Prognostic value of preoperative positron emission tomography in resected stage I non-small cell lung cancer

Positron emission tomography/computed tomography and lymphovascular invasion predict recurrence in stage I lung cancers

BACKGROUND

Although pathologic stage I lung cancers generally have a favorable prognosis, approximately 20% of patients experience recurrence after surgery. Therefore, a method of selecting patients who need adjuvant therapy is necessary. The goal of this study was to evaluate the significance of positron emission tomography (PET)/computed tomography (CT) results after lung cancer surgery and to identify the predictive factors for recurrence in cases of pathologic stage I lung cancer.

METHODS

From January 2004 to December 2008, 356 patients with lung cancer underwent surgery at our institution. Of these, 282 patients received F-18 fluorodeoxyglucose PET/CT, and the maximum standardized uptake value (max SUV) was measured. There were 201 patients with pathologic stages IA and IB evaluated. The associations between disease-free survival (DFS) and the following clinicopathological factors were analyzed: age, gender, smoking history, carcinoembryonic antigen level, tumor size, max SUV values, histology, and lymphovascular and pleural invasion.

RESULTS

The 4-year DFS rate was 86.3%. Multivariate analysis revealed lymphovascular invasion (LVI; p < 0.01) and max SUV ≥4.7 (p < 0.01) to be independent predictive factors. Patients with a max SUV more than 4.7 had a significantly high risk of recurrence. DFS of patients with high max SUVs and LVI (n = 18) was significantly reduced compared with other patients (n = 183, p < 0.01).

CONCLUSIONS

The PET-CT results significantly correlated with recurrence in pathologic stage I lung cancers. Patients with high max SUVs and LVI were more likely to have recurrence and should be candidates for adjuvant chemotherapy.

PET/CT imaging in different types of lung cancer: an overview

Lung cancer (LC) still represents one of the most common tumours in both women and men. PET/CT is a whole-body non-invasive imaging procedure that has been increasingly used for the assessment of LC patients. In particular, PET/CT added value to CT is mainly related to a more accurate staging of nodal and metastatic sites and to the evaluation of the response to therapy. Although the most common PET tracer for LC evaluation is 18F-FDG, new tracers have been proposed for the evaluation of lung neuroendocrine tumours (68Ga-DOTA-peptides, 18F-DOPA) and for the assessment of central nervous system metastasis (11C-methionine). This review focuses on the main clinical applications and accuracy of PET/CT for the detection of non-small cells lung cancer (NSCLC), broncho-alveolar carcinoma (BAC), small cells lung cancer (SCLC), lung neuroendocrine tumours (NET) and solitary pulmonary nodules (SPN).

[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.

18-Fluorodeoxyglucose positron emission tomography as a tool for response prediction in solid tumours

Current response guidelines for the treatment of solid tumours are based on CT criteria. Over the last decades new techniques have emerged to evaluate cancer therapy. FDG-PET scanning is a more functional imaging technique, which can measure differences in metabolic activity. Although it has a low specificity, studies show that it can outperform classical CT scanning criteria. Especially in lung, breast and oesophageal cancer it can predict response earlier in the neo-adjuvant setting. This could reduce the use of ineffective cancer therapies, reducing costs and patient toxicity, and direct patients sooner towards effective therapy. The main problem with FDG-PET remains the difficulty in defining thresholds for response, as there is clearly a lack in large prospective randomized studies validating the use of FDG-PET in response guidelines.We give an overview of data on response prediction in solid tumours by the application of PET.

Primary tumor standardized uptake value measured on fluorodeoxyglucose positron emission tomography is of prognostic value for survival in non-small cell lung cancer: update of a systematic review and meta-analysis by the European Lung Cancer Working Party for the International Association for the Study of Lung Cancer Staging Project

INTRODUCTION

Few validated prognostic factors are available for survival in patients with lung cancer. [F]-fluoro-2-deoxy-d-glucose positron emission tomography has been shown to be of additional value to conventional imaging for staging lung cancer. The prognostic value of this lung tumor metabolic activity was studied in a first systematic review of studies published until 2006.

METHODS

As further studies have appeared since 2006, this report has as objective to confirm and to estimate with less variability the prognostic value of primary tumor standardized uptake value (SUV) measured with [F]-fluoro-2-deoxy-d-glucose positron emission tomography on the basis of an updated search of eligible studies.

RESULTS

Ten additional studies were eligible for the updated review and eight of them provided, in the publication, data allowing survival results aggregation. All together, 21 studies were analyzed. Comparing patients with low and high SUV, using preferentially the median SUV value of each study as threshold, we obtained a poor prognostic value for high SUV compared with low SUV with an overall combined hazard ratio of 2.08, significantly different from one with a 95% confidence interval ranging from 1.69 to 2.56. No interaction between older and newer studies was detectable (P = 0.60) as well as between studies having selected non metastatic patients or studies without selection criterion related to stage (P = 0.46).

CONCLUSIONS

We confirmed the results of our previous review showing that SUV is potentially a very interesting factor for predicting patient outcome. We believe that a meta-analysis based on individual patient data would be of great value as allowing to assess the independent prognostic value, to take into account some factors responsible for heterogeneity between studies (SUV assessment method, disease stage, and histology), and to update survival data. We are planning to conduct such a meta-analysis on behalf of the International Association for the Study of Lung Cancer Staging Project.

[PET-CT for evaluation of the solitary pulmonary nodule: an update]

INTRODUCTION

Positron emission tomography (PET) with 18F-FDG has become an important tool for the characterization of solitary pulmonary nodules (SPN).

BACKGROUND

The results of the main meta-analyses show that the sensitivity and specificity of 18F-FDG PET for determining malignancy of SPN are close to 95% and 80% respectively. The limits of the technology are now well known. False negative results are mainly due to certain histological types with low metabolic activity (such as bronchiolo-alveolar carcinoma and typical carcinoid), or small size (nodules less than 8 mm). False positives are mainly represented by granulomatous and infectious processes.

VIEWPOINTS

A gain in accuracy occurred with the advent of hybrid PET/CT machines that combine the functional data from 18FDG-PET and the morphological data of computed tomography. Improved imaging protocols (eg. injection of iodinated contrast media) could further enhance the performance of PET-CT. Further improvements will rely on respiratory synchronization protocols and on the advent of new PET tracers.

CONCLUSION

18F-FDG PET-CT should be performed for any nodule over 8 mm in size when the pre-test probability of malignancy is not deemed negligible.

Maximum standardized uptake value from staging FDG-PET/CT does not predict treatment outcome for early-stage non-small-cell lung cancer treated with stereotactic body radiotherapy

PURPOSE

To perform a retrospective review to determine whether maximum standardized uptake values (SUV(max)) from staging 2-deoxy-2- [(18)F] fluoro-D-glucose (FDG) positron emission tomography/computed tomography (PET/CT) studies are associated with outcomes for early-stage non-small-cell lung cancer (NSCLC) treated with stereotactic body radiotherapy (SBRT).

METHODS AND MATERIALS

Seventy-two medically inoperable patients were treated between October 17, 2003 and August 17, 2007 with SBRT for T1-2N0M0 NSCLC. SBRT was administered as 60 Gy in 3 fractions, 50 Gy in 5 fractions, or 50 Gy in 10 fractions using abdominal compression and image-guided SBRT. Cox proportional hazards regression was performed to determine whether PET SUV(max) and other variables influenced outcomes: mediastinal failure (MF), distant metastases (DM), and overall survival (OS).

RESULTS

Biopsy was feasible in 49 patients (68.1%). Forty-nine patients had T1N0 disease, and 23 had T2N0 disease. Median SUV(max) was 6.55 (range, 1.5-21). Median follow-up was 16.9 months (range, 0.1-37.9 months). There were 3 local failures, 8 MF, 19 DM, and 30 deaths. Two-year local control, MF, DM, and OS rates were 94.0%, 10.4%, 30.1%, and 61.3%, respectively. In univariate analysis, PET/CT SUV(max), defined either as a continuous or dichotomous variable, did not predict for MF, DM, or OS. On multivariable analysis, the only predictors for overall survival were T1 stage (hazard ratio = 0.331 [95% confidence interval, 0.156-0.701], p = 0.0039) and smoking pack-year history (hazard ratio = 1.015 [95% confidence interval, 1.004-1.026], p = 0.0084).

CONCLUSIONS

Pretreatment PET SUV(max) did not predict for MF, DM, or OS in patients treated with SBRT for early-stage NSCLC.

Positron emission tomography 18F-fluorodeoxyglucose uptake and prognosis in patients with surgically treated, stage I non-small cell lung cancer: a systematic review

BACKGROUND

18F-fluorodeoxyglucose (FDG) uptake holds potential as a noninvasive biomarker in patients with non-small cell lung cancer (NSCLC). We aimed to investigate the association between tumor FDG uptake and survival in patients with surgically resected, stage I NSCLC.

METHODS

We used systematic methods to identify studies for inclusion, assess methodological quality, and abstract relevant data about study design and results.

RESULTS

Our literature search identified 1578 citations, of which nine retrospective, cross-sectional studies met eligibility criteria. In all studies, higher degrees of FDG uptake in the primary tumor were associated with worse overall or disease free survival after 2 to 5 years of follow-up, but these differences were statistically significant in only five studies. Across studies, the median overall or disease free survival was 70% for patients with higher FDG uptake compared with 88% for patients with lower FDG uptake. In three studies that performed multivariable analysis, the adjusted hazard of death or recurrence was 1.9 to 8.6 times greater in patients with higher FDG uptake.

CONCLUSION

Current evidence suggests that increasing tumor FDG uptake is associated with worse survival in patients with stage I NSCLC. FDG uptake has the potential to be used as a biomarker for identifying stage I patients who are at increased risk of death or recurrence and therefore could identify candidates for participation in future trials of adjuvant therapy.

18F-FDG uptake and EGFR mutations in patients with non-small cell lung cancer: a single-institution retrospective analysis

This retrospective study was performed to evaluate a possible association between the presence of epidermal growth factor receptor (EGFR) mutations and the standardized uptake value (SUV) of (18)F-fluoro-2-deoxy-glucose ((18)F-FDG) uptake in patients with non-small cell lung cancer (NSCLC). We included 100 patients who were tested for EGFR mutations by direct sequencing of resected tissues and who underwent preoperative positron emission tomography/computed tomography at the time of diagnosis. The maximum SUV by the primary tumor was chosen for further analysis. EGFR mutations in exons 19 and 21 were detected in 21 NSCLC patients (21%). EGFR mutations were more frequent in never-smokers than ever-smokers (35% versus 11%; P=0.003), in adenocarcinomas than non-adenocarcinomas (34% versus 6%; P=0.001), and in females than males (41% versus 12%; P=0.001). The SUV ranged from 1.3 to 33.0 (median 10.6). Area under receiver operating characteristic curve for SUVs in respect to the presence of EGFR mutations was 0.74 (95% CI: 0.62-0.85). When a cut off value was used, patients with low SUVs were more likely to have EGFR mutations than those with high SUVs (40% versus 11%; P=0.001). On multivariate analysis, a low SUV remained a significant predictors for EGFR mutations (P=0.025). (18)F-FDG uptake was associated with the presence of EGFR mutation. These results extrapolate that (18)F-FDG uptake might be helpful to discriminate patients who harbor EGFR mutations, especially when a genetic test is not feasible.

Risk stratification of solitary pulmonary nodules by means of PET using (18)F-fluorodeoxyglucose and SUV quantification

PURPOSE

(18)F-fluorodeoxyglucose (FDG) PET is the most accurate imaging modality in characterizing a solitary pulmonary nodule (SPN). Besides visual image interpretation, semiquantitative analysis using standardized uptake values (SUV) is performed to improve diagnostic accuracy. Mostly, an SUV threshold of 2.5 is applied to differentiate between benign and malignant lesions. In this study we analysed the use different SUV thresholds to predict the post-test probability of malignancy for the individual patient considering his pre-test probability. Furthermore, we investigated the prognostic value of SUV in SPN for survival.

METHODS

This retrospective study included 140 consecutive patients who underwent FDG PET for evaluation of SPN. Visual interpretation was performed by two readers. For semiquantitative analysis, maximum SUV (SUV(max)) was measured in all SPN. A final diagnosis was obtained by pathological examination or follow-up of more than 2 years. In a nomogram, positive and negative predictive values (PPV and NPV) were plotted against the hypothetical SUV threshold to determine the optimum SUV threshold. Survival was analysed using the Kaplan-Meier method and log-rank test.

RESULTS

The prevalence of malignancy was 57%. The FDG uptake in malignant SPNs was higher than in benign SPNs (SUV 9.7 +/- 5.5 vs 2.6 +/- 2.5, p < 0.01). More than 90% of SPNs with an SUV below 2.0 were benign (sensitivity, specificity, NPV of 96, 55 and 92%). The highest diagnostic accuracy was achieved with an SUV of 4.0 (sensitivity, specificity and accuracy of 85%). Visual interpretation achieved corresponding values of 94, 70 and 84%, respectively. In lung cancer higher FDG uptake (SUV(max) >or= 9.5) was associated with shorter survival (median survival 20 months) and low FDG uptake with longer survival (>75 months).

CONCLUSION

FDG PET allows assessment of the individual risk for malignancy in SPNs by considering tumoural SUV and pre-test probability. Higher FDG uptake in lung cancer as measured by SUV analysis is a prognostic factor. In patients with low FDG uptake in an SPN and increased risk during surgery omission of diagnostic thoracotomy may be warranted.

Prognostic value of 18F-FDG uptake on positron emission tomography in patients with pathologic stage I non-small cell lung cancer

INTRODUCTION

The intensity of 18F-fluorodeoxyglucose (18F-FDG) uptake in positron emission tomography could be of prognostic significance for patients with non-small cell lung cancer (NSCLC). The aim of this retrospective study was to evaluate the prognostic value of the FDG uptake in patients with resected pathologic stage I NSCLC according to histologic types of the tumors.

METHODS

For each patient, a maximum standardized uptake value (SUVmax) and a partial volume corrected (PVC) SUVmax were calculated for the primary lesion on positron emission tomography. To find optimal cutoff values for cancer recurrences, receiver operating characteristic curves were used.

RESULTS

Among 145 study patients, the mean values of SUVmax were 7.7 in those with adenocarcinoma (n = 70) and 16.0 in those with other histologies (n = 75; p < 0.001). Furthermore, the optimal cutoff values of SUVmax to predict cancer recurrences were identified as 5.2 in patients with adenocarcinoma and 13.8 in those with other histologies. In whole patients with pathologic stage I NSCLC, SUVmax (p = 0.025), PVC SUVmax (p = 0.014), tumor size (p = 0.048), and weight loss (p = 0.041) were significantly associated with disease-free survival (DFS). Moreover, PVC SUVmax (p = 0.034) and SUVmax (p = 0.012) were significantly associated with DFS in the multivariate analyses.

CONCLUSIONS

The intensity of FDG uptake for the primary tumor was an independent prognostic factor for DFS in whole patients with pathologic stage I NSCLC. However, caution is needed for the interpretation of optimal cutoff values of SUVmax according to tumor histologies.

The variation of prognostic significance of Maximum Standardized Uptake Value of [18F]-fluoro-2-deoxy-glucose positron emission tomography in different histological subtypes and pathological stages of surgically resected Non-Small Cell Lung Carcinoma

Even if the prognostic role of SUVmax of 18-FDG-PET has been largely investigated, many issues regarding its relationship with pathologic staging and histological subtypes still remain controversial. This retrospective study investigated the prognostic significance of SUVmax in 119 completely resected, pathologically proven NSCLC. The SUVmax values resulted significantly related to histological subtypes (p<0.001), histological grading (p<0.001), and pathologic stage (p<0.001). The optimal cut-off value of SUVmax to predict prognosis in the whole series was 6.7 (p=0.029). 2-Year disease-specific survival (DSS) was 91% for SUVmax < or =6.7 and 55% for SUVmax >6.7 (p<0.001). SUVmax still remain a significant predictor of survival in Stage IB (2-year DSS of 100% for SUVmax < or =6.7; 51% for SUVmax >6.7, p=0.016). The optimal cut-off values of SUVmax to predict prognosis were 5 for adenocarcinoma (p=0.027) and 10.7 for other non-adenocarcinoma NSCLC subtypes (p=0.010). These histologic-specific cut-offs resulted significantly related to survival when stratified for stage: 2-year DSS for Stage IB adenocarcinoma were 100% for SUV< or =5 and 40% for SUVmax >5 (p=0.051); 2-year DSS for Stage IB non-adenocarcinoma were 83% for SUVmax < or =10.7 and 26% for SUVmax >10.7 (p=0.018). Adenocarcinomas showed significantly lower survival results respect to other NSCLC for intermediate SUVmax level (range 5.5-11.3) (p=0.021). High SUVmax resulted an independent negative prognostic factor at multivariate analysis (HR of 15.7, 95% CI of 2.50-98.44, p=0.003). In conclusion, SUVmax represents a significant prognostic factor in surgically resected NSCLC but a great variability between different histological subtypes, even when adjusted for stage, is present and could be considered when planning future trials on prognostic role of FDG uptake.

Revisiting the prognostic value of preoperative (18)F-fluoro-2-deoxyglucose ( (18)F-FDG) positron emission tomography (PET) in early-stage (I & II) non-small cell lung cancers (NSCLC)

PURPOSE

The aims were to determine if the maximum standardized uptake value (SUV(max)) of the primary tumor as determined by preoperative (18)F-fluoro-2-deoxyglucose ((18)F-FDG) positron emission tomography (PET) is an independent predictor of overall survival and to assess its prognostic value after stratification according to pathological staging.

METHODS

A retrospective clinicopathologic review of 363 patients who had a preoperative (18)F-FDG PET done before undergoing attempted curative resection for early-stage (I & II) non-small cell lung cancer (NSCLC) was performed. Patients who had received any adjuvant or neoadjuvant chemotherapy or radiation therapy were excluded. The primary outcome measure was duration of overall survival. Receiver-operating characteristic (ROC) curves were plotted to find out the optimal cutoff values of SUV(max) yielding the maximal sensitivity plus specificity for predicting the overall survival. Survival curves stratified by median SUV(max) and optimal cutoff SUV(max) were estimated by the Kaplan-Meier method and statistical differences were assessed using the log-rank test. Multivariate proportional hazards (Cox) regression analyses were applied to test the SUV(max)'s independency of other prognostic factors for the prediction of overall survival.

RESULTS

The median duration of follow-up was 981 days (2.7 years). The median SUV(max) was 5.9 for all subjects, 4.5 for stage IA, 8.4 for stage IB, and 10.9 for stage IIB. The optimal cutoff SUV(max) was 8.2 for all subjects. No optimal cutoff could be established for specific stages. In univariate analyses, each doubling of SUV(max) [i.e., each log (base 2) unit increase in SUV(max)] was associated with a 1.28-fold [95% confidence interval (CI): 1.03-1.59, p = 0.029] increase in hazard of death. Univariate analyses did not show any significant difference in survival by SUV(max) when data were stratified according to pathological stage (p = 0.119, p = 0.818, and p = 0.882 for stages IA, IB, and IIB, respectively). Multivariate analyses demonstrated that SUV(max) was not an independent predictor of overall survival (p > 0.05).

CONCLUSION

Each doubling of SUV(max) as determined by preoperative PET is associated with a 1.28-fold increase in hazard of death in early-stage (I & II) NSCLC. Preoperative SUV(max) is not an independent predictor of overall survival.

18F-FDG PET and PET/CT in the evaluation of cancer treatment response

Multimodality imaging, as represented by its greatest exponent, PET/CT, has a firm place in the evaluation of a patient presenting with cancer. With 18F-FDG, PET/CT is rapidly becoming the key investigative tool for the staging and assessment of cancer recurrence. In the last 5 y, PET/CT has also gained widespread acceptance as a key tool used to demonstrate early response to intervention and therapy. In this setting, a major clinical need is being addressed with 18F-FDG PET/CT, because of its inherent ability to demonstrate (before other markers of response) if disease modification has occurred. This review presents available evidence to this effect.

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.

PET/CT for staging and monitoring non small cell lung cancer

Correct staging of non small cell lung cancer (NSCLC) is vital for appropriate management. Initial staging is usually performed with computerised tomography (CT), but increasingly functional imaging using integrated positron emission tomography and CT (PET/CT) is being used to provide more accurate staging, guide biopsies, assess response to therapy and identify recurrent disease.