Staging of colon cancer: whole-body MRI vs. whole-body PET-CT—initial clinical experience

Contribution of Metabolic Parameters and Pericolic Fat Stranding on Preoperative 18F-FDG PET/CT in Predicting Post-operative Histopathology and Outcome in Colorectal Cancer

Purpose

We aimed to investigate the additional value of preoperative PET/CT and reveal relationships between metabolic parameters, pericolic fat stranding finding, postoperative histopathology, and overall survival in colorectal cancer (CRC).

Methods

CRC patients who underwent preoperative PET/CT between January 2017-December 2021 were analyzed. Lymph nodes, organ metastases, and metabolic parameters were evaluated from PET/CT. The pericolic fat stranding was evaluated from CT component. Relationships between these factors and postoperative histopathological findings were statistically analyzed. Survival analyses were performed.

Results

Ninety-one patients (59 males, 32 females) were included in the study. All tumors showed high FDG uptake (mean SUVmax 19.5 ± 9.9). SUVmax of the tumor differed significantly at T3 and T4 stages (p = 0.041). A significant correlation was found between MTV, TLG values and the differentiation degree (p = 0.005, 0.003, respectively). PET/CT predicted the N stage with a high accuracy rate (80%). PET/CT found additional metastases that changed treatment decisions in one-third of patients. A relationship was found between tumor length, surgical margin, lymphovascular invasion and pericolic fat stranding. In multivariate analysis, differentiation degree (HR = 26.1, 95%CI 1.672-408.467), MTV (HR = 0.3, 95%CI 0.071-0.841), TLG (HR = 3.5, 95%CI 1.065-11.193), and lymphovascular invasion (HR = 0.2, 95%CI 0.026-0.853, p = 0.033) were independent factors affecting overall survival.

Conclusion

Preoperative PET/CT contributes to CRC management by detecting additional metastases as well as predicting prognosis and postoperative findings such as T stage, N stage and tumor differentiation. The SUVmax may differentiate between T3 and T4 tumor. Reporting of pericolic fat stranding may contribute to the estimation of lymphatic invasion and positive surgical margin.

The Management of Oligometastatic Disease in Colorectal Cancer: Present Strategies and Future Perspectives

Oligometastatic disease has been described as an intermediate clinical state between localized cancer and systemically metastasized disease. Recent clinical studies have shown prolonged survival when aggressive locoregional approaches are added to systemic therapies in patients with oligometastases. The aim of this review is to outline the newest options to treat oligometastatic colorectal cancer (CRC), also considering its molecular patterns. We present an overview of the available local treatment strategies, including surgical procedures, stereotactic body radiation therapy (SBRT), thermal ablation, as well as trans-arterial chemoembolization (TACE) and selective internal radiotherapy (SIRT). Moreover, since imaging methods provide crucial information for the early diagnosis and management of oligometastatic CRC, we discuss the role of modern radiologic techniques in selecting patients that are amenable to potentially curative locoregional treatments.

Diagnostic performance of the FDG-PET/CT in patients with resected mucinous colorectal liver metastases

BACKGROUND

and purpose: FDG-PET/CT has gained acceptance for tumours staging. Few and conflicting data exist on the sensitivity of FDG-PET/CT in identifying colorectal mucinous liver metastases (mucCRLM). The aim of this study was to evaluate the diagnostic performance of the FDG-PET/CT in patients with mucCRLM who underwent liver surgery.

METHODS

All patients affected by mucCRLM scheduled for liver resection who had undergone preoperative FDG-PET/CT between 2005 and 2018 were analyzed. Diagnostic performance of FDG-PET/CT was assessed in organ and lesion-based analysis.

RESULTS

58 patients out of 131 (44.2%) affected by mucCRLM fulfilled the inclusion criteria. 118 mucCRLM were detected. FDG-PET/CT confirmed 71 (60.2%) CRLM in 51 patients. The sensitivity and specificity of FDG-PET/CT were 89.4% and 100% in the organ-based analysis and 60.7% and 100% in lesion-based analysis. Absence of micro-vascular invasion (100% vs. 23%, p < 0.001) and median percentage of viable tumour cells were associated with FDG-PET/CT false negative (15% vs. 60%, p = 0.007). At ROC analysis viable tumour cells percentage >25% was associated with low risk of false negative (AUC 0.848; p = 0.006).

CONCLUSIONS

FDG-PET/CT had a significant rate of false negative results in patients with mucinous colorectal liver metastases. Negative FDG-PET/CT in patients with low percentage of viable tumour cells after chemotherapy should be considered with caution.

The Impact of Patient Characteristics and Tumor Biology on the Accuracy of Preoperative Staging of Colon Cancer in Denmark. A Nationwide Cohort Study

Simple Summary

The roles of mismatch repair and other colon tumor characteristics were investigated in a nationwide registry study with data extracted from the Danish Colorectal Cancer Group. Mismatch repair can arise during DNA replication. In this study, 6102 patients were included with a median age of 72 (range 23–97 years). The mismatch repair was deficient in 24% and proficient in 76%. Mismatch repair deficiency impacted the accuracy of the preoperative staging of colon cancer. In the future, mismatch repair status should be taken into consideration in the clinical staging of colon cancer.

Abstract

Background: Colon cancer is a common disease in western populations. The aim of this study was to assess the impact of mismatch repair (MMR) deficiency and other patient and tumor characteristics on the accuracy of preoperative staging by comparing histopathological T- and N-categories of the resected specimen with the preoperative clinical stage in a nationwide cohort of patients treated for colon cancer by elective bowel resection with curative intent. Methods: A register study of a cohort extracted from the Danish Colorectal Cancer Group (DCCG) database, which holds prospective data on all new cases of colon and rectum cancer in Denmark. Patients diagnosed with colon cancer and treated with an elective bowel resection with curative intent in the years 2016–2019 were analyzed. Results: A total of 6102 patients were included (n = 3161 (52%) men and n = 2941 (48%) women) with a median age of 72 years (range 23–97 years). MMR was deficient in 24% of the patients and proficient in 76%. MMR deficiency, tumor sidedness and histopathological type were significant predictors of the accuracy of preoperative staging of colon cancer in univariate and multivariate analysis. MMR status in particular showed a strong impact on the risk of overstaging. Conclusions: MMR deficiency, but also tumor sidedness and to some degree histopathological type, impacted the accuracy of preoperative staging of colon cancer. MMR status should be taken into consideration in everyday clinical staging.

Brain Metastases from Colorectal Cancer: A Systematic Review of the Literature and Meta-Analysis to Establish a Guideline for Daily Treatment

Colorectal cancer (CRC) is the third most common malignancy worldwide. Most patients with metastatic CRC develop liver or lung metastases, while a minority suffer from brain metastases. There is little information available regarding the presentation, treatment, and overall survival of brain metastases (BM) from CRC. This systematic review and meta-analysis includes data collected from three major databases (PubMed, Cochrane, and Embase) based on the key words "brain", "metastas*", "tumor", "colorectal", "cancer", and "malignancy". In total, 1318 articles were identified in the search and 86 studies matched the inclusion criteria. The incidence of BM varied between 0.1% and 11.5%. Most patients developed metastases at other sites prior to developing BM. Lung metastases and KRAS mutations were described as risk factors for additional BM. Patients with BM suffered from various symptoms, but up to 96.8% of BM patients were asymptomatic at the time of BM diagnosis. Median survival time ranged from 2 to 9.6 months, and overall survival (OS) increased up to 41.1 months in patients on a multimodal therapy regimen. Several factors including age, blood levels of carcinoembryonic antigen (CEA), multiple metastases sites, number of brain lesions, and presence of the KRAS mutation were predictors of OS. For BM diagnosis, MRI was considered to be state of the art. Treatment consisted of a combination of surgery, radiation, or systemic treatment.

Whole-body MRI compared with standard pathways for staging metastatic disease in lung and colorectal cancer: the Streamline diagnostic accuracy studies

BACKGROUND

Whole-body magnetic resonance imaging is advocated as an alternative to standard pathways for staging cancer.

OBJECTIVES

The objectives were to compare diagnostic accuracy, efficiency, patient acceptability, observer variability and cost-effectiveness of whole-body magnetic resonance imaging and standard pathways in staging newly diagnosed non-small-cell lung cancer (Streamline L) and colorectal cancer (Streamline C).

DESIGN

The design was a prospective multicentre cohort study.

SETTING

The setting was 16 NHS hospitals.

PARTICIPANTS

Consecutive patients aged ≥ 18 years with histologically proven or suspected colorectal (Streamline C) or non-small-cell lung cancer (Streamline L).

INTERVENTIONS

Whole-body magnetic resonance imaging. Standard staging investigations (e.g. computed tomography and positron emission tomography-computed tomography).

REFERENCE STANDARD

Consensus panel decision using 12-month follow-up data.

MAIN OUTCOME MEASURES

The primary outcome was per-patient sensitivity difference between whole-body magnetic resonance imaging and standard staging pathways for metastasis. Secondary outcomes included differences in specificity, the nature of the first major treatment decision, time and number of tests to complete staging, patient experience and cost-effectiveness.

RESULTS

Streamline C - 299 participants were included. Per-patient sensitivity for metastatic disease was 67% (95% confidence interval 56% to 78%) and 63% (95% confidence interval 51% to 74%) for whole-body magnetic resonance imaging and standard pathways, respectively, a difference in sensitivity of 4% (95% confidence interval -5% to 13%; p = 0.51). Specificity was 95% (95% confidence interval 92% to 97%) and 93% (95% confidence interval 90% to 96%) respectively, a difference of 2% (95% confidence interval -2% to 6%). Pathway treatment decisions agreed with the multidisciplinary team treatment decision in 96% and 95% of cases, respectively, a difference of 1% (95% confidence interval -2% to 4%). Time for staging was 8 days (95% confidence interval 6 to 9 days) and 13 days (95% confidence interval 11 to 15 days) for whole-body magnetic resonance imaging and standard pathways, respectively, a difference of 5 days (95% confidence interval 3 to 7 days). The whole-body magnetic resonance imaging pathway was cheaper than the standard staging pathway: £216 (95% confidence interval £211 to £221) versus £285 (95% confidence interval £260 to £310). Streamline L - 187 participants were included. Per-patient sensitivity for metastatic disease was 50% (95% confidence interval 37% to 63%) and 54% (95% confidence interval 41% to 67%) for whole-body magnetic resonance imaging and standard pathways, respectively, a difference in sensitivity of 4% (95% confidence interval -7% to 15%; p = 0.73). Specificity was 93% (95% confidence interval 88% to 96%) and 95% (95% confidence interval 91% to 98%), respectively, a difference of 2% (95% confidence interval -2% to 7%). Pathway treatment decisions agreed with the multidisciplinary team treatment decision in 98% and 99% of cases, respectively, a difference of 1% (95% confidence interval -2% to 4%). Time for staging was 13 days (95% confidence interval 12 to 14 days) and 19 days (95% confidence interval 17 to 21 days) for whole-body magnetic resonance imaging and standard pathways, respectively, a difference of 6 days (95% confidence interval 4 to 8 days). The whole-body magnetic resonance imaging pathway was cheaper than the standard staging pathway: £317 (95% confidence interval £273 to £361) versus £620 (95% confidence interval £574 to £666). Participants generally found whole-body magnetic resonance imaging more burdensome than standard imaging but most participants preferred the whole-body magnetic resonance imaging staging pathway if it reduced time to staging and/or number of tests.

LIMITATIONS

Whole-body magnetic resonance imaging was interpreted by practitioners blinded to other clinical data, which may not fully reflect how it is used in clinical practice.

CONCLUSIONS

In colorectal and non-small-cell lung cancer, the whole-body magnetic resonance imaging staging pathway has similar accuracy to standard staging pathways, is generally preferred by patients, improves staging efficiency and has lower staging costs. Future work should address the utility of whole-body magnetic resonance imaging for treatment response assessment.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN43958015 and ISRCTN50436483.

FUNDING

This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 66. See the NIHR Journals Library website for further project information.

Suppression of KIF22 Inhibits Cell Proliferation and Xenograft Tumor Growth in Colon Cancer

Background: Kinesin family member 22 (KIF22) is known as a regulator of cell mitosis and cellular vesicle transport. The alterations of KIF22 are associated with a series of tumors; however, its possible role in the progression of colon cancer is still unclear. Materials and Methods: This retrospective research collected 82 paired tissues with colon cancer. KIF22 protein and mRNA expression levels were detected by immunohistochemistry assays and Immunoblot assays, respectively. Short hairpin RNA (shRNA) plasmids were used to suppress the expression of KIF22 in HCT116 and HT29 cells, and the silencing efficiencies of shRNA plasmids targeted KIF22 were detected by quantitative PCR assays and immunoblot assays. In addition, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assays and xenograft tumor growth assays were performed to observe cell proliferation in vitro and in vivo. Results: In human colon cancer tissues, the expression level of KIF22 was increased and correlated with clinical pathological features, including tumor stage and clinical stage (p = 0.034, and p = 0.015, respectively). Suppression of KIF22 inhibited cell proliferation and xenograft tumor growth. Conclusion: KIF22 might play an important role in the regulation of cell proliferation in colon cancer and might therefore serve as a promising therapeutic target.

Diagnostic accuracy of whole-body MRI versus standard imaging pathways for metastatic disease in newly diagnosed colorectal cancer: the prospective Streamline C trial

BACKGROUND

Whole-body MRI (WB-MRI) could be an alternative to multimodality staging of colorectal cancer, but its diagnostic accuracy, effect on staging times, number of tests needed, cost, and effect on treatment decisions are unknown. We aimed to prospectively compare the diagnostic accuracy and efficiency of WB-MRI-based staging pathways with standard pathways in colorectal cancer.

METHODS

The Streamline C trial was a prospective, multicentre trial done in 16 hospitals in England. Eligible patients were 18 years or older, with newly diagnosed colorectal cancer. Exclusion criteria were severe systemic disease, pregnancy, contraindications to MRI, or polyp cancer. Patients underwent WB-MRI, the result of which was withheld until standard staging investigations were complete and the first treatment decision made. The multidisciplinary team recorded its treatment decision based on standard investigations, then on the WB-MRI staging pathway (WB-MRI plus additional tests generated), and finally on all tests. The primary outcome was difference in per-patient sensitivity for metastases between standard and WB-MRI staging pathways against a consensus reference standard at 12 months, in the per-protocol population. Secondary outcomes were difference in per-patient specificity for metastatic disease detection between standard and WB-MRI staging pathways, differences in treatment decisions, staging efficiency (time taken, test number, and costs), and per-organ sensitivity and specificity for metastases and per-patient agreement for local T and N stage. This trial is registered with the International Standard Randomised Controlled Trial registry, number ISRCTN43958015, and is complete.

FINDINGS

Between March 26, 2013, and Aug 19, 2016, 1020 patients were screened for eligibility. 370 patients were recruited, 299 of whom completed the trial; 68 (23%) had metastasis at baseline. Pathway sensitivity was 67% (95% CI 56 to 78) for WB-MRI and 63% (51 to 74) for standard pathways, a difference in sensitivity of 4% (-5 to 13, p=0·51). No adverse events related to imaging were reported. Specificity did not differ between WB-MRI (95% [95% CI 92-97]) and standard pathways (93% [90-96], p=0·48). Agreement with the multidisciplinary team's final treatment decision was 96% for WB-MRI and 95% for the standard pathway. Time to complete staging was shorter for WB-MRI (median, 8 days [IQR 6-9]) than for the standard pathway (13 days [11-15]); a 5-day (3-7) difference. WB-MRI required fewer tests (median, one [95% CI 1 to 1]) than did standard pathways (two [2 to 2]), a difference of one (1 to 1). Mean per-patient staging costs were £216 (95% CI 211-221) for WB-MRI and £285 (260-310) for standard pathways.

INTERPRETATION

WB-MRI staging pathways have similar accuracy to standard pathways and reduce the number of tests needed, staging time, and cost.

FUNDING

UK National Institute for Health Research.

Clinical utility of simultaneous whole-body 18F-FDG PET/MRI as a single-step imaging modality in the staging of primary nasopharyngeal carcinoma

PURPOSE

Both head and neck magnetic resonance imaging (MRI) and 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) play a crucial role in the staging of primary nasopharyngeal carcinoma (NPC). In this study, we sought to prospectively investigate the clinical utility of simultaneous whole-body 18F-FDG PET/MRI for primary staging of NPC patients.

METHODS

We examined 113 patients with histologically confirmed NPC who underwent pretreatment, simultaneous whole-body PET/MRI and PET/CT for primary tumor staging. The images obtained with the different imaging modalities were interpreted independently and compared with each other.

RESULTS

PET/MRI increased the accuracy of head and neck MRI for assessment of primary tumor extent in four patients via addition of FDG uptake information to increase the conspicuity of morphologically subtle lesions. PET/MR images were more discernible than PET/CT images for mapping tumor extension, especially intracranial invasion. Regarding the N staging assessment, the sensitivity of PET/MRI (99.5%) was higher than that of head and neck MRI (94.2%) and PET/CT (90.9%). PET/MRI was particularly useful for distinguishing retropharyngeal nodal metastasis from adjacent nasopharyngeal tumors. For distant metastasis evaluation, PET/MRI exhibited a similar sensitivity (90% vs. 86.7% vs. 83.3%), but higher positive predictive value (93.1% vs. 78.8% vs. 83.3%) than whole-body MRI and PET/CT, respectively.

CONCLUSIONS

For tumor staging of NPC, simultaneous whole-body PET/MRI was more accurate than head and neck MRI and PET/CT, and may serve as a single-step staging modality.

Comparison of four MRI protocols for detection of extrahepatic colorectal cancer metastases

PURPOSE

To compare three magnetic resonance imaging (MRI) protocols containing diffusion-weighted imaging with background suppression (DWIBS) and one traditional protocol for detecting extrahepatic colorectal cancer metastases.

MATERIALS AND METHODS

Thirty patients with extrahepatic colorectal cancer metastases were scanned in three stations from the skull base to the upper thighs using a 1.5T MRI system with six different MRI sequences; transverse and coronal T₂ -weighted (T₂ W) turbo spin-echo (TSE), coronal short tau inversion recovery (STIR), 3D T₁ W TSE, DWIBS, and a contrast-enhanced T₁ W 3D gradient echo (GRE) sequence. The six sequences were used to build four hypothetical MRI interpretive sets which were read by two readers in consensus, blinded to prior imaging. Lesions were categorized into 13 anatomic regions. Fluorodeoxyglucose / positron emission tomography / computed tomography (FDG-PET/CT) read with full access to prior imaging and clinical records was used as the reference standard. Sensitivity, specificity, and false discovery rate (FDR) were calculated as appropriate and receiver operating characteristic (ROC) curves were constructed.

RESULTS

In all, 177 malignant lesions were detected by FDG-PET/CT and distributed in 92 out of 390 scanned anatomic regions. The sensitivity was statistically higher in two out of three sets incorporating DWIBS on a per-lesion basis (66.7%, 63.3%, and 66.7% vs. 57.6%) (P = 0.01, P = 0.11, and P = 0.01, respectively) and in all sets incorporating DWIBS on a per-region basis (75.0%, 75.0%, and 77.2 vs. 66.3%) (P = 0.04, P = 0.04, and P = 0.01, respectively). There was no difference in specificity, FDR, or AUC_ROC . There was no difference between sets containing DWIBS irrespective of the use of a contrast-enhanced sequence.

CONCLUSION

MRI sets containing DWIBS had superior sensitivity. This sensitivity was retained when omitting a contrast-enhanced sequence.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017;46:1619-1630.

Update and current status of diffusion-weighted MRI in anorectal malignancy

SUMMARY 

Diffusion-weighted imaging (DWI) is an MRI technique that yields unique information regarding the movement of water molecules at the cellular level. Now widely available and rapid to perform the sequence is increasingly utilized within abdominopelvic oncology, including anorectal cancer imaging. Unfortunately, the diffusion properties of anorectal tumors are complex and not fully understood, with areas of cellular tumor, necrosis and fibrosis co-existing. While DWI shows promise both for staging and in assessing treatment response in anorectal cancer, there remains a lack of consensus regarding its role and integration into standard MRI protocols. This article outlines the basic science behind DWI and reviews the current evidence base for its use in anorectal cancer.

Clinical competence in the surgery of rectal cancer: the Italian Consensus Conference

BACKGROUND AND AIM

The literature continues to emphasize the advantages of treating patients in "high volume" units by "expert" surgeons, but there is no agreed definition of what is meant by either term. In September 2012, a Consensus Conference on Clinical Competence was organized in Rome as part of the meeting of the National Congress of Italian Surgery (I Congresso Nazionale della Chirurgia Italiana: Unità e valore della chirurgia italiana). The aims were to provide a definition of "expert surgeon" and "high-volume facility" in rectal cancer surgery and to assess their influence on patient outcome.

METHOD

An Organizing Committee (OC), a Scientific Committee (SC), a Group of Experts (E) and a Panel/Jury (P) were set up for the conduct of the Consensus Conference. Review of the literature focused on three main questions including training, "measuring" of quality and to what extent hospital and surgeon volume affects sphincter-preserving procedures, local recurrence, 30-day morbidity and mortality, survival, function, choice of laparoscopic approach and the choice of transanal endoscopic microsurgery (TEM).

RESULTS AND CONCLUSION

The difficulties encountered in defining competence in rectal surgery arise from the great heterogeneity of the parameters described in the literature to quantify it. Acquisition of data is difficult as many articles were published many years ago. Even with a focus on surgeon and hospital volume, it is difficult to define their role owing to the variability and the quality of the relevant studies.

Comparison between whole-body MRI and Fluorine-18-Fluorodeoxyglucose PET or PET/CT in oncology: a systematic review

BACKGROUND

The aim of the article is to systematically review published data about the comparison between positron emission tomography (PET) or PET/computed tomography (PET/CT) using Fluorine-18-Fluorodeoxyglucose (FDG) and whole-body magnetic resonance imaging (WB-MRI) in patients with different tumours.

METHODS

A comprehensive literature search of studies published in PubMed/MEDLINE, Scopus and Embase databases through April 2012 and regarding the comparison between FDG-PET or PET/CT and WB-MRI in patients with various tumours was carried out.

RESULTS

Forty-four articles comprising 2287 patients were retrieved in full-text version, included and discussed in this systematic review. Several articles evaluated mixed tumours with both diagnostic methods. Concerning the specific tumour types, more evidence exists for lymphomas, bone tumours, head and neck tumours and lung tumours, whereas there is less evidence for other tumour types.

CONCLUSIONS

Overall, based on the literature findings, WB-MRI seems to be a valid alternative method compared to PET/CT in oncology. Further larger prospective studies and in particular cost-effectiveness analysis comparing these two whole-body imaging techniques are needed to better assess the role of WB-MRI compared to FDG-PET or PET/CT in specific tumour types.

The oncological outcome after right hemicolectomy and accuracy of CT scan as a preoperative tool for staging in right sided colonic cancers

AIM

Neoadjuvant chemotherapy may have a role in the management of colonic carcinoma but clinical trials are required to determine whether this approach is superior to the standard policy of radical surgery, high-quality histopathology and selective postoperative chemotherapy. The selection of appropriate patients for such trials will depend on accurate locoregional staging of disease by preoperative CT scanning. We studied the outcome after radical right hemicolectomy and assessed the accuracy of preoperative CT scans in the prediction of postoperative pathology.

METHOD

A retrospective analysis of right hemicolectomies performed with curative intent for colon cancer under the care of a single colorectal surgeon (D.J.A.) was performed. Preoperative CT-proven Dukes D patients were excluded. Patient demographics, postoperative histology, use of adjuvant chemotherapy and survival data were collected. Kaplan-Meier curves were constructed and log-rank testing was performed to compare cancer-specific survival. Fifty patients had their preoperative CT scan images reviewed by two radiologists both blinded to the results of the postoperative histology. The accuracy of preoperative CT for T and N staging was studied. A P-value of < 0.05 was significant.

RESULTS

There were 136 patients (79 women). Median age was 76 (interquartile ratio 67-82) years. Median period of follow-up was 72 (interquartile ratio 39-92) months. There were 56 deaths (39 medical, 16 oncological and 1 postoperative). There were three groups of patients: node negative (n = 84), node positive with postoperative adjuvant chemotherapy (n = 30) and node positive without chemotherapy (n = 22). Five-year cancer-specific survival for node negative disease was 84% and was poorer for node positive patients who received adjuvant chemotherapy when compared with those who did not (62 vs 72%, P-value = 0.046 on log-rank testing). Sensitivity, specificity, positive and negative predictive value of CT scan for tumour (T) stage were 90, 33, 86 and 43% respectively, while that for nodal (N) stage was 83, 38, 57 and 69%, respectively.

CONCLUSION

CT scan has limited accuracy in predicting those patients with advanced locoregional disease who might benefit from neoadjuvant treatment. When this finding is combined with relatively high cancer-specific survival with surgery alone the impact of adjuvant chemotherapy on survival after radical surgery for right colon carcinoma may be marginal.

A systematic review and meta-analysis of pretherapeutic lymph node staging of colorectal cancer by 18F-FDG PET or PET/CT

The purpose of the present study was to conduct a systematic review and meta-analysis of the published literature to evaluate the diagnostic performance of fluorine-18 2-fluoro-2-deoxy-D-glucose (18F-FDG) PET in the pretherapeutic assessment of nodal staging in patients with colorectal cancer (CRC). We conducted a systematic MEDLINE search of articles in the published literature (last update, February 2012). Two reviewers independently assessed the methodological quality of each study. We estimated pooled sensitivity, specificity, summary receiver operating characteristic curves, and summary likelihood ratios. A total of 409 patients from 10 studies were analyzed. The pooled estimates of sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of 18F-FDG PET [PET/computed tomography (CT)] in the detection of pretherapeutic lymph node involvement in patients with CRC were 42.9% [95% confidence interval (CI): 36.0-50.0%], 87.9% (95% CI: 82.6-92.0%), 2.82 (95% CI: 1.96-4.07), and 0.69 (95% CI: 0.62-0.78), respectively. There is no solid evidence to support the routine clinical application of 18F-FDG PET (PET/CT) in the pretherapeutic evaluation of lymph node status in patients with CRC. However, 18F-FDG PET (PET/CT) could be used to strengthen the possibility of suspected metastatic lymph nodes detected by other imaging modalities.

[Importance of whole body MRI for staging of colorectal cancer]

CLINICAL/METHODICAL ISSUE

Staging and follow-up of colorectal cancer are usually performed with multimodal imaging strategies. These can be time-intensive and potentially lead to examiner-dependent bias. Alternatively, whole body magnetic resonance imaging (WB-MRI) provides oncologic imaging with a systemic approach.

STANDARD RADIOLOGICAL METHODS

Ultrasound, multislice computed tomography (MSCT), dedicated MRI and positron emission tomography/CT (PET/CT).

METHODICAL INNOVATIONS

High-resolution WB-MRI with focused examination of various organs, such as the pelvis and abdomen, lungs, brain and skeletal system, using different sequence and contrast techniques.

PERFORMANCE

Detection of colorectal tumor recurrence with WB-MRI provides 83% accuracy (lymph node metastases 80%, organ metastases 86%).

ACHIEVEMENTS

Potential cost reduction through decreased examination time and personnel costs.

PRACTICAL RECOMMENDATIONS

Whole body MRI is a radiation-free alternative to standard sequential algorithms of staging and follow-up of colorectal cancer.

Discrimination of metastatic from hyperplastic pelvic lymph nodes in patients with cervical cancer by diffusion-weighted magnetic resonance imaging

PURPOSE

To evaluate the diagnostic value of diffusion-weighted MR imaging for differentiating metastatic and hyperplastic pelvic lymph nodes in patients with cervical carcinoma.

MATERIALS AND METHODS

In this prospective study, 61 untreated patients were scanned with both morphological MR and diffusion-weighted imaging (DWI). Bilateral pelvic lymphadenectomy was then performed in all patients. Of the 1118 total dissected and histopathologically evaluated pelvic lymph nodes, 153 enlarged nodes with short-axis diameter larger than 5 mm were included for further study. The mean ADC values of all enlarged lymph nodes and the relative ADC values between tumors and nodes were also measured and, respectively, compared between the metastatic and hyperplastic node groups.

RESULTS

The mean ADC value of metastatic [(1.046 ± 0.198) × 10⁻³ mm²/s] nodes was significantly lower than that of hyperplastic [(1.289 ± 0.194) × 10⁻³ mm²/s] nodes (P < 0. 001). The relative ADC values between tumor and nodes were significantly lower in malignant [(0.19 ± 0.17) × 10⁻³ mm²/s] than hyperplastic [(0.4 ± 0.21) × 10⁻³ mm²/s] nodes (P < 0. 001). When a mean ADC value of 1.15 × 10⁻³ mm²/s was used as a threshold value for differentiating metastatic from hyperplastic nodes, the best results were obtained with a sensitivity of 83.3%, specificity of 74.7%, and accuracy of 78.4%.

CONCLUSION

DWI is useful in differentiating metastatic and hyperplastic pelvic lymph nodes in patients with cervical carcinoma.

The peak-standardized uptake value (P-SUV) by preoperative positron emission tomography-computed tomography (PET-CT) is a useful indicator of lymph node metastasis in gastric cancer

BACKGROUND AND OBJECTIVES

Little data is currently available on the usefulness of peak-standardized uptake value (P-SUV) by positron emission tomography-computed tomography (PET-CT) in gastric cancer. The purpose of the present study was to evaluate the value of PET-CT for the preoperative evaluation of patients with gastric cancer. The aim of this study was to assess the relation of between primary tumor P-SUV, as determined by preoperative PET-CT, and lymph node metastasis in gastric cancer.

METHODS

From December 2007 to March 2010, we analyzed the PET-CT of 147 patients that underwent gastrectomy for gastric cancer. P-SUV in PET-CT were measured by single nuclear medicine physician. Statistical analysis was performed to determine relations between clinicopathologic parameters including P-SUV and lymph node metastasis using the chi-square test, the independent t-test, and using logistic regression analysis.

RESULTS

Age, tumor depth, tumor size, and lymph node metastasis were found to be associated with primary tumor P-SUV by PET-CT (P=0.009, <0.001, <0.001, and <0.001, respectively). No association was found between P-SUV and tumor histology or tumor location (P=0.099). Advanced gastric cancer was found to have a higher P-SUV than early gastric cancer, and a higher P-SUV was found to be associated with lymph node metastases by both univariate and multivariate analysis.

CONCLUSIONS

P-SUV of primary tumor could be an independent indicator of lymph node metastasis in gastric cancer. Gastric surgeons should pay more attention to the dissection of lymph nodes when primary tumors have higher P-SUV values by PET-CT.

What is the most accurate whole-body imaging modality for assessment of local and distant recurrent disease in colorectal cancer? A meta-analysis : imaging for recurrent colorectal cancer

PURPOSE

The objective of this study was to compare the diagnostic performance of positron emission tomography (PET), PET/CT, CT and MRI as whole-body imaging modalities for the detection of local and/or distant recurrent disease in colorectal cancer (CRC) patients who have a (high) suspicion of recurrent disease, based on clinical findings or rise in carcinoembryonic antigen (CEA).

METHODS

A meta-analysis was undertaken. PubMed and Embase were searched for studies on the accuracy of whole-body imaging for patients with suspected local and/or distant recurrence of their CRC. Additionally, studies had to have included at least 20 patients with CRC and 2 × 2 contingency tables had to be provided or derivable. Articles evaluating only local recurrence or liver metastasis were excluded. Summary receiver-operating characteristic (ROC) curves were constructed from the data on sensitivity and specificity of individual studies and pooled estimates of diagnostic odds ratios (DORs) and areas under the ROC curve (AUCs) were calculated. To test for heterogeneity the Cochran Q test was used.

RESULTS

Fourteen observational studies were included which evaluated PET, PET/CT, CT and/or MRI. Study results were available in 12 studies for PET, in 5 studies for CT, in 5 studies for PET/CT and in 1 study for MRI. AUCs for PET, PET/CT and CT were 0.94 (0.90-0.97), 0.94 (0.87-0.98) and 0.83 (0.72-0.90), respectively. In patient based analyses PET/CT had a higher diagnostic performance than PET with an AUC of 0.95 (0.89-0.97) for PET/CT vs 0.92 (0.86-0.96) for PET.

CONCLUSION

Both whole-body PET and PET/CT are very accurate for the detection of local and/or distant recurrent disease in CRC patients with a (high) suspicion of recurrent disease. CT has the lowest diagnostic performance. This difference is probably mainly due to the lower accuracy of CT for detection of extrahepatic metastases (including local recurrence). For clinical practice PET/CT might be the modality of choice when evaluating patients with a (high) suspicion of recurrent disease, because of its best performance in patient based analyses and confident prediction of disease status.

Preoperative staging of rectal cancer

Preoperative staging is now an essential factor in the multidisciplinary management of rectal cancer because tumor stage is the strongest predictive factor for recurrence. Preoperative staging of rectal cancer can be divided into either local or distant staging. Local staging incorporates the assessment of mural wall invasion, circumferential resection margin involvement, as well as the nodal status for metastasis. Distant staging assesses for evidence of metastatic disease. The aim of this review is to consider the indications and limitations of the current preoperative imaging modalities for rectal cancer staging including clinical examination, endorectal ultrasound, magnetic resonance imaging, computed tomography and positron emission tomography–computed tomography, with respect to local and distant disease.

Secondary hepatic resection as a therapeutic goal in advanced colorectal cancer

Surgery is the only curative option for patients with liver metastases of colorectal cancer, but few patients present with resectable hepatic lesions. Chemotherapy is increasingly used to downstage initially unresectable disease and allow for potentially curative surgery. Standard chemotherapy regimens convert 10%-20% of cases to resectable disease in unselected populations and 30%-40% of those with disease confined to the liver. One strategy to further increase the number of candidates eligible for surgery is the addition of active targeted agents such as cetuximab and bevacizumab to standard chemotherapy. Data from a phase III trial indicate that cetuximab increases the number of patients eligible for secondary hepatic resection, as well as the rate of complete resection when combined with first-line treatment with the FOLFIRI regimen. The safety profiles of preoperative cetuximab or bevacizumab have not been thoroughly assessed, but preliminary evidence indicates that these agents do not increase surgical mortality or exacerbate chemotherapy-related hepatotoxicity, such as steatosis (5-fluorouracil), steatohepatitis (irinotecan), and sinusoidal obstruction (oxaliplatin). Secondary resection is a valid treatment goal for certain patients with initially unresectable liver metastases and an important end point for future clinical trials.

New methods in diffusion-weighted and diffusion tensor imaging

Considerable strides have been made by countless individual researchers in diffusion-weighted imaging (DWI) to push DWI from an experimental tool, limited to a few institutions with specialized instrumentation, to a powerful tool used routinely for diagnostic imaging. The field of DWI constantly evolves, and progress has been made on several fronts. These developments are primarily composed of improved robustness against patient and physiologic motion, increased spatial resolution, new biophysical and tissue models, and new clinical applications for DWI. This article aims to provide a succinct overview of some of these new developments and a description of some of the major challenges associated with DWI.

Imaging bone metastases in breast cancer: techniques and recommendations for diagnosis

Bone is the most common site of distant metastases from breast carcinoma. The presence of bone metastases affects a patient's prognosis, quality of life, and the planning of their treatment. We discuss recent innovations in bone imaging and present algorithms, based on the strengths and weaknesses of each technique, to facilitate the most successful and cost-effective choice of imaging studies for the detection of osseous metastases. Skeletal scintigraphy (bone scan) is very sensitive in the detection of osseous metastases and is recommended as the first imaging study in patients who are asymptomatic. Radiographs are recommended for the assessment of abnormal radionuclide uptake or the risk of pathological fracture and as initial imaging studies in patients with bone pain. MRI or PET-CT can be considered for cases of abnormal radionuclide uptake that are not addressed by radiography. Osseous metastases can lead to emergent situations, such as spinal-cord compression or impending fracture of a weight-bearing bone, and imaging guidelines are essential for early detection and initiation of appropriate therapy. The imaging method used in non-emergent situations, such as assessment of the ribs, sternum, pelvis, hips, and joints, should be guided by the strengths and limitations of each technique.

Combined PET/MRI: a new dimension in whole-body oncology imaging?

INTRODUCTION

Hybrid imaging systems providing morphological and functional data in a single session have been available for oncological imaging for some time. So far, computed tomography (CT) has been the morphological method-of-choice for inclusion into these hybrid imaging systems. However, recently, research has focused on hardware-based fusion of function with magnetic resonance imaging (MRI) rather than CT.

OBJECTIVES

Now that the first head-only positron emission tomography (PET)/MRI systems have been installed and whole-body systems are to be expected in the near future, potential indications in clinical oncology have to be addressed.

DISCUSSION

This article discusses potential indications of PET/MRI in whole-body oncology imaging. Potential advantages and disadvantages compared with currently available hybrid imaging systems will be reviewed.

Performance of integrated FDG PET/contrast-enhanced CT in the diagnosis of recurrent colorectal cancer: Comparison with integrated FDG PET/non-contrast-enhanced CT and enhanced CT

PURPOSE

The aim of our study was to evaluate the accuracy of integrated positron emission tomography and computed tomography (PET/CT) using (18)F-fluorodeoxyglucose (FDG) with IV contrast for depiction of suspected recurrent colorectal cancer and to assess the impact of PET/contrast-enhanced CT findings on clinical management compared with PET/non-contrast-enhanced CT and CT component.

METHODS

One hundred seventy patients previously treated for colorectal cancer underwent PET/CT consisting of non-enhanced and contrast-enhanced CT for suspected recurrence. PET/contrast-enhanced CT, PET/non-contrast-enhanced CT and enhanced CT were interpreted by two experienced radiologists by consensus for each investigation. Lesion status was determined on the basis of histopathology, radiological imaging and clinical follow-up for longer than 6 months.

RESULTS

Patient-based analysis showed that the sensitivity, specificity and accuracy of PET/contrast-enhanced CT were 93.2 (69/74), 95.8 (92/96) and 94.7% (161/170), respectively, whereas those of PET/non-contrast-enhanced CT were 89.2 (66/74), 94.8 (91/96) and 92.4% (157/170), respectively, and those of enhanced CT were 79.7 (59/74), 93.8 (90/96) and 87.6% (149/170), respectively. Sensitivity and accuracy differed significantly among the three modalities (Cochran's Q test: p = 0.0004 and p = 0.0001, respectively).The findings of PET/contrast-enhanced CT resulted in a change of management for 64 of the 170 patients (38%) and had an effect on patient management in 12 patients (7%) diagnosed by enhanced CT alone and 4 patients (2%) diagnosed by PET/non-contrast-enhanced CT.

CONCLUSION

Integrated PET/contrast-enhanced CT is an accurate modality for assessing colorectal cancer recurrence and led to changes in the subsequent appropriate therapy.

Functional imaging of colorectal cancer: positron emission tomography, magnetic resonance imaging, and computed tomography

In the past 10 years, overall survival and disease-free survival of patients with colorectal cancer (CRC) has improved substantially because of a combination of factors: (1) more accurate staging as a result of advances in imaging technology; (2) refinements in surgical technique; (3) 'curative' metastasectomy for patients with limited metastatic disease; (4) improvements in radiation therapy planning and greater precision of radiation therapy delivery; and (5) increasing chemotherapeutic options, including antiangiogenic and vascular targeting drugs. In this era of 'personalized medicine,' the increasingly individualized treatment of patients with CRC has highlighted the need for functional imaging techniques in addition to conventional anatomic-based imaging. This review discusses the contribution of positron emission tomography to the clinical management of CRC. In addition, evolving techniques such as dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), DCE computed tomography (perfusion CT), diffusion-weighted MRI, and blood oxygenation level-dependent MRI that might have a future role will be covered.

Whole-body MRI at 1.5 T and 3 T compared with FDG-PET-CT for the detection of tumour recurrence in patients with colorectal cancer

The purpose of this study was to assess the diagnostic accuracy of whole-body MRI (WB-MRI) at 1.5 T or 3 T compared with FDG-PET-CT in the follow-up of patients suffering from colorectal cancer. In a retrospective study, 24 patients with a history of colorectal cancer and suspected tumour recurrence underwent FDG-PET-CT and WB-MRI with the use of parallel imaging (PAT) for follow-up. High resolution coronal T1w-TSE and STIR sequences at four body levels, HASTE imaging of the lungs, contrast-enhanced T1w- and T2w-TSE sequences of the liver, brain, abdomen and pelvis were performed, using WB-MRI at either 1.5 T (n = 14) or 3 T (n = 10). Presence of local recurrent tumour, lymph node involvement and distant metastatic disease was confirmed using radiological follow-up within at least 5 months as a standard of reference. Seventy seven malignant foci in 17 of 24 patients (71%) were detected with both WB-MRI and PET-CT. Both investigations concordantly revealed two local recurrent tumours. PET-CT detected significantly more lymph node metastases (sensitivity 93%, n = 27/29) than WB-MRI (sensitivity 63%, n = 18/29). PET-CT and WB-MRI achieved a similar sensitivity for the detection of organ metastases with 80% and 78%, respectively (37/46 and 36/46). WB-MRI detected brain metastases in one patient. One false-positive local tumour recurrence was indicated by PET-CT. Overall diagnostic accuracy for PET-CT was 91% (sensitivity 86%, specificity 96%) and 83% for WB-MRI (sensitivity 72%, specificity 93%), respectively. Examination time for WB-MRI at 1.5 T and 3 T was 52 min and 43 min, respectively; examination time for PET-CT was 103 min. Initial results suggest that differences in accuracy for local and distant metastases detection using FDG-PET-CT and WB-MRI for integrated screening of tumour recurrence in colorectal cancer depend on the location of the malignant focus. Our results show that nodal disease is better detected using PET-CT, whereas organ disease is depicted equally well by both investigations.