Role of FDG-PET staging in selecting the optimum patient for hepatic resection of metastatic colorectal cancer

PET/MRI and PET/CT hybrid imaging of rectal cancer - description and initial observations from the RECTOPET (REctal Cancer trial on PET/MRI/CT) study

Purpose

The role of hybrid imaging using ¹⁸F-fluoro-2-deoxy-D-glucose positron-emission tomography (FDG-PET), computed tomography (CT) and magnetic resonance imaging (MRI) to improve preoperative evaluation of rectal cancer is largely unknown. To investigate this, the RECTOPET (REctal Cancer Trial on PET/MRI/CT) study has been launched with the aim to assess staging and restaging of primary rectal cancer. This report presents the study workflow and the initial experiences of the impact of PET/CT on staging and management of the first patients included in the RECTOPET study.

Methods

This prospective cohort study, initiated in September 2016, is actively recruiting patients from Region Västerbotten in Sweden. This pilot study includes patients recruited and followed up until December 2017. All patients had a biopsy-verified rectal adenocarcinoma and underwent a minimum of one preoperative FDG-PET/CT and FDG-PET/MRI examination. These patients were referred to the colorectal cancer multidisciplinary team meeting at Umeå University Hospital. All available data were evaluated when making management recommendations. The clinical course was noted and changes consequent to PET imaging were described; surgical specimens underwent dedicated MRI for anatomical matching between imaging and histopathology.

Results

Twenty-four patients have so far been included in the study. Four patients were deemed unresectable, while 19 patients underwent or were scheduled for surgery; one patient was enrolled in a watch-and-wait programme after restaging. Consequent to taking part in the study, two patients were upstaged to M1 disease: one patient was diagnosed with a solitary hepatic metastasis detected using PET/CT and underwent metastasectomy prior to rectal cancer surgery, while one patient with a small, but metabolically active, lung nodulus experienced no change of management. PET/MRI did not contribute to any recorded change in patient management.

Conclusions

The RECTOPET study investigating the role of PET/CT and PET/MRI for preoperative staging of primary rectal cancer patients will provide novel data that clarify the value of adding hybrid to conventional imaging, and the role of PET/CT versus PET/MRI.

Trial registration

NCT03846882.

Respiratory gated and prolonged acquisition 18F-FDG PET improve preoperative assessment of colorectal liver metastases

BACKGROUND

Detection of small liver metastases from colorectal cancer by 18F-FDG PET/CT is hampered by high physiologic uptake in the liver parenchyma and respiratory movements during image acquisition.

PURPOSE

To investigate whether two tailored 18F-FDG PET liver acquisitions (prolonged liver acquisition time [PL-PET] and repeated breath-hold respiratory gated liver acquisition [RGL-PET]) would improve detection of colorectal liver metastases, when added to a standard whole body PET (WB-PET).

MATERIAL AND METHODS

Twenty consecutive patients referred to our hospital for surgical treatment of colorectal liver metastases diagnosed with contrast-enhanced CT underwent preoperative 18F-FDG PET/CT tailored for detection of liver metastases. Concordance between preoperative imaging results and true findings (histology and/or follow-up imaging) as well as changes in clinical management, based on 18F-FDG PET/CT findings, were documented. Background noise, defined as the standard deviation measured in a reference region within the normal liver parenchyma, was compared between the three 18F-FDG PET/CT protocols.

RESULTS

WB-PET, PL-PET, and RGL-PET showed suspicious liver lesions in 18 out of 20 patients. Compared to WB-PET alone, the combination of PL-PET and RGL-PET showed additional lesions in the liver in seven out of the 18 patients. The combination of all three PET acquisitions changed clinical management in four patients. Two patients with negative PET results were later found to have benign liver lesions.

CONCLUSION

The addition of tailored liver-specific 18F-FDG PET/CT protocols (PL-PET and RGL-PET) to a WB-PET, improved the detection of intrahepatic colorectal metastases, compared to WB-PET alone. Such add-ons can change clinical patient management of potentially resectable colorectal liver metastases.

[18F]Fluorodeoxyglucose PET for Interventional Oncology in Liver Malignancy

[(18)F]Fluorodeoxyglucose (FDG) PET is a functional imaging tool that provides metabolic information, which has the potential to detect a lesion before it becomes anatomically apparent. This ability constitutes a strong argument for using FDG-PET/computed tomography (CT) in the management of oncology patients. Many studies have investigated the accuracy of FDG-PET or FDG-PET/CT for these purposes, but with small sample sizes based on retrospective cohorts. This article provides an overview of the role of FDG-PET or FDG-PET/CT in patients with liver malignancies treated by means of surgical resection, ablative therapy, chemoembolization, radioembolization, and brachytherapy, all being liver-directed oncologic interventions.

Consistent surgeon evaluations of three-dimensional rendering of PET/CT scans of the abdomen of a patient with a ductal pancreatic mass

Two-dimensional (2D) positron emission tomography (PET) and computed tomography (CT) are used for diagnosis and evaluation of cancer patients, requiring surgeons to look through multiple planar images to comprehend the tumor and surrounding tissues. We hypothesized that experienced surgeons would consistently evaluate three-dimensional (3D) presentation of CT images overlaid with PET images when preparing for a procedure. We recruited six Jefferson surgeons to evaluate the accuracy, usefulness, and applicability of 3D renderings of the organs surrounding a malignant pancreas prior to surgery. PET/CT and contrast-enhanced CT abdominal scans of a patient with a ductal pancreatic mass were segmented into 3D surface renderings, followed by co-registration. Version A used only the PET/CT image, while version B used the contrast-enhanced CT scans co-registered with the PET images. The six surgeons answered 15 questions covering a) the ease of use and accuracy of models, b) how these models, with/without PET, changed their understanding of the tumor, and c) what are the best applications of the 3D visualization, on a scale of 1 to 5. The six evaluations revealed a statistically significant improvement from version A (score 3.6±0.5) to version B (score 4.4±0.4). A paired-samples t-test yielded t(14) = -8.964, p<0.001. Across the surgeon cohort, contrast-enhanced CT fused with PET provided a more lifelike presentation than standard CT, increasing the usefulness of the presentation. The experienced surgeons consistently reported positive reactions to 3D surface renderings of fused PET and contrast-enhanced CT scans of a pancreatic cancer and surrounding organs. Thus, the 3D presentation could be a useful preparative tool for surgeons prior to making the first incision. This result supports proceeding to a larger surgeon cohort, viewing prospective 3D images from multiple types of cancer.

Manejo atual das metástases hepáticas de câncer colorretal: recomendações do Clube do Fígado de São Paulo

Aproximadamente metade dos pacientes portadores de câncer colorretal apresenta metástases hepáticas durante a evolução de sua doença que afetam diretamente o prognóstico e são diretamente responsáveis por 2/3 dos óbitos relacionados à doença. Nas últimas duas décadas o tratamento das metástases hepáticas de câncer colorretal (MHCCR) proporcionou ganho expressivo na sobrevida quando todas as opções terapêuticas são colocadas à disposição do paciente. Nesse contexto, o tratamento cirúrgico persiste como a única possibilidade de cura com índices de sobrevida em cinco anos de 25 a 58%. No entanto, apenas 1/4 dos pacientes tem doença ressecável ao diagnóstico. Por essa razão, um dos pontos fundamentais no manejo atual dos pacientes com MHCCR é o desenvolvimento de estratégias que possibilitem a ressecção completa das lesões hepáticas. O advento e aperfeiçoamento dos métodos ablativos expandiram as possibilidades da terapêutica cirúrgica, além disto, o surgimento de novos esquemas quimioterápicos e a introdução das terapias-alvo proporcionou altas taxas de resposta e alteraram definitivamente o manejo destes pacientes. O tratamento multimodal e a utilização da experiência de diversas especialidades médicas permitiram que o tratamento das MHCCR se aproximasse cada vez mais do tratamento ideal, ou seja, individualizado. Baseado em uma extensa revisão da literatura e na experiência de alguns dos centros especializados mais importantes do Brasil, o Clube do Fígado de São Paulo iniciou um trabalho de discussão multi-institucional que resultou nas recomendações que se seguem. Essas recomendações, no entanto, não visam ser absolutas, mas sim ferramentas úteis no processo de decisão terapêutica desse grupo complexo de pacientes.

Indeterminate pulmonary nodules represent lung metastases in a significant portion of patients undergoing liver resection for malignancy

INTRODUCTION

Despite detection on imaging before resection of hepatic malignancies, the natural history of indeterminate pulmonary nodules (IPN) is unknown. The objective of this study is to determine how often IPN detected on imaging before surgery for hepatic malignancies represent lung metastases.

METHODS

Demographics, comorbidities, tumor characteristics, and surgical treatments of patients with pre-operative IPN who underwent liver resection and/or radiofrequency ablation for malignant diagnoses were reviewed.

RESULTS

From 2000 to 2010, 90 patients with at least one IPN underwent liver resection or radiofrequency ablation for malignancy. Of these, 44 (48.9 %), 32 (35.6 %), and 14 (15.6 %) patients had colorectal cancer liver metastases (CRCLM), primary hepatobiliary malignancies (HB), and other cancers, respectively. The median number of IPN was 1. The median size was 4 mm. Twenty (22 %) patients had isolated lung recurrence after hepatic surgical therapy. Eighty percent occurred in the exact location of the pre-operative IPN. Isolated lung recurrence was more common among patients with CRCLM compared to those with HB and other cancers (42.9 vs. 9.4 vs. 14.3 %, p = 0.004).

CONCLUSION

Pre-operatively detected IPN represent lung metastases in a substantial portion of patients undergoing surgery for hepatic malignancy. IPN are more likely to represent lung metastases in patients with CRCLM compared to those with primary HB and other cancers.

Added value of FDG-PET imaging in the diagnostic workup for yttrium-90 radioembolisation in patients with colorectal cancer liver metastases

OBJECTIVE

Yttrium-90 radioembolisation (Y90-RE) is recommended for unresectable, chemorefractory liver-dominant disease; however, the incidence of extrahepatic disease (EHD) is high. FDG-PET may have additional value to CT in demonstrating EHD. Our aim was to evaluate the added diagnostic value of FDG-PET to abdominal CT and study the influence of FDG-PET findings on treatment decisions.

METHODS

All consecutive patients with colorectal cancer liver metastases (CRCLM) referred for Y90-RE were included. Patients who underwent both CT and FDG-PET in the diagnostic workup were selected. Imaging reports were scrutinised for documented sites of EHD, and changes of management due to FDG-PET findings were determined.

RESULTS

A total of 42 patients were included. Findings on CT and FDG-PET matched in 20 patients (no EHD, n = 15; identical EHD, n = 5). In 4 patients, lesions detected on CT were not FDG-avid, and in 18 patients, FDG-PET showed more lesions than CT (P < 0.05). In 7/42 patients (17 %) a change of management was made based on the additional FDG-PET findings, i.e. exclusion from Y90-RE treatment (n = 6) and change in treatment plan (whole liver rather than segmental treatment, n = 1).

CONCLUSIONS

In patients with CRCLM referred for Y90-RE, FDG-PET showed significantly more EHD and led to a considerable change of management.

Liver metastases from colorectal cancer: how to best complement medical treatment with surgical approaches

Colorectal liver metastases (CLM) represent a major challenge for oncologists and surgeons. In fact, in this setting, the optimal treatment of patients can achieve a long-term survival and sometimes a definitive cure of disease. In recent years, improvements in both medical therapies and surgical approaches have led to an increased rate of patients considered amenable for surgery on CLM. New perspectives in the management of CLM underline the need for a comprehensive assessment of patient and tumor characteristics, to integrate technical and prognostic issues into an individualized therapeutic strategy in different patient subgroups. The multidisciplinary evaluation from the onset and during treatment remains the key element to maximizing the benefit of more intensive treatment modalities.