Is standardised 18F-FDG uptake value an outcome predictor in patients with stage III non-small cell lung cancer?

Consistency and prognostic value of preoperative staging and postoperative pathological staging using 18F-FDG PET/MRI in patients with non-small cell lung cancer

OBJECTIVE

In recent years, positron emission tomography/magnetic resonance imaging (PET/MRI) has been clinically used as a method to diagnose non-small cell lung cancer (NSCLC). This study aimed to evaluate the concordance of staging and prognostic ability of NSCLC patients using thin-slice computed tomography (CT) and ¹⁸F-fluorodeoxyglucose (FDG) PET/MRI.

METHODS

This retrospective study was performed on consecutive NSCLC patients who underwent both diagnostic CT and ¹⁸F-FDG PET/MRI before surgery between November 2015 and May 2019. The cTNM staging yielded from PET/MRI was compared with CT and pathological staging, and concordance was investigated, defining pathological findings as reference. To assess the prognostic value of disease-free survival (DFS) and overall survival (OS), we dichotomized the typical prognostic factors and TNM classification staging (Stage I vs. Stage II or higher). Kaplan-Meier curves derived by the log-rank test were generated, and univariate and multivariate analyses were performed to identify the factors associated with DFS and OS.

RESULTS

A total of 82 subjects were included; PET/MRI staging was more consistent (59 of 82) with pathological staging than with CT staging. There was a total of 21 cases of CT and 11 cases of PET/MRI that were judged as cStage I, but were actually pStage II or pStage III. CT tended to judge pN1 or pN2 as cN0 compared to PET/MRI. There was a significant difference between NSCLC patients with Stage I and Stage II or higher by PET/MRI staging as well as prognosis prediction of DFS by pathological staging (P < 0.001). In univariate analysis, PET/MRI, CT, and pathological staging (Stage I or lower vs. Stage II or higher) all showed significant differences as prognostic factors of recurrence or metastases. In multivariate analysis, pathological staging was the only independent factor for recurrence (P = 0.009), and preoperative PET/MRI staging was a predictor of patient survival (P = 0.013).

CONCLUSIONS

In NSCLC, pathologic staging was better at predicting recurrence, and preoperative PET/MRI staging was better at predicting survival. Preoperative staging by PET/MRI was superior to CT in diagnosing hilar and mediastinal lymph-node metastases, which contributed to the high concordance with pathologic staging.

Cervical Cancer Diagnosis: Insights into Biochemical Biomarkers and Imaging Techniques

Cervical malignancy is known as one of the important cancers which is originated from cervix. This malignancy has been observed in women infected with papillomavirus who had regular oral contraceptives, multiple pregnancies, and sexual relations. Early and fast cervical cancer diagnosis is known as two important aspects of cervical cancer therapy. Several investigations indicated that early and fast detection of cervical cancer could be associated with better treatment process and increasing survival rate of patients with this malignancy. Imaging techniques are very important diagnosis tools that could be employed for diagnosis and following responses to therapy in various cervical cancer stages. Multiple lines of evidence indicated that utilization of imaging techniques is related to some limitations (i.e. high cost, and invasive effects). Hence, it seems that along with using imaging techniques, finding and developing new biomarkers could be useful in the diagnosis and treatment of subjects with cervical cancer. Taken together, many studies showed that a variety of biomarkers including, several proteins, mRNAs, microRNAs, exosomes and polymorphisms might be introduced as prognostic, diagnostic and therapeutic biomarkers in cervical cancer therapy. In this review article, we highlighted imaging techniques as well as novel biomarkers for the diagnosis of cervical cancer.

PET-Based Volumetric Biomarkers for Risk Stratification of Non-Small Cell Lung Cancer Patients

Despite the recent advances in lung cancer biology, molecular pathology, and treatment, this malignancy remains the leading cause of cancer-related death worldwide and non-small cell lung cancer (NSCLC) is the most common form found at diagnosis. Accurate staging of the disease is a fundamental prognostic factor that correctly predicts progression-free (PFS) and overall survival (OS) of NSCLC patients. However, outcome of patients within each TNM staging group can change widely highlighting the need to identify additional prognostic biomarkers to better stratify patients on the basis of risk. 18F-FDG PET/CT plays an essential role in staging, evaluation of treatment response, and tumoral target delineation in NSCLC patients. Moreover, a number of studies showed the prognostic role of imaging parameters derived from PET images, such as metabolic tumor volume (MTV) and total lesion glycolysis (TLG). These parameters represent three-dimensional PET-based measurements providing information on both tumor volume and metabolic activity and previous studies reported their ability to predict OS and PFS of NSCLC patients. This review will primarily focus on the studies that showed the prognostic and predictive role of MTV and TLG in NSCLC patients, addressing also their potential utility in the new era of immunotherapy of NSCLC.

Prognostic impact of maximum standardized uptake value on 18 F-FDG PET/CT imaging of the primary lung lesion on survival in advanced non-small cell lung cancer: A retrospective study

Background

Positron emission tomography/computed tomography (PET/CT) has been recognized for diagnosing and staging lung cancer, but the prognostic value of standardized uptake value (SUV) on ¹⁸F‐FDG PET/CT imaging in patients with advanced non‐small cell lung cancer (NSCLC) remains controversial.

Methods

We performed a retrospective analysis of patients with advanced NSCLC who had undergone ¹⁸F‐FDG PET/CT before systemic treatment between June 2012 and June 2016. The relationship between the maximum SUV (SUVmax) of the pulmonary lesion and lesion size was evaluated via Spearman's correlation analysis. We collected patients' clinical and pathological data. Univariate and multivariate analyses were performed to analyze the factors influencing survival.

Results

We included 157 patients with advanced NSCLC. Among these, 135 died, 13 survived, and nine were lost to follow‐up (median follow‐up period, 69 months). SUVmax was correlated with lesion size and was significantly greater for tumors ≥3 cm than for tumors <3 cm (10.2 ± 5.4 vs. 5.6 ± 3.3, t = −6.709, p = 0.000). Univariate analysis showed that survival was associated with gender, tumor size, epidermal growth factor receptor gene mutation or anaplastic lymphoma kinase rearrangement, SUVmax of the primary lung lesion, and treatment lines. Multivariate analysis showed a significant correlation between SUVmax of the primary lung lesion and survival. The mortality risk of patients with SUVmax ≤6 was 35% lower than that of patients with SUVmax >6 (HR = 0.651, 95% confidence interval, 0.436–0.972; Wald value, 4.400; p = 0.036).

Conclusions

The SUVmax of the primary lung lesion on PET/CT is significantly correlated with survival in treatment‐naive patients with advanced NSCLC.

Prognostic factors in potentially resectable stage III non-small cell lung cancer receiving neoadjuvant treatment-a narrative review

Lung cancer is the leading cause of cancer-related death in worldwide. The most important treatment for patients with stage I and II non-small cell lung cancer (NSCLC) is surgery. Resected stage II and III NSCLC patients should be offered adjuvant chemotherapy and in patients with resected stage IB disease and with a primary tumor >4 cm this treatment could be considered. The treatment of resectable locally advanced NSCLC should be evaluated within an experienced multidisciplinary team. Neoadjuvant chemotherapy can be considered in patients with resectable disease and clear candidates for complementary chemotherapy. Neoadjuvant chemotherapy has similar impact on overall survival (OS) than adjuvant chemotherapy, however postoperative chemotherapy has more evidence-based support. Immunotherapy is being studied in early and locally advanced NSCLC as a neoadjuvant or adjuvant treatment. Different prognostic factors have been described in patients with stage III who have received neoadjuvant treatment, which we intend to review in this article.

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.

Prediction of FDG-PET stage and uptake for non-small cell lung cancer on non-contrast enhanced CT scans via fractal analysis

PURPOSE

To investigate whether the FD of non-small cell lung cancer (NSCLC) on CT predicts tumor stage and uptake on ¹⁸F-fluorodeoxyglucose positron emission tomography.

MATERIAL AND METHODS

The FD within a tumor region was determined using a box counting algorithm and compared to the lymph node involvement (NI) and metastatic involvement (MI) and overall stage as determined from PET. A Mann-Whitney U test was applied to the extracted FD features for the NI and the MI.

RESULTS

The two tests showed good significance with p < .05 (p_NI = 0.0139, p_MI = 0.0194). Also after performing fractal analysis to all cases, it was found that for those who had a CT of stage I or II had a higher likelihood of the NI and/or MI stage being upstaged by PET, Odds Ratio 5.38 (95% CI 0.99-29.3). For those who are CT stage III or IV had an increased likelihood of the NI and/or MI stage being down staged by PET, Odds Ratio: 7.33 (95% CI 0.48-111.2).

CONCLUSION

Initial results of this study indicate higher FD in CT images of NSCLC is associated with advanced stage and greater FDG uptake on PET. Measurements of tumor fractal analysis on conventional non-contrast CT examinations could potentially be used as a prognostic marker and/or to select patients for PET.

Prognostic importance of 18F-fluorodeoxyglucose uptake by positron emission tomography for stage III non-small cell lung cancer treated with definitive chemoradiotherapy

OBJECTIVES

Survival heterogeneity exists among patients with non-small cell lung cancer (NSCLC), even within the same stage. We aimed to evaluate the prognostic role of pre-treatment maximum standardized uptake value (SUV_max) in patients treated with definitive concurrent chemoradiotherapy for stage III NSCLC.

MATERIALS AND METHODS

Between 2010 and 2017, 103 patients with stage III NSCLC who underwent ¹⁸F-FDG PET/CT at the time of diagnosis were included in the study.

RESULTS

Higher tumor stages were correlated with higher pre-treatment SUV_max of lymph nodes (LNs) (p=0.005) but were not correlated with higher SUV_max of primary tumor (p=0.2). The median SUV_max of LNs was 2.84, 8.06, and 11.11 in stage IIIa, IIIb and IIIc, respectively. Higher nodal stage was also correlated with higher SUV_max of LNs (p=0.01). According to ROC analysis, there was no significant cut-off value of SUV_max observed for primary tumor, therefore continuous variables were used for survival analyses. The best SUV_max cut-off was 3.5 for the LNs, therefore the SUV_max of LNs was evaluated as both a dichotomous and a continuous variable. Pre-treatment SUV_max of primary tumor did not predict survival outcomes but both the continuous and dichotomous variables of SUV_max of LNs predicted recurrence free survival and overall survival. Nodal stage (N0-2 vs. N3) and AJCC stage (IIIa vs IIIb vs. IIIc) were the other prognostic factors.

CONCLUSIONS

Pre-treatment SUV_max of LNs had prognostic value in patients treated with definitive concurrent chemoradiotherapy for stage III NSCLC. In future trials, pre-treatment SUV_max of the LNs would serve as a guide for patients who might benefit from more aggressive treatments.

Effect of PET/CT standardized uptake values on complete response to treatment before definitive chemoradiotherapy in stage III non-small cell lung cancer

PURPOSE

The standard treatment for patients with stage III non-small cell lung cancer (NSCLC), unsuitable for resection and with good performance, is definitive radiotherapy with cisplatin-based chemotherapy. Our aim is to evaluate the effect of the maximum value of standardized uptake values (SUVmax) of the primary tumor in positron emission tomography-computed tomography (PET/CT) before treatment on complete response (CR) and overall survival.

METHODS

The data of 73 stage III NSCLC patients treated with concurrent definitive chemoradiotherapy (CRT) between 2008 and 2017 and had PET/CT staging in the pretreatment period were evaluated. ROC curve analysis was performed to determine the ideal cut-off value of pretreatment SUVmax to predict CR.

RESULTS

Median age was 58 years (range 27-83 years) and 66 patients were male (90.4%). Median follow-up time was 18 months (range 3-98 months); median survival was 23 months. 1-year overall survival (OS) rate and 5-year OS rate were 72 and 19%, respectively. Median progression-free survival (PFS) was 9 months; 1-year PFS rate and 5-year PFS rate were 38 and 19%, respectively. The ideal cut-off value of pretreatment SUVmax that predicted the complete response of CRT was 12 in the ROC analysis [AUC 0.699 (0.550-0.833)/P < 0.01] with a sensitivity of 83%, and specificity of 55%. In patients with SUVmax < 12, CR rate was 60%, while, in patients with SUV ≥ 12, it was only 19% (P = 0.002). Median OS was 26 months in patients with pretreatment SUVmax < 12, and 21 months in patients with SUVmax ≥ 12 (HR = 2.93; 95% CI 17.24-28.75; P = 0.087). CR rate of the whole patient population was 26%, and it was the only factor that showed a significant benefit on survival in both univariate and multivariate analyses.

CONCLUSION

Pretreatment SUVmax of the primary tumor in PET/CT may predict CR in stage III NSCLC patients who were treated with definitive CRT. Having clinical CR is the only positive predictive factor for prolonged survival.

Why harmonization is needed when using FDG PET/CT as a prognosticator: demonstration with EARL-compliant SUV as an independent prognostic factor in lung cancer

BACKGROUND

To determine EARL-compliant prognostic SUV thresholds in a mature cohort of patients with locally advanced NSCLC, and to demonstrate how detrimental it is to use a threshold determined on an older-generation PET system with a newer PET/CT machine, and vice versa, or to use such a threshold with non-harmonized multicentre pooled data.

MATERIALS AND METHODS

This was a single-centre retrospective study including 139 consecutive stage IIIA-IIIB patients. PET data were acquired as per the EANM guidelines and reconstructed with unfiltered point spread function (PSF) reconstruction. Subsequently, a 6.3 mm Gaussian filter was applied using the EQ.PET (Siemens Healthineers) methodology to meet the EANM/EARL harmonizing standards (PSF_EARL). A multicentre study including non-EARL-compliant systems was simulated by randomly creating four groups of patients whose images were reconstructed with unfiltered PSF and PSF with Gaussian post-filtering of 3, 5, and 10 mm. Identification of optimal SUV thresholds was based on a two-fold cross-validation process that partitioned the overall sample into learning and validation subsamples. Proportional Cox hazards models were used to estimate age-adjusted and multivariable-adjusted hazard ratios (HRs) and their 95% confidence intervals. Kaplan-Meier curves were compared using the log rank test.

RESULTS

Median follow-up was 28 months (1-104 months). For the whole population, the estimated overall survival rate at 36 months was 0.39 [0.31-0.47]. The optimal SUV_max cutoff value was 25.43 (95% CI: 23.41-26.31) and 8.47 (95% CI: 7.23-9.31) for the PSF and for the EARL-compliant dataset respectively. These SUV_max cutoff values were both significantly and independently associated with lung cancer mortality; HRs were 1.73 (1.05-2.84) and 1.92 (1.16-3.19) for the PSF and the EARL-compliant dataset respectively. When (i) applying the optimal PSF SUV_max cutoff on an EARL-compliant dataset and the optimal EARL SUV_max cutoff on a PSF dataset or (ii) applying the optimal EARL compliant SUV_max cutoff to a simulated multicentre dataset, the tumour SUV_max was no longer significantly associated with lung cancer mortality.

CONCLUSION

The present study provides the PET community with an EARL-compliant SUV_max as an independent prognosticator for advanced NSCLC that should be confirmed in a larger cohort, ideally at other EARL accredited centres, and highlights the need to harmonize PET quantitative metrics when using them for risk stratification of patients.

Rationale and Protocol for a Canadian Multicenter Phase II Randomized Trial Assessing Selective Metabolically Adaptive Radiation Dose Escalation in Locally Advanced Non-small-cell Lung Cancer (NCT02788461)

We explain the rationale for metabolically adaptive radiation dose escalation in stage III non-small-cell lung cancer and describe the design of a Canadian phase II randomized trial investigating this approach. In the trial, patients are randomized to either conventional chemoradiation treatment (60 Gy in 30 fractions) or metabolically adaptive chemoradiation, where fluorodeoxyglucose-avid tumor sub-volumes receive an integrated boost dose to a maximum of 85 Gy in 30 fractions. The trial sample size is 78 patients, and the target population is patients with newly diagnosed, inoperable stage III non-small-cell lung cancer treated with radical intent chemoradiation. The primary objective of the trial is to determine if dose escalation to metabolically active sub-volumes will reduce 2-year local-regional failure rate from 42.3% to 22.3%, when compared with standard treatment. The secondary objectives are to determine the effect of dose escalation on overall survival, progression-free survival, quality of life, and rate of grade 3 to 5 toxicities.

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.

Prognostic Value of 18F-Fluorodeoxyglucose PET/Computed Tomography in Non-Small-Cell Lung Cancer

Non-small cell lung cancer (NSCLC) is a leading cause of cancer-related death with a poor prognosis. Numerous factors contribute to treatment outcome. 18F-fluorodeoxyglucose (FDG) uptake reflects tumor metabolic activity and is an important prognosticator in patients with NSCLC. Volume-based FDG-PET parameters reflect the metabolic status of a malignancy more accurately than maximum standardized uptake value and thus are better prognostic markers in lung cancer. FDG-avid tumor burden parameters may help clinicians to predict treatment outcomes before and during therapy so that treatment can be adjusted to achieve the best possible outcomes while avoiding side effects.

Local Radiotherapy Intensification for Locally Advanced Non-small-cell Lung Cancer - A Call to Arms

Chemoradiotherapy, the standard of care for locally advanced non-small-cell lung cancer (NSCLC), often fails to eradicate all known disease. Despite advances in chemotherapeutic regimens, locally advanced NSCLC remains a difficult disease to treat, and locoregional failure remains common. Improved radiographic detection can identify patients at significant risk of locoregional failure after definitive treatment, and newer methods of escalating locoregional treatment may allow for improvements in locoregional control with acceptable toxicity. This review addresses critical issues in escalating local therapy, focusing on using serial positron emission tomography-computed tomography to select high-risk patients and employing stereotactic radiotherapy to intensify treatment. We further propose a clinical trial concept that incorporates the review's findings.

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

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

Prognostic factors in non-small cell lung cancer patients who received neoadjuvant therapy and curative resection

BACKGROUND

Lung cancer is the leading cause of cancer deaths in the world, and more and more treatment modalities have been introduced in order to improve patients' survival. For patients with advanced non-small cell lung cancer (NSCLC), survival prognosis is poor and multimodality neoadjuvant therapies are given to improve patients' survival. However, the possibility of occult metastases may lead to discrepancy between clinical and pathologic staging and underestimation of the disease severity. This discrepancy could be the reason for poor survival prediction reported by previous studies which conducted their analysis from the point of view of clinical stage. The aim of this study was to analyze the relationship between clinico-pathologic factors and survival from the pathologic point of view and to try to identify survival prognostic factors.

METHODS

From January 2005 to June 2011, 88 patients received neoadjuvant therapy because of initial locally advanced disease, followed by anatomic resection and mediastinal lymph node (LN) dissection. All their clinico-pathologic data were collected from a retrospective review of the medical records and subjected to further analysis.

RESULTS

We found that total metastatic LN ratio (P=0.01) and tumor size (P=0.02) were predictive factors for disease free survival (DFS). We used these two prognostic factors to stratify all patients into four groups. Group 4 (tumor size ≤5, total metastatic LN ratio ≤0.065) had the best DFS curve, while the DFS curve progressively deteriorated across group 3 (tumor size ≤5, total metastatic LN ratio >0.065), group 2 (tumor size >5, total metastatic LN ratio ≤0.065) and group 1 (tumor size >5, total metastatic LN ratio >0.065). However, no definitive prognostic factor could be identified in this study.

CONCLUSIONS

In conclusion, tumor size greater than 5 cm and total metastatic LN ratio greater than 0.065 could predict the DFS of patients with advanced NSCLC after multimodality therapies followed by surgical resection. Tumor size plays a more important role than total metastatic LN ratio in DFS. Moreover, patients identified with these factors need active post-operation surveillance and additional aggressive adjuvant therapies.

Positron emission tomography response evaluation from a randomized phase III trial of weekly nab-paclitaxel plus gemcitabine versus gemcitabine alone for patients with metastatic adenocarcinoma of the pancreas

BACKGROUND

In the phase III MPACT trial, nab-paclitaxel plus gemcitabine (nab-P + Gem) demonstrated superior efficacy versus Gem alone for patients with metastatic pancreatic cancer. We sought to examine the feasibility of positron emission tomography (PET) and to compare metabolic response rates and associated correlations with efficacy in the MPACT trial.

PATIENTS AND METHODS

Patients with previously untreated metastatic adenocarcinoma of the pancreas were randomized 1:1 to receive nab-P + Gem or Gem alone. Treatment continued until disease progression by RECIST or unacceptable toxicity.

RESULTS

PET scans were carried out on the first 257 patients enrolled at PET-equipped centers (PET cohort). Most patients (252 of 257) had ≥2 PET-avid lesions, and median maximum standardized uptake values at baseline were 4.6 and 4.5 in the nab-P + Gem and Gem-alone arms, respectively. In a pooled treatment arm analysis, a metabolic response by PET (best response at any time during study) was associated with longer overall survival (OS) (median 11.3 versus 6.9 months; HR, 0.56; P < 0.001). Efficacy results within each treatment arm appeared better for patients with a metabolic response. The metabolic response rate (best response and week 8 response) was higher for nab-P + Gem (best response: 72% versus 53%, P = 0.002; week 8: 67% versus 51%; P = 0.014). Efficacy in the PET cohort was greater for nab-P + Gem versus Gem alone, including for OS (median 10.5 versus 8.4 months; hazard ratio [HR], 0.71; P = 0.009) and ORR by RECIST (31% versus 11%; P < 0.001).

CONCLUSION

Pancreatic lesions were PET avid at baseline, and the rate of metabolic response was significantly higher for nab-P + Gem versus Gem alone at week 8 and for best response during study. Having a metabolic response was associated with longer survival, and more patients experienced a metabolic response than a RECIST-defined response.

CLINICALTRIALSGOV

NCT00844649.

Prognostic value of (18) F-fluoroazomycin arabinoside PET/CT in patients with advanced non-small-cell lung cancer

This study evaluated the prognostic value of positron emission tomography/computed tomography (PET/CT) using ¹⁸F‐fluoroazomycin arabinoside (FAZA) in patients with advanced non‐small‐cell lung cancer (NSCLC) compared with ¹⁸F‐fluorodeoxyglucose (FDG). Thirty‐eight patients with advanced NSCLC (stage III, 23 patients; stage IV, 15 patients) underwent FAZA and FDG PET/CT before treatment. The PET parameters (tumor‐to‐muscle ratio [T/M] at 1 and 2 h for FAZA, maximum standardized uptake value for FDG) in the primary lesion and lymph node (LN) metastasis and clinical parameters were compared concerning their effects on progression‐free survival (PFS) and overall survival (OS). In our univariate analysis of all patients, clinical stage and FAZA T/M in LNs at 1 and 2 h were predictive of PFS (P = 0.021, 0.028, and 0.002, respectively). Multivariate analysis also indicated that clinical stage and FAZA T/M in LNs at 1 and 2 h were independent predictors of PFS. Subgroup analysis of chemoradiotherapy‐treated stage III patients revealed that only FAZA T/M in LNs at 2 h was predictive of PFS (P = 0.025). The FDG PET/CT parameters were not predictive of PFS. No parameter was a significant predictor of OS. In patients with advanced NSCLC, FAZA uptake in LNs, but not in primary lesions, was predictive of treatment outcome. These results suggest the importance of characterization of LN metastases in advanced NSCLC patients.

Primary tumour standardised uptake value is prognostic in nonsmall cell lung cancer: a multivariate pooled analysis of individual data

(18)F-fluoro-2-deoxy-d-glucose positron emission tomography (PET) complements conventional imaging for diagnosing and staging lung cancer. Two literature-based meta-analyses suggest that maximum standardised uptake value (SUVmax) on PET has univariate prognostic value in nonsmall cell lung cancer (NSCLC). We analysed individual data pooled from 12 studies to assess the independent prognostic value of binary SUVmax for overall survival.After searching the published literature and identifying unpublished data, study coordinators were contacted and requested to provide data on individual patients. Cox regression models stratified for study were used.Data were collected for 1526 patients (median age 64 years, 60% male, 34% squamous cell carcinoma, 47% adenocarcinoma, 58% stage I-II). The combined univariate hazard ratio for SUVmax was 1.43 (95% CI 1.22-1.66) and nearly identical if the SUV threshold was calculated stratifying for histology. Multivariate analysis of patients with stage I-III disease identified age, stage, tumour size and receipt of surgery as independent prognostic factors; adding SUV (HR 1.58, 95% CI 1.27-1.96) improved the model significantly. The only detected interaction was between SUV and stage IV disease.SUV seems to have independent prognostic value in stage I-III NSCLC, for squamous cell carcinoma and for adenocarcinoma.

Value of metabolic tumor volume on repeated 18F-FDG PET/CT for early prediction of survival in locally advanced non-small cell lung cancer treated with concurrent chemoradiotherapy

The aim of this study was to investigate the value of standardized uptake values (SUVs) and metabolic tumor volume (MTV) in (18)F-FDG PET/CT to predict the survival of patients with locally advanced non-small cell lung cancer during the early stage of concurrent chemoradiotherapy.

METHODS

A total of 53 patients were included in the prospective study. All patients were evaluated by (18)F-FDG PET before and after 40 Gy of radiotherapy with a concurrent cisplatin-based chemotherapy regimen. Semiquantitative assessment was used to determine the maximum and mean SUVs (SUV(max) and SUV(mean), respectively) and MTV of the primary tumor. The cutoffs for changes in SUV(max), SUV(mean), and MTV (37.2%, 41.7%, and 29.7%, respectively) determined in a previous study were used with Kaplan-Meier curves to separate the groups. The prognostic significance of PET/CT parameters and other clinical variables was assessed using Cox regression analysis.

RESULTS

Overall survival (OS) at 1 and 2 y was 83.0% (46/53) and 52.8% (28/53), respectively. Survival curves for SUV(mean) and MTV were significantly different using the cutoffs. However, Cox regression analysis showed that the only prognostic factor for OS was a decrease in MTV.

CONCLUSION

The use of repeated (18)F-FDG PET to assess survival early during concurrent chemoradiotherapy is possible in patients with locally advanced non-small cell lung cancer. A decrease in MTV according to (18)F-FDG uptake by the primary tumor correlates with higher long-term OS.

Prognostic Value of Fluoro-D-glucose Uptake of Primary Tumor and Metastatic Lesions in Advanced Nonsmall Cell Lung Cancer

To assess the prognostic value of maximum standardized uptake value (maxSUV) of the primary tumor (maxSUVpt), maxSUV of whole-body tumors (maxSUVwb) and sum of maximum standardized uptake value (sumaxSUV) measured by the sum of maxSUVs of the primary tumor, metastatic lymph nodes, and metastatic lesions per each organ on fluoro-D-glucose-positron emission tomography/computed tomography in advanced non-small cell lung cancer (NSCLC). Eighty-three patients (49 male, 34 female) with advanced NSCLC were enrolled. Seventeen patients had Stage IIIA, 21 Stage IIIB, and 45 Stage IV. maxSUVpt, maxSUVwb, sumaxSUV, age, gender, tumor-cell type, T stage, N stage, overall stage, primary tumor size, and specific treatment were analyzed for correlation with overall survival. Median follow-up duration was 13 months. Fifty patients were dead during a median follow-up time of 11 months and 33 patients were alive with a median time of 15 months. Univariate analysis revealed that overall survival was significantly correlated with sumaxSUV (≥35 vs. <35, P = 0.004), T stage (T4 vs. T1-T3, P = 0.025), overall stage (IV vs. III, P = 0.002), gender (male vs. female, P = 0.029) and specific treatment (no vs. yes, P = 0.011). maxSUVpt and maxSUVwb were not correlated with overall survival with P value of 0.139 and 0.168, respectively. Multivariate analysis identified sumaxSUV, T stage, gender, and specific treatment as independent prognostic indicators. Patients with a sumaxSUV of ≥35 were 1.921 times more likely to die than those with a sumaxSUV of < 35 (P = 0.047). Median survival time was 14 months for patients with sumaxSUV ≥ 35 compared with 20 months for those with sumaxSUV < 35. In patients with metastatic NSCLC, sumaxSUV with cut-off of 35 was much more significant for survival prognosis (P = 0.021). sumaxSUV is a new prognostic measure, independent of tumor stage, gender, and specific treatment in advanced NSCLC. sumaxSUV may be better than maxSUVpt and maxSUVwb in prediction of survival. A large prospective cohort study is necessary to validate these results.

High FDG uptake predicts poorer survival in locally advanced nonsmall cell lung cancer patients undergoing curative radiotherapy, independently of tumor size

OBJECTIVES

Despite radical radiotherapy and chemotherapy (CT), the prognosis of locally advanced nonsmall cell lung cancer (NSCLC) is poor. New prognostic indicators are being looked forward to improve the survival. [18F]-fluorodeoxyglucose (FDG) uptake on PET/CT has been observed as a prognostic marker mainly in early-stage disease. Our aim was to examine the prognostic value of FDG uptake in locally advanced NSCLC.

MATERIALS AND METHODS

Between 2009 and 2011, 103 NSCLC patients underwent disease staging using FDG PET/CT before conformal radiotherapy. Thoracic radiation was administered at a daily fraction of 2 Gy. Total dose was prescribed according to the tumor response against CT. All patients underwent CT. Survival was estimated using the Kaplan-Meier method.

RESULTS

The median age of the patients was 59 years (range 39-83). The median follow-up time was 22.63 months (range 6-48.03 months). There was a statistically significant difference in overall survival (OS) between the low (<10.7) and high (≥10.7) standardized uptake value (SUVmax) groups (p = 0.006) on univariate analysis (3-year OS was 42% in the low (<10.7) and 23% in the high (≥10.7) SUVmax groups). On multivariate analysis with determining tumor size, tumor SUVmax provided additional significant prognostic information on OS (HR 1.046; 95 % CI 1.009-1.085, p = 0.015).

CONCLUSIONS

FDG uptake has predictive value in locally advanced NSCLC, independently of tumor size.

The maximum standardized FDG uptake on PET-CT in patients with non-small cell lung cancer

Background

Non-small cell lung cancer (NSCLC) accounts for approximately 80% of new diagnoses of pulmonary carcinoma. This study investigated the correlation between 18 F-fluorodeoxyglucose uptake in computerized tomography integrated positron emission tomography and tumor size, lymph node metastasis, and distant metastasis in patients with NSCLC.

Methods

The records of 151 NSCLC patients (139 male, 12 female; mean age 59.60 years) were evaluated retrospectively.

Results

Forty-one cases were adenocarcinomas; 45 squamous cell carcinomas; and 65 unspecified NSCLC. When the cases were categorized according to tumor size (group 1, ≤ 3 cm; group 2, > 3 and ≤ 5 cm; group 3, > 5 cm), the maximum standardized uptake value (SUVmax) was significantly lower in groups 1 and 2 compared with group 3 (p = 0.006 for each). Considering all cases, tumor SUVmax was not correlated with age, gender, or histopathological type. Lymph node metastases were pathologically proven in 24 cases: 24% of these were adenocarcinomas, 6% squamous cell carcinomas, and 16% unspecified NSCLC. Neither lymph node involvement nor distant metastases were correlated with tumor SUVmax, although lymph node size was positively correlated with lymph node SUVmax (r = 0.775; p < 0.001).

Conclusions

SUVmax was significantly associated with tumor size, but not with distant metastases or lymph node involvement. Therefore, SUVmax on positron emission tomography is not predictive of the presence of metastases.

Application of FDG-PET/CT in Radiation Oncology

Positron emission tomography (PET)/computed tomography (CT), which combines the advantages of high sensitivity and specificity of PET and high resolution of CT, is a unique tool for cancer management. PET/CT has been widely used in cancer diagnosis and treatment. The article reviews the recent applications of PET/CT in radiation oncology, with a focus on ¹⁸F-fluorodeoxyglucose (FDG)-PET/CT, addressing the applications in treatment planning and treatment response assessment of radiation therapy.

Prognostic value of the standardized uptake value for (18)F-fluorodeoxyglucose in patients with stage IIIB melanoma

Purpose

FDG PET/CT is an excellent tool to detect melanoma metastases and also allows quantification of FDG uptake using standardized uptake value (SUV). The aim of this study was to prospectively investigate the potential prognostic value of SUV for disease-free survival (DFS) and disease-specific survival (DSS) for patients with stage IIIB melanoma.

Methods

From November 2003 to March 2008, all consecutive patients were included in the present study. Inclusion criteria were: palpable, histology- or cytology-proven lymph node metastases of melanoma, and referred to the University Medical Centre Groningen for FDG PET and CT examination. Patients without distant metastases were evaluated. Multivariable survival analysis was performed to determine whether SUV was associated with DFS and DSS (Cox proportional hazard analysis).

Results

In 80 patients (without distant metastases, 65 %) SUV could be measured. Overall 5-year DFS was 41 % (95% CI 26–56 %) and 24 % (95% CI 12–38 %) in patients with a low and high SUVmean (p = 0.02), respectively. Overall 5-year DSS was 48 % (95% CI 31–62 %) and 30 % (95% CI 17–45 %) in patients with a low and high SUVmean (p = 0.04), respectively. In the multivariable analysis, SUVmean was associated with DFS (hazard ratio 1.7; p = 0.048), but was not associated with DSS (hazard ratio 1.6; p = 0.1). The number of positive nodes, extranodal growth and gender were also associated with survival.

Conclusion

FDG uptake in clinically overt nodal melanoma metastases is inversely associated with DFS. Univariate analysis showed an association with DSS. However, after adjustment for potential confounders this association was no longer significant. If these findings are confirmed in larger studies, SUVmean could potentially be used (in addition to the number of positive nodes, tumour size and extranodal growth) as a factor in deciding on adjuvant systemic treatment.

Electronic supplementary material

The online version of this article (doi:10.1007/s00259-012-2182-0) contains supplementary material, which is available to authorized users.

Baseline SUVmax at PET-CT in stage IIIA non-small-cell lung cancer patients undergoing surgery after neoadjuvant therapy: prognostic implication focused on histopathologic subtypes

RATIONALE AND OBJECTIVES

To evaluate the prognostic significance of maximum standardized uptake value (SUVmax) at (18)F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography in patients with stage IIIA non-small-cell lung cancer (NSCLC) who underwent surgical resection after neoadjuvant chemoradiotherapy, focused on the relationship between SUVmax values and tumor histology.

MATERIALS AND METHODS

We retrospectively evaluated the initial SUVmax of 205 patients (112 adenocarcinomas, 82 squamous cell carcinomas [SCCs], and 11 of other histology) with a stage IIIA NSCLC who underwent surgical resection after neoadjuvant chemoradiotherapy, and who were followed for up to 6 years. Clinical data, including histologic type, pathologic response, and treatment, were reviewed, and the relationship between the SUVmax and patient overall survival was examined.

RESULTS

Overall, the 2-year survival rate was 68%. Between the two histologic subtypes of adenocarcinoma and SCC, we noted significant differences in all variables of gender (male predominance in SCC), initial SUVmax (greater in SCC), pathologic response (more complete remission in SCC), and overall survival (better in SCC) (all P values, < .05). SUVmax remained as a sole independent factor for survival in multivariate analysis in whole series (SUVmax cutoff, 13; median survival, 3.0 years vs. 4.0 years; P = .016) and in adenocarcinomas (SUVmax cutoff, 11.5; median survival, 2.6 years vs. 3.6 years; P = .045), but not in SCCs.

CONCLUSION

The initial SUVmax is a sole significant prognostic factor in patients with a surgically resected NSCLC after neoadjuvant chemoradiotherapy, particularly in patients with an adenocarcinoma.

Prognostic factors in stage III non-small cell lung cancer: a review of conventional, metabolic and new biological variables

Lung cancer is one of the most frequently occurring neoplasms and usually has a poor prognosis because most of the patients present with advanced or metastatic disease at the time of diagnosis. Numerous prognostic factors (PFs) have been studied, but the two most prominent, having both prognostic and operational values, are disease stage and performance status. Even if the literature on PFs in lung cancer is impressive, the number of publications specifically dealing with PFs in stage III non-small cell lung cancer (NSCLC) is limited. We reviewed the literature on this topic and separated the available information into three groups: conventional PFs, metabolic criteria (standardized uptake value [SUV] measured on(18)F-FDG-PET) and new biomarkers. Performance status and the distinction between stage IIIA and IIIB confirmed their prognostic value in stage III NSCLC. Other conventional PFs have been suggested such as age, weight loss, response to treatment and some characteristics describing the locoregional extension of the tumour. There is a place for the SUV as a PF for survival in early NSCLC, but its role in stage III NSCLC has to be further assessed. Some new biomarkers involved in cell cycle regulation or in apoptosis have been shown to have potential value. Their role needs to be confirmed in large prospective studies including conventional PFs to determine their independent value as a PF in stage III NSCLC. In conclusion, few PFs have been well evaluated in stage III NSCLC. New studies, taking into account the modifications derived from the 7th international staging system of the UICC, have to be performed.

Measurement of tumor volume by PET to evaluate prognosis in patients with advanced non-small cell lung cancer treated by non-surgical therapy

BACKGROUND

Patients with advanced non-small cell lung cancer (NSCLC) seem to have disparity in prognosis. Accurate prediction of prognosis could be useful in the future to predict individual risk and to develop more aggressive or alternative treatment strategies.

PURPOSE

To evaluate the prognostic value of metabolic tumor volume (MTV) measured by 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) in patients with NSCLC.

MATERIAL AND METHODS

We retrospectively reviewed 120 patients with pathologically proven NSCLC (61 squamous cell carcinomas and 59 adenocarcinomas) who underwent pretreatment 18F-FDG PET. MTV and maximum standardized uptake value (SUVmax) for the primary tumors were measured by 18F-FDG PET. Pretreatment variables (age, sex, American Joint Committee on Cancer [AJCC] stage, histological type, SUVmax, and MTV) were analyzed to identify their correlation with two-year survival. To further evaluate and compare the predictive value of PET parameters, MTV, and SUVmax, time-dependent receiver-operating characteristic curve (ROC) analysis was used.

RESULTS

In the univariate analysis, AJCC stage, histological type, MTV, and SUVmax of primary tumor were significant predictors of survival. On multivariate analysis, independent prognostic factors associated with decreased two-year survival were AJCC stage (hazard ratio [HR] 2.236, P = 0.003), histological type (HR 2.038, P = 0. 004), and MTV (HR 1.016, P = 0.001). SUVmax was not a significant factor (HR 0.96, P = 0.490). On time-dependent ROC analysis, MTV showed good predictive performance for two-year survival consistently better than SUVmax.

CONCLUSION

MTV, a volumetric parameter of 18F-FDG PET, is an important independent prognostic factor for survival and a better predictor of survival than SUVmax for the primary tumor in patients with advanced NSCLC.

Low-Radiation-Dose Modified Small Bowel CT for Evaluation of Recurrent Crohn's Disease

Crohn's disease affects any part of the GI tract, commonly the terminal ileum. To decrease radiation exposure we developed a low-radiation-dose unenhanced CT (modified small Bowel CT, MBCT) to evaluate the small bowel using hyperdense oral contrast. Technique. MBCT was investigated in patients with pathologically proven Crohn's disease presenting with new symptoms from recurrent inflammation or stricture. After ethics board approval, 98 consecutive patients were retrospectively evaluated. Kappa values from two independent reviewers were calculated for presence of obstruction, active inflammation versus chronic stricture, and ancillary findings. Forty-two patients underwent surgery or colonoscopy within 3 months. Results. Kappa was 0.84 for presence of abnormality versus a normal exam and 0.89 for differentiating active inflammation from chronic stricture. Level of agreement for presence of skip areas, abscess formation, and fistula was 0.62, 0.75, and 0.78, respectively. In the subset with “gold standard” follow-up, there was 83% agreement. Conclusions. MBCT is a low-radiation technique with good to very good interobserver agreement for determining presence of obstruction and degree of disease activity in patients with Crohn's disease. Further investigation is required to refine parameters of disease activity compared to CT enterography and small bowel follow through.

Therapeutic implications of molecular imaging with PET in the combined modality treatment of lung cancer

Molecular imaging with PET, and certainly integrated PET-CT, combining functional and anatomical imaging, has many potential advantages over anatomical imaging alone in the combined modality treatment of lung cancer. The aim of the current article is to review the available evidence regarding PET with FDG and other tracers in the combined modality treatment of locally advanced lung cancer. The following topics are addressed: tumor volume definition, outcome prediction and the added value of PET after therapy, and finally its clinical implications and future perspectives. The additional value of FDG-PET in defining the primary tumor volume has been established, mainly in regions with atelectasis or post-treatment effects. Selective nodal irradiation (SNI) of FDG-PET positive nodal stations is the preferred treatment in NSCLC, being safe and leading to decreased normal tissue exposure, providing opportunities for dose escalation. First results in SCLC show similar results. FDG-uptake on the pre-treatment PET scan is of prognostic value. Data on the value of pre-treatment FDG-uptake to predict response to combined modality treatment are conflicting, but the limited data regarding early metabolic response during treatment do show predictive value. The FDG response after radical treatment is of prognostic significance. FDG-PET in the follow-up has potential benefit in NSCLC, while data in SCLC are lacking. Radiotherapy boosting of radioresistant areas identified with FDG-PET is subject of current research. Tracers other than (18)FDG are promising for treatment response assessment and the visualization of intra-tumor heterogeneity, but more research is needed before they can be clinically implemented.

Optimal gating compared to 3D and 4D PET reconstruction for characterization of lung tumours

PURPOSE

We investigated the added value of a new respiratory amplitude-based PET reconstruction method called optimal gating (OG) with the aim of providing accurate image quantification in lung cancer.

METHODS

FDG-PET imaging was performed in 26 lung cancer patients during free breathing using a 24-min list-mode acquisition on a PET/CT scanner. The data were reconstructed using three methods: standard 3D PET, respiratory-correlated 4D PET using a phase-binning algorithm, and OG. These datasets were compared in terms of the maximum SUV (SUVmax) in the primary tumour (main endpoint), noise characteristics, and volumes using thresholded regions of SUV 2.5 and 40% of the SUVmax.

RESULTS

SUVmax values from the 4D method (13.7 ± 5.6) and the OG method (14.1 ± 6.5) were higher (4.9 ± 4.8%, p < 0.001 and 6.9 ± 8.8%, p < 0.001, respectively) than that from the 3D method (13.1 ± 5.4). SUVmax did not differ between the 4D and OG methods (2.0 ± 8.4%, p = NS). Absolute and relative threshold volumes did not differ between methods, except for the 40% SUVmax volume in which the value from the 3D method was lower than that from the 4D method (-5.3 ± 7.1%, p = 0.007). The OG method exhibited less noise than the 4D method. Variations in volumes and SUVmax of up to 40% and 27%, respectively, of the individual gates of the 4D method were also observed.

CONCLUSION

The maximum SUVs from the OG and 4D methods were comparable and significantly higher than that from the 3D method, yet the OG method was visibly less noisy than the 4D method. Based on the better quantification of the maximum and the less noisy appearance, we conclude that OG PET is a better alternative to both 3D PET, which suffers from breathing averaging, and the noisy images of a 4D PET.

The Prognostic Value of the Metabolic Tumor Volume in FIGO stage IA to IIB Cervical Cancer for Tumor Recurrence: Measured by F-18 FDG PET/CT

PURPOSE

The purpose of this study was to evaluate the prognostic value of the metabolic tumor volume (MTV), in FIGO stage IA-IIB cervical cancer patients, measured by F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) imaging.

METHODS

Forty-five patients with invasive cervical cancer who underwent FDG-PET imaging were recruited. Metabolically active tumor regions were delineated on the pretreatment FDG-PET scans by encompassing regions equal to or greater than an standardized uptake value (SUV) of 40% of the peak tumor intensity. The relationship of the metabolic tumor volume (MTV) to the disease-free survival was analyzed. The MTV of the cervical cancer was compared with pathological and clinical prognostic factors, including lymph node metastasis, parametrial invasion, the depth of invasion, resection margins, tumor differentiation and FIGO stages.

RESULTS

Cox proportional hazard regression analysis showed that the MTV was a significant independent predictor of recurrence of cervical cancer (p = 0.027). Patients with an MTV of >20 cm(3) had a significantly reduced disease-free survival compared with patients with an MTV ≤ 20 cm(3) (p = 0.029). The correlation of the MTV with traditional prognostic factors showed significantly higher values in patients that were lymph node (LN) metastasis positive (p = 0.028) and parametrial invasion positive (p = 0.022). The MTV significantly differed among the groups according to tumor differentiation (p = 0.0319) and FIGO stage (p = 0.001).

CONCLUSION

The MTV measured by FDG-PET was an independent prognostic factor for tumor recurrence in patients with stage IA-IIB cervical cancer. These findings must be confirmed by large population based prospective studies.

Four-dimensional positron emission tomography: implications for dose painting of high-uptake regions

PURPOSE

To investigate the behavior of tumor subvolumes of high [18F]-fluorodeoxyglucose (FDG) uptake as seen on clinical four-dimensional (4D) FDG-positron emission tomography (PET) scans.

METHODS AND MATERIALS

Four-dimensional FDG-PET/computed tomography scans from 13 patients taken before radiotherapy were available. The analysis was focused on regions of high uptake that are potential dose-painting targets. A total of 17 lesions (primary tumors and lymph nodes) were analyzed. On each one of the five phases of the 4D scan a classification algorithm was applied to obtain the region of highest uptake and segment the tumor volume. We looked at the behavior of both the high-uptake subvolume, called "Boost," and the segmented tumor volume, called "Target." We measured several quantities that characterize the Target and Boost volumes and quantified correlations between them.

RESULTS

The behavior of the Target could not always predict the behavior of the Boost. The shape deformation of the Boost regions was on average 133% higher than that of the Target. The gross to internal target volume expansion was on average 27.4% for the Target and 64% for the Boost, a statistically significant difference (p < 0.05). Finally, the inhale-to-exhale phase (20%) had the highest shape deformation for the Boost regions.

CONCLUSIONS

A complex relationship between the measured quantities for the Boost and Target volumes is revealed. The results suggest that in cases in which advanced therapy techniques such as dose painting are being used, a close examination of the 4D PET scan should be performed.

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.

Predictive value of 18F-fluorodeoxyglucose uptake by positron emission tomography for non-small cell lung cancer patients treated with radical radiotherapy

The purpose of this study is to assess predictive value of the positron emission tomography (PET) with 18F-fluoro-deoxyglucose (FDG) for recurrence and survival after radiotherapy (RT) for non-small cell lung cancer (NSCLC). One hundred forty-nine patients underwent pretreatment PET (n = 67) or PET/computed tomography (CT) (n = 82) and definitive RT for NSCLC. We evaluated the relationship between the maximum-pixel standardized uptake value (SUV(max)) and clinical tumor features. Univariate Cox proportional hazard analysis (UVA) was used to quantify the risk for local-regional recurrence, distant metastases, and death. Multivariate Cox proportional hazard analysis (MVA) was used to assess the potential independent effect of SUV(max). In the PET group, T1 tumors showed significantly lower SUV(max) than T2, T3, and T4 tumors; in the PET/CT group, T1 tumors showed significantly lower SUV(max) than T3 and T4 tumors. A high SUV(max )was a negative factor for local-regional control (LRC) (p < 0.001), distant metastasis-free survival (DMFS) (p = 0.02), and overall survival (OS) (p = 0.001) on UVA in the PET group. However, the significance decreased to 0.05 for LRC, 0.04 for DMFS, and 0.04 for OS by MVA when tumor size was included in the analysis. A high SUV(max) was not a negative factor for LRC, DMFS, or OS on UVA and MVA in the PET/CT group. In conclusion, assessment of predictive value of SUV(max) for NSCLC requires consideration of primary tumor size, and the evidence is not sufficient to suggest that FDG uptake in a primary NSCLC provides prognostic information.

Use of new imaging techniques to predict tumour response to therapy

Imaging of tumour response to therapy has steadily evolved over the past few years as a result of advances in existing imaging modalities and the introduction of new functional techniques. The use of imaging as an early surrogate biomarker of response is appealing, because it might allow for a window of opportunity during which treatment regimens can be tailored accordingly, depending on the expected response. The clinical effect of this would ultimately result in a reduction in morbidity and undue costs. The aim of this review is to describe the potential of various new imaging techniques as biomarkers of early tumour response. We have reviewed the literature and identified studies that have assessed these techniques, such as diffusion-weighted MRI, dynamic contrast-enhanced MRI, magnetic resonance spectroscopy, and 18-fluorodeoxyglucose-PET as early response indicators, and highlight the current clinical awareness of their use.

Measurement of tumor volume by PET to evaluate prognosis in patients with head and neck cancer treated by chemo-radiation therapy

PURPOSE

To evaluate the prognostic value of the metabolic tumor volume measured on 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging and other clinical factors in patients treated for locally advanced head-and-neck cancer (HNC) at a single institution.

MATERIALS AND METHODS

Between June 2005 and August 2008, 59 patients with HNC that underwent pretreatment FDG-PET studies received neoadjuvant chemotherapy and radiation therapy. Metabolically active tumor regions were delineated on the pretreatment PET scans by a fixed SUV of 2.5. We evaluated the relationship of the 18F-fluorodeoxyglucose-PET maximum standardized uptake value (SUV) and the metabolic tumor volume (MTV) with the progression-free survival (PFS) and overall survival (OS).

RESULTS

The MTV and lymph node metastasis were predictive of the PFS and OS. The lymph node status did not correlate with the MTV. A higher MTV of 9.3 cm(3) was significantly associated with an increased risk of recurrence (2.19-fold, p = 0.006) and death (1.62-fold, p = 0.051). Separation of patients with tumor volumes <or= 9.3 cm(3) and no lymph node disease vs. any other combination was strongly predictive of the PFS and the OS.

CONCLUSIONS

MTV and lymph node status were prognostic values associated with survival. Quantitative measurement of tumor volume separates patients with a good prognosis from those with a poorer prognosis. A subset of patients with relatively small tumors and no lymph node involvement did very well.