanning has limited ability either to rule in or exclude mediastinal metastasis. For PET scanning, estimates of sensitivity and specificity for identifying mediastinal metastasis were approximately 77% and 86%, respectively. These findings demonstrate that PET scanning is more accurate than CT scanning, but tissue biopsy is still required to confirm PET scan findings. The needle techniques endobronchial ultrasound-needle aspiration, endoscopic ultrasound-needle aspiration, and combined endobronchial ultrasound/endoscopic ultrasound-needle aspiration have sensitivities of approximately 89%, 89%, and 91%, respectively. In direct comparison with surgical staging, needle techniques have emerged as the best first diagnostic tools to obtain tissue. Based on randomized controlled trials, PET or PET-CT scanning is recommended for staging and to detect unsuspected metastatic disease and avoid noncurative resections.

CONCLUSIONS

Since the last iteration of the staging guidelines, PET scanning has assumed a more prominent role both in its use prior to surgery and when evaluating for metastatic disease. Minimally invasive needle techniques to stage the mediastinum have become increasingly accepted and are the tests of first choice to confirm mediastinal disease in accessible lymph node stations. If negative, these needle techniques should be followed by surgical biopsy. All abnormal scans should be confirmed by tissue biopsy (by whatever method is available) to ensure accurate staging. Evidence suggests that more complete staging improves patient outcomes.

Serum vascular endothelial growth factor-C levels: A possible diagnostic marker for lymph node metastasis in patients with primary non-small cell lung cancer

Accurate tumor staging is essential for selecting the appropriate treatment strategy for lung cancer. Computed tomography (CT), or positron emission tomography (PET), is the most commonly used non-invasive staging method of lymph node (LN) metastases (LNM), but this method remains unsatisfactory. The present study measured vascular endothelial growth factor (VEGF)-C levels in serum, tumor tissue and LNs to determine the correlation between serum VEGF-C and LNM, and also assessed the usefulness of serum VEGF-C as an additional diagnostic marker for identifying LNM. A total of 66 patients with non-small cell lung carcinoma (NSCLC) or benign tumors of the lung were included in this study, and circulating VEGF-C levels were assessed with enzyme-linked immunosorbent assays. RNA fractions extracted from the tumor tissues and LNs were subjected to quantitative polymerase chain reaction (qPCR) to assess the mRNA levels of VEGF-C. The VEGF-C levels in serum, tumor tissue and LNM were significantly higher compared with the control group (P<0.05). The VEGF-C levels of patients with LNM were significantly higher compared with those without LNM (P<0.05). The VEGF-C levels in the serum, tumor tissue and LNM were significantly correlated (P<0.05). With regard to the diagnosis of LNM using VEGF-C levels, the serum levels of VEGF-C reached a sensitivity of 65.0% and a specificity of 72.2% when a cutoff value of 655.65 pg/ml was applied. Serum VEGF-C levels may provide additional information for distinguishing between the absence and presence of LNM in patients with lung carcinoma. The evaluation of serum VEGF-C is complementary to accurate LN staging in NSCLC.

Challenges and opportunities in patient-specific, motion-managed and PET/CT-guided radiation therapy of lung cancer: review and perspective

The increasing interest in combined positron emission tomography (PET) and computed tomography (CT) to guide lung cancer radiation therapy planning has been well documented. Motion management strategies during treatment simulation PET/CT imaging and treatment delivery have been proposed to improve the precision and accuracy of radiotherapy. In light of these research advances, why has translation of motion-managed PET/CT to clinical radiotherapy been slow and infrequent? Solutions to this problem are as complex as they are numerous, driven by large inter-patient variability in tumor motion trajectories across a highly heterogeneous population. Such variation dictates a comprehensive and patient-specific incorporation of motion management strategies into PET/CT-guided radiotherapy rather than a one-size-fits-all tactic. This review summarizes challenges and opportunities for clinical translation of advances in PET/CT-guided radiotherapy, as well as in respiratory motion-managed radiotherapy of lung cancer. These two concepts are then integrated into proposed patient-specific workflows that span classification schemes, PET/CT image formation, treatment planning, and adaptive image-guided radiotherapy delivery techniques.

Current concepts in F18 FDG PET/CT-based radiation therapy planning for lung cancer

Radiation therapy is an important component of cancer therapy for early stage as well as locally advanced lung cancer. The use of F18 FDG PET/CT has come to the forefront of lung cancer staging and overall treatment decision-making. FDG PET/CT parameters such as standard uptake value and metabolic tumor volume provide important prognostic and predictive information in lung cancer. Importantly, FDG PET/CT for radiation planning has added biological information in defining the gross tumor volume as well as involved nodal disease. For example, accurate target delineation between tumor and atelectasis is facilitated by utilizing PET and CT imaging. Furthermore, there has been meaningful progress in incorporating metabolic information from FDG PET/CT imaging in radiation treatment planning strategies such as radiation dose escalation based on standard uptake value thresholds as well as using respiratory-gated PET and CT planning for improved target delineation of moving targets. In addition, PET/CT-based follow-up after radiation therapy has provided the possibility of early detection of local as well as distant recurrences after treatment. More research is needed to incorporate other biomarkers such as proliferative and hypoxia biomarkers in PET as well as integrating metabolic information in adaptive, patient-centered, tailored radiation therapy.

MicroRNAs and lymph node metastatic disease in lung cancer

Lymphatic and distant metastases are primary factors in determining survival in patients with lung cancer. The identification of novel molecular biomarkers that can predict the presence of micrometastasis in lymph nodes and their incorporation in traditional histologic staging is needed. MicroRNAs are emerging as powerful biomarkers for several neoplastic disorders. This article reports the experimental results that have recently led to the identification of several microRNAs deregulated in lung cancer that are strongly associated with lymph node metastasis and advanced clinical stage. This evidence indicates that microRNAs are a promising tool for the clinical management of lung cancer.

PET and PET-CT of lung cancer

Accurate staging is essential to offer the patient the most effective available treatment and the best estimate of prognosis. In non-small cell lung cancer (NSCLC), surgical resection offers the best chance of cure in the early stages, either alone or in combination with chemo- or radiotherapy at the more advanced stages. However, many patients present with metastatic disease at the time of diagnosis. Both computed tomography (CT) and positron emission tomography (PET) using fluorodeoxyglucose (FDG) play an important role in the diagnosis and staging of lung cancer. CT provides excellent morphologic information but has significant limitations in differentiating between benign and malignant lesions either in an organ or in lymph nodes. FDG-PET is highly accurate in the detection of mediastinal lymph node metastases as well as extratharacic metastases. However, due to the poor anatomic information provided by PET, additional morphologic information is needed to properly locate a lesion. Imaging with PET integrated with computed tomography (PET/CT) offers essential advantages in comparison to PET alone, CT alone, or visual correlation of separate PET and CT. A combined PET/CT system provides PET and CT images perfectly coregistered so that lesions can be exactly localized.

[What is the role of FDG-PET in thoracic oncology in 2010?]

18F-Fluorodeoxyglucose-Positron Emission Tomography (FGD-PET) has been considered to have a major impact on the management of lung malignancies since the beginning of this century. Its value has been demonstrated by many publications, meta-analysis and European/American/Japanese recommendations. PET combined with computed tomography has provided useful information regarding the diagnosis and staging of lung cancer and allows for the delivery of adaptive radiotherapy. In its more common uses, PET has been shown to be cost-effective. With the widespread use of new radiotracers, PET will play an increasing role in the evaluation of response to treatment.

[Application of videomediastinoscopy in positive PET finding for mediastinal lymph node of lung cancer]

BACKGROUND AND OBJECTIVE

Positron emission tomography (PET) is used increasingly in staging of non-small cell lung cancer (NSCLC) as a non-invasive tool. However, the role of PET in mediastinal lymphatic staging of NSCLC is not clear. The aim of this study was to demonstrate the efficacy of mediastinoscopy in determining mediastinal lymphatic metastasis in cases of positive PET finding.

METHODS

We performed PET preoperatively in 68 patients with clinically operable NSCLC between 2003 and 2008. Mediastinal lymphatic defined as metastasis by PET (SUV(max) > 2.5) was recorded. Mediastinoscopy being performed initially in all patients. Involvement of mediastinal lymph nodes was verified to compare the sensitivity and specificity of mediastinoscopy and the related PET results.

RESULTS

From 2003 to 2008, 61 mediastinoscopy were performed. There were 38 men and 23 women, aged from 41 to 81 years (mean 60 years). Localization of the tumor was right lung in 41 patients and left lung in 20 patients. After the operation, 45 patients were demonstrated to have N2 or N3 disease. Ten patients with N3 mediastinal metastasis for chemotherapy, 38 patients with N2 mediastinal metastasis for neuadjuvant chemotherapy while lung resection and systemic mediastinal lymphatic dissection through thoracotomy was performed in the remaining 16 patients with no mediastinal metastasis. The positive prediction value of PET scan was 73.8% (45/61). The sensitivity, specificity, accuracy, positive prediction value and negative prediction value in diagnosis of metastasis of mediastinal lymph nodes were 93.8% (45/48), 100% (13/13), 95.1% (58/61), 100% (45/45), 81.3% (13/16) for mediastinoscopy, respectively.

CONCLUSION

PET results do not provide acceptable accuracy rates. Mediastinoscopy still remains the gold standard for mediastinal staging of NSCLC.

Intratumoural chemotherapy of lung cancer for diagnosis and treatment of draining lymph node metastasis

Objectives

Reviewed here is the potential effectiveness of cytotoxic drugs delivered by intratumoural injection into endobronchial tumours through a bronchoscope for the treatment of non-small cell lung cancer and the diagnosis of occult or obvious cancer cell metastasis to mediastinal lymph nodes.

Key findings

Intratumoural lymphatic treatment may be achieved by injection of cisplatin or other cytotoxic drugs into the malignant tissue located in the lumen of the airways or in the peribronchial structures using a needle catheter through a flexible bronchoscope. This procedure is termed endobronchial intratumoural chemotherapy and its use before systemic chemotherapy and/or radiotherapy or surgery may provide a prophylactic or therapeutic treatment for eradication of micrometastases or occult metastases that migrate to the regional lymph nodes draining the tumour area.

Conclusions

To better elucidate the mode of action of direct injection of cytotoxic drugs into tumours, we review the physiology of lymphatic drainage and sentinel lymph node function. In this light, the potential efficacy of intratumoural chemotherapy for prophylaxis and locoregional therapy of cancer metastasis via the sentinel and regional lymph nodes is indicated. Randomized multicenter clinical studies are needed to evaluate this new and safe procedure designed to improve the condition of non-small cell lung cancer patients and prolong their survival.

Positron-Emission Tomography for Lung Cancer in a Tuberculosis-Endemic Region

A potential limitation of integrated positron-emission tomography and computed tomography in non-small-cell lung cancer may be false-positive results due to granulomatous disease. This retrospective study examined the accuracy of this imaging modality for mediastinal nodal staging of non-small-cell lung cancer in Hong Kong where tuberculosis remains endemic. There were 249 lymph node stations evaluated in 107 patients, of whom 38 (36%) had active tuberculosis or evidence of previous tuberculosis. Imaging results were compared with histological findings. The sensitivity, specificity, and accuracy of integrated imaging for mediastinal nodal staging were 52%, 86%, and 80%, respectively; the overall positive-predictive value for mediastinal nodal metastasis was 46%, and the overall negative-predictive value was 89%. The positive-predictive value for mediastinal nodal metastasis was 39% in patients with tuberculosis and 50% in controls; the negative-predictive value was high in both groups (92% and 87%). The likelihood ratio for true positives was 6.47 in patients with tuberculosis vs. 10.97 in controls. This suggests that the reliability of positron-emission/computed tomography may be substantially poorer in patients with tuberculosis. Histological confirmation should be considered mandatory in patients with suspected metastasis on integrated imaging.

[Comparison between PET(-FDG) and computed tomography in the staging of lung cancer. Consequences for operability in 94 patients]

INTRODUCTION

Lung cancer, a major application of FDG/PET-CT, has recently been introduced in daily practice in France. The authors retrospectively studied its impact on the management of this disease.

METHODS

The results of PET-CT and conventional assessment (brain imaging, chest and abdominal CT and possibly bone scintigraphy) were compared in 94 patients, referred for the staging of non-small cell lung cancer, or the assessment of a solitary lung lesion. The impact of thoracic lymph node involvement on the operability of patients was studied in 44 patients.

RESULTS

PET-CT revealed metastases in 20% of the patients without metastases found by conventional imaging and modified the stage of the disease in 28% of the cases. It changed the indication of surgical treatment in 19% of the cases and led to induction chemotherapy in two patients. In addition, two synchronous cancers were discovered. Regarding lymph node involvement, PET-CT remains of diagnostic value regardless of the scanner results.

CONCLUSION

The impact of PET-CT in assessing non-small cell lung cancer was confirmed in the authors' practice. Its interest and the consequences in some patients misclassified with conventional assessment have been demonstrated.

Point: Clinical stage IA non-small cell lung cancer determined by computed tomography and positron emission tomography is frequently not pathologic IA non-small cell lung cancer: the problem of understaging

OBJECTIVE

There is an increase in interest in limited resection for clinical stage IA non-small cell lung cancer. The purpose of this study was to evaluate the accuracy of the diagnosis of clinical stage IA non-small cell lung cancer when determined by both computed tomography and positron emission tomography scans and to determine factors associated with understaging.

METHODS

A retrospective review of a prospectively maintained database of patients with non-small cell lung cancer was performed. Patients with clinical stage IA cancer determined by preoperative computed tomography and positron emission tomography scan were reviewed. The influence of the following factors was analyzed with regard to accuracy of clinical staging: tumor size, location, histology, and positron emission tomography positivity.

RESULTS

Of the 266 patients identified, cancer was correctly staged in 65%. Final pathologic stages also included IB (15%), IIA (2.6%), IIB (4.1%), IIIA (4.9%), IIIB (7.5%), and IV (.08%). Positive lymph nodes were found in 11.7% of patients. Pathologic T classification changed in 28.2% of patients. Cancer in patients with clinical tumor size greater than 2 cm (n = 68) was significantly more likely to be understaged than in patients with tumors 2 cm or less (49% vs 29%, P = .003). Cancer in patients with a positron emission tomography-positive (positron emission tomography +VE) primary evaluation (n = 218) was also more likely to be understaged (39% vs 15%, P = .001). Of patients with positron emission tomography +VE tumors greater than 2 cm, cancer was clinically understaged in 55%, compared with 32% for positron emission tomography +VE tumors 2 cm or less, and only 17% for positron emission tomography negative (-VE) tumors less than 2 cm.

CONCLUSION

Clinical stage IA lung cancer is frequently understaged in patients. Size greater than 2 cm and positron emission tomography positivity are risk factors for understaging. Limited resection should be undertaken with caution in such patients.

Positron Emission Tomography (PET) radiotracers in oncology--utility of 18F-Fluoro-deoxy-glucose (FDG)-PET in the management of patients with non-small-cell lung cancer (NSCLC)

PET (Positron Emission Tomography) is a nuclear medicine imaging method, frequently used in oncology during the last years. It is a non-invasive technique that provides quantitative in vivo assessment of physiological and biological phenomena. PET has found its application in common practice for the management of various cancers.Lung cancer is the most common cause of death for cancer in western countries.This review focuses on radiotracers used for PET scan with particular attention to Non Small Cell Lung Cancer diagnosis, staging, response to treatment and follow-up.

Evaluation of dual-time-point 18F-FDG PET for staging in patients with lung cancer

(18)F-FDG PET is increasingly used for lung cancer; however, some insufficient results have been reported. The purpose of this study was to evaluate the efficacy of dual-time-point (18)F-FDG PET for staging lung cancer and for differentiating metastatic from nonmetastatic lung cancer lesions.

METHODS

One hundred fifty-five lung cancer patients with known or suspected mediastinal and hilar lymph node involvement or distant metastases underwent whole-body (18)F-FDG PET at 2 time points: scan 1 at 60 min (early imaging) and scan 2 at 180 min (delayed imaging) after (18)F-FDG injection. (18)F-FDG PET findings of nodal and distant metastases were evaluated using conventional imaging, clinical follow-up findings, and the results of autopsy or biopsy.

RESULTS

A total of 580 lesions (155 primary lesions, 315 metastatic lesions, and 110 nonmetastatic lesions) were used for analysis. A closer correlation between the primary lesions and metastases was observed for the retention index (RI) standardized uptake value (SUV) than for early and delayed SUV. There was no relationship between the RI SUV results of primary lesions and those of nonmetastatic lesions. The RI SUV of metastatic lesions was approximately 0.5-2 times the RI SUV of primary tumors. We found that the accuracy of (18)F-FDG PET was improved when RI SUV was used for detecting lymph node and distant metastases, because of the significant improvement in specificity relative to early and delayed SUV.

CONCLUSION

RI SUV raised the accuracy for diagnosis of metastases and was superior to early and delayed imaging in terms of differentiating malignancy from nonmetastatic uptake.

Identifying patients with peripheral-type early non-small cell lung cancer (T1N0M0) for whom irradiation of the primary focus alone could lead to successful treatment

We investigated the indication of radiotherapy in operable patients with peripheral-type early non-small cell lung cancer (T1N0M0 (TNM staging in 1997)). The subjects comprised 396 patients with non-small cell lung cancer in whom the clinical stage was evaluated as IA. We examined age, gender, Brinkmann's index, histopathological type, the grade of histopathological differentiation, tumour diameter and the level of carcinoembryonic antigen as factors involved in lymph node metastasis. Lymph node metastasis was detected in 79 patients (20%). Factors such as the grade of histopathological differentiation and tumour diameter were involved in lymph node metastasis. In well-differentiated lesions, the probability of metastasis was <10% even when the tumour diameter exceeded 2 cm. However, the probability rapidly increased with tumour size in moderately and poorly differentiated lesions. Among the patients with peripheral-type early non-small cell lung cancer (T1N0M0), the risk of lymph node metastasis was low in those with well-differentiated carcinoma and those with moderately differentiated lesions measuring </=1.5 cm in diameter. The proportion of our patients fitting these criteria was approximately 30%. For these patients, stereotactic body radiotherapy and particle therapy may be indicated.

[Imaging and PET/CT of lung cancer]

Lung cancer is one of the most frequently occurring cancer in the world. Imaging plays a critical role for screening, diagnosing, staging, and following patients. Although morphologic imaging such as chest X-ray and CT are still useful for these purpose, major limitations occur in the proper evaluation of diagnosing and staging. Metabolic imaging using PET significantly increases the accuracy of staging. This paper will review the role of imaging in patients suspected or diagnosed with lung cancer.

Restaging of mediastinal nodes with transbronchial needle aspiration after induction chemoradiation for locally advanced non-small cell lung cancer

INTRODUCTION

Selecting the appropriate treatment strategy for patients with locally advanced non-small cell carcinoma (NSCLC) is of utmost importance to determine patient outcome. Previous studies have shown that nodal down-staging after induction therapy and definitive local irradiation in these patients better predict survival when combined with surgery. However, nodal restaging can be technically difficult. We investigated the role of transbronchial needle aspiration (TBNA) in mediastinal restaging of patients who had completed induction cytotoxic therapy.

METHODS

A total of 14 patients with proven stage IIIa-N2 NSCLC who received chemotherapy or chemo-radiotherapy as induction regimen between 2005 and 2006 were studied. Outpatient flexible bronchoscopy with TBNA was performed in all patients under local anesthesia, and 17 TBNA procedures were performed. TBNA results were matched against the histopathology of surgical specimens.

RESULTS

Seventeen lymph nodes in 14 patients who had undergone induction therapy were sampled. Positron emission tomography (PET) scan results of 11 patients were also available for comparison. All positive TBNA procedures had positive PET scans. However, for five patients with lymph nodes measuring 9 to 17 mm, the PET scans were falsely positive, as mediastinoscopy and subsequent surgically resected lymph nodes revealed no tumor. TBNA achieved a correct diagnosis in 71% of patients who underwent mediastinal restaging and obviated further need for invasive procedures in 35%.

CONCLUSION

For patients presenting with locally advanced NSCLC who are surgical candidates after induction chemo- and/or radiotherapy, TBNA should be considered as the initial procedure of choice for restaging of the mediastinum.

Noninvasive staging of non-small cell lung cancer: ACCP evidenced-based clinical practice guidelines (2nd edition)

BACKGROUND

Correctly staging lung cancer is important because the treatment options and the prognosis differ significantly by stage. Several noninvasive imaging studies including chest CT scanning and positron emission tomography (PET) scanning are available. Understanding the test characteristics of these noninvasive staging studies is critical to decision making.

METHODS

Test characteristics for the noninvasive staging studies were updated from the first iteration of the lung cancer guidelines using systematic searches of the MEDLINE, HealthStar, and Cochrane Library databases up to May 2006, including selected metaanalyses, practice guidelines, and reviews. Study designs and results are summarized in evidence tables.

RESULTS

The pooled sensitivity and specificity of CT scanning for identifying mediastinal lymph node metastasis were 51% (95% confidence interval [CI], 47 to 54%) and 85% (95% CI, 84 to 88%), respectively, confirming that CT scanning has limited ability either to rule in or exclude mediastinal metastasis. For PET scanning, the pooled estimates of sensitivity and specificity for identifying mediastinal metastasis were 74% (95% CI, 69 to 79%) and 85% (95% CI, 82 to 88%), respectively. These findings demonstrate that PET scanning is more accurate than CT scanning. If the clinical evaluation in search of metastatic disease is negative, the likelihood of finding metastasis is low.

CONCLUSIONS

CT scanning of the chest is useful in providing anatomic detail, but the accuracy of chest CT scanning in differentiating benign from malignant lymph nodes in the mediastinum is poor. PET scanning has much better sensitivity and specificity than chest CT scanning for staging lung cancer in the mediastinum, and distant metastatic disease can be detected by PET scanning. With either test, abnormal findings must be confirmed by tissue biopsy to ensure accurate staging.

Factors involved in lymph node metastasis in clinical stage I non-small cell lung cancer—From studies of 604 surgical cases

PURPOSE

To identify the factors involved in lymph node metastasis, 604 clinical stage I non-small cell lung cancer cases were studied.

MATERIALS AND METHODS

Age, sex, Brinkmann Index (BI), histopathological type, histopathological differentiation degree, tumor size and CEA value were studied as factors involved in lymph node metastasis for 604 cases that were diagnosed to be clinical stage I (T1-T2N0M0; 1997 TNM categorization) non-small cell lung cancer.

RESULTS

Lymph node metastasis was observed in 161 cases (27%). The factors involved in lymph node metastasis included the degree of histopathological differentiation and the tumor size. While the metastasis rate was less than 10% in well-differentiated cancers (even when the tumor size exceeded 4cm), in moderately differentiated and poorly differentiated cancers, the lymph node metastasis rate increased in proportion to tumor size.

CONCLUSION

In stage I non-small cell lung cancer cases, cases with a low probability of lymph node metastasis are well-differentiated cancers. In these cases, lymph node dissection may be omitted in surgery (reduction surgery), and such cases may thus be good subjects for undergoing either stereotactic body radiotherapy (SBRT) or particle therapy.

The Additional Value of FDG PET Imaging for Distinguishing N0 or N1 From N2 Stage in Preoperative Staging of Non-small Cell Lung Cancer in Region Where the Prevalence of Inflammatory Lung Disease Is High

PURPOSE

The aim of this study was to evaluate the efficacy of PET imaging and compare it with the performance of CT in mediastinal and hilar lymph node staging in potentially operable non-small cell lung cancer (NSCLC).

METHODS

Fifty-nine patients with potentially resectable NSCLC who underwent preoperative PET and CT imaging were enrolled into this prospective study. All patients underwent surgical evaluation by means of mediastinoscopy with mediastinal lymph node sampling (14 patients) or thoracotomy (45 patients).

RESULTS

The prevalence of lymph node metastases was 53%. Overall, the sensitivity, specificity, accuracy, PPV, and NPV of PET were 79%, 76%, 78%, 86%, and 76% for N0 and N1 lymph nodes and 76%, 79%, 80%, 67%, and 83% for N2 lymph nodes, while those values for CT were 66%, 43%, 58%, 68%, and 43% for N0 and N1 stations and 43%, 66%, 54%, 41%, and 66% for N2 lymph nodes, respectively. PET correctly differentiated cases with mediastinal lymph node involvement (N2) from those without such involvement (N0 or N1) in 76% of cases. Statistical analysis of the diagnostic accuracy of nodal involvement showed that PET improves diagnostic accuracy significantly in the detection of both N0 or N1 and N2 status in the individual patient based on analysis, compared with CT (P < 0.01 and P < 0.01, respectively). When preoperative nodal staging was compared with postoperative histopathological staging, 38 (65%) patients were correctly staged, 9 (15%) were overstaged, and 12 (20%) were understaged by PET, while 29 patients (49%) were correctly staged, 13 (22%) were overstaged, and 17 (29%) were understaged by CT.

CONCLUSION

It has been clearly shown that PET is more accurate than CT for the differentiation of N0 or N1 from N2 disease in patients with NSCLC. However, PET imaging alone does not appear to be sufficient to replace mediastinoscopy for mediastinal staging in patients with lung cancer, especially in geographic regions with high granulomatous or inflammatory mediastinal disease prevalence.

Risk factors for occult mediastinal metastases in clinical stage I non-small cell lung cancer

BACKGROUND

In patients deemed to have clinical stage I for non-small cell lung cancer (NSCLC) after computerized tomography (CT) and positron emission tomography (PET) scans, the utility of mediastinoscopy to detect occult mediastinal metastases is unclear. The goal of this study was to analyze the risk factors for occult mediastinal metastases in this subset of patients.

METHODS

We conducted a retrospective review during a 7-year period to identify patients with potentially operable clinical stage I NSCLC screened by CT and PET scans. Medical records were reviewed, and the prevalence of pathologic N2 disease was analyzed according to clinical tumor location, size, histology, and PET uptake of the primary tumor.

RESULTS

Of 224 patients identified with clinical stage I NSCLC with a CT-negative and PET-negative mediastinum, 16 patients had pathologic N2 disease proven by mediastinoscopy (n = 11) or after resection (n = 5). The overall prevalence of histologically confirmed N2 disease was 6.5% in clinical T1 patients and 8.7% in clinical T2 patients. Central tumors had a higher prevalence of N2 disease compared with peripheral tumors, 21.6% versus 2.9% (p < 0.001). Larger clinical T size predicted a higher prevalence of occult N2 disease (p < 0.001). All 16 patients with occult N2 metastases had adenocarcinoma as the primary tumor cell type. When the PET maximum standardized uptake value (SUV(max)) of the primary tumors was analyzed, patients with occult N2 metastases had a higher median SUV(max) of the primary tumor compared with patients without N2 metastases, 6.0 g/mL versus 3.6 g/mL (p = 0.017).

CONCLUSIONS

For patients deemed at clinical stage I NSCLC by CT and PET, the prevalence of missed N2 metastases increased significantly with larger tumor size and central location. Adenocarcinoma cell type and a high PET SUV(max) of the primary tumor were other risk factors. Mediastinoscopy may have improved yield in the select subset of patients with one or more risk factor.

Lung cancer: New surgical approaches

Over the past two decades, many surgical specialties have seen a dramatic shift from large, open operations with wide incisions towards more-minimal incisions and less-invasive procedures. Surgical techniques for lung cancer are no exception, and today, video-assisted thoracic surgical lobectomies are being performed with increasing frequency in large-volume thoracic practices. Despite these new surgical techniques, however, the most substantial innovations that have changed surgical outcomes occurred away from the operative theatre. In lung cancer, in particular, the last 20 years have witnessed the clinical debut of more sophisticated, more elegant and more accurate imaging modalities for improved screening, diagnostic and staging, such as the spiral CT scan, PET scan, PET/CT and the endobronchial ultrasound machine. This technology has been complimented by more targeted chemotherapeutic regimens, novel methods of administering more accurate and more concentrated doses of radiation therapy, and innovative local excisional methods, such as the Cyberknife and radiofrequency ablation. The result has been that surgical excision, although remaining the most effective local therapeutic modality in early-stage lung cancer, is no longer the 'lone ranger' treatment, but rather is part of a complex mosaic of multimodality therapy. As scientific advances continue to be translated into the clinic, this trend will inexorably continue with the advent of a molecular staging system using molecular markers and tumour profiling, which ultimately could enhance our ability to predict tumour chemosensitivity. In this brave new world, however, complete surgical resection of the lung cancer will continue to be critical.

Is PET-based treatment planning the new standard in modern radiotherapy? The head and neck paradigm

The use of positron-emission tomography (PET) in the treatment planning process has become more and more popular over the years, although important questions such as how, when, and for which clinical benefit have never been answered. In this framework, the objective of this article is to review the evidence supporting the use of PET in radiotherapy treatment planning, with special emphasis on its application for head and neck tumors. The use of positron-labeled fluorodeoxyglucose for target volume selection should be discussed in terms of sensitivity and specificity in comparison with typical anatomic imaging modalities. It will not be of similar utility across all tumor sites. The use of PET for target volume delineation requires specific tuning of parameters such as image acquisition, processing, and segmentation, and this may vary from one tumor site to another. Molecular imaging with other tracers and "theragnostic" are in the pipeline, but how much the patient will gain from it and how these advances should be implemented in routine clinical practice are unresolved questions. Therefore, although integration of PET images into the radiotherapy process seems promising, for the moment it should remain in the research arena.

La tomographie par émission de positons au 18fluorodésoxyglucose (18FDG-TEP) dans la prise en charge du cancer bronchique non à petites cellules en 2006

Technological progress and numerous published studies allow to estimate the best place of the 18F-fluorodeoxyglucose positron emission tomography, a real functional metabolic imagery, in the clinical and therapeutic strategy of non small cell lung cancers.

Clinical implications of defining the gross tumor volume with combination of CT and 18FDG-positron emission tomography in non-small-cell lung cancer

PURPOSE

To compare the planning target volume (PTV) definitions for computed tomography (CT) vs. positron emission tomography (PET) in non-small-cell lung cancer (NSCLC).

METHODS AND MATERIALS

A total of 21 patients with NSCLC underwent three-dimensional conformal radiotherapy planning. All underwent a staging F-18 fluorodeoxyglucose-position emission tomography (18FDG-PET) scan and underwent treatment simulation using CT plus a separate planning 18FDG-PET scan. Three sets of target volumes were defined: Set 1, CT volumes (CT tumor + staging PET nodal disease); Set 2, PET volumes (planning PET tumor {gross tumor volume (GTV) = [(0.3069 x mean standardized uptake value) + 0.5853])}; Set 3, composite CT-PET volumes (fused CT-PET tumor). Sets 1 and 2 were compared using a matching index. Three-dimensional conformal radiotherapy plans were created using the Set 1 (CT) volumes; and coverage of the Set 3 (composite) volumes was evaluated. Separate three-dimensional conformal radiotherapy plans were designed for the Set 3 volumes.

RESULTS

For the primary tumor GTV, the Set 1 (CT) volume was larger than the Set 2 (PET) volume in 48%, smaller in 33%, and equal in 19%. The mean matching index was 0.65 (35% CT-PET mismatch). Although quantitatively similar, the volumes differed qualitatively. The Set 3 (composite) volume was larger than either CT or PET alone in 62%, smaller in 24%, and equal in 14%. The dose-volume histogram parameters did not differ among the plans for Set 1 (CT) vs. Set 3 (composite) volumes. Small portions of the Set 3 PTV were significantly underdosed in 40% of cases using the CT-only plan.

CONCLUSION

Computed tomography and PET are complementary and should be obtained in the treatment position and fused to define the GTV for NSCLC. Although the quantitative absolute target volume is sometimes similar, the qualitative target locations can be substantially different, leading to underdosage of the target when planning is done using CT alone without PET fusion.

The Future in Diagnosis and Staging of Lung Cancer

Surgical techniques remain central to the diagnosis and staging of lung cancer. Clinical situations which invoke the role of surgery include the diagnosis of solitary pulmonary masses, staging of the mediastinum, restaging of the mediastinum and the assessment of resectability. The techniques available include cervical mediastinoscopy, anterior mediastinotomy, video-assisted thoracoscopy and different procedures for intra-operative mediastinal lymph node assessment including systematic nodal dissection, lobe-specific nodal dissection and sentinel node mapping. The staging of lung cancer is continuously evolving as technological advances combine with clinical advances to better stratify patients into treatment and prognostic categories and alter pre-operative investigation algorithms. Although most of the surgical techniques have been around for many years, it is their application in future which is likely to change. The increasing use of positron emission tomography/computed tomography fusion imaging is raising the proportion of patients being shown to have additional lesions that could contraindicate surgical treatment but which require tissue confirmation to exclude a false-positive examination. Many such lesions are amenable to the expanding techniques available to the interventional endoscopist. The relationship between the surgeon and the endoscopist must become closer to ensure that the appropriate technique is used at each point in the patient's pathway. The future of surgical techniques will be driven by: (1) developments in screening and imaging, with a likelihood that more early stage cancers will present and may be amenable to minimally invasive surgical approaches with the possibility of a role for robotics and nanotechnology; (2) improvements in neoadjuvant therapies which will demand flawless mediastinal staging and restaging; (3) advances in molecular biology which, whilst currently requiring that surgery provide samples of tumour and lymph node tissue to fully characterize the disease, do hold the promise that ever smaller amounts of tissue will be required and that eventually the genetic fingerprint will provide a biological ultrastaging to perhaps supersede anatomical staging.

[PET in primary pulmonary or pleural cancer]

In our hospital as in many others, primary lung cancer is the most frequent indication for FDG PET. Studies have assessed the clinical utility of this imaging modality in characterizing solitary pulmonary nodules or masses, initial staging, defining tumor volume in radiotherapy and searching for recurrence of or restaging non-small cell carcinoma; studies are currently underway to evaluate its use in early assessment of chemotherapy response. Small cell lung cancer has a high FDG uptake and PET/CT can be useful for rapid staging. False negative results may be due to pure bronchioloalveolar carcinomas and endocrine tumors. FDG-PET will certainly play a more important role in the diagnosis and follow-up of pleural cancers in the future. An unexpected positive FDG PET focus should be considered as a warning, but histological proof should precede any irrevocable decisions.