Positron emission tomography scanning with 2-fluoro-2-deoxy-d-glucose as a predictor of response of neoadjuvant treatment for non-small cell carcinoma

Patient Selection of Sublobar Resection Using Visual Evaluation of Positron-Emission Tomography (PET) for Early-Stage Lung Adenocarcinoma

BACKGROUND

This study aimed to investigate the efficacy of the Deauville criteria (a 5-point visual scale criteria) in assessing the accumulation of [18F]-fluoro-2-deoxy-D-glucose (FDG) on positron-emission tomography (PET)/computed tomography (CT) for predicting prognosis of early-stage lung adenocarcinoma and selecting candidates for sublobar resection.

METHODS

This retrospective study included 648 patients undergoing curative resection for clinical N0 lung adenocarcinoma with a whole tumor size of 3 cm or smaller between April 2007 and March 2019. Accumulations of the FDG on PET/CT scans were scored using the Deauville criteria (Deauville score), and correlations between the Deauville score and prognosis were analyzed.

RESULTS

The recurrence-free survival (RFS) was significantly better for the patients with a Deauville score of 1 or 2 (n = 415, 5-year RFS, 92.6%) than for those with a score of 3 (n = 82, 5-year RFS, 72.7%; P < 0.001) or a score of 4 or 5 (n = 151, RFS, 70.8%; P < 0.001). The RFS did not differ significantly among the patients with Deauville scores of 1 and 2 who underwent wedge resection (n = 102, 5-year RFS, 90.5%), segmentectomy (n = 188, RFS, 95.1%; P = 0.355), and lobectomy (n = 125, RFS, 91.1%; P = 0.462).

CONCLUSION

The 5-point-scale evaluation of FDG accumulation on PET/CT was useful in predicting the prognosis for patients with early-stage lung adenocarcinoma. Lung adenocarcinoma patients with a whole tumor size of 3 cm or smaller and a Deauville score of 1 or 2 can be candidates for sublobar resection.

Enhanced prognostic stratification of neoadjuvant treated lung squamous cell carcinoma by computationally-guided tumor regression scoring

INTRODUCTION

The amount of residual tumor burden after neoadjuvant chemotherapy is an important prognosticator, but for non-small cell lung carcinoma (NSCLC), no official regression scoring system is yet established. Computationally derived histological regression scores could provide unbiased and quantitative readouts to complement the clinical assessment of treatment response.

METHODS

Histopathologic tumor regression was microscopically assessed on whole cases in a neoadjuvant chemotherapy-treated cohort (NAC, n = 55 patients) of lung squamous cell carcinomas (LSCC). For each patient, the slide showing the least pathologic regression was selected for subsequent computational analysis and histological features were quantified: percentage of vital tumor cells (cTu.Percentage), total surface covered by vital tumor cells (cTu.Area), area of the largest vital tumor fragment (cTu.Size.max), and total number of vital tumor fragments (cTu.Fragments). A chemo-naïve LSCC cohort (CN, n = 104) was used for reference. For 23 of the 55 patients [¹⁸F]-Fluorodeoxyglucose (FDG) PET/CT measurements of maximum standard uptake value (SUV_max), background subtracted lesion activity (BSL) and background subtracted volume (BSV) were correlated with pathologic regression. Survival analysis was carried out using Cox regression and receiver operating characteristic (ROC) curve analysis using a 3-years cutoff.

RESULTS

All computational regression parameters significantly correlated with relative changes of BSV FDG PET/CT values after neoadjuvant chemotherapy. ROC curve analysis of histological parameters of NAC patients showed that cTu.Percentage was the most accurate prognosticator of overall survival (ROC curve AUC = 0.77, p-value = 0.001, Cox regression HR = 3.6, p = 0.001, variable cutoff < = 30 %).

CONCLUSIONS

This study demonstrates the prognostic relevance of computer-derived histopathologic scores. Additionally, the analysis carried out on slides displaying the least pathologic regression correlated with overall pathologic response and PET/CT values. This might improve the objective histopathologic assessment of tumor response in neoadjuvant setting.

ICORG 06-35: a prospective evaluation of PET-CT scan in patients with non-operable or non-resectable non-small cell lung cancer treated by radical 3-dimensional conformal radiation therapy: a phase II study

BACKGROUND

Radiotherapy (RT) is a key treatment modality in the curative treatment of patients with non-small cell lung cancer (NSCLC). Incorrect definition of the gross, or clinical, target volume is a common source of error which can lead to a reduced probability of tumour control.

OBJECTIVE

This was a pilot and a phase II study. The pilot evaluated the technical feasibility of integrating positron emission tomography-computed tomography (PET-CT) fusion. The primary outcome of the phase II study was to evaluate the safety of PET-CT scan-based RT by evaluating the rate of loco-regional recurrence outside the PET-CT planning target volume (PTV) but within conventional 3-D PTV.

METHODS

Patients underwent standard post-treatment follow-up, including repeated three monthly CT scans of the thorax. In case of loco-regional recurrence, three categories were considered, with only extra-PET scan PTV and intra-CT scan PTV recurrences considered as a failure. Our hypothesis was that the rate of these events would be < 10%.

RESULTS

Twelve patients were recruited; the study closed early due to poor recruitment. The primary endpoint of the pilot was met; it was feasible to deliver a PET-CT-based plan to ≥ 60% of patients. Two patients had intra-PET scan PTV recurrences, six had extra-PET scan PTV and extra-CT, and three patients had both. Another patient had extra-PET scan PTV and extra-CT as well as extra-PET scan PTV and intra-CT scan PTV recurrence.

CONCLUSION/ADVANCES IN KNOWLEDGE

PET-based planning has the potential to reduce radiation treatment volumes because of the avoidance of mediastinal lymph nodes that are PET negative.

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.

Role of positron emission tomography-computed tomography in non-small cell lung cancer

Lung cancer is the leading cause of cancer-related mortality worldwide. Non-small cell carcinoma and small cell carcinoma are the main histological subtypes and constitutes around 85% and 15% of all lung cancer respectively. Multimodality treatment plays a key role in the successful management of lung cancer depending upon the histological subtype, stage of disease, and performance status. Imaging modalities play an important role in the diagnosis and accurate staging of the disease, in assessing the response to neoadjuvant therapy, and in the follow-up of the patients. Last decade has witnessed voluminous upsurge in the use of positron emission tomography-computed tomography (PET-CT); role of PET-CT has widened exponentially in the management of lung cancer. The present article reviews the role of 18-fluoro-deoxyglucose PET-CT in the management of non small cell lung cancer with emphasis on staging of the disease and the assessment of response to neoadjuvant therapy based on available literature.

Early assessment of metabolic response by 18F-FDG PET during concomitant radiochemotherapy of non-small cell lung carcinoma is associated with survival: a retrospective single-center study

BACKGROUND AND PURPOSE

We performed a retrospective single-center study to assess if midtreatment 18F-FDG PET/CT could predict local control and survival in patients with locally advanced non-small cell lung cancer treated with concurrent chemoradiotherapy.

METHODS

Thirty-one consecutive patients with unresectable or locally advanced lung cancer (T2-4 N0-3 M0) were treated with concurrent chemoradiotherapy in our center. Each patient received 18F-FDG PET/CT before treatment and at midtreatment time when a radiation therapy dose of 30 Gy was delivered. We assessed several PET/CT parameters as follows: SUV max, ΔSUV mean, ΔSUV max, variation of hypermetabolic tumor volume, and the variation of tumor total lesion glycolysis (ΔTLG). Univariate analysis was performed, and a stepwise procedure was used to define final multivariate model.

RESULTS

The ΔTLG was statistically correlated to overall survival (OS) (P = 0.035), progression-free survival (P = 0.023), and local control (P = 0.043) in univariate analysis. A decrease in TLG over 15% was statistically correlated to a better OS (P = 0.007; hazards ratio [HR], 7.439; 95% confidence interval [CI], 1.168-28.897) and progression-free survival (P = 0.010; HR, 5.695; 95% CI, 1.506-21.537) in univariate analysis. In multivariate analysis, ΔTLG superior to -15% was significantly correlated to a worse OS (P = 0.020; HR, 5.973; 95% CI, 1.324-26.953).

CONCLUSIONS

Early assessment of TLG response by 18F-FDG PET/CT during concomitant radiochemotherapy of non-small cell lung cancer might be associated with survival.

Staging of lung cancer: the role of noninvasive, minimally invasive and invasive techniques

Accurate staging and restaging of primary tumour and mediastinal nodes in patients with lung cancer is of significant importance. For primary tumours, computed tomography (CT) scans of the chest are recommended. Positron emission tomography (PET) imaging should be used in patients with curative intent treatment to evaluate metastatic disease. Diagnosis of the primary tumour should be performed using bronchoscopy or CT-guided transthoracic needle aspiration. In patients with enlarged mediastinal nodes and no distant metastasis, invasive staging of the mediastinum is required. For suspicious N2 or N3 disease, endoscopic needle techniques, such as endobronchial ultrasound and transbronchial needle aspiration, oesophageal ultrasound and fine needle aspiration, or a combination of both, are preferred to any surgical staging technique. In cases of suspicious nodes and negative results using needle aspiration techniques, invasive surgical staging using mediastinoscopy or video-assisted thoracic surgery should be performed. In central tumours or N1 nodes, preoperative invasive staging is indicated.Restaging after induction therapy remains a controversial topic. Today, neither CT, PET nor PET/CT scans are accurate enough to make final further therapeutic decisions for mediastinal nodal involvement. An invasive technique providing cytohistological information is still recommended.

18F-FDG-PET evaluation of pathological tumour response to neoadjuvant therapy in patients with NSCLC

OBJECTIVES

The ability to identify potential responders to neoadjuvant treatment may improve patient selection or surgery and may help in the development of response criteria suitable for routine monitoring of response. The aim of this study was to evaluate the value of PET in predicting the pathological tumour response of non-small-cell lung cancer (NSCLC) to neoadjuvant therapy using a meta-analysis.

METHODS

All available published studies investigating the value of PET in predicting the pathological response of NSCLC to neoadjuvant therapy were collected. Pooled sensitivity and specificity data were obtained using statistical software. Subgroup analysis was performed to explore the sources of heterogeneity.

RESULTS

A total of 13 studies comprising 414 patients with NSCLC were included in the meta-analysis. Pooled sensitivity, specificity, positive predictive value and negative predictive value for PET-predicted response was 83% [95% confidence interval (CI); 76-89%], 84% (95% CI; 79-88%), 74% (95% CI; 67-81%) and 91% (95% CI; 87-94%), respectively. Significant heterogeneity (P<0.05) was observed. On the basis of our subgroup analyses, methodological quality could be responsible for this heterogeneity in our metaregression. The predictive value of PET in NSCLC patients with pathological response (considered the gold standard) was significantly higher than that of computed tomography (P<0.05).

CONCLUSION

PET scanning has an important role in predicting nonresponders to neoadjuvant therapy in cases of NSCLC, and the predictive value of PET for evaluating pathologically documented responses is superior to that of computed tomography. However, additional evaluations using prospective clinical trials will be required to assess the clinical benefit of this strategy.

Prospective phase II trial of preresection thoracoscopic mediastinal restaging after neoadjuvant therapy for IIIA (N2) non-small cell lung cancer: results of CALGB Protocol 39803

OBJECTIVE

Accurate pathologic restaging of N2 stations after neoadjuvant therapy in stage IIIA (N2) non-small cell lung cancer is needed.

METHODS

A prospective multi-institutional trial was designed to judge the feasibility of videothoracoscopy to restage the ipsilateral nodes in mediastinoscopy-proven stage IIIA (N2) non-small cell lung cancer after 2 cycles of platinum-based chemotherapy and/or 40 Gy or more of radiotherapy. The goals included biopsy of 3 negative N2 node stations or to identify 1 positive N2 node or pleural carcinomatosis.

RESULTS

Ten institutions accrued 68 subjects. Of the 68 subjects, 46 (68%) underwent radiotherapy and 66 (97%) underwent chemotherapy. Videothoracoscopy successfully met the prestudy feasibility in 27 patients (40%): 3 negative stations confirmed at thoracotomy in 7, persistent stage N2 disease in 16, and pleural carcinomatosis in 4. In 20 procedures (29%), no N2 disease was found, 3 stations were not biopsied because of unanticipated nodal obliteration. Thus, 47 videothoracoscopy procedures (69%, 95% confidence interval, 57%-80%) restaged the mediastinum. Videothoracoscopy was unsuccessful in 21 patients (31%) because the procedure had to be aborted (n = 11) or because of false-negative stations (n = 10). Of the 21 failures, 15 were right-sided, and 10 had a positive 4R node. The sensitivity of videothoracoscopy was 67% (95% confidence interval, 47%-83%), and the negative predictive value was 73% (95% confidence interval, 56%-86%) if patients with obliterated nodal tissue were included. The sensitivity was 83% (95% confidence interval, 63%-95%) and the negative predictive value was 64% (95% confidence interval, 31%-89%) if those patients were excluded. The specificity was 100%. One death occurred after thoracotomy.

CONCLUSIONS

Videothoracoscopy restaging was "feasible" in this prospective multi-institutional trial and provided pathologic specimens of the ipsilateral nodes. Videothoracoscopy restaging was limited by radiation and the 4R nodal station.

Performance of integrated positron emission tomography/computed tomography for mediastinal nodal staging in non-small cell lung carcinoma

Integrated positron emission tomography (PET)/CT is routinely used for mediastinal nodal staging of non-small cell lung carcinoma in centers throughout the world. This modality is the most accurate noninvasive means by which to identify metastatic disease in mediastinal lymph nodes. This article reviews the evidence supporting the use of PET/CT and discusses the clinical applicability of this modality.

Restaging after induction therapy for non-small-cell lung cancer

SUMMARY Select patients with stage IIIa-N2 non-small-cell lung cancer will benefit from treatment with induction chemoradiotherapy followed by surgical resection. The identification of patients with residual N2 disease may allow for selection of those patients most likely to benefit from resection. The optimal strategy for restaging of mediastinal lymph nodes following induction therapy is controversial. Noninvasive, imaging-based strategies are largely ineffective. Minimally invasive approaches such as endobronchial ultrasound-transbronchial needle aspiration and endoscopic ultrasound-guided fine needle aspiration may identify residual nodal disease, but require surgical confirmation of negative results. Repeat mediastinoscopy may be effective at centers that specialize in this technique, but in the authors opinion its use cannot be broadly recommended. A thoughtful and minimally invasive approach to initial staging of N2 nodes is recommended, reserving mediastinoscopy for restaging whenever possible.

¹⁸F-FDG PET-CT during chemo-radiotherapy in patients with non-small cell lung cancer: the early metabolic response correlates with the delivered radiation dose

Background

To evaluate the metabolic changes on ¹⁸ F-fluoro-2-deoxyglucose positron emission tomography integrated with computed tomography (¹⁸ F-FDG PET-CT) performed before, during and after concurrent chemo-radiotherapy in patients with locally advanced non-small cell lung cancer (NSCLC); to correlate the metabolic response with the delivered radiation dose and with the clinical outcome.

Methods

Twenty-five NSCLC patients candidates for concurrent chemo-radiotherapy underwent ¹⁸ F-FDG PET-CT before treatment (pre-RT PET-CT), during the third week (during-RT PET-CT) of chemo-radiotherapy, and 4 weeks from the end of chemo-radiotherapy (post-RT PET-CT). The parameters evaluated were: the maximum standardized uptake value (SUVmax) of the primary tumor, the SUVmax of the lymph nodes, and the Metabolic Tumor Volume (MTV).

Results

SUVmax of the tumor and MTV significantly (p=0.0001, p=0.002, respectively) decreased earlier during the third week of chemo-radiotherapy, with a further reduction 4 weeks from the end of treatment (p<0.0000, p<0.0002, respectively). SUVmax of lymph nodes showed a trend towards a reduction during chemo-radiotherapy (p=0.06) and decreased significantly (p=0.0006) at the end of treatment. There was a significant correlation (r=0.53, p=0.001) between SUVmax of the tumor measured at during-RT PET-CT and the total dose of radiotherapy reached at the moment of the scan. Disease progression free survival was significantly (p=0.01) longer in patients with complete metabolic response measured at post-RT PET-CT.

Conclusions

In patients with locally advanced NSCLC, ¹⁸ F-FDG PET-CT performed during and after treatment allows early metabolic modifications to be detected, and for this SUVmax is the more sensitive parameter. Further studies are needed to investigate the correlation between the metabolic modifications during therapy and the clinical outcome in order to optimize the therapeutic strategy. Since the metabolic activity during chemo-radiotherapy correlates with the cumulative dose of fractionated radiotherapy delivered at the moment of the scan, special attention should be paid to methodological aspects, such as the radiation dose reached at the time of PET.

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

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

Significance of a new fluorodeoxyglucose-positive lesion on restaging positron emission tomography/computed tomography after induction therapy for non-small-cell lung cancer

OBJECTIVES

Restaging of patients with locally advanced non-small-cell lung cancer (NSCLC) is of paramount importance, since only patients with down-staging after induction therapy will benefit from surgery. In this study, we assessed the aetiology of new (18)fluoro-2-deoxy-d-glucose (FDG)-positive focal abnormalities on restaging positron emission tomography/computed tomography (PET/CT) in patients with a good response after induction chemotherapy in the primary tumour and lymph nodes.

METHODS

Between 2004 and 2008, 31 patients with histological proven stage III NSCLC had a PET/CT prior and after induction chemotherapy. Their medical charts were retrospectively reviewed.

RESULTS

Restaging PET/CT revealed a new FDG-positive lesion in 6 of 31 (20%) patients. The initial clinical stage of the disease was IIIA N2 in four and IIIB T4 in two patients. The maximal standard uptake value in the primary tumour (P = 0.043) and in the initially involved mediastinal nodes (P = 0.068) decreased after induction treatment in all patients. The new PET/CT findings were located in an ipsilateral cervical lymph node in two patients, a contralateral mediastinal in one patient and an ipsilateral mammary internal lymph node in one patient. Two other patients had a lesion on the contralateral lung. Malignant lymph node infiltrations were excluded following fine-needle puncture, intraoperative biopsy or follow-up PET/CT. Contralateral pulmonary lesions were diagnosed as benign following mini thoracotomy and pulmonary wedge resection.

CONCLUSIONS

New solitary FDG-positive lesions on restaging PET/CT after induction chemotherapy for NSCLC are not rare in good responders to chemotherapy. In our experience, all these lesions were not associated with malignancy.

A phase II study of ¹⁸F-fluorodeoxyglucose PET-CT in non-small cell lung cancer patients receiving erlotinib (Tarceva); objective and symptomatic responses at 6 and 12 weeks

BACKGROUND

The aim of this study was to assess if (18)F-fluorodeoxyglucose (FDG) Positron Emission Tomography (PET)-CT scanning could minimise the time non-responding patients were exposed to erlotinib (Tarceva).

METHODS

Patients were selected for clinical factors that would predict response to erlotinib. A FDG PET-CT and diagnostic contrast-enhanced (traditional) CT scan were carried out at baseline, and then a FDG PET-CT at 6 weeks and a traditional CT at 12 weeks were repeated. The primary end-point was rate of early progression in patients after 6 weeks, of which a minimum 12 out of 35 were required to make the study worthwhile. The responses at 6 (PET-CT) and 12 weeks (traditional CT) were compared and correlated with symptomatic response at both these time points.

RESULTS

Forty seven patients were recruited with 38 and 33 patients assessable by FDG PET-CT at 6 weeks and traditional CT at 12weeks, respectively. There was good correlation between Partial response (PR) at both time points and all 10 patients who had a PR at 12 weeks had a PR at 6 weeks. Of the 13 patients with progressive disease (PD) at 12 weeks, seven had PD at 6 weeks and could have had their treatment stopped early. No evaluable patient with stable disease (SD) (8/38) or PD (9/38) on FDG PET-CT at 6 weeks went on to have a later response. Symptomatic response at 6 or 12 weeks did not correlate well with objective response on scanning at either time point.

CONCLUSIONS

The primary end-point of this study was met as >12 (15/38) patients could have stopped treatment early on the basis of the FDG PET-CT scan result. A FDG PET-CT evaluable response of SD or PD at 6 weeks does predict future lack of response. No correlation was found between response and symptomatic response at either 6 or 12 weeks.

Is FDG-PET suitable for evaluating neoadjuvant therapy in non-small cell lung cancer? Evidence with systematic review of the literature

BACKGROUND

Neoadjuvant therapy response assessment is crucial in patients with non-small cell lung cancer (NSCLC). FDG-PET has emerged as a valuable tool for defining therapy response assessment in other tumours.

AIM

To systematically review publications appearing in the literature describing induction therapy response assessment with FDG-PET in NSCLC.

METHODS

We performed a bibliographic search and selected only prospective studies in order to include the highest levels of evidence.

RESULTS

Nine of 497 potentially relevant publications were selected. The ranges of sensitivity, specificity, positive predictive value and negative predictive value for primary tumour response assessment were 80-100%, 0-100%, 42.9-100%, and 66.7-100%, respectively. Pooling data for N2 restaging after neoadjuvant response the overall sensitivity was 63.8% (95% CI, 53.3-73.7%) and overall specificity was 85.3% (95% CI, 80.4-89.4%).

CONCLUSION

The results of the analysis do not support the use of FDG-PET as the only re-assessment tool for mediastinal lymph node evaluation for routine clinical use. FDG-PET seems to predict primary tumour response to induction therapy but it could not be shown by pooling analysis.

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.

Impact of fluorodeoxyglucose PET on the management of esophageal cancer

Esophageal cancer is the third most common malignancy of the alimentary tract. The incidence of esophageal cancer has steadily increased over the past three decades. Almost all therapeutic modalities for esophageal cancer are associated with a considerable mortality and morbidity. Consequently, there has been growing concern regarding effective management of esophageal cancer. 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) is playing an increasing role in the management of esophageal cancer, offering potential advantages in the accuracy of disease assessment at a number of decision points in the management pathway. This review evaluates the critical role of FDG-PET in (i) diagnosis, (ii) preoperative staging, (iii) monitoring of response to neoadjuvant therapy, (iv) assessment of recurrence and (v) prediction of prognosis of esophageal cancer. We have also compared diagnostic performance of FDG-PET and other current technologies such as computed tomography scan and endoscopic ultrasonography based on available evidence.

Endobronchial ultrasound with transbronchial needle aspiration for restaging the mediastinum in lung cancer

PURPOSE

To investigate the sensitivity and accuracy of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) for restaging the mediastinum after induction chemotherapy in patients with non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

One hundred twenty-four consecutive patients with tissue-proven stage IIIA-N2 disease who were treated with induction chemotherapy and who had undergone mediastinal restaging by EBUS-TBNA were reviewed. On the basis of computed tomography, 58 patients were classified as having stable disease and 66 were judged to have had a partial response. All patients subsequently underwent thoracotomy with attempted curative resection and a lymph node dissection regardless of EBUS-TBNA findings.

RESULTS

Persistent nodal metastases were detected by using EBUS-TBNA in 89 patients (72%). Of the 35 patients in whom no metastases were assessed by EBUS-TBNA, 28 were found to have residual stage IIIA-N2 disease at thoracotomy. The majority (91%) of these false negative results were due to nodal sampling error rather than detection error. Overall sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of EBUS-TBNA for mediastinal restaging after induction chemotherapy were 76%, 100%, 100%, 20%, and 77%, respectively.

CONCLUSION

EBUS-TBNA is a sensitive, specific, accurate, and minimally invasive test for mediastinal restaging of patients with NSCLC. However, because of the low negative predictive value, tumor-negative findings should be confirmed by surgical staging before thoracotomy.

Correlation of PET/CT findings and histopathology after neoadjuvant therapy in non-small cell lung cancer

OBJECTIVES

Prediction of histopathological response with PET/CT scans after neoadjuvant chemoradiotherapy is limited by confounding factors which have been evaluated in this analysis.

METHODS

(18)F-2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT findings [standard uptake value (SUV), residual tumor volume] were correlated with histopathological parameters of the resection specimens (tumor cell density, necrosis, scar, macrophage infiltration) in patients with locally advanced non-small cell lung cancer (stage IIIA/IIIB) after neoadjuvant induction chemotherapy (platinum-based doublet) and concurrent chemoradiotherapy (cisplatin/vinorelbine/45 Gy).

RESULTS

Sixty patients [40 male/20 female, median age 56 years (34-78)] completed induction therapy, 46 patients (stage IIIA/IIIB: 16/30; squamous cell carcinoma 41%, adenocarcinoma 48%, large cell carcinoma 11%) were resected. Pathologic complete response of the primary tumor was observed in 19 patients (41%) with a broad range of SUV(mean) (0.4-9.8, mean 3.0) after neoadjuvant therapy. A high rate of histopathological complete remissions (44%) was observed in tumors with a postinduction SUV >2.5 and volumes larger than the median (7.9 cm(3)) before resection. SUV(mean) was positively correlated with the macrophage score (r = 0.39, p = 0.007) and tumor cell density (r = 0.32, p = 0.03).

CONCLUSIONS

These observations suggest that postinduction FDG uptake should be interpreted with caution in larger residual tumor volumes, since high SUV levels may be due to macrophage infiltration and not viable tumor tissue.

Targeted molecular imaging in oncology: focus on radiation therapy

Anatomically based technologies (computed tomography scans, magnetic resonance imaging, and so on) are in routine use in radiotherapy for planning and assessment purposes. Even with improvements in imaging, however, radiotherapy is still limited in efficacy and toxicity in certain applications. Further advances may be provided by technologies that image the molecular activities of tumors and normal tissues. Possible uses for molecular imaging include better localization of tumor regions and early assay for the radiation response of tumors and normal tissues. Critical to the success of this approach is the identification and validation of molecular probes that are suitable in the radiotherapy context. Recent developments in molecular-imaging probes and integration of functional imaging with radiotherapy are promising. This review focuses on recent advances in molecular imaging strategies and probes that may aid in improving the efficacy of radiotherapy.

When is it best to repeat a 2-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography scan on patients with non-small cell lung cancer who have received neoadjuvant chemoradiotherapy?

BACKGROUND

The ideal time to repeat a 2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)/computed tomography (CT) scan to accurately restage a patient after neoadjuvant chemoradiotherapy for non-small cell lung cancer (NSCLC) is unknown.

METHODS

This retrospective cohort study used a prospective database of patients who underwent neoadjuvant chemoradiotherapy, an initial and repeat FDG-PET/CT scan, and pathologic staging. The accuracy of the clinical stage suggested by repeat FDG-PET/CT was compared with the actual pathologic stage. Receiver operating characteristic (ROC) curves were used to determine when it was most accurate to repeat the FDG-PET/CT after the completion of the last dose of chest radiation.

RESULTS

The study comprised 109 patients, 93 of whom patients received 60 Gy (or higher) of radiotherapy. The median time to restaging was 24 days (range, 2 to 88 days). ROC analysis showed the optimal time to restage patients was 26 days for overall staging (area under the curve [AUC], 0.88) and 29 days for N2 restaging (AUC, 0.82). The accuracy for overall stage was 3 (38%) of 8 for patients for less than 10 days, 28 (72%) of 39 for patients between 11 and 20 days, 42 (88%) of 49 between 21 and 30 days, and 8 (62%) of 13 for 31 days or more. The accuracy for these time intervals for the restaging of the N2 lymph node was 50% (1/2) 40% (2/5), 88% (7/8), and 100% (3/3), respectively.

CONCLUSIONS

The optimal time to perform a repeat FDG-PET/CT scan after the completion of neoadjuvant chemotherapy and high-dose radiotherapy to maximize its accuracy for restaging patients with NSCLC is about 1 month after the last dose of radiation.

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.

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.

The role of integrated computed tomography positron-emission tomography in esophageal cancer: staging and assessment of therapeutic response

Computed tomography (CT) and endoscopy/endoscopic ultrasonography are usually performed to initially stage patients with esophageal cancer, to determine primary tumor response, and to detect nodal and distant metastases after preoperative therapy. Positron-emission tomography (PET) with [18F]-fluoro-2-deoxy-D-glucose and integrated CT-PET are useful in the initial staging of patients with esophageal cancer as well as in the prediction of pathologic response, disease-free interval, and overall survival after preoperative therapy. Importantly, integrated CT-PET imaging decreases the number of futile attempts at surgical resection, mainly because of the detection of occult distant metastases. The following sections review the use of integrated CT-PET imaging in determining the T, N, and M descriptors of the American Joint Commission on Cancer's 2002 guidelines for pathologic and clinical staging at initial diagnosis and after chemoradiation therapy in those patients being considered for surgical resection.

Surgery of non-small cell lung cancer in the elderly

PURPOSE OF REVIEW

The aim of this review is to analyze recent evidence for optimal treatment of elderly patients with non-small cell lung cancer, focusing on surgery, and possibly to foresee the future strategies to apply in these patients.

RECENT FINDINGS

Surgery in elderly patients affected by non-small cell lung cancer is safe and feasible when careful preoperative respiratory and cardiac studies have been carried out and the disease has been properly staged. The surgical treatment is not to be denied in elderly patients due to age per se, but when a major contraindication to surgery has been recognized. Long term survival for elderly patients with early stage lung cancer treated by anatomical pulmonary resection is comparable to the survival rate of younger patients. Pneumonectomy, extended surgical procedure or preoperative induction chemotherapy are major risk factors for an increased postoperative morbidity and mortality rate. When co-morbidities are present or a patient is 80 years or older, there is evidence that a non-anatomical resection can be performed without affecting long-term results.

SUMMARY

Due to the aging of the general population, elderly patients will become a large percentage of the cases of non-small cell lung cancer to be treated. Implementing preoperative cardiologic studies and redefining selective respiratory criteria specifically could dramatically improve results.

Positron emission tomography in nonsmall cell lung cancer

PURPOSE OF REVIEW

Positron emission tomography (PET) has become a major adjunct to structural imaging for nonsmall cell lung cancer. Established indications are the differential diagnosis of lung nodules, as well as mediastinal lymph node and extrathoracic staging.

RECENT FINDINGS

More details for small or faint pulmonary nodules became available--information of interest in the era of lung cancer screening trials, in which PET might help to reduce unwanted invasive procedures for benign findings. The strength of PET in mediastinal staging (its high negative predictive value) was confirmed in a randomized study, in which PET reduced the number of invasive procedures without loss of accuracy in staging. Isolated positive lesions that are decisive for radical compared with palliative treatment should be confirmed by other tests, as they may be benign or due to second primary cancer. PET with integrated computed tomography (CT) may guide modern radiotherapy, by improving radiation fields. Integrated PET-CT is a promising tool in the indication for surgery in stage IIIA-N2 patients after induction treatment. Predictive values for lymph node downstaging become in acceptable ranges and PET response in the primary tumor could be clearly linked to pathologic response and survival.

SUMMARY

In recent years, PET has seen further refinements in established indications and definition of new indications.

Restaging patients with N2 (stage IIIa) non-small cell lung cancer after neoadjuvant chemoradiotherapy: a prospective study

BACKGROUND

The accuracy of restaging in patients with stage IIIa non-small cell lung cancer after neoadjuvant chemoradiotherapy is unknown.

METHODS

A prospective trial of patients with biopsy-proven N2 disease who underwent initial clinical staging with mediastinoscopy, integrated positron emission tomography/computed tomography (PET/CT), and CT. Patients then were clinically restaged by the same imaging techniques 4 to 12 weeks after their induction chemoradiation therapy and then underwent definitive pathologic staging.

RESULTS

Ninety-three patients had their lymph nodes pathologically restaged. Repeat PET/CT after neoadjuvant therapy missed residual N2 disease in 13/65 (20%) patients and falsely suggested it in 7 of 28 (25%). It was more accurate than repeat CT for restaging at all pathologic stages (stage 0, 92% vs 39%, P = .03; and stage I 89% vs 36%, P = .04). When the maximum standardized uptake value of the primary tumor is decreased by 75% or more, it is highly likely (likelihood ratio, +LR, 6.1) the patient is a complete responder; when it decreased by 55% or more, it is highly likely (+LR, 9.1) the patient is a partial responder. When the maximum standardized uptake value of the N2 node initially involved with metastatic cancer is decreased by more than 50%, it is highly likely (+LR, 7.9) the node is now benign.

CONCLUSION

Repeat integrated PET/CT is superior to repeat CT for the restaging of patients with stage IIIa non-small cell lung cancer. The percent decrease in the maximum standardized uptake value of the primary and of the involved lymph node is predictive of pathology; however, nodal biopsies are required since a persistently high maximum standardized uptake value does not equate to residual cancer.

Prospective comparative study of integrated positron emission tomography-computed tomography scan compared with remediastinoscopy in the assessment of residual mediastinal lymph node disease after induction chemotherapy for mediastinoscopy-proven stage IIIA-N2 Non-small-cell lung cancer: a Leuven Lung Cancer Group Study

PURPOSE

Mediastinal restaging after induction therapy for non-small-cell lung cancer remains a difficult and controversial issue. The goal of this prospective study was to compare the performance of integrated positron emission tomography (PET)--computed tomography (CT) and remediastinoscopy in the evaluation of mediastinal lymph node metastasis after induction chemotherapy.

PATIENTS AND METHODS

Thirty consecutive stage IIIA-N2 non-small-cell lung cancer patients surgically treated at our institution were entered onto this prospective study. N2 disease was proven by cervical mediastinoscopy, at which a mean number of 3.8 lymph node levels were biopsied. After completion of induction chemotherapy, the mediastinum was reassessed by integrated PET-CT and remediastinoscopy. All patients underwent thoracotomy with attempted complete resection and systematic nodal dissection.

RESULTS

PET-CT showed no evidence of nodal disease (N0) in 13 patients, Hilar nodal disease (N1) disease in three patients, and residual mediastinal disease (N2) in 14 patients. Remediastinoscopy was positive in only five patients. The preinduction involved lymph node level could be accurately re-evaluated in 18 patients. This was not the case in the other 12 because of extensive fibrosis and adhesions. In 17 patients, persistent N2 disease was found at thoracotomy. The sensitivity, specificity, and accuracy of PET-CT were 77%, 92%, and 83%, respectively. These parameters for remediastinoscopy were 29%, 100%, and 60%, respectively. Sensitivity (P < .0001) and accuracy (P = .012) were significantly better for PET-CT.

CONCLUSION

After a thorough staging mediastinoscopy, postinduction remediastinoscopy had a disappointing sensitivity because of adhesions and fibrosis. Integrated PET-CT yielded a better result than that obtained in previous studies with side-by-side PET and CT images.

Truncation artifact on PET/CT: impact on measurements of activity concentration and assessment of a correction algorithm

OBJECTIVE

Discrepancy between fields of view (FOVs) in a PET/CT scanner causes a truncation artifact when imaging extends beyond the CT FOV. The purposes of this study were to evaluate the impact of this artifact on measurements of 18F-FDG activity concentrations and to assess a truncation correction algorithm.

MATERIALS AND METHODS

Two phantoms and five patients were used in this study. In the first phantom, three inserts (water, air, bone equivalent) were placed in a water-filled cylinder containing 18F-FDG. In the second phantom study, a chest phantom and a 2-L bottle fitted with a bone insert were used to simulate a patient's torso and arm. Both phantoms were imaged while positioned centrally (baseline) and at the edge of the CT FOV to induce truncation. PET images were reconstructed using attenuation maps from truncated and truncation-corrected CT images. Regions of interest (ROIs) drawn on the inserts, simulated arm, and background water of the baseline truncated and truncation-corrected PET images were compared. In addition, extremity malignancies of five patients truncated on CT images were reconstructed with and without correction and the maximum standard uptake values (SUVs) of the malignancies were compared.

RESULTS

Truncation artifact manifests as a rim of high activity concentration at the edge of the truncated CT image with an adjacent low-concentration region peripherally. The correction algorithm minimizes these effects. Phantom studies showed a maximum variation of -5.4% in the truncation-corrected background water image compared with the baseline image. Activity concentration in the water insert was 6.3% higher while that of air and bone inserts was similar to baseline. Extremity malignancies showed a consistent increase in the maximum SUV after truncation correction.

CONCLUSION

Truncation affects measurements of 18F-FDG activity concentrations in PET/CT. A truncation-correction algorithm corrects truncation artifacts with small residual error.