The impact of fluor-18-deoxyglucose-positron emission tomography in the management of colorectal liver metastases

The Use of Hepatic Artery Infusion Chemotherapy for Unresectable Colorectal Cancer Liver Metastases

Colorectal cancer (CRC) is the third most commonly diagnosed cancer in men and women (Siegel et al. in CA Cancer J Clin 72(1):7-33). Over one-half of newly diagnosed individuals will develop liver metastases. Among those with liver-only metastatic disease, only about one in five will be candidates for potentially curable resection.

PET/CT in assessment of colorectal liver metastases: a comprehensive review with emphasis on 18F-FDG

Approximately 25% of those who are diagnosed with colorectal cancer will develop colorectal liver metastases (CRLM) as their illness advances. Despite major improvements in both diagnostic and treatment methods, the prognosis for patients with CRLM is still poor, with low survival rates. Accurate employment of imaging methods is critical in identifying the most effective treatment approach for CRLM. Different imaging modalities are used to evaluate CRLM, including positron emission tomography (PET)/computed tomography (CT). Among the PET radiotracers, fluoro-18-deoxyglucose (18F-FDG), a glucose analog, is commonly used as the primary radiotracer in assessment of CRLM. As the importance of 18F-FDG-PET/CT continues to grow in assessment of CRLM, developing a comprehensive understanding of this subject becomes imperative for healthcare professionals from diverse disciplines. The primary aim of this article is to offer a simplified and comprehensive explanation of PET/CT in the evaluation of CRLM, with a deliberate effort to minimize the use of technical nuclear medicine terminology. This approach intends to provide various healthcare professionals and researchers with a thorough understanding of the subject matter.

Imaging of Colorectal Liver Metastasis

Colorectal cancer (CRC) is one of the most common cancers in the world. The most important determinant of survival and prognosis is the stage and presence of metastasis. The liver is the most common location for CRC metastasis. The only curative treatment for CRC liver metastasis (CRLM) is resection; however, many patients are ineligible for surgical resection of CRLM. Locoregional treatments such as ablation and intra-arterial therapy are also available for patients with CRLM. Assessment of response after chemotherapy is challenging due to anatomical and functional changes. Antiangiogenic agents such as bevacizumab that are used in the treatment of CRLM may show atypical patterns of response on imaging. It is vital to distinguish patterns of response in addition to toxicities to various treatments. Imaging plays a critical role in evaluating the characteristics of CRLM and the approach to treatment. CT is the modality of choice in the diagnosis and management of CRLM. MRI is best used for indeterminate lesions and to assess response to intra-arterial therapy. PET-CT is often utilized to detect extrahepatic metastasis. State-of-the-art imaging is critical to characterize patterns of response to various treatments. We herein review the imaging characteristics of CRLM with an emphasis on imaging changes following the most common CRLM treatments.

Is It Time to Introduce PET/CT in Rectal Cancer Guidelines?

At the moment, international guidelines for rectal cancer suggest to consider F-FDG PET/CT scan in a few conditions: (1) at disease presentation in case of suspected or proven metastatic synchronous adenocarcinoma with potentially curable M1 disease; (2) in the recurrence workup for serial carcinoembryonic antigen level elevation; (3) in the recurrence workup with metachronous metastases documented by CT, MRI, or biopsy; (4) in case of strong contraindication to IV contrast agent administration; and (5) to evaluate an equivocal finding on a contrast-enhanced CT or MRI. PET/CT is not indicated in the follow-up or surveillance of rectal cancer. On the other hand, an attentive evaluation of the literature shows that PET/CT may also be used in some circumstances with significant levels of diagnostic accuracy. This review article aims to emphasize differences between current international guidelines and scientific literature in the role of PET/CT in rectal cancer.

Multimodality Approach in Detection and Characterization of Hepatic Metastases

Early detection of liver metastases is important in patients with known primary malignancies. This plays an important role in treatment planning and impacts on further management of certain primary malignancies.

Magnetic resonance imaging (MRI), computed tomography (CT), and positron emission tomography-computed tomography scans are reported to have high accuracy in the diagnosis of intrahepatic lesions. MRI in particular has the advantages of its high tissue sensitivity and its multiparametric approach.

Hepatic metastatic lesions have considerable overlap in their radiological appearance, and in this article the imaging appearance of various hepatic metastasis and approach is described.

Additional value of gadoxetic acid-enhanced MRI to conventional extracellular gadolinium-enhanced MRI for the surgical management of colorectal and neuroendocrine liver metastases

BACKGROUND

Liver resection being the only potentially curative treatment for patients with liver metastasis, it is critical to select the appropriate preoperative imaging modality. The aim of this study was to assess the impact of preoperative gadoxetic acid-enhanced MRI compared to a conventional extracellular gadolinium-enhanced MRI on the surgical management of colorectal and neuroendocrine liver metastasis.

METHODS

We included 110 patients who underwent both a gadoxetic acid-enhanced MRI (hepatospecific contrast) and conventional extracellular gadolinium for the evaluation of colorectal or neuroendocrine liver metastases, from January 2012 to December 2015 at the CHU de Québec - Université Laval. When the number of lesions differed, a hepatobiliary surgeon evaluated if the gadoxetic acid-enhanced MRI modified the surgical management.

RESULTS

Gadoxetic acid-enhanced MRI found new lesions in 25 patients (22.7%), excluded lesions in 18 patients (16.4%) and identified the same number in 67 patients (60.9%). The addition of the gadoxetic acid-enhanced MRI directly altered the surgical management in 19 patients overall (17.3% (95% CI [10.73-25.65])).

CONCLUSION

Despite the additional cost associated with gadoxetic acid-enhanced MRI compared to conventional extracellular gadolinium-enhanced MRI, the use of this contrast agent has a significant impact on the surgical management of patients with liver metastases.

Outcomes after hypofractionated stereotactic radiotherapy for colorectal cancer oligometastases

BACKGROUND AND OBJECTIVES

To assess the efficacy and the effect of biologic effective dose (BED) on outcomes treated by hypofractionated stereotactic radiotherapy for colorectal cancer (CRC) oligometastases.

METHODS

Patients with CRC oligometastases treated at our hospital between 2009 and 2016 were included. The relationship between BED and risk of local recurrence was assessed. Recursive partitioning analysis (RPA) was used to evaluate the effect of BED on outcomes.

RESULTS

A total of 48 patients were included in this study. Median follow-up time of surviving patient was 15 months (range, 3-82 months). The 1-year local control rate was 85%. The risk of local recurrence decreased sharply when BED was >90 Gy10 . RPA showed BED of 100 Gy 10 was the appropriate dose for recurrence risk stratification. BED ≥ 100 Gy 10 was significantly better than BED < 100 Gy 10 for achieving 1-year local control (94.4% vs 63.2%; P = 0.022) and 1-year OS (100% vs 73.4%; P = 0.028). One patient who received long-term antiangiogenic treatment died of massive intestinal hemorrhage; no other grade 3 or above early or late events were observed.

CONCLUSIONS

Hypofractionated stereotactic radiotherapy provides favorable outcomes with acceptable toxicities in CRC oligometastases. BED ≥ 100 Gy is associated with better outcomes.

Mediastinal recurrence after curative resection of colon cancer: A case report and review of literature

Colorectal carcinoma is one of the most common and significant causes of cancer-related death. Metastasis to mediastinal lymph nodes and/or pleura without liver or lung involvement is an atypical pattern of colon cancer metastasis. A 70-year-old male underwent curative right side hemicolectomy and omentectomy for ascending colon cancer followed by adjuvant chemotherapy. Around nine months after surgery, the patient was noted to have bilateral large pleural effusions on the restaging computed tomography scan of the chest/abdomen/pelvis. No intraabdominal or intrathoracic mass/metastasis was seen on the imaging. Multiple thoracentesis performed over the course of next few months revealed exudative effusion but failed to demonstrate malignant cells. A few months later, new mediastinal and right hilar lymphadenopathy was noted on the repeat computed tomography scan. A subsequent positron-emission tomography scan revealed multiple sites of fluorodeoxyglucose (FDG)-avid mediastinal lymphadenopathy. The sites of pleural effusion were not fluorodeoxyglucose-avid. Endobronchial ultrasound and biopsy of mediastinal nodes showed adenocarcinoma with signet-ring features. Immunohistochemistry confirmed the diagnosis of metastatic colon cancer. Systemic treatment with chemotherapy was initiated. Our case highlights the importance of mediastinal evaluation by imaging during the follow-up of patients with colorectal carcinoma. The ideal management strategy for mediastinal metastasis of colorectal carcinoma remains a question, two major options being local metastasectomy or systemic chemotherapy.

Outcome of indeterminate liver lesions on computed tomography in patients with colorectal cancer

Introduction The aim of this study was to determinate the outcome of indeterminate liver lesions on computed tomography (CT) in patients with a background history of colorectal cancer (CRC) and to identify clinicopathological variables associated with malignancy in these lesions. A secondary aim was to devise a management algorithm for such patients. Methods Patients referred to our institution with indeterminate liver lesions on CT with a background history of CRC between January 2012 and December 2014 were included in the study. Clinicopathological factors, surveillance period and histological findings were analysed. Results Fifty-six patients with indeterminate liver lesions were identified. Fifty-three (94.6%) of these required further imaging (magnetic resonance imaging [MRI; n=50] and positron emission tomography combined with CT [n=3]). For the patients who had MRI, the underlying diagnosis was benign in 19 and colorectal liver metastasis (CRLM) in 8 while 23 patients and an indeterminate lesion. In cases that remained indeterminate following MRI, liver resection was performed in 2 patients for a high suspicion of CRLM while the 21 remaining patients underwent interval surveillance (median: 9 months, range: 3-52 months). Of these 21 patients, 14 had benign lesions while CRLM was noted in 6 patients and an incidental hepatocellular carcinoma in a single patient. Age ≥65 years was the only statistically significant clinicopathological factor in predicting an underlying malignancy in patients with indeterminate liver lesions on CT. Conclusions Over a third of the patients diagnosed with indeterminate liver lesions on CT subsequently showed evidence of CRLM. These indeterminate lesions are more likely to be malignant in patients aged ≥65 years.

ACR Appropriateness Criteria® Suspected Liver Metastases

Liver metastases are the most common malignant liver tumors. The accurate and early detection and characterization of liver lesions is the key to successful treatment strategies. Increasingly, surgical resection in combination with chemotherapy is effective in significantly improving survival if all metastases are successfully resected. MRI and multiphase CT are the primary imaging modalities in the assessment of liver metastasis, with the relative preference toward multiphase CT or MRI depending upon the clinical setting (ie, surveillance or presurgical planning). The optimization of imaging parameters is a vital factor in the success of either modality. PET/CT, intraoperative ultrasound are used to supplement CT and MRI. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

The prognostic value of positron emission tomography/computed tomography in pulmonary metastasectomy

Background

Although positron emission tomography/computed tomography (PET/CT) findings are prognostic in lung cancer patients, the prognostic value of PET/CT findings in patients with pulmonary metastases has neither been comprehensively investigated nor clarified. The aims of this retrospective study were to evaluate the value of PET/CT and identify novel prognostic indicators for pulmonary metastasectomy.

Methods

Between May 2004 and February 2017, 178 patients underwent PET/CT and resection of pulmonary metastases. After exclusion of patients who underwent biopsy only or duplicate cases, 142 patients were analyzed. Prognostic indicators, including PET/CT findings and outcomes were investigated.

Results

The median follow-up time was 42 months. The primary tumor site was colorectal in 76, kidney in 14, head and neck in 13, breast in 12, stomach in 8, urinary tract in 7, and other organs in 12 patients. The median maximal standardized uptake value (SUV_max) was 4.6. The optimal cut-off value, determined by receiver operating characteristic (ROC) analysis, identified the following cut-off values: disease-free interval (DFI) (12 months; SUV_max =4.5). Univariable analysis revealed that DFI ≤12 months, incomplete resection, and SUV_max ≥4.5 were significant for poor outcome. Multivariable analysis revealed incomplete resection and SUV_max ≥4.5 were significant for poor outcome. The 5-year survival rates of patients with SUV_max ≥4.5 and SUV_max <4.5 were 51.6% and 74.0%, respectively.

Conclusions

Analysis of patients undergoing pulmonary metastasectomy demonstrated that incomplete resection and an SUV_max ≥4.5 are significant prognostic indicators. PET/CT findings should be included in estimations of these patients' prognosis.

Clinical Usefulness of 18F-Fluorodeoxyglucose Positron Emission Tomography in the Diagnostic Algorithm of Advanced Entero-Pancreatic Neuroendocrine Neoplasms

Background

The role of 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) in the diagnostic algorithm of entero-pancreatic neuroendocrine neoplasms (EP NENs) is unclear because most available data derive from heterogeneous populations in terms of tumor biology and disease status at time of examination. The aim of this study was to determine the ability of 18F-FDG PET to identify patients with more aggressive disease among those with advanced EP NENs.

Subjects, Materials, and Methods . Patients with advanced EP NENs and known disease status (progressive disease [PD] or stable disease [SD]) according to imaging procedures, who received 18F-FDG PET and computed tomography scans during a time frame of 1 month, were included.

Results

A total of 93 patients, including 69 patients with pancreatic NENs and 24 patients with small-intestine NENs, were included. At the time of study entry, 64 patients (68.8%) had PD, and the remaining 29 patients (31.2%) had SD. A total of 62 patients (66.7%) had positive 18F-FDG PET, whereas 18F-FDG PET was negative in the remaining 31 patients (33.3%). Overall, 18F-FDG PET sensitivity and specificity to detect PD were 90.6% and 86.2%, respectively, resulting in a diagnostic accuracy of 89.2%. A positive 18F-FDG PET was significantly associated with PD at the time of study entry (p &lt; .0001 at multivariate analysis). Although a higher proportion of 18F-FDG PET-positive examinations were observed in patients with higher tumor grade (p = .01), 53.8% of patients with grade 1 neuroendocrine tumors (NETs) had positive 18F-FDG PET, and 37.5% of patients with grade 2 NETs had negative 18F-FDG PET. Overall survival was significantly shorter in 18F-FDG PET-positive patients (median: 60 months) in comparison with 18F-FDG PET-negative patients (median not reached; p = .008).

Conclusion

18F-FDG PET has a high diagnostic accuracy to identify progression of disease with unfavorable clinical outcome in patients with advanced EP NENs. Knowledge of disease status and G grading are key factors for physicians to better select patients for whom 18F-FDG PET is clinically useful.

Implications for Practice

The findings of the present study may help physicians dealing with advanced neuroendocrine neoplasms to select patients for whom 18F-fluorodeoxyglucose positron emission tomography is useful to predict poor clinical outcome.

Clinical Usefulness of 18F-Fluorodeoxyglucose Positron Emission Tomography in the Diagnostic Algorithm of Advanced Entero-Pancreatic Neuroendocrine Neoplasms

BACKGROUND

The role of 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) in the diagnostic algorithm of entero-pancreatic neuroendocrine neoplasms (EP NENs) is unclear because most available data derive from heterogeneous populations in terms of tumor biology and disease status at time of examination. The aim of this study was to determine the ability of 18F-FDG PET to identify patients with more aggressive disease among those with advanced EP NENs. Subjects, Materials, and Methods . Patients with advanced EP NENs and known disease status (progressive disease [PD] or stable disease [SD]) according to imaging procedures, who received 18F-FDG PET and computed tomography scans during a time frame of 1 month, were included.

RESULTS

A total of 93 patients, including 69 patients with pancreatic NENs and 24 patients with small-intestine NENs, were included. At the time of study entry, 64 patients (68.8%) had PD, and the remaining 29 patients (31.2%) had SD. A total of 62 patients (66.7%) had positive 18F-FDG PET, whereas 18F-FDG PET was negative in the remaining 31 patients (33.3%). Overall, 18F-FDG PET sensitivity and specificity to detect PD were 90.6% and 86.2%, respectively, resulting in a diagnostic accuracy of 89.2%. A positive 18F-FDG PET was significantly associated with PD at the time of study entry (p < .0001 at multivariate analysis). Although a higher proportion of 18F-FDG PET-positive examinations were observed in patients with higher tumor grade (p = .01), 53.8% of patients with grade 1 neuroendocrine tumors (NETs) had positive 18F-FDG PET, and 37.5% of patients with grade 2 NETs had negative 18F-FDG PET. Overall survival was significantly shorter in 18F-FDG PET-positive patients (median: 60 months) in comparison with 18F-FDG PET-negative patients (median not reached; p = .008).

CONCLUSION

18F-FDG PET has a high diagnostic accuracy to identify progression of disease with unfavorable clinical outcome in patients with advanced EP NENs. Knowledge of disease status and G grading are key factors for physicians to better select patients for whom 18F-FDG PET is clinically useful.

IMPLICATIONS FOR PRACTICE

The findings of the present study may help physicians dealing with advanced neuroendocrine neoplasms to select patients for whom 18F-fluorodeoxyglucose positron emission tomography is useful to predict poor clinical outcome.

Colorectal Cancer:: Imaging Conundrums

Progressive technological advancements in imaging have significantly improved the preoperative sensitivity for the detection of very small foci of regionally- or hematogenously-metastatic colorectal cancer. Unfortunately, this information has not translated to continued linear gains in patient survival, and might even result in the false-positive upstaging of some cases: these are two conundrums in the imaging of colorectal cancer. Both conundrums might be resolved by the widespread use of real-time imaging guidance during operative procedures. This might open the way for the widespread use of fluorodeoxyglucose PET/CT for the initial staging of patients with colorectal cancer.

The value of preoperative computed tomography combined with ultrasound in the investigation of small indeterminate liver lesions in patients with colorectal cancer

Background Computed tomography (CT) is used routinely for the preoperative detection of colorectal cancer (CRC) metastases. When small indeterminate focal liver lesions are detected that are too small to characterize (TSTC) on CT, additional imaging is usually needed, resulting in a potential delay in obtaining a complete diagnostic work-up. Purpose To determine the diagnostic accuracy of ultrasound (US) of the liver performed in direct conjunction to CT in the preoperative investigation among patients with newly diagnosed CRC when indeterminate liver lesions were found on CT. Material and Methods Preoperative investigations with CT and consecutive US where CT had shown at least one focal liver lesion in 74 patients diagnosed with CRC between June 2009 and February 2012 were retrospectively reviewed. Either histopathological findings or a combination of imaging and clinical follow-up one to three years after surgery was used as the reference. Results Liver metastases were diagnosed with CT/US in 13 out of 74 patients (17.6%). In one patient, a liver cyst was preoperatively regarded as liver metastasis by a combined CT/US. The sensitivity and specificity for the CT with consecutive US procedure was 100% (13/13) and 98.4% (60/61). Conclusion US performed in conjunction with CT in patients with indeterminate focal liver lesions on CT is an accurate work-up for detection of liver metastases in patients with newly diagnosed CRC. Although our results are promising, they cannot be considered safely generalizable to all hospitals.

FDG-PET/CT in the Postoperative Period: Utility, Expected Findings, Complications, and Pitfalls

FDG-PET/CT as a modality is increasingly used for detection of recurrence and for restaging in patients with clinical suspicion of malignancy, as well as in patients with elevated tumor markers. However, there are many pitfalls in the interpretation of these scans when the studies are performed after some treatment. Some of these are attributed to normal physiological distribution and are compounded when there are inflammatory changes occurring after surgery. The body's inherent response to the surgical insult results in this inflammation. In addition, there are also complications that can happen following surgery, causing increased FDG uptake. Despite various fallacies, FDG-PET/CT provides valuable information in evaluation of residual and recurrent malignant disease. In this article, we aim to describe some of these postsurgical changes secondary to inflammation, common surgical complications, and finally, the utility of FDG-PET/CT in these patients to detect recurrent disease, even in the background of postsurgical changes.

Long-term outcomes of patients with 10 or more colorectal liver metastases

BACKGROUND

Although the number of colorectal liver metastases (CLM) is decreasingly considered as a contraindication to surgery, patients with 10 CLM or more are often denied liver surgery. This study aimed to evaluate the outcome after liver surgery and to identify prognostic factors of survival in such patients.

METHODS

The study population consisted of a multicentre cohort of patients with CLM (N=12 406) operated on, with intention to resect, from January 2005-June 2013 and whose data were prospectively collected in the LiverMetSurvey registry.

RESULTS

Overall, the group ⩾10 CLM (N=529, 4.3%) experienced a 5-year overall survival (OS) of 30%. A macroscopically complete (R0/R1) resection (72.8% of patients) was associated with a 3- and 5-year OS of 61% and 39% vs 29% and 5% for R2/no resection patients (P<0.0001). At multivariate analysis, R0/R1 resection emerged as the strongest favourable factor of OS (HR 0.35 (0.26-0.48)). Other independent favourable factors were as follows: maximal tumour size <40 mm (HR 0.67 (0.49-0.92)); age <60 years (HR 0.66 (0.50-0.88)); preoperative MRI (HR 0.65 (0.47-0.89)); and adjuvant chemotherapy (HR 0.73 (0.55-0.98)). The model showed that 5-year OS rates of 30% was possible provided R0/R1 resection associated with at least an additional favourable factor.

CONCLUSIONS

Liver resection might provide long-term survival in patients with ⩾10 CLM staged with preoperative MRI, provided R0/R1 resection followed by adjuvant therapy. A validation of these results in another cohort is needed.

Short-Course Radiotherapy Followed by Neoadjuvant Bevacizumab, Capecitabine, and Oxaliplatin and Subsequent Radical Treatment in Primary Stage IV Rectal Cancer: Long-Term Results of a Phase II Study

Background

In a Dutch phase II trial conducted between 2006 and 2010, short-course radiotherapy followed by systemic therapy with capecitabine, oxaliplatin, and bevacizumab as neoadjuvant treatment and subsequent radical surgical treatment of primary tumor and metastatic sites was evaluated. In this study, we report the long-term results after a minimum follow-up of 6 years.

Methods

Patients with histologically confirmed rectal adenocarcinoma with potentially resectable or ablatable metastases in liver or lungs were eligible. Follow-up data were collected for all patients enrolled in the trial. Overall and recurrence-free survival were calculated using the Kaplan–Meier method.

Results

Follow-up data were available for all 50 patients. After a median follow-up time of 8.1 years (range 6.0–9.8), 16 patients (32.0%) were still alive and 14 (28%) were disease-free. The median overall survival was 3.8 years (range 0.5–9.4). From the 36 patients who received radical treatment, two (5.6%) had a local recurrence and 29 (80.6%) had a distant recurrence.

Conclusions

Long-term survival can be achieved in patients with primary metastatic rectal cancer after neoadjuvant radio- and chemotherapy. Despite a high number of recurrences, 32% of patients were alive after a median follow-up time of 8.1 years.

Colorectal cancer statistics, 2017

Colorectal cancer (CRC) is one of the most common malignancies in the United States. Every 3 years, the American Cancer Society provides an update of CRC incidence, survival, and mortality rates and trends. Incidence data through 2013 were provided by the Surveillance, Epidemiology, and End Results program, the National Program of Cancer Registries, and the North American Association of Central Cancer Registries. Mortality data through 2014 were provided by the National Center for Health Statistics. CRC incidence rates are highest in Alaska Natives and blacks and lowest in Asian/Pacific Islanders, and they are 30% to 40% higher in men than in women. Recent temporal patterns are generally similar by race and sex, but differ by age. Between 2000 and 2013, incidence rates in adults aged ≥50 years declined by 32%, with the drop largest for distal tumors in people aged ≥65 years (incidence rate ratio [IRR], 0.50; 95% confidence interval [95% CI], 0.48-0.52) and smallest for rectal tumors in ages 50 to 64 years (male IRR, 0.91; 95% CI, 0.85-0.96; female IRR, 1.00; 95% CI, 0.93-1.08). Overall CRC incidence in individuals ages ≥50 years declined from 2009 to 2013 in every state except Arkansas, with the decrease exceeding 5% annually in 7 states; however, rectal tumor incidence in those ages 50 to 64 years was stable in most states. Among adults aged <50 years, CRC incidence rates increased by 22% from 2000 to 2013, driven solely by tumors in the distal colon (IRR, 1.24; 95% CI, 1.13-1.35) and rectum (IRR, 1.22; 95% CI, 1.13-1.31). Similar to incidence patterns, CRC death rates decreased by 34% among individuals aged ≥50 years during 2000 through 2014, but increased by 13% in those aged <50 years. Progress against CRC can be accelerated by increasing initiation of screening at age 50 years (average risk) or earlier (eg, family history of CRC/advanced adenomas) and eliminating disparities in high-quality treatment. In addition, research is needed to elucidate causes for increasing CRC in young adults. CA Cancer J Clin 2017. © 2017 American Cancer Society. CA Cancer J Clin 2017;67:177-193. © 2017 American Cancer Society.

Positron Emission Tomography-Computed Tomography for Patients with Recurrent Colorectal Liver Metastases: Impact on Restaging and Treatment Planning

BACKGROUND

The impact of fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) for patients with colorectal liver metastases (CLM) still is debated. Its relevance could be enhanced in the case of recurrent disease. The current study aimed to elucidate the role of PET-CT in restaging and treatment planning for recurrent CLM.

METHODS

A series of 352 consecutive patients undergoing their first liver resection for CLM between 2005 and 2014 was reviewed. Of these patients, 224 (63.6 %) had a recurrence. The 107 patients who had received PET-CT at diagnosis of recurrence before chemotherapy were analyzed. CT was available in all cases, and magnetic resonance imaging (MRI) was available in 64 cases.

RESULTS

Extrahepatic lesions were found in 59 patients. Liver and lung recurrences were detected with excellent sensitivity by CT/MRI and PET-CT (liver: 100 vs. 96.7 %; lung: 95.8 vs. 95.8 %). In detecting other recurrence sites, PET-CT had higher sensitivity than CT/MRI (91.5 vs. 54.2 %, p < 0.01; lymph nodes: 93.5 vs. 64.5 %, p = 0.011; peritoneum: 80 vs. 20 %, p = 0.023; bones: 87.5 vs. 37.5 %, nonsignificant difference). For 28.8 % (17/59) of the patients, the diagnosis of extrahepatic disease was obtained thanks to PET-CT (39.5 % considering nonpulmonary lesions). PET-CT modified treatment strategy in 16 (14.9 %) patients, excluding from surgery 15 (20.3 %) of 74 patients resectable at CT/MRI. This latter subgroup had a lower survival rate than the patients resectable after PET-CT (2-year survival, 22.7 vs. 77.8 %; p = 0.004), similar to the patients unresectable at CT/MRI (57.6 %).

CONCLUSIONS

In the authors' experience, PET-CT has offered a relevant contribution to restaging of recurrent CLM. It disclosed one fourth of extrahepatic lesions and prevented worthless surgery for about 20 % of patients.

Survival Outcomes for Patients With Indeterminate 18FDG-PET Scan for Extrahepatic Disease Before Liver Resection for Metastatic Colorectal Cancer: A Retrospective Cohort Study Using a Prospectively Maintained Database to Analyze Survival Outcomes for Patients With Indeterminate Extrahepatic Disease on 18FDG-PET Scan Before Liver Resection for Metastatic Colorectal Cancer

OBJECTIVE

The aim of this study was to evaluate overall survival (OS) and cancer recurrence for patients with indeterminate positron emission tomography (PET) scan for extrahepatic disease (EHD) before liver resection (LR) for colorectal liver metastases (CLMs).

SUMMARY OF BACKGROUND DATA

Indeterminate EHD as determined by PET imaging indicates a probability of extrahepatic malignancy and potentially excludes patients from undergoing LR for CLM.

METHODS

In a retrospective analysis of prospectively collected data from February 2006 to December 2014, OS for patients with indeterminate EHD on FDG-PET scan before LR for CLM was performed using standard survival analysis methods, including Kaplan-Meier estimator and Cox proportional hazard models for multivariate analyses. Postoperative imaging was used as reference to evaluate the association between indeterminate EHD and recurrence.

RESULTS

Of 267 patients with PET scans before LR, 197 patients had no EHD and 70 patients had indeterminate EHD. Median follow-up was 33 months. The estimated 5-year OS was 60.8% versus 59.4% for indeterminate and absent EHD, respectively (P = 0.625). Disease-free survival was comparable between both groups (P = 0.975) and overall recurrence was 57.1% and 59.5% for indeterminate and absent EHD, respectively (P = 0.742). About 16.9% of recurrence was associated with the site of indeterminate EHD, with 80% of associated recurrence occurring in the thorax.

CONCLUSIONS

The site of indeterminate EHD appears to have a predictive value for recurrence, with indeterminate EHD in the thorax having a higher probability of malignancy. The evidence in this report supports the critical evaluation of PET scan results and that patients are not denied potential curative LR unless the evidence for unresectable EHD is certain.

Effect of chemotherapy on the impact of FDG-PET/CT in selection of patients for surgical resection of colorectal liver metastases: single center analysis of PET-CAM randomized trial

The largest randomized controlled trial (RCT) on the effect of FDG-PET on surgical management for metastatic colorectal adenocarcinoma to liver ("PET-CAM") reported only a modest change in surgical management (8%).

PURPOSE

To explore the relationship between prior chemotherapy and detection of metastatic disease on PET in patients from PET-CAM. Secondary aim: to determine whether centralized imaging interpretation could have impacted trial results.

METHODS

The study included 120 patients from a single institution. Local PET interpretation (PET-L) was recorded from the original database. Retrospective PET interpretation was performed independently by at least one additional reader (PET-C). The presence of extrahepatic disease (EHD) and significant additional liver metastases (=SALM), defined as metastases not originally planned for resection, was recorded. Patients were stratified to responders to recent chemotherapy (Group R) versus all others (Group O) according to surgical pathology and RECIST criteria.

RESULTS

Thirty-seven of 50 patients who received recent chemotherapy (<90 days) were responders (Group R). EHD was present in 30/120 (25%) patients. There was no difference in detection of EHD on PET-L (7/37;18.9%), PET-C (7/37;18.9%), and CT (4/37;10.8%) for Group R (p = 0.375), but in Group O more EHD was detected on both PET-L (15/83;18.1%) and PET-C (22/83;26.5%) than CT (8/83;9.6%); p = 0.039 and p < 0.001, respectively. For the entire cohort, PET-L and PET-C detected EHD and/or SALM not reported on CT in 14 (11.7%) and 22 (18.3%) patients.

CONCLUSION

The impact of recent chemotherapy on detection of colorectal metastases with PET suggests that the utility of PET in patient selection for liver resection in the prior PET-CAM-RCT may have been underestimated.

Role of imaging for patients with colorectal hepatic metastases: what the radiologist needs to know

Surgical resection of colorectal metastatic disease has increased as surgeons have adopted a more aggressive ideology. Current exclusion criteria are patients for whom a negative resection margin is not feasible or a future liver remnant (FLR) of greater than 20% is not achievable. The goal of preoperative imaging is to identify the number and distribution of liver metastases, in addition to establishing their relation to relevant intrahepatic structures. FLR can be calculated utilizing cross-sectional imaging to select out patients at risk for hepatic dysfunction after resection. MRI, specifically with gadoxetic acid contrast, is currently the preferred modality for assessment of hepatic involvement for patients with newly diagnosed colorectal cancer, to include those who have undergone neoadjuvant chemotherapy. Employment of liver-directed therapies has recently expanded and they may provide an alternative to hepatectomy in order to obtain locoregional control in poor surgical candidates or convert patients with initially unresectable disease into surgical candidates.

Quantitative volumetric functional MR imaging: an imaging biomarker of early treatment response in hypo-vascular liver metastasis patients after yttrium-90 transarterial radioembolization

PURPOSE

To evaluate the value of quantitative volumetric functional MR imaging in early assessment of response to yttrium-90-labeled ((90)Y) transarterial radioembolization (TARE) in patients with hypo-vascular liver metastases.

MATERIALS AND METHODS

Seventy four metastatic lesions in 14 patients with hypo-vascular liver metastases after TARE were included in this retrospective study. Diffusion and contrast-enhanced MR imaging was performed before and early after treatment. All MR images were analyzed by two experienced radiologists. Response by anatomic metrics (RECIST, mRECIST, EASL) and functional metrics (ADC and arterial and venous enhancement) were reported in targeted and non-targeted lesions. A two-sample paired t test was used to compare the changes after TARE. A p value of <0.05 was considered statistically significant.

RESULTS

The anatomic metrics did not show any significant changes in both targeted and non-targeted groups. Targeted lesions demonstrated an increase in mean volumetric ADC (23.4%; p = 0.01), a decrease in arterial and venous enhancement (-22.9% and -6.7%, respectively; p < 0.001 and p = 0.002, respectively) 1 month after treatment. Twenty one responding lesions (42%) by RECIST at 6 months demonstrated a significant increase in volumetric ADC (37.2%; p = 0.01), decrease in arterial and venous enhancement (-58.5% and -23.9%, respectively; p < 0.001) at 1 month post-treatment. Responding lesions did not change significantly by anatomic metrics.

CONCLUSIONS

RECIST, mRECIST, and EASL criteria failed to stratify lesions into responders and non-responders early after TARE in hypo-vascular liver metastasis. Quantitative volumetric functional MR imaging could be a promising tool as a biomarker for predicting early response and can potentially be utilized in clinical trials.

Positron Emission Tomography–Computed Tomography (PET-CT) Versus No PET-CT in the Management of Potentially Resectable Colorectal Cancer Liver Metastases: Cost Implications of a Randomized Controlled Trial

Purpose:

To evaluate whether positron emission tomography (PET) combined with computed tomography (PET-CT) is cost saving, or cost neutral, compared with conventional imaging in management of patients with resectable colorectal cancer liver metastases.

Methods:

Cost evaluation of a randomized trial that compared the effect of PET-CT on surgical management of patients with resectable colorectal cancer liver metastases. Health care use data ≤ 1 year after random assignment was obtained from administrative databases. Cost analysis was undertaken from the perspective of a third-party payer (ie, Ministry of Health). Mean costs with 95% credible intervals (CrI) were estimated by using a Bayesian approach.

Results:

The estimated mean cost per patient in the 263 patients who underwent PET-CT was $45,454 CAD (range, $1,340 to $181,420) and in the 134 control patients, $40,859 CAD (range, $279 to $293,558), with a net difference of $4,327 CAD (95% CrI, −$2,207 to $10,614). The primary cost driver was hospitalization for liver surgery (difference of $2,997 CAD for PET-CT; 95% CrI, −$2,144 to $8,010), which was mainly a result of a longer length of hospital stay for the PET-CT arm (median, 7 v 6 days; P = .03) and a higher postoperative complication rate (20% v 10%; P = .01). Baseline characteristics were similar between groups, including the number of liver segments involved with cancer, number of segments resected, and type of liver resection performed. No difference in survival was detected between arms.

Conclusion:

PET-CT was associated with limited clinical benefit and a nonsignificant increased cost. Universal funding of PET-CT in the management of patients with resectable colorectal cancer liver metastases does not seem justified.

Advantages of L-3-[(18)F] fluoro-alpha-methyl tyrosine over 2-[(18)F]-fluoro-2-deoxyglucose in detecting liver metastasis during positron emission tomography scan

Purpose

We aimed to assess the usefulness of positron emission tomography (PET) using the amino acid tracer L-3-[18F] fluoro-alpha-methyl tyrosine (FAMT) in detecting metastatic liver lesions compared with 2-[18F]-fluoro-2-deoxyglucose (FDG).

Methods

We included 24 patients with liver metastases who underwent both FDG-PET/computed tomography (CT) and FAMT-PET/CT. Maximum standardized uptake value (SUVmax) and tumor-to-liver parenchymal (T/L) ratio were analyzed to evaluate the correlation between FDG and FAMT uptakes in metastatic liver lesions; adenocarcinoma (AC, n = 21), squamous cell carcinoma (SCC, n = 23), neuroendocrine tumor (NET, n = 9), and carcinoid tumor (CAR, n = 6).

Results

We detected 59 lesions on performing either FDG-PET or FAMT-PET. NETs had significantly lower T/L ratios for FAMT (median, 1.00; range, 0.86–1.34) compared with those for FDG (median 2.86; range 1.70–6.13, p < 0.01). CAR tumors tended to reveal lower T/L ratios for FDG (median 1.10; range 0.78–1.92) than those for FAMT (median 1.80; range 0.80–2.34). Comparison of T/L ratios of SCC and AC revealed that FAMT in the metastatic liver lesions of SCC was higher than those of AC (p < 0.05).

Conclusion

FAMT-PET could detect metastatic liver lesions from various cancers, except NET.

Determination of Resectability

The nuances of determining resectability for liver tumors can be difficult to navigate, owing to the variety of primary and secondary malignancies involving the liver, the range of patient-specific factors to consider, and the hepatic anatomic and functional variability that seems inevitable. The basic principles, however, are simple;if surgery is deemed appropriate from an oncologic standpoint, the patient is in reasonably good health, and the tumor can be safely removed without compromising the integrity of the future remnant, nearly all patients will be candidates for resection.

Does the Gadoxetic Acid-Enhanced Liver MRI Impact on the Treatment of Patients with Colorectal Cancer? Comparison Study with ¹⁸F-FDG PET/CT

Objectives. We evaluated the value of Gadoxetic acid-enhanced liver MRI in the preoperative staging of colorectal cancer and estimated the clinical impact of liver MRI in the management plan of liver metastasis. Methods. We identified 108 patients who underwent PET/CT and liver MRI as preoperative evaluation of colorectal cancer, between January 2011 and December 2013. We evaluated the per nodule sensitivity of PET/CT and liver MRI for liver metastasis. Management plan changes were estimated for patients with metastatic nodules newly detected on liver MRI, to assess the clinical impact. Results. We enrolled 131 metastatic nodules (mean size 1.6 cm) in 41 patients (mean age 65 years). The per nodule sensitivities of PET/CT and liver MRI were both 100% for nodules measuring 2 cm or larger but were significantly different for nodules measuring less than 2 cm (59.8% and 95.1%, resp., P = 0.0001). At least one more metastatic nodule was detected on MRI in 16 patients. Among these, 7 patients indicated changes of management plan after performing MRI. Conclusions. Gadoxetic acid-enhanced liver MRI detected more metastatic nodules compared with PET/CT, especially for small (<2 cm) nodules. The newly detected nodules induced management plan change in 43.8% (7/16) of patients.

Role of fluorine 18 fluorodeoxyglucose positron emission tomography/computed tomography in gastrointestinal cancers

Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) has become a routine imaging modality for many malignancies and its use is currently increasing. In the present review article, we will summarize the evidence for FDG-PET/CT use in digestive cancers (excluding neuroendocrine tumours), and review the existing recommendations. While PET/CT is nowadays considered to be an important tool in the initial workup of oesophageal and anal cancers, new data are emerging regarding its use in assessing therapeutic efficacy, radiotherapy treatment planning, and detection of recurrence in case of isolated tumour marker elevation. Moreover, PET/CT may help decision making by detecting distant metastatic sites especially in potentially resectable metastatic colorectal cancer and, to a lesser extent, in localized gastric and pancreatic cancers. Finally, incidental focal colonic FDG uptakes require exploration by colonoscopy, as they are often associated with premalignant or malignant lesions.

FDG PET/CT in the liver: lesions mimicking malignancies

PURPOSE

18F-fluorodeoxyglucose (FDG) PET/CT is invaluable in managing liver lesions, in particular in the evaluation of suspected liver metastases. It is both sensitive and specific in detecting liver metastases from a wide range of primary cancers, and may change clinical management, most commonly by detecting additional lesions and decreasing the number of futile surgeries. However, some benign lesions may also show increased metabolic activity which can lead to false positive PET findings. We describe some of these lesions and their imaging characteristics that may help in differentiating them from malignant metastases.

METHODS

e reviewed all whole body FDG PET/CT studies performed over a 5-year period in our institution, and identified those with focal liver lesions showing increased FDG uptake for which histological results were available.

RESULTS

majority of lesions showing increased metabolic activity were due to malignant disease, such as metastases or primary liver tumours. However, we also found increased FDG uptake in non-neoplastic lesions such as Cryptococcosis, abscesses, and secondary inflammation from cholecystitis. Increased metabolic activity was also seen in some benign neoplasms such as hepatic adenomas and hemangioendotheliomas.

CONCLUSION

DG PET/CT is currently the most sensitive non-invasive imaging modality for the detection of hepatic metastases, particularly from the gastrointestinal tract. False positive results are rare, and have been described mainly in abscesses. However, other lesions can also show increased metabolic activity, and failure to differentiate these from metastases may result in inappropriate treatment.

[18F]fludeoxyglucose positron emission tomography and computed tomography as a prognostic tool before liver transplantation, resection, and loco-ablative therapies for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer and the third most common cause of cancer-related death worldwide. Orthotopic liver transplantation (OLT) and resection are curative treatment options for well-selected patients with HCC, whereas loco-ablative therapy has been shown to prolong survival. Organ and treatment allocations for these patients are currently based on the number and size of tumors, as defined by the Milan criteria, and on functional capacity, and they are incorporated into the Barcelona Clinic Liver Cancer staging system and treatment strategy. Even though these staging criteria have markedly improved the outcomes of patients with HCC, they still lack accuracy in predicting the risk of tumor recurrence because they do not incorporate markers of tumor biology and behavior. Positron emission tomography (PET) and computed tomography (CT) with [(18) F]fludeoxyglucose ([(18) F]FDG) constitute an imaging modality for detecting tumor tissue that is metabolically active. Uptake of [(18) F]FDG is highly associated with tumor aggressiveness. In this review, we present the accumulating data on the use of [(18) F]FDG PET-CT as an in vivo biomarker and its predictive value in identifying patients at risk for HCC recurrence after liver transplantation, resection, or ablation. These data suggest that the introduction of [(18) F]FDG PET-CT into the imaging algorithm of patients planned for liver transplantation, resection, or ablation may improve outcomes.

Bevacizumab-based neoadjuvant chemotherapy for colorectal cancer liver metastases: Pitfalls and helpful tricks in a review for clinicians

Bevacizumab added to chemotherapy has shown encouraging efficacy in the neoadjuvant therapy of colorectal cancer liver metastases. In absence of biological predictor factors of efficacy to bevacizumab-based treatment, the assessment of response may be a crucial point to select patients who may benefit the most from surgery. At the same time the pathological response after liver resection could represent a guide for the next therapeutic plan. In the pre-surgical phase, conventional computed tomography and response evaluation with RECIST criteria may underestimate the response to anti-angiogenic drugs. Modified computed tomography criteria of response, morphologic changes as well as novel imaging techniques and metabolic assessment by fluorodeoxyglucose positron emission tomography seem to be promising methods for the assessment of response and for leading the clinical choices. Pathological response at the time of surgery is an important prognostic factor and a surrogate of survival for resected patients. Different classification criteria to assess pathological response have been developed, residual viable tumor, tumor regression grade (TRG), modified TRG and tumor thickness at the tumor-normal interface, but to date a superiority of one approach over the others has not been clearly established. In this review, we evaluate the available data with the aim to help the clinicians in the pre- and post-surgical care of patient with colorectal cancer liver metastases treated with bevacizumab-based neoadjuvant strategy.

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.

The impact of PET/CT on the management of hepatic and extra hepatic metastases from gastrointestinal cancers

PURPOSE

To investigate the efficacy of positron emission tomography/computed tomography (PET/CT) in detection and management of hepatic and extrahepatic metastases from gastrointestinal cancers.

MATERIALS AND METHODS

Between February 2008 and July 2010, patients histopathologically diagnosed with gastrointestinal cancer and showing suspected metastasis on CT screening were subsequently evaluated with PET/CT. All patients were subgrouped according to histopathological origin and localization of the primary tumor. Localization of gastrointestinal cancers was further specified as lower gastrointestinal system (GIS), upper GIS, or hepato-pancreato-biliary (HPB). Both accuracy and impact of CT and PET/CT on patient management were retrospectively evaluated.

RESULTS

One hundred and thirteen patients diagnosed histopathologically with gastrointestinal cancers were retrospectively evaluated. Seventy-nine patients had adenocarcinoma and 34 patients other gastrointestinal tumors. Forty-one patients were in the upper GIS group, 30 patients in the HPB group, and 42 patients in the lower GIS group. Evaluation the diagnostic performance of PET/CT for suspected metastasis according to histopathological origin of the tumor, revealed that the sensitivity of PET/CT - although statistically not different - was higher in adenocarcinomas than in non-adenocarcinomas (90% (95% CI, 0.78-0.96) vs. 71.4% (95% CI, 0.45-0.88), P=0.86). The specificity was not significantly different (85.7% (95% CI, 0.70-0.93) vs. 85% (95% CI, 0.63-0.94), P=1.00). In the overall patient group; CT was significantly more sensitive than PET/CT for detection of hepatic metastases (94.7% vs. 78.9%, P=0.042), whereas PET/CT was significantly more specific than CT (48% vs. 98.7%, P<0.001). In subgroup analysis, sensitivity was not significantly different (P>0.05) but specificity was significantly higher in PET/CT than CT (P<0.05). The specificity of PET/CT was highest in upper GIS (100%) and HPB (100%) subgroups. In the overall patient group; for detection of extrahepatic metastasis, the sensitivity of CT (75%) and PET/CT (87.5%) showed no significant difference (P=0.437). However, PET/CT was significantly more specific than CT (88.7% vs. 70.4%, P=0.007). In subgroup analysis, no significant difference was found between CT and PET/CT either in sensitivity or in specificity (P>0.05). The specificity of PET/CT was highest in the lower GIS subgroup (93%). The management of 45 patients (39.8%) was revised after PET/CT evaluation.

CONCLUSIONS

PET/CT has a higher specificity than CT in detecting suspected hepatic and extrahepatic metastases of gastrointestinal cancers, and has an impact of nearly 40% on changing patient management strategies.

Impact of pre-operative positron emission tomography in gallbladder cancer

BACKGROUND

Current pre-operative staging methods for gallbladder cancer (GBC) are suboptimal in detecting metastatic disease. Positron emission tomography (PET) may have a role but data are lacking.

METHODS

Patients with GBC and PET assessed by a hepatobiliary surgeon in clinic between January 2001 and June 2013 were retrospectively reviewed. Computed tomography (CT)/magnetic resonace imaging (MRI) were correlated with PET scans and analysed for evidence of metastatic or locally unresectable disease. Medical records were reviewed to determine if PET scanning was helpful by preventing non-therapeutic surgery or enabling resection in patients initially deemed unresectable.

RESULTS

There were 100 patients including 63 incidental GBC. Thirty-eight patients did not proceed to surgery, 35 were resected and 27 patients were explored but had unresectable disease. PET was positive for metastatic disease in 39 patients (sensitivity 56%, specificity 94%). Five patients definitively benefitted from PET: in 3 patients PET found disease not seen on CT, and 2 patients with suspicious CT findings had negative PET and successful resections. In a further 12 patients PET confirmed equivocal CT findings. Three patients had additional invasive procedures performed owing to PET avidity in other sites. Utility of PET was higher in patients with suspicious nodal disease on CT [odds ratio (OR) 7.1 versus no nodal disease, P = 0.0004], and in patients without a prior cholecystectomy (OR 3.1 versus post-cholecystectomy, P = 0.04).

CONCLUSION

Addition of PET to conventional cross-sectional imaging has a modest impact on management pre-operatively particularly in patients without a prior cholecystectomy and to confirm suspicious nodal disease on CT.

Early post-treatment FDG PET predicts survival after 90Y microsphere radioembolization in liver-dominant metastatic colorectal cancer

PURPOSE

The aim of this study was to evaluate the predictive value of early metabolic response 4 weeks post-treatment using (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT in patients with unresectable hepatic metastases of colorectal cancer (CRC) undergoing radioembolization (RE) with (90)Y-labelled microspheres.

METHODS

A total of 51 consecutive patients with liver-dominant metastases of CRC were treated with RE and underwent (18)F-FDG PET/CT at baseline and 4 weeks after RE. In each patient, three hepatic metastases with the highest maximum standardized uptake value (SUVmax) were selected as target lesions. Metabolic response was defined as >50 % reduction of tumour to liver ratios. Survival analyses using Kaplan-Meier and multivariate analyses were performed to identify prognostic factors for overall survival (OS). Investigated baseline characteristics included age (>60 years), performance status (Eastern Cooperative Oncology Group >1), bilirubin (>1.0 mg/dl), hepatic tumour burden (>25 %) and presence of extrahepatic disease.

RESULTS

The median OS after RE was 7 months [95 % confidence interval (CI) 5-8]; early metabolic responders (n = 33) survived longer than non-responders (p < 0.001) with a median OS of 10 months (95 % CI 3-16) versus 4 months (95 % CI 2-6). Hepatic tumour burden also had significant impact on treatment outcome (p < 0.001) with a median OS of 5 months (95 % CI, 3-7) for patients with >25 % metastatic liver replacement vs 14 months (95 % CI 6-22) for the less advanced patients. Both factors (early metabolic response and low hepatic tumour burden) remained as independent predictors of improved survival on multivariate analysis.

CONCLUSION

These are the first findings to show that molecular response assessment in CRC using (18)F-FDG PET/CT appears feasible as early as 4 weeks post-RE, allowing risk stratification and potentially facilitating early response-adapted treatment strategies.

Diagnostic accuracy and impact on management of (18)F-FDG PET and PET/CT in colorectal liver metastasis: a meta-analysis and systematic review

PURPOSE

The first aim of the review (aim 1) was to obtain the diagnostic performance values of (18)F-FDG PET for the detection and staging of liver metastases in patients with colorectal cancer (CRC), the second aim (aim 2) was to compare PET and conventional imaging modalities, and the third aim (aim 3) was to evaluate the impact of PET on patient management. The incidence of extrahepatic disease (EHD) detected by PET is also reviewed.

METHODS

A comprehensive search was performed on PubMed/MEDLINE for studies evaluating PET and PET/CT in CRC patients with liver metastases up to June 2014. For inclusion PET had to have been performed prior to surgery, there had to be at least 18 patients in the study, and the reported data had to allow calculation of 2 × 2 contingency tables (for aim 1). A total of 18 studies were eligible for at least one of the three intended subanalyses including a total of 1,059 patients. Pooled sensitivity, specificity and accuracy and the corresponding 95 % confidence intervals were derived from the contingency tables on a patient basis (patient-based analysis, PBA) and a lesion basis (lesion-based analysis, LBA) for eight studies.

RESULTS

Pooled sensitivity and specificity of PET on PBA were both 93 %. Corresponding values for LBA were 60 % and 79 %, respectively. Areas under the summary ROC were 0.97 for PBA and 0.67 for LBA. Regarding aim 2, PET had a slightly lower sensitivity than MRI and CT on PBA (93 %, 100 % and 98 %, respectively) and LBA (66 %, 89 % and 79 %, respectively) but appeared to be more specific than MRI and CT (86 %, 81 % and 67 %, respectively). PET findings resulted in changes in the management of a mean of 24 % of patients. The mean incidence of PET-based EHD was 32 %.

CONCLUSION

This meta-analysis suggests that FDG PET/CT is highly accurate for the detection of liver metastases on a patient basis but less accurate on a lesion basis. Compared to MRI, PET is less sensitive but more specific and affects the management of about one-quarter of patients.