Role of PET/PET CT in the staging and restaging of thoracic oesophageal cancer and gastro-oesophageal cancer: a literature review

Anorectal leiomyoma with GLUT1 overexpression mimicking malignancy on FDG-PET/CT

A 43-year-old female underwent pelvic magnetic resonance imaging for uterine myoma that incidentally revealed a 4.6 × 2.8 cm soft tissue mass in the anorectal region. Rectal endoscopy showed a submucosal tumor just above the anal canal. Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) revealed an anorectal tumor with very high FDG uptake. Aspiration cytology and needle biopsy were inconclusive, and the patient underwent trans-perineal tumor resection. The excised tumor was a 4.6 × 3.5 × 2.7 cm gray-white bifurcated nodular tumor. Light microscopy revealed fenestrated growth of poorly dysmorphic short spindle-shaped cells with eosinophilic sporophytes. Immunohistochemical staining was positive for αSMA and desmin, negative for CD117 (KIT) and S100, and the patient was diagnosed with benign leiomyoma. Tumor cells were also positive for glucose transporter-1 (GLUT1) immunohistochemically. It is important to keep in mind that FDG-PET/CT may show false-positive results even in benign anal leiomyoma for various reasons, including GLUT1 overexpression.

A comparative study of the normal oesophageal wall thickness based on 3-dimensional, 4-dimensional, and cone beam computed tomography

BACKGROUND

The study aimed to compare normal oesophageal wall thickness based on 3-dimensional computed tomography (3DCT), 4-dimensional computed tomography (4DCT) and cone beam computed tomography (CBCT).

METHODS

Contrast-enhanced 3DCT, 4DCT, and CBCT scans were acquired from 50 patients with lung cancer or metastatic lung cancer. The outer oesophageal wall was manually contoured on each 3DCT, the maximum intensity projection of 4DCT (4DCTMIP) the end expiration phase of 4DCT (4DCT50) (the end expiration phase of 4DCT) and the CBCT data sets. The average wall thicknesses were measured (defined as R3DCT, R50, RMIP, and RCBCT).

RESULTS

Whether for thoracic or for intra-abdominal segments, there were no significant differences between R3DCT and R50, but significant differences between R3DCT and RMIP, R3DCT and RCBCT. For upper and middle oesophagus, RCBCT were larger than RMIP. There was no significant difference between upper and middle segments on 3DCT, 4DCT, and CBCT. Intra-abdominal oesophageal wall thickness was greater than that of thoracic oesophagus. There were no differences between upper and lower, and middle and lower oesophagus on CBCT.

CONCLUSION

Our findings indicate normal oesophageal wall thickness differed along the length of oesophagus whatever it was delineated on 3DCT, 4DCT (4DCT50 and 4DCTMIP) or CBCT. It is reasonable to use uniform criterion to identify normal esophageal wall thickness when delineating gross tumor volume on 3DCT and 4DCT50, the same is true of delineating internal gross tumor volume on 4DCTMIP or CBCT images for lower and intra-abdominal oesophagus. But, in spite of using contrast-enhanced scanning, relatively blurred boundary on the CBCT images is noteworthy, especially for upper and middle thoracic esophagus.

FDG PET Hybrid Imaging

Molecular imaging with positron emission tomography (PET) using tumour-seeking radiopharmaceuticals has gained wide acceptance in oncology with many clinical applications. The hybrid imaging modality PET/CT (computed tomography) allows assessing molecular as well as morphologic information at the same time. Therefore, PET/CT represents an efficient tool for whole-body staging and re-staging within one imaging modality. In oncology, the glucose analogue 18-F-fluorodeoxyglucose (FDG) is the most widely used PET/CT radiopharmaceutical in clinical routine. FDG PET and FDG PET/CT have been used for staging and re-staging of tumour patients in numerous studies. This chapter will discuss the use and the main indications of FDG PET/CT in oncology with special emphasis on lung cancer, lymphoma, head and neck cancer, melanoma and breast cancer (among other tumour entities). A review of the current literature is given with respect to primary diagnosis, staging and diagnosis of recurrent disease. Besides its integral role in diagnosis, staging and re-staging of disease in oncology, there is increasing evidence that FDG PET/CT can be used for therapy response assessment (possibly influencing therapeutic management and treatment planning) by evaluating tumour control, which will also be discussed in this chapter.

Positron emission tomography-computed tomography in oesophageal cancer staging: a tailored approach

BACKGROUND

Positron emission tomography-computed tomography (PET-CT) scanning is used routinely in the staging of oesophageal cancer to identify occult metastases not apparent on CT and changes the management in typically 3-18% patients. The authors aim to re-evaluate its role in the management of oesophageal cancer, investigating whether it is possible to identify a group of patients that will not benefit and can safely be spared from this investigation.

METHODS

Consecutive patients with oesophageal cancer undergoing PET-CT staging between 2010 and 2013 were identified from a specialist modern multidisciplinary team database. Without knowledge of the PET-CT result, patients were stratified into low-risk or high-risk groups according to the likelihood of identifying metastatic disease on PET-CT based on specified criteria routinely available from endoscopy and CT reports. Clinical outcomes in the two groups were investigated.

RESULTS

In 383 undergoing PET-CT, metastatic disease was identified in 52 (13.6%) patients. Eighty-three patients were stratified as low risk and 300 as high risk. None of the low-risk patients went on to have metastatic disease identified on PET-CT. Of the high-risk patients, 17% had metastatic disease identified on PET-CT.

CONCLUSIONS

In one of the largest studies to date investigating the influence of staging PET-CT on management of patients with oesophageal cancer, the authors report a classification based on endoscopy/CT criteria is able to accurately stratify patients according to the risk of having metastatic disease. This could be used to avoid unnecessary PET-CT 22% of patients, saving cost, inconvenience and reducing potential delay to definitive treatment in this group.

The current role of staging laparoscopy in oesophagogastric cancer

INTRODUCTION

Oesophagogastric cancers are known to spread rapidly to locoregional lymph nodes and by transcoelomic spread to the peritoneal cavity. Staging laparoscopy combined with peritoneal cytology can detect advanced disease that may not be apparent on other staging investigations. The aim of this study was to determine the current value of staging laparoscopy and peritoneal cytology in light of the ubiquitous use of computed tomography in all oesophagogastric cancers and the addition of positron emission tomography in oesophageal cancer.

METHODS

All patients undergoing staging laparoscopy for distal oesophageal or gastric cancer between March 2007 and August 2013 were identified from a prospectively maintained database. Demographic details, preoperative staging, staging laparoscopy findings, cytology and histopathology results were analysed.

RESULTS

A total of 317 patients were identified: 159 (50.1%) had gastric adenocarcinoma, 136 (43.0%) oesophageal adenocarcinoma and 22 (6.9%) oesophageal squamous carcinoma. Staging laparoscopy revealed macroscopic metastases in 36 patients (22.6%) with gastric adenocarcinoma and 16 patients (11.8%) with oesophageal adenocarcinoma. Positive peritoneal cytology in the absence of macroscopic peritoneal metastases was identified in a further five patients with gastric adenocarcinoma and six patients with oesophageal adenocarcinoma. There was no significant difference in survival between patients with macroscopic peritoneal disease and those with positive peritoneal cytology (p=0.219).

CONCLUSIONS

Staging laparoscopy and peritoneal cytology should be performed routinely in the staging of distal oesophageal and gastric cancers where other investigations indicate resectability. Currently, in our opinion, patients with positive peritoneal cytology should not be treated with curative intent.

A systematic review of the predictive value of (18)FDG-PET in esophageal and esophagogastric junction cancer after neoadjuvant chemoradiation on the survival outcome stratification

PURPOSE

We studied the predictive value of [(18) F]fluorodeoxyglucose-positron emission tomography ((18)FDG-PET) for assessing disease-free (DFS) and overall survival (OS) in esophageal and esophagogastric junction cancer.

MATERIALS AND METHODS

A literature search (PUBMED/MEDLINE, EMBASE, Cochrane) was performed to identify full papers with (18)FDG-PET and survival data, using indexing terms and free text words. Studies with >10 patients with locally advanced esophageal cancer, presenting sequential or at least one post-adjuvant treatment (18)FDG-PET data and Kaplan-Meier survival curves with >6 months median follow-up period were included. We performed a meta-analysis for DFS and OS using the hazard ratio (HRs) as outcome measure. Sources of heterogeneity study were also explored.

RESULTS

We identified 26 eligible studies including a total of 1,544 patients (average age 62 years, 82% males). The TNM distribution was as follows: stage I 7%, II 24%, III 53% and IV 15%. The pooled HRs for complete metabolic response versus no response were 0.51 for OS (95% CI, 0.4-0.64; P < 0.00001) and 0.47 for DFS (95% CI, 0.38-0.57; P < 0.00001), respectively. No statistical heterogeneity was present. To explore sources of clinical heterogeneity, we also realised subgroup and regression analyses. Taken into account the moderate correlation between OS and DFS (ρ = 0.54), we used joint bivariate random regression model. These analyses did not show a statistically significant impact of study characteristics and PET modalities on the pooled outcome estimates.

CONCLUSION

Despite methodological and clinical heterogeneity, metabolic response on (18)FDG-PET is a significant predictor of long-term survival data.

(18)F-FDG-PET/CT in assessing response to neoadjuvant chemoradiotherapy for potentially resectable locally advanced esophageal cancer

PURPOSE

To correlate metabolic response to neoadjuvant chemoradiotherapy (NACR) on FDG-PET/CT using PERCIST-based criteria to pathologic and clinical response, and survival in patients with locally advanced esophageal cancer (LAEC).

MATERIALS AND METHODS

Forty-five patients with LAEC underwent PET/CT at baseline and after NACR. Tumors were evaluated using PERCIST (PET response criteria in solid tumors)-based criteria including SUL, SUL tumor/liver ratio, % change in SUL. These parameters were compared to pathology regression grade (PRG), clinical response (including residual or new disease beyond the surgical specimen), and overall survival.

RESULTS

On surgical pathology, there was complete or near-complete regression of tumor in 51.1 %, partial response in 42.2 %, and lack regression in 4.4 %. One patient (2.2 %) had progression of disease on imaging and did not undergo surgical resection. None of the baseline PET parameters had significant correlation to pathology regression grade or clinical response. On follow-up, a positive correlation was found between post-therapy SUL ratio, %∆ SUL and %∆ SUL ratio and clinical response (p = 0.025, 0.035, 0.030, respectively). A weak correlation was found between post-therapy SUL ratio to PRG (p = 0.049). A strong correlation was found between the metabolic response score and PRG (p = 0.002) as well as between metabolic response and clinical response (p < 0.001).

CONCLUSION

PERCIST-based metabolic response assessment to NACR in LAEC may correlate with clinical outcome and survival.

Endobronchial ultrasonography added to endoscopic ultrasonography improves staging in esophageal cancer

BACKGROUND

The gold standard for staging the local extension (T stage) and lymph node (LN) status (N stage) of esophageal cancer is endoscopic ultrasonography (EUS). When biopsy of the peritumoral LNs is performed using EUS, there is a risk of specimen contamination secondary to piercing the primary tumor; this shortcoming can be circumvented with endobronchial ultrasonography (EBUS). Moreover, EBUS allows for biopsy of LN stations not accessible with EUS.

METHODS

The study consisted of a prospective clinical trial. Fifty-two consecutive patients with potentially resectable esophageal cancer referred for endoscopic staging were prospectively enrolled. Radial and convex EUS followed by convex EBUS were performed during a single staging procedure. The LNs not accessible by EUS were biopsied using EBUS. Results of the EBUS procedure were compared to those of EUS in terms of the addition of staging information, upstaging, and confirmation of stage.

RESULTS

The combined EBUS-EUS procedure was performed in 42 patients. Ten patients were excluded. In all, 54 LNs were biopsied under EUS guidance and 48 LNs were biopsied under EBUS guidance. The EUS results were positive for metastatic esophageal cancer in 29 LNs (54%), and EBUS was positive in 10 LNs (21%). The addition of EBUS to EUS in the staging of esophageal cancer led to nodal and patient upstaging in 5 patients (12%) and confirmed the EUS stage with additional negative or positive LN sampling in 29 patients (69%). Positive EBUS that led to upstaging (5 patients) changed the treatment plan from potentially resectable to palliative. There was no morbidity related to EBUS.

CONCLUSIONS

A combined EBUS-EUS staging procedure improves precision in staging, leads to upstaging, and can change the treatment plan in patients with esophageal cancer.

Diagnostic accuracy of lymph node metastasis depends on metabolic activity of the primary lesion in thoracic squamous esophageal cancer

The metabolic activity of the primary tumor is an important variable in (18)F-FDG PET interpretation for presurgical staging, because this activity is likely to affect the possibility of detection of malignant involvement in lymph nodes (LNs). The purpose of this study was to reevaluate the diagnostic accuracy of (18)F-FDG PET/CT for the presurgical staging of esophageal squamous cell carcinoma (SCC) in correlation with the (18)F-FDG avidity of the primary lesions.

METHODS

One hundred fifty-six patients (mean age ± SD, 61.4 ± 8.0 y) underwent (18)F-FDG PET/CT before surgical esophagectomy and LN dissection. LN metastasis was identified using the fusion of PET and CT images with increased (18)F-FDG uptake greater than the background activity of the adjacent structures. The results of the patients' (18)F-FDG PET/CT examinations for LN involvement were compared with the histopathologic results to investigate the diagnostic accuracy of (18)F-FDG PET/CT for tumor staging. In addition, we examined the correlation between the diagnostic accuracy of (18)F-FDG PET/CT for LN involvement and the (18)F-FDG avidity of the primary lesions, to investigate the effect of tumor aggressiveness on the diagnosis of LN metastasis.

RESULTS

The diagnostic accuracy of (18)F-FDG PET/CT for LN metastasis showed a low sensitivity, ranging from 29.3% to 53.3%, whereas the specificity was higher than 89.8% in regional thoracic nodes and in remote areas of the cervical and abdominal regions. The (18)F-FDG uptake of the primary lesions positively correlated with that of the metastatic LNs in the thoracic field (R = 0.52, P < 0.05). As a result, our receiver-operating-characteristic analyses demonstrated an area under the curve value of 0.73, with the optimal cutoff value at a maximum standardized uptake value of 3.3 in patients with mid to high (18)F-FDG avidity in the primary lesions (maximum standardized uptake value ≥ 5).

CONCLUSION

This study showed that the avidity of the primary esophageal SCCs affected the detectability of lymph nodal metastases. If primary lesions of esophageal SCC present with a low (18)F-FDG uptake, PET/CT may have a limited role for initial staging because of low sensitivity to detect lymph node metastases.

18F-FDG PET-CT for detecting recurrent gastric adenocarcinoma: results from a Non-Oriental Asian population

OBJECTIVE

To evaluate the utility of fluorine-18 fluorodeoxyglucose (18F-FDG) PET-CT in the diagnosis of recurrent gastric adenocarcinoma in a Non-Oriental Asian population.

METHODS

In this retrospective analysis, data from 72 Non-Oriental Asian patients, who underwent 93 18F-FDG PET-CT studies, were evaluated. All patients had histopathologically proven gastric adenocarcinoma, for which they had undergone primary treatment. PET-CT was performed for suspected recurrence or for post-therapy surveillance. PET-CT findings were analysed on a per-patient and per-region basis (local/lymph node/liver/lung/bone/others). A combination of clinical follow-up (minimum 6 months; range: 6-36 months), imaging follow-up and/or histopathology (when available) was taken as the reference standard. Sensitivity, specificity and predictive values were calculated for PET-CT on both a per-study and per-lesion basis.

RESULTS

The mean patient age was 52.8 ± 11.8 years (male/female: 52/20). Out of 93 PET-CT studies, 56 (60.2%) were positive and 37 (39.8%) were negative for recurrent disease. On per-study-based analysis, 18F-FDG PET-CT has a sensitivity, specificity and accuracy of 95.9, 79.5 and 88.1%, respectively. The accuracy of 18F-FDG PET-CT was 89.2% for local recurrence, 94.6% for lymph nodes, 96.7% for liver, 96.7% for lung, 98.9% for bone and 98.9% for other sites. The accuracy of 18F-FDG PET-CT was lower for local recurrence as compared with that for liver (P=0.012) and bone (P=0.012). No significant difference was found in the diagnostic accuracies for other regions.

CONCLUSION

18F-FDG PET-CT is highly sensitive and specific for detecting recurrence in patients with gastric adenocarcinoma. It shows high accuracy both on a per-patient and per-lesion basis.

Japanese Gastric Cancer Association Task Force for Research Promotion: clinical utility of ¹⁸F-fluoro-2-deoxyglucose positron emission tomography in gastric cancer. A systematic review of the literature

Since April 2010, the Japanese Public Health Insurance System has covered the costs incurred for performing ¹⁸F-fluoro-2-deoxyglucose positron emission tomography (FDG-PET) imaging for patients with advanced gastric cancer. The aim of this review was to evaluate the clinical impact of PET for patients with gastric cancer. A systematic literature search was performed in PubMed/MEDLINE using the keywords "gastric cancer" and "PET" to search for relevant articles published from January 2000 to September 2010. The clinical impact of selected articles was assessed by the authors to evaluate the following: (a) tumor staging, (b) diagnosis for recurrent disease, (c) evaluation of treatment response, and (d) screening for gastric cancer. FDG uptake increases in papillary adenocarcinoma, tubular adenocarcinoma, and solid-type poorly differentiated adenocarcinoma. This uptake is also associated with glucose transporter 1 expression. The sensitivity and specificity of FDG-PET for metastatic lymph node detection were 21-40% and 89-100%, respectively. The sensitivity and specificity for distant metastasis detection were 35-74% and 74-99%, respectively. Treatment response can be detectable at an earlier stage by PET than by computed tomography (CT), because FDG uptake by cancer cells decreases according to the treatment response. In summary, although PET has limitations such as frequent false-negative cases in signet-ring cell carcinoma and non-solid type poorly differentiated carcinoma, it can contribute to the selection of a more appropriate treatment modality by detecting distant metastases and treatment response.

Computed tomography overestimation of esophageal tumor length: Implications for radiotherapy planning

AIM: To assess the relationship between preoperative computed tomography (CT) and postoperative pathological measurements of esophageal tumor length and the prognostic significance of CT tumor length data.

METHODS: A retrospective study was carried out in 56 patients who underwent curative esophagogastrectomy. Tumor lengths were measured on the immediate preoperative CT and on the post-operative resection specimens. Inter- and intra-observer variations in CT measurements were assessed. Survival data were collected.

RESULTS: There was a weak correlation between CT and pathological tumor length (r = 0.30, P = 0.025). CT lengths were longer than pathological lengths in 68% (38/56) of patients with a mean difference of 1.67 cm (95% CI: 1.18-2.97). The mean difference in measurements by two radiologists was 0.39 cm (95% CI: -0.59-1.44). The mean difference between repeat CT measured tumor length (intra-observer variation) were 0.04 cm (95% CI: -0.59-0.66) and 0.47 cm (95% CI: -0.53-1.47). When stratified, patients not receiving neoadjuvant chemotherapy showed a strong correlation between CT and pathological tumor length (r = 0.69, P = 0.0014, n = 37) than patients that did (r = 0.13, P = 0.43, n = 19). Median survival with CT tumor length > 5.6 cm was poorer than with smaller tumors, but the difference was not statistically significant.

CONCLUSION: Esophageal tumor length assessed using CT does not reflect pathological tumor extent and should not be the only modality used for management decisions, particularly for planning radiotherapy.

Association of C-reactive protein levels and long-term survival after neoadjuvant therapy and esophagectomy for esophageal cancer

BACKGROUND

Preoperative C-reactive protein (CRP) levels have been shown to be prognostic markers of survival in patients undergoing esophagectomy for cancer. No study has evaluated the predictive value for survival of CRP levels after neoadjuvant chemoradiotherapy.

METHODS

Preoperative CRP levels were assessed in patients undergoing neoadjuvant therapy and esophagectomy for cancer. Groups were defined according to normal value cutoffs of the CRP measurements.

RESULTS

Seventy patients had normal CRP, and 20 patients had raised CRP. The groups did not differ in descriptives, comorbidities, white cell counts, pathological data, or morbidity. In-hospital death was higher in the raised CRP group (three versus one patient, p = 0.048). The Kaplan-Meier survival analysis showed a significant survival advantage of patients with normal CRP compared to patients with raised CRP levels (median survival, 65.4 versus 18.7 months; log rank test, p = 0.027). The Cox regression analysis identified three independent prognostic factors for survival: UICC stage (IIB/III versus I/IIA, HR 3.48, p = 0.007), completeness of resection (HR 6.33, p = 0.002), and CRP levels (raised versus normal, HR 5.07, p = 0.001).

CONCLUSION

Preoperative CRP levels are an independent prognostic marker for survival after neoadjuvant treatment in patients with esophageal cancer and may be of value in the re-staging process after neoadjuvant treatment.

Hybrid imaging (SPECT/CT and PET/CT): improving therapeutic decisions

The incremental diagnostic value of integrated positron emission tomography-computed tomography (PET/CT) or single-photon emission computed tomography (SPECT)/CT images compared with PET or SPECT alone, or PET or SPECT correlated with a CT obtained at a different time includes the following: (1) improvement in lesion detection on both CT and PET or SPECT images, (2) improvement in the localization of foci of uptake resulting in better differentiation of physiological from pathologic uptake, (3) precise localization of the malignant foci, for example, in the skeleton vs soft tissue or liver vs adjacent bowel or node (4) characterization of serendipitous lesions, and (5) confirmation of small, subtle, or unusual lesions. The use of these techniques can occur at the time of initial diagnosis, in assessing the early response of disease to treatment, at the conclusion of treatment, and in continuing follow-up of patients. PET/CT and SPECT/CT fusion images affect the clinical management in a significant proportion of patients with a wide range of diseases by (1) guiding further procedures, (2) excluding the need of further procedures, (3) changing both inter- and intramodality therapy, including soon after treatment has been initiated, and (4) by providing prognostic information. PET/CT fusion images have the potential to provide important information to guide the biopsy of a mass to active regions of the tumor and to provide better maps than CT alone to modulate field and dose of radiation therapy. It is expected that the role of PET/CT and SPECT/CT in changing management will continue to evolve in the future and that these tools will be fundamental components of the truly "personalized medicine" we are striving to deliver.

Positron emission tomography changes management and prognostic stratification in patients with oesophageal cancer: results of a multicentre prospective study

OBJECTIVES

The aims of this study were (1) to determine the incremental information provided by (18)F-FDG positron emission tomography (PET) in staging patients with oesophageal cancer, and (2) to determine the impact of PET staging on post-PET clinical management of oesophageal cancer, and on prognosis.

METHODS

In a multicentre, single-arm open study, patients with proved oesophageal cancer without definite distant metastases and regarded as suitable for potentially curative treatment were examined by PET. Clinicians were requested to supply a management plan before and another plan after being supplied with the PET scan results. Patients were followed for at least 1 year for outcome analysis.

RESULTS

A total of 129 patients (104 men, mean age 67 y) were recruited. PET detected additional sites of disease in 53 patients (41%). Significant changes in management (high or medium impact) were observed in 38% of patients, primarily as a result of identifying additional sites of disease and/or confirming previously equivocal regional and distant metastases. Progression-free survival was significantly shorter in patients found to have additional lesions on PET (p < 0.05), but was not related to SUV(max).

CONCLUSION

These findings demonstrate the significant impact of PET on the clinical management of patients with newly diagnosed oesophageal carcinoma, and on prognostic stratification of these patients.

Surgical outcomes in esophageal cancer patients with tumor recurrence after curative esophagectomy

This study aimed to identify predictive factors and to evaluate appropriate treatments for recurrence of esophageal cancer after curative esophagectomy. About 166 consecutive patients, who underwent curative esophagectomy, were enrolled between April 1994 and March 2003. Recurrence was classified as loco-regional or distant. Logistic regression analysis was used to identify predictive factors for recurrence. Prognostic factors were evaluated by Log-rank test and Cox proportional hazard regression analysis. The disease-specific 5-year survival was 56.8%. Recurrence was observed in 72 patients (43.4%), with 64 of these occurring within 3 years. The number of metastatic lymph nodes and lymphatic invasion independently predicted recurrence. There were significant differences in time to recurrence and survival time between loco-regional, distant recurrence, and combined recurrence. The 5-year survival time in patients with recurrence was 11.9%, and median survival time was 24 months. There was also a significant difference in survival after recurrence between treatment methods (no treatment vs chemo-radiotherapy, p=0.0063; chemotherapy, p=0.0247; and radiotherapy, p<0.0001). Meticulous, long-term follow-up is particularly necessary in patients with four or more metastatic lymph nodes to achieve early detection of recurrence. Randomized controlled trials should be used to develop effective modalities for each recurrence pattern to improve therapeutic outcomes.