Follow-up with 18FDG-PET–CT after radical radiotherapy with or without chemotherapy allows the detection of potentially curable progressive disease in non-small cell lung cancer patients: A prospective study

Role of 18F-FDG PET/CT in establishing new clinical and therapeutic modalities in lung cancer. A short review

Lung cancer is a fairly common malignancy. An early diagnosis and a reliable staging and re-staging with the aim to detect both local and distant relapse are of utmost importance in planning the therapeutic management. The imaging diagnostic work-up of patients with lung cancer usually includes conventional imaging (chest X-ray, contrast-enhanced CT, bone scan) and more recently ¹⁸F-FDG PET/CT. Great advances in the management of lung cancer are based on the information provided by ¹⁸F-FDG PET/CT, as it supplies both metabolic and anatomic information (better localisation). There is vast evidence in the literature demonstrating its utility in (a) characterising benign versus malignant solitary nodules, (b) staging and re-staging lung cancer, (c) guiding the type of therapy, (d) monitoring treatment response and (e) predicting outcome. In particular, given its specificity in differentiating ¹⁸F-FDG-avid relapse from post-surgical changes or post-radiation fibrosis (which do not take up ¹⁸F-FDG), PET/CT can detect recurrent disease after initial treatment and (being a whole-body technique) has demonstrated high accuracy in the detection of distant metastases or secondary tumours. In conclusion, ¹⁸F-FDG PET/CT can be considered a highly accurate and reliable method for staging and re-staging lung cancer, and is highly effective in guiding personalised therapies.

Analysis of Relapse Events After Definitive Chemoradiotherapy in Locally Advanced Non-Small-Cell Lung Cancer Patients

BACKGROUND

The appropriate follow-up frequency after definitive chemoradiotherapy (CRT) for locally advanced non-small-cell lung cancer patients is unknown. Although surveillance guidelines have been proposed, very few data support current recommendations. Here we analyze relapse events after CRT and investigate whether symptomatic relapses versus those detected by surveillance imaging influences outcomes.

PATIENTS AND METHODS

Stage III non-small-cell lung cancer patients treated with CRT at our institution between 2005 and 2014 were retrospectively analyzed. Relapse events were grouped into posttreatment intervals and analyzed with cumulative tables. Time to relapse and overall survival (OS) were compared between patients with relapse detection via symptomatic presentation versus surveillance imaging.

RESULTS

A total of 211 patients were identified for analysis. The median follow-up was 43 months for patients alive at the time of analysis. The median age was 63 years, and equal proportions had IIIA or IIIB disease. A total of 135 patients (64%) experienced disease relapse, and of these, 74% did so within 12 months. In those who did not experience relapse at ≤ 12 months, 16%, 6%, and < 5% experienced relapse during 12 to 24, 24 to 36, and > 36 months of follow-up, respectively. In patients with relapse, 56% presented symptomatically, which led to inferior median OS compared to those identified by surveillance imaging (23 vs. 36 months; P = .013).

CONCLUSION

This study identified that most relapses occur within 1 year of completing CRT, and approximately half of these occur within 6 months. A symptomatic relapse led to inferior OS. More aggressive surveillance imaging may therefore identify asymptomatic relapses that are amenable to earlier salvage therapy.

Surveillance imaging following definitive radiotherapy for non-small cell lung cancer: What is the clinical impact?

Lung cancer is the leading cause of cancer death worldwide. Recurrence rates at all stages are high, but evidence-based post-treatment surveillance imaging strategies to detect recurrence are poorly defined, and salvage options are frequently limited. A number of national and international oncology guidelines address post-treatment imaging, but are largely based on low-level, retrospective evidence because of a paucity of high-quality data, particularly in regard to cost-effectiveness and quality-of-life endpoints. Given the lack of randomized data addressing appropriate surveillance imaging modality and interval following definitive treatment of lung cancer, there remains an unmet clinical need. Meaningful surveillance endpoints should include the financial impact, patient quality-of-life outcomes, and access-to-care issues associated with intensive follow-up to ensure that guidelines reflect quality and sustainability. A need for prospective randomized data on the subject of imaging surveillance after definitive local therapy remains an unmet need, and an opportunity for collaboration and further research.

Clinical Impact of Frequent Surveillance Imaging in the First Year Following Chemoradiation for Locally Advanced Non-small-cell Lung Cancer

OBJECTIVE

Uncertainty exists regarding the optimal surveillance imaging schedule following definitive chemoradiation (CRT) for locally advanced non-small-cell lung cancer (LA-NSCLC) with regards to both frequency and modality. We sought to document the clinical impact of frequent (at least every 4 months) surveillance imaging.

MATERIALS AND METHODS

The records of all patients treated with CRT for stage IIIA/IIIB NSCLC between August 1999 and April 2014 were reviewed. Patients were included if they underwent frequent (at least every 4 months) chest computed tomography or positron emission tomography for routine surveillance following CRT for at least 1 year or until progression or death. Radiographic findings and clinical interventions within the first year were identified.

RESULTS

We identified 145 patients with LA-NSCLC treated with CRT, 63 with eligible imaging. Median age was 63.6 years (range, 41.0-86.9 years). Asymptomatic recurrence was radiographically detected in 38 (60.3%). Twenty-one (33.3%) initiated systemic therapy. Two (3.2%) underwent definitive-intent treatment for isolated disease, including lobectomy for a histologically distinct primary NSCLC and stereotactic radiotherapy for an isolated recurrence, both of whom subsequently progressed. Eleven patients (17.5%) received no further therapy. Five patients (7.9%) underwent additional diagnostic procedures for false-positive findings.

CONCLUSIONS

Frequent surveillance within the first year following CRT for LA-NSCLC lung cancer detects asymptomatic recurrence in a high proportion of patients. However, definitive-intent interventions were infrequent. The predominant benefit of frequent surveillance appears to be expedient initiation of palliative systemic therapy. Evidence-based algorithms for surveillance are needed, and should account for expected patient tolerance of and willingness to undergo additional cancer-directed therapies.

Influence of Surveillance PET/CT on Detection of Early Recurrence After Definitive Radiation in Stage III Non-small-cell Lung Cancer

BACKGROUND

There are few data to support the use of varying imaging modalities in evaluating recurrence in non-small-cell lung cancer (NSCLC). We compared the efficacy of surveillance positron emission tomography (PET)/computed tomography (CT) versus CT scans of the chest in detecting recurrences after definitive radiation for NSCLC.

MATERIALS AND METHODS

We retrospectively analyzed 200 patients treated between 2000 and 2011 who met the inclusion criteria of stage III NSCLC, completion of definitive radiation treatment, and absence of recurrence within the initial 6 months. These patients were then grouped on the basis of the use of PET/CT imaging during postradiation surveillance. Patients who received ≥ 1 PET/CT scans within 6 months of the end of radiation treatment were placed in the PET group whereas all others were placed in the CT group. We compared survival times from the end of treatment to the date of death or last follow-up using log rank tests. Multivariate analysis was conducted to identify factors associated with decreased survival.

RESULTS

In the entire cohort, median event-free survival (EFS) was 26.7 months, and median overall survival (OS) was 41.2 months. The CT group had a median EFS of 21.4 months versus 29.4 months for the PET group (P = .59). There was no difference in OS between the CT and PET groups (median OS of 41.2 and 41.3 months, respectively; P = .59). There was also no difference in local recurrence-free survival or distant metastases-free survival between the CT-only and PET/CT groups (P = .92 and P = .30, respectively). Similarly, in multivariate analysis, stratification into the PET group was not associated with improved EFS (hazard ratio [HR], 0.90; 95% confidence interval [CI], 0.61-1.34; P = .60) or OS (HR, 1.2; 95% CI, 0.83-1.7; P = .34).

CONCLUSIONS

In stage III NSCLC patients treated with definitive radiation and without early recurrence, PET/CT scan surveillance did not result in decreased time to detection of locoregional or distant recurrence or improved survival.

Surveillance Practice Patterns after Curative Intent Therapy for Stage I Non-Small-Cell Lung Cancer in the Medicare Population

OBJECTIVES

Recurrence after treatment for non-small cell lung cancer (NSCLC) is common, and routine imaging surveillance is recommended by evidence-based guidelines. Little is known about surveillance patterns after curative intent therapy for early stage NSCLC. We sought to understand recent practice patterns for surveillance of stage I NSCLC in the first two years after curative intent therapy in the Medicare population.

MATERIALS AND METHODS

Using the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database we selected patients diagnosed with stage I NSCLC between 1998 and 2008. We studied adherence to surveillance guidelines based on specialty society recommendations for chest radiography and computed tomography (CT) scanning. We also tracked the use of Positron Emission Tomography (PET) scans, which are not recommended for surveillance. We calculated the percent of patients who received guideline-adherent surveillance imaging and used logistic regression to determine associations between patient and provider factors and guideline adherence.

RESULTS

Overall, 61.4% of patients received guideline-adherent surveillance during the initial 2 years after treatment. Use of CT scans in the first year after treatment increased from 47.4% in 1998-78.5% in 2008, and PET use increased from 5.8% to 28.9%. Adherence with surveillance imaging was associated with younger age, higher income, more comorbidities, access to primary care, and receipt of SBRT as the primary treatment.

CONCLUSIONS

Adherence to specialty society guidelines for surveillance after treatment for stage I NSCLC was poor in this population of Medicare beneficiaries, with less than two-thirds of patients receiving recommended imaging, and almost 30% receiving non-recommended PET scans.

Monitoring and management of lung cancer patients following curative-intent treatment: clinical utility of 2-deoxy-2-[fluorine-18]fluoro-d-glucose positron emission tomography/computed tomography

A large number of studies have demonstrated that 2-deoxy-2-[fluorine-18]fluoro-d-glucose positron emission tomography/computed tomography (FDG-PET/CT) is superior to conventional modalities for the diagnosis of lung cancer and the evaluation of the extent of the disease. However, the efficacy of PET/CT in a follow-up surveillance setting following curative-intent treatments for lung cancer has not yet been established. We reviewed previous papers and evaluated the potential efficacy of PET-CT in the setting of follow-up surveillance. The following are our findings: 1) PET/CT is considered to be superior or equivalent to conventional modalities for the detection of local recurrence. However, inflammatory changes and fibrosis after treatments in local areas often result in false-positive findings; 2) the detection of asymptomatic distant metastasis is considered to be an advantage of PET/CT in a follow-up setting. However, it should be noted that detection of brain metastasis with PET/CT has some limitation, similar to its use in pretreatment staging; 3) additional radiation exposure and higher medical cost arising from the use of PET/CT should be taken into consideration, particularly in patients who might not have cancer after curative-intent treatment and are expected to have a long lifespan. The absence of any data regarding survival benefits and/or improvements in quality of life is another critical issue. In summary, PET/CT is considered to be more accurate and sensitive than conventional modalities for the detection of asymptomatic recurrence after curative-intent treatments. These advantages could modify subsequent management in patients with suspected recurrence and might contribute to the selection of appropriate treatments for recurrence. Therefore, PET/CT may be an alternative to conventional follow-up modalities. However, several important issues remain to be solved. PET/CT in a follow-up surveillance setting is generally not recommended in clinical practice at the moment.

Planned FDG PET-CT Scan in Follow-Up Detects Disease Progression in Patients With Locally Advanced NSCLC Receiving Curative Chemoradiotherapy Earlier Than Standard CT

The role of positron emission tomography-computed tomography (PET-CT) in surveillance of patients with nonsmall cell lung cancer (NSCLC) treated with curatively intended chemoradiotherapy remains controversial. However, conventional chest X-ray and computed tomography (CT) are of limited value in discriminating postradiotherapy changes from tumor relapse. The aim of this study was to evaluate the clinical value of PET-CT scan in the follow-up for patients with locally advanced (LA) NSCLC receiving concomitant chemoradiotherapy (CCRT).Between 2009 and 2013, eligible patients with stages IIB-IIIB NSCLC were enrolled in the clinical trial NARLAL and treated in Odense University Hospital (OUH). All patients had a PET-CT scan scheduled 9 months (PET-CT9) after the start of the radiation treatment in addition to standard follow-up (group A). Patients who presented with same clinical stage of NSCLC and received similar treatment, but outside protocol in OUH during this period were selected as control group (group B). Patients in group B were followed in a conventional way without PET-CT9. All patients were treated with induction chemotherapy followed by CCRT.Group A included 37 and group B 55 patients. The median follow-up was 16 months. Sixty-six (72%) patients were diagnosed with progression after treatment. At the time of tumor progression, patients in group A had better performance status (PS) than those in group B (P = 0.02). Because of death (2 patients), poor PS (3) or retreatment of relapse (9), only 23 patients had PET-CT9 in group A. Eleven (48%) patients were firstly diagnosed with progression by PET-CT9 without any clinical symptoms of progression. The median progression-free survival (PFS) was 8.8 months in group A and 12.5 months in group B (P = 0.04). Hazard function PFS showed that patients in group A had higher risk of relapse than in group B.Additional FDG PET-CT scan at 9 months in surveillance increases probability of early detection of disease progression in advanced NSCLC patients treated with curatively intended CCRT.

Post-therapeutic positron emission tomography/computed tomography for early detection of non-small cell lung cancer recurrence

Patients after curative treatment of non-small cell lung cancer (NSCLC) have a high risk of loco-regional and/or distant tumor recurrence, especially within the first two years. Timely and accurate detection of recurrence is crucial in order to start salvage or palliative therapies with the overall goal of increasing patients' survival and quality of life. However, with the emerging use of non-surgical curative-intended therapies, follow-up of patients becomes even more challenging, as local recurrence has to be distinguished from various post-therapeutic changes at the site of the primary cancer. Integrated positron emission tomography/computed tomography (PET/CT), which is already an established imaging modality in the staging of NSCLC, is increasingly used in recurrence surveillance algorithms. By detailed morphological information being combined with additional information about the metabolic activity of suspicious sites, determination of suspicious lesions as benign or malignant can be improved. This article reviews the value of integrated PET/CT in assessing recurrence in NSCLC patients after potentially curative surgery and after curative-intended non-surgical therapies and raises as well the issue of cost-effectiveness of PET/CT for follow-up.

Metabolic response assessment with 18F-FDG PET/CT: inter-method comparison and prognostic significance for patients with non-small cell lung cancer

OBJECTIVE

This study aimed to (1) compare the agreement of two evaluation methods of metabolic response in patients with non-small cell lung cancer (NSCLC) and determine their prognostic value and (2) explore an optimal cutoff of metabolic reduction to distinguish a more favorable subset of responders.

METHODS

This is a secondary analysis of prospective studies. Enrolled patients underwent 18F-PET/CT within 2 weeks before, during, and months after radiotherapy (post-RT). Metabolic response was assessed using both Peter MacCallum (PM) method of qualitative visual assessment and University of Michigan (UM) method of semiquantitative measurement. The agreement between two methods determined response, and their prediction of outcome was analyzed.

RESULTS

Forty-four patients with median follow-up of 25.2 months were analyzed. A moderate agreement was observed between PM- and UM-based response assessment (Kappa coefficient = 0.434), unveiling a significant difference in CMR rate (p = 0.001). Categorical responses derived from either method were significantly predictive of overall survival (OS) and progression-free survival (PFS) (p < 0.0001). Numerical percentage decrease of FDG uptake also showed significant correlations with survival, presenting a hazard ratio of 0.97 for both OS and PFS. A 75 % of SUV decrease was found to be the optimal cutoff to predict OS and 2-year progression.

CONCLUSIONS

There was a modest discrepancy in metabolic response rates between PM and UM criteria, though both could offer predictive classification for survival. The percentage decrease provides an ordinal value that correlates with prolonged survival, recommending 75 % as the optimal threshold at identifying better responders.

Lung cancer

(18)F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) plays a key role in the evaluation of undiagnosed lung nodules, when primary lung cancer is strongly suspected, or when it has already been diagnosed by other techniques. Although technical factors may compromise characterization of small or highly mobile lesions, lesions without apparent FDG uptake can generally be safely observed, whereas FDG-avid lung nodules almost always need further evaluation. FDG-PET/CT is now the primary staging imaging modality for patients with lung cancer who are being considered for curative therapy with either surgery or definitive radiation therapy.

Estimate of the impact of FDG-avidity on the dose required for head and neck radiotherapy local control

Background and purpose

Although FDG-avid tumors are recognized as a potential target for dose escalation, there is no clear basis for selecting a boost dose to counter this apparent radioresistance. Using a novel analysis method, based on the new concept of an outcome-equivalent dose, we estimate the extra dose required to equalize local control between FDG-avid and non-avid head and neck tumors.

Materials and methods

Based on a literature review, five reports of head and neck cancer (423 patients in total), along with an internal validation dataset from our institution (135 oropharynx patients), were used in this analysis. To compensate for the heterogeneity among multi-institutional patient cohorts and corresponding treatment techniques, local control data of the cohorts were fit to a single dose–response curve with a clinically representative steepness (γ₅₀ = 2), thereby defining an ‘outcome-equivalent dose’ (OED) for each institutional cohort. Separate dose–response curves were then determined for the FDG-avid and FDG-non-avid patient cohorts, and the ratio of TD₅₀ (tumor dose required for 50% of control) values between the high- and low-FDG-uptake groups (TD_50,high/TD_50,low) was estimated, resulting in an estimated metabolic dose-modifying factor (mDMF) due to FDG-avidity.

Results

For individual datasets, the estimated mDMFs were found to be in the range of 1.07–1.62, decreasing if the assumed slope (γ₅₀) increased. Weighted logistic regression for the six datasets resulted in a mDMF of 1.19 [95% CI: 1.04–1.34] for a γ₅₀ value of 2, which translates to a needed dose increase of about 1.5 Gy per unit increase in the maximum standardized uptake value (SUV_m) of FDG-PET [95% CI: 0.3–2.7]. Assumptions of lower or higher γ₅₀ values (1.5 or 2.5) resulted in slightly different mDMFs: 1.26 or 1.15, respectively. A validation analysis with seven additional datasets, based on relaxed criteria, was consistent with the estimated mDMF.

Conclusions

We introduced a novel outcome-equivalent dose analysis method to estimate the dose– response modifying effect of FDG uptake variation. To reach equal response rates, FDG-avid tumors are likely to require 10% to 30% more dose than FDG-non-avid tumors. These estimates provide a rational starting point for selecting IMRT boosts for FDG-avid tumors. However, independent tests and refinements of the estimated dose-modifying effect, using high-quality prospective clinical trial data, are needed.

Detecting lung cancer relapse using self-evaluation forms weekly filled at home: the sentinel follow-up

PURPOSE

We aimed to assess if patients' ratings of symptoms can be used to provide an early indication of disease recurrence or progression in lung cancer. We proposed a simple self-evaluation form made of six clinical parameters weekly scored by patients at home as a follow-up--here named sentinel--to improve relapse detection. Its performances were compared to those of a routine imaging follow-up.

METHODS

Patients with lung cancer were prospectively recruited to weekly fill a form at home for self-assessing weight, fatigue, pain, appetite, cough, and breathlessness during at least 4 months. Each patient reported weight and assessed the severity of each symptom by grading it from 0 (no symptom) to 3 (major symptom). A score was retrospectively designed for discriminating patients with relapse from those without. Accuracy of relapse detection was then compared to values of the routine planned imaging.

RESULTS

Forty-three patients were included in our center and recruited for 16 weeks or more follow-up during which at least one tumor imaging assessment was performed (CT scan or PET-CT). Forty-one completed the form weekly. Sensitivity, specificity, and positive and negative predictive values of sentinel were high (86, 93, 86 % and 93 vs 79, 96, 92, and 90 % for routine imaging--p = ns) and well correlated with relapse (pχ2 > 0.001). Moreover, relapses were detectable with sentinel on average 6 weeks earlier than the planned imaging.

CONCLUSION

This study suggests that a personalized cancer follow-up based on a weekly self-evaluation of six symptoms is feasible and may be accurate for earlier detection of lung cancer relapse, allowing integration in electronic devices for real-time patient outcome follow-up.

Differentiation of tumor recurrence from radiation-induced pulmonary fibrosis after stereotactic ablative radiotherapy for lung cancer: characterization of 18F-FDG PET/CT findings

OBJECTIVE

Stereotactic ablative radiotherapy (SABR), also known as stereotactic body radiotherapy (SBRT), is now a standard treatment option for patients with stage I non-small cell lung cancer or oligometastatic lung tumor who are medically inoperable or medically operable but refuse surgery. When mass-like consolidation is observed on follow-up CT after SABR, it is sometimes difficult to differentiate tumor recurrence from SABR-induced pulmonary fibrosis. In this study, we evaluated the role of (18)F-fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG-PET/CT) in differentiating tumor recurrence from radiation fibrosis after SABR.

METHODS

Between June 2006 and June 2009, 130 patients received SABR for stage I non-small cell lung cancer or metastatic lung cancer at our institution. Fifty-nine patients of them were imaged with FDG-PET/CT after SABR. There were a total of 137 FDG-PET/CT scans for retrospective analysis. The FDG uptake in the pulmonary region was assessed qualitatively using a 3-point scale (0, none or faint; 1, mild; or 2, moderate to intense), and the shape (mass-like or non mass-like) was evaluated. For semi-quantitative analysis, the maximum standardized uptake value (SUV(max)) was calculated.

RESULTS

Sixteen of 59 patients had local failure. In recurrent tumor, the combination of intensity grade 2 and mass-like shape was most common (21/23; 91%). By contrast, in cases of radiation fibrosis, the combination of intensity grade 0 or 1 and non mass-like shape was most common (48/59; 81%). The SUV(max) of tumor recurrence after 12 months was significantly higher than that of radiation fibrosis (8.0 ± 3.2 vs. 2.1 ± 0.9, p < 0.001), and all tumor recurrence showed the SUV(max) > 4.5 at diagnosis of local failure. At ≥12 months after SABR, these two variables, the combination of intensity 2 and mass-like FDG uptake or SUV(max) > 4.5 acquired a significant high predictive value of local recurrence, finding sensitivity 100% and specificity 100% for both of them.

CONCLUSIONS

The combination of FDG uptake patterns and SUV(max) was useful for distinguishing tumor recurrence from radiation fibrosis after SABR.

Survival benefits from follow-up of patients with lung cancer: a systematic review and meta-analysis

INTRODUCTION

The burden of lung cancer is high for patients and carers. Care after treatment may have the potential to impact on this. We reviewed the published literature on follow-up strategies intended to improve survival and quality of life.

METHODS

We systematically reviewed studies comparing follow-up regimes in lung cancer. Primary outcomes were overall survival (comparing more intensive versus less intensive follow-up) and survival comparing symptomatic with asymptomatic recurrence. Quality of life was identified as a secondary outcome measure. Hazard ratios (HRs) and 95% confidence intervals from eligible studies were synthesized.

RESULTS

Nine studies that examined the role of more intensive follow-up for patients with lung cancer were included (eight observational studies and one randomized controlled trial). The studies of curative resection included patients with non-small cell lung cancer Stages I to III disease, and studies of palliative treatment follow-up included limited and extensive stage patients with small cell lung cancer. A total of 1669 patients were included in the studies. Follow-up programs were heterogeneous and multifaceted. A nonsignificant trend for intensive follow-up to improve survival was identified, for the curative intent treatment subgroup (HR: 0.83; 95% confidence interval: 0.66-1.05). Asymptomatic recurrence was associated with increased survival, which was statistically significant HR: 0.61 (0.50-0.74) (p < 0.01); quality of life was only assessed in one study.

CONCLUSIONS

This meta-analysis must be interpreted with caution due to the potential for bias in the included studies: observed benefit may be due to systematic differences in outcomes rather than intervention effects. Some benefit was noted from intensive follow-up strategies. More robust data, in the form of randomized controlled trials, are needed to confirm these findings as the review is based primarily on observational studies. Future research should also include patient-centered outcomes to investigate the impact of follow-up regimes on living with lung cancer and psychosocial well-being.

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.

A systematic review of PET and PET/CT in oncology: a way to personalize cancer treatment in a cost-effective manner?

BACKGROUND

A number of diagnostic tests are required for the detection and management of cancer. Most imaging modalities such as computerized tomography (CT) are anatomical. However, positron emission tomography (PET) is a functional diagnostic imaging technique using compounds labelled with positron-emitting radioisotopes to measure cell metabolism. It has been a useful tool in studying soft tissues such as the brain, cardiovascular system, and cancer. The aim of this systematic review is to critically summarize the health economic evidence of oncologic PET in the literature.

METHODS

Eight electronic databases were searched from 2005 until February 2010 to identify economic evaluation studies not included in previous Health Technology Assessment (HTA) reports. Only full health economic evaluations in English, French, or German were considered for inclusion. Economic evaluations were appraised using published quality criteria for assessing the quality of decision-analytic models. Given the variety of methods used in the health economic evaluations, the economic evidence has been summarized in qualitative form.

RESULTS

From this new search, 14 publications were identified that met the inclusion criteria. All publications were decision-analytic models and evaluated PET using Fluorodeoxyglucose F18 (FDG-PET). Eight publications were cost-effectiveness analyses; six were cost-utility analyses. The studies were from Australia, Belgium, Canada, France, Italy, Taiwan, Japan, the Netherlands, the United Kingdom, and the United States. In the base case analyses of these studies, cost-effectiveness results ranged from dominated to dominant. The methodology of the economic evaluations was of varying quality. Cost-effectiveness was primarily influenced by the cost of PET, the specificity of PET, and the risk of malignancy.

CONCLUSIONS

Owing to improved care and less exposure to ineffective treatments, personalized medicine using PET may be cost-effective. However, the strongest evidence for the cost-effectiveness of PET is still in the staging of non-small cell lung cancer. Management decisions relating to the assessment of treatment response or radiotherapy treatment planning require further research to show the impact of PET on patient management and its cost-effectiveness. Because of the potential for increased patient throughput and the possible greater accuracy, the cost-effectiveness of PET/CT may be superior to that of PET. Only four studies of the cost-effectiveness of PET/CT were found in this review, and this is clearly an area for future research.

[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.

18FDG-PET-CT in the follow-up of non-small cell lung cancer patients after radical radiotherapy with or without chemotherapy: an economic evaluation

BACKGROUND

The optimal follow-up strategy of non-small cell lung cancer (NSCLC) patients after curative intent therapy is still not established. In a recent prospective study with 100 patients, we showed that a FDG-PET-CT 3 months after radiotherapy (RT) could identify progression amenable for curative treatment in 2% (95% confidence interval (CI): 1-7%) of patients, who were all asymptomatic. Here, we report on the economic evaluation of this study.

PATIENTS AND METHODS

A decision-analytic Markov model was developed in which the long-term cost-effectiveness of 3 follow-up strategies was modelled with different imaging methods 3 months after therapy: a PET-CT scan; a chest CT scan; and conventional follow-up with a chest X-ray. A probabilistic sensitivity analysis was performed to account for uncertainty. Because the results of the prospective study indicated that the advantage seems to be confined to asymptomatic patients, we additionally examined a strategy where a PET-CT was applied only in the subgroup of asymptomatic patients. Cost-effectiveness of the different follow-up strategies was expressed in incremental cost-effectiveness ratios (ICERs), calculating the incremental costs per quality adjusted life year (QALY) gained.

RESULTS

Both PET-CT- and CT-based follow-up were more costly but also more effective than conventional follow-up. CT-based follow-up was only slightly more effective than conventional follow-up, resulting in an incremental cost-effectiveness ratio (ICER) of euro 264.033 per QALY gained. For PET-CT-based follow-up, the ICER was euro 69.086 per QALY gained compared to conventional follow-up. The strategy in which a PET-CT was only performed in the asymptomatic subgroup resulted in an ICER of euro 42.265 per QALY gained as opposed to conventional follow-up. With this strategy, given a ceiling ratio of euro 80.000, PET-CT-based follow-up had the highest probability of being cost-effective (73%).

CONCLUSIONS

This economic evaluation shows that a PET-CT scan 3 months after (chemo)radiotherapy with curative intent is a potentially cost-effective follow-up method, and is more cost-effective than CT alone. Applying a PET-CT scan only in asymptomatic patients is probably as effective and more cost-effective. It is worthwhile to perform additional research to reduce uncertainty regarding the decision concerning imaging in the follow-up of NSCLC.