Economic evaluation of PET and PET/CT in oncology: evidence and methodologic approaches

PET/CT imaging in gynecologic malignancies: a critical overview of its clinical impact and our retrospective single center analysis

Gynecologic cancers represent a major global healthcare problem since they are associated with a significant mortality and morbidity. Over the last decade, considerable efforts have been spent in the development and optimization of novel diagnostic modalities to achieve an early diagnosis, aid in choosing appropriate treatment, improving long term surveillance, with the ultimate goal of increasing survival of gynecologic cancer patients. A growing body of evidence defines PET/CT as one of the most powerful tools for tumor, nodal and metastasis (TNM) cancer staging both in pre-treatment and in post treatment follow-up settings. At any phase of cancer evaluation, detection of metastasis represents one of the most critical impediments to the cure of tumor; traditional diagnostic imaging modalities, such as computed tomography (CT), are frequently found to inadequately stage the tumor, based on subsequent outcomes. As a consequence, patients may undergo pointless surgery for disease that could be treated with local medical therapies. In the setting of restaging, the ability to describe primary lesion, lymph nodes, possible metastases to peritoneum, bone, liver, lungs and brain renders PET/CT a potential alternative for a series of tests, including bone scanning, MRI or ultrasound, diagnostic CT, lymph node surgical sampling, that need to be used in combination in order to obtain a level of clinical confidence. In this review, we describe, the theoretical advantage and prognostic implications of PET/CT in the management of gynecologic cancer patients.

Role of (18F) 2-fluoro-2-deoxyglucose positron emission tomography in upper gastrointestinal malignancies

The role of whole-body FDG [(¹⁸F) 2-fluoro-2-deoxyglucose] positron emission tomography (PET) scanning as an imaging modality in the management of patients with malignancy has evolved enormously over the past two decades. FDG-PET has demonstrated significant efficacy in the staging, prognostication and detection of occult metastatic disease in malignancies of the gastrointestinal tract, in addition to assessment of the response to cytotoxic chemotherapy in a more timely manner than has traditionally been possible by more conventional imaging tools. The sensitivity and specificity of FDG-PET for the detection and staging of malignancy depend not only on the site and size of the primary tumor and metastases, but also on histological cell type, reflecting underlying disparities in glucose metabolism. The metabolic response to neo-adjuvant chemotherapy or to chemo-radiotherapy in cancers of the gastro-esophageal junction or stomach has been demonstrated in several prospective studies to correlate significantly with both the histological tumor response to treatment and with consequent improvements in overall survival. This may offer a future paradigm of personalized treatment based on the PET response to chemotherapy. FDG-PET has been less successful in efforts to screen for and detect recurrent upper gastrointestinal malignancies, and in the detection of low volume metastatic peritoneal disease. Efforts to improve the accuracy of PET include the use of novel radiotracers such as (¹⁸F) FLT (3-deoxy-3-fluorothymidine) or ¹¹C-choline, or fusion PET-CT with concurrent high-resolution computed tomography. This review focuses on the role of FDG-PET scanning in staging and response assessment in malignancies of the upper gastrointestinal tract, specifically gastric, esophageal and pancreas carcinoma.

A fluoride-derived electrophilic late-stage fluorination reagent for PET imaging

The unnatural isotope fluorine-18 ((18)F) is used as a positron emitter in molecular imaging. Currently, many potentially useful (18)F-labeled probe molecules are inaccessible for imaging because no fluorination chemistry is available to make them. The 110-minute half-life of (18)F requires rapid syntheses for which [(18)F]fluoride is the preferred source of fluorine because of its practical access and suitable isotope enrichment. However, conventional [(18)F]fluoride chemistry has been limited to nucleophilic fluorination reactions. We report the development of a palladium-based electrophilic fluorination reagent derived from fluoride and its application to the synthesis of aromatic (18)F-labeled molecules via late-stage fluorination. Late-stage fluorination enables the synthesis of conventionally unavailable positron emission tomography (PET) tracers for anticipated applications in pharmaceutical development as well as preclinical and clinical PET imaging.

Clinical impact of FDG PET-CT in patients with potentially operable metastatic colorectal cancer

AIM

To assess the clinical impact of 2-[(18)F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography-computed tomography (PET-CT) in patients with potentially resectable metastatic colorectal cancer.

MATERIALS AND METHODS

One hundred and two patients with potentially resectable metastatic colorectal cancer underwent FDG PET-CT in addition to conventional imaging over an 18-month period. The findings were compared to conventional imaging, with histological or clinico-radiological validation. The impact on subsequent management was evaluated using information from clinico-radiological databases.

RESULTS

Of 102 patients (mean age 67 years, range 27-85 years), 94 had liver, five had isolated lung, and three had limited peritoneal metastases. In 31 patients (30%) PET-CT had a major impact on subsequent management, by correctly clarifying indeterminate lesions on conventional imaging as inoperable metastatic disease in 16 patients, detecting previously unsuspected metastatic disease in nine patients, identifying occult second primary tumours in three patients, and correctly down-staging three patients. PET-CT had a minor impact in 12 patients (12%), no impact in 49 cases (48%), and a potentially negative impact in 10 cases (10%). Following PET-CT, 36 (35%) patients were no longer considered for surgery. Of those remaining operative 45 of 66 (68%) underwent potentially curative metastatic surgery. In this cohort PET-CT saved 16 futile laparotomies.

CONCLUSION

FDG PET-CT has a valuable role in selected patients with metastatic colorectal cancer by improving staging accuracy and characterizing indeterminate lesions and helps triage patients to the appropriate treatment.

Initial staging impact of fluorodeoxyglucose positron emission tomography/computed tomography in locally advanced breast cancer

PURPOSE

Fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) may reveal distant metastases more accurately than conventional imaging (CT, skeletal scintigraphy, chest radiography). We hypothesized that patients diagnosed with stage III noninflammatory breast cancer (non-IBC) and IBC by conventional imaging with PET/CT have a better prognosis than patients diagnosed without PET/CT.

PATIENTS AND METHODS

We retrospectively identified 935 patients with stage III breast cancer in 2000-2009. We compared the relapse-free survival (RFS) and overall survival (OS) times of patients diagnosed by conventional imaging with those of patients diagnosed by conventional imaging plus PET/CT. Univariate and multivariate Cox proportional hazards regression models were used to assess associations between survival and PET/CT.

RESULTS

RFS and OS times were not significantly different between patients imaged with PET/CT and those imaged without PET/CT. However, the RFS time in IBC patients was significantly different between patients imaged with PET/CT and those imaged without PET/CT on both univariate (hazard ratio [HR], 0.43; p = .014) and multivariate (HR, 0.33; p = .004) analysis. There was a trend for a longer OS duration in IBC patients imaged with PET/CT.

CONCLUSION

Among IBC patients, adding PET/CT to staging based on conventional imaging might detect patients with metastases that were not detected by conventional imaging. The use of conventional imaging with PET/CT for staging in non-IBC patients is not justified on the basis of these retrospective data. The use of conventional imaging plus PET/CT in staging IBC needs to be studied prospectively to determine whether it will improve prognosis.

Convergence technology in cancer medicine

The field of convergence technology may be defined as an area of technologic innovation in which multiple devices or functionalities are combined within a single platform in a way that adds functional, operational or economic synergies. Within the field of medical devices, this concept embodies many different types of novel combinations representing syntheses of therapeutic, diagnostic and digital information technologies. In the current era of healthcare reform, such combinatorial technologies will be pressed to demonstrate improvements in comparative effectiveness compared with the use of separate independent components. Moreover, the new more stringent regulatory environment will require much greater levels of pre- and post-market safety reviews conducted under the auspices and authority of the US FDA Office of Combination Products. This branch of the FDA scrutinizes submissions and divides them into drugs, devices and biological products and includes many submissions previously regulated by disparate centers, such as the Center for Devices and Radiologic Health and the Center for Drug Evaluation and Research. The field of convergence technologies already amounts to a worldwide market extending to tens of billions of dollars and this article will attempt to summarize some of the key elements of this continued push for added value and more personalized medicine.

[PET/CT for diagnostics and therapy stratification of lung cancer]

With the introduction of positron emission tomography (PET) and more recently the hybrid systems PET/CT, the management of cancer patients in the treatment strategy has changed tremendously. The combination of PET with multidetector CT scanning enables the integration of metabolic and high resolution morphological image information. PET/CT is nowadays an established modality for tumor detection, characterization, staging and response monitoring. The increased installation of PET/CT systems worldwide and also the increased scientific publications underline the importance of this imaging modality. PET/CT is particular the imaging modality of choice in lung cancer staging and re-staging (T, N and M staging). The possible increased success of surgery in lung cancer patients and also the expected reduction in additional invasive diagnostics lead to benefits for both the individual patient and the healthcare system. In this review article PET and PET/CT is presented for diagnostic and therapeutic stratification in lung cancer. The fundamentals of glucose metabolism, staging, tumor recurrence and therapeutic monitoring are presented.

Translocator protein (18 kDa) (TSPO) as a therapeutic target for neurological and psychiatric disorders

The translocator protein (18 kDa) (TSPO) is localized primarily in the outer mitochondrial membrane of steroid-synthesizing cells, including those in the central and peripheral nervous system. One of its main functions is the transport of the substrate cholesterol into mitochondria, a prerequisite for steroid synthesis. TSPO expression may constitute a biomarker of brain inflammation and reactive gliosis that could be monitored by using TSPO ligands as neuroimaging agents. Moreover, initial clinical trials have indicated that TSPO ligands might be valuable in the treatment of neurological and psychiatric disorders. This Review focuses on the biology and pathophysiology of TSPO and the potential of currently available TSPO ligands for the diagnosis and treatment of neurological and psychiatric disorders.

Preoperative staging of lung cancer with PET/CT: cost-effectiveness evaluation alongside a randomized controlled trial

PURPOSE

Positron emission tomography (PET)/CT has become a widely used technology for preoperative staging of non-small cell lung cancer (NSCLC). Two recent randomized controlled trials (RCT) have established its efficacy over conventional staging, but no studies have assessed its cost-effectiveness. The objective of this study was to assess the cost-effectiveness of PET/CT as an adjunct to conventional workup for preoperative staging of NSCLC.

METHODS

The study was conducted alongside an RCT in which 189 patients were allocated to conventional staging (n = 91) or conventional staging + PET/CT (n = 98) and followed for 1 year after which the numbers of futile thoracotomies in each group were monitored. A full health care sector perspective was adapted for costing resource use. The outcome parameter was defined as the number needed to treat (NNT)-here number of PET/CT scans needed-to avoid one futile thoracotomy. All monetary estimates were inflated to 2010 <euro>.

RESULTS

The incremental cost of the PET/CT-based regimen was estimated at 3,927 <euro> [95% confidence interval (CI) -3,331; 10,586] and the NNT at 4.92 (95% CI 3.00; 13.62). These resulted in an average incremental cost-effectiveness ratio of 19,314 <euro>, which would be cost-effective at a probability of 0.90 given a willingness to pay of 50,000 <euro> per avoided futile thoracotomy. When costs of comorbidity-related hospital services were excluded, the PET/CT regimen appeared dominant.

CONCLUSION

Applying a full health care sector perspective, the cost-effectiveness of PET/CT for staging NSCLC seems to depend on the willingness to pay in order to avoid a futile thoracotomy. However, given that four outliers in terms of extreme comorbidity were all randomized to the PET/CT arm, there is uncertainty about the conclusion. When hospital costs of comorbidity were excluded, the PET/CT regimen was found to be both more accurate and cost saving.

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.

PET/CT and breast cancer

This paper summarises the current status of PET/CT in relation to breast cancer.