Fluorodeoxyglucose positron emission tomography and the prognosis of pancreatic carcinoma

Prognostic Strength of CA 19-9, Demographic Parameters, and Maximum Standardized Uptake Value of Baseline 18F-FDG PET/CT in Treatment-naïve Patients with Pancreatic Carcinoma

Aim and Background

The aim of this study was to evaluate the prognostic value of imaging-based variables and tumor marker in predicting the progression-free survival (PFS) in treatment-naïve pancreatic cancer (PC) using baseline 18-fluorodeoxyglucose (18FDG) positron emission tomography/computed tomography (PET/CT).

Materials and Methods

This retro-prospective study was conducted at PET/CT imaging facility of JCIA health-care facility of Pakistan. Total 68 patients with PCs were retrospectively included who had 18FDG PET/CT for staging from March 2017 to December 2020. Thirty-two patients had unresectable Stage IV disease on baseline imaging while the remaining 36 underwent Whipple's procedure and both categories were followed by chemotherapy with/without immunotherapy. These patients were followed for a median period of 18 months (1-62 months) for PFS. Logistic regression analysis and receiver operating characteristic (ROC) analysis were used for independent predictors of patients' demographics, tumor characteristics, CA 19-9, and maximum standardized uptake value (SUVmax) in PFS. Kaplan-Meier's survival curves were analyzed to measure PFS using ROC-derived significant cutoff values of CA 19-9 and SUVmax.

Results

Median PFS was 18 months (11-45) with 60% (41/68) patients were either died or labelled having metabolic progressive disease (MPD. Using logistic regression analysis, significant correlations were found for Stage IV disease and pancreatic body/tail tumor with disease progression (odd ratio: 7.535 and 4.803, respectively; P < 0.05). Gender, obesity, histological tumor type, and 18FDG-avid regional nodes did not show a significant impact on PFS. On ROC analysis, SUVmax >5.3 of primary tumor and baseline CA 19-9 >197 U/ml were found to have a significant negative correlation with PFS (area under the curve: 0.827 and 0.911, respectively; P < 0.0001) and no association of age and primary tumor size in PFS. Significantly, shorter PFS was found using ROC-derived cutoff values of SUVmax >5.3 versus ≤5.3 of primary tumor (mean and 95% confidence interval [CI]: 16.7 vs. 48.5 and 10-23 vs. 41-56; log-rank = 25.014; P < 0.0001) and baseline CA 19-9 >197 versus ≤197 U/ml (mean and 95% CI: 11.8 vs. 46.9 and 7-16 vs. 39-55; log-rank = 38.217; P < 0.0001).

Conclusion

SUVmax >5.3 of primary tumor and baseline CA 19-9 >197 U/ml were found to have a significant negative correlation with PFS in treatment-naïve PC patients. Among demographics, only Stage IV disease and pancreatic tail and body tumors were found to have a negative association with disease progression.

Prognostic Implications of 18-FDG Positron Emission Tomography/Computed Tomography in Resectable Pancreatic Cancer

There are currently no known preoperative factors for determining the prognosis in pancreatic cancer. The aim of this study was to examine the role of 18-fluorodeoxyglucose (18-FDG) positron emission tomography/computed tomography (18-FDG-PET/CT) as a prognostic factor for patients with resectable pancreatic cancer. Data were obtained from a retrospective analysis of patients who had a preoperative PET scan and then underwent pancreatic resection from January 2007 to December 2015. The maximum standardized uptake value (SUVmax) of 18-FDG-PET/CT was calculated. Patients were divided into high (>3.65) and low (≤3.65) SUVmax groups, and compared in terms of their TNM classification (Union for International Cancer Contro classification), pathological grade, surgical treatment, state of resection margins, lymph node involvement, age, sex, diabetes and serum Carbohydrate Antigen 19-9 (CA 19-9) levels. The study involved 144 patients, 82 with high SUVmax pancreatic cancer and 62 with low SUVmax disease. The two groups’ disease-free and overall survival rates were significantly influenced by tumor stage, lymph node involvement, pathological grade, resection margins and SUVmax. Patients with an SUVmax ≤ 3.65 had a significantly better survival than those with SUVmax > 3.65 (p < 0.001). The same variables were independent predictors of survival on multivariate analysis. The SUVmax calculated with 18-FDG-PET/CT is an important prognostic factor for patients with pancreatic cancer, and may be useful in decisions concerning patients’ therapeutic management.

Can 18F-FDG PET/CT predict recurrence in patients with cutaneous malignant melanoma?

The aim of this study was to evaluate the prognostic significance of maximum standardized uptake value (SUVmax) of primary cutaneous malignant melanoma (CMM) lesions by 18F-FDG positron emission tomography/ computerized tomography (PET/ CT) in terms of recurrence. Patients, methods: 37 CMM patients (17 men, mean age: 61.7 ± 13.6 years) that underwent PET/CT at presentation were enrolled in this study. Recurrence was determined by histological confirmation or by radiological and clinical follow- up for at least 8 months after curative surgery. Clinical variables such as age, sex, clinical stage, and primary lesion location, thickness, and ulceration, and SUVmax values were analyzed with respect to their usefulness for predicting recurrence. Results: SUVmax was found to be significantly higher in patients with ulceration of primary lesion of CMM (p = 0.004) and in patients with a stage ≥ III (p < 0.000). Patients that experience recurrence had a significantly higher mean SUVmax value (4.9 ± 2.9) than patients who did not (2.1 ± 1.5, p = 0.024). ROC analysis showed that a SUVmax cut-off value 2.2 had high sensitivity (88.9%) and specificity (67.9%) for predicting recurrence. Kaplan-Meier analysis identified ulceration of primary lesion (p = 0.034), stage ≥ III (p = 0.019) and SUVmax ≥ 2.2 (p = 0.002) as predictors of recurrence. However, Cox proportional-hazards analysis showed that only SUVmax (p = 0.025, relative risk 11.063) significantly predicted recurrence. Conclusion: Preoperative SUVmax of primary lesion was found to be the most potent predictor of recurrence in CMM patient. Patients with high SUV max of primary lesion should be followed meticulously for recurrence.

Application of 18F-FDG PET/CT combined with carbohydrate antigen 19-9 for differentiating pancreatic carcinoma from chronic mass-forming pancreatitis in Chinese elderly

OBJECTIVE

The current study was designed to analyze the value of 18F-FDG positron emission tomography/computed tomography (PET/CT) combined with carbohydrate antigen 19-9 (CA19-9) in differentiating pancreatic carcinoma (PC) from chronic mass-forming pancreatitis (CMFP) in Chinese elderly.

METHODS

As it is impossible to differentially diagnose PC from CMFP, 60 participants older than 65 years with focal pancreatic lesions were scanned by 18F-FDG PET/CT and their CA19-9 levels were tested. Diagnoses of all participants were confirmed by comprehensive methods including aspiration biopsy, surgical pathology, and clinical follow-up of 12 months. Twenty participants with CMFP were included in CMFP group and 40 participants with PC in PC group.

RESULTS

In CMFP and PC groups, 46 participants showed increased 18F-FDG uptake, 43 had elevated CA19-9 levels, and 38 participants had both increased 18F-FDG uptake and elevated CA19-9 levels. Standardized uptake value maximum of PC group (5.98±2.27) was significantly different from CMFP group (2.58±1.81, P<0.05). Sensitivity, specificity, and accuracy of 18F-FDG PET/CT in differentiating PC from CMFP were 95%, 60%, and 83.3%, respectively. CA19-9 levels of PC group (917.44±1,088.24) were significantly different from CMFP group (19.09±19.54, P<0.05). Sensitivity, specificity, and accuracy of CA19-9 levels in differentiating PC from CMFP were 87.5%, 60%, and 78.3%, respectively. Sensitivity, specificity, and accuracy of 18F-FDG PET/CT combined with CA19-9 levels in differentiating PC from CMFP were 90%, 90%, and 90%, respectively.

CONCLUSION

18F-FDG PET/CT had reliable sensitivity, specificity, and accuracy in differentiating PC from CMFP, and CA19-9 levels could be helpful in 18F-FDG PET/CT for differentiating PC from CMFP in Chinese elderly. Moreover, 18F-FDG PET/CT combined with CA19-9 levels was found to be an effective method to differentially diagnose PC from CMFP and has paved the way for the timely and safe treatment of PC and CMFP in Chinese elderly.

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.

18F-fluoro-2-deoxy-D-glucose retention index as a prognostic parameter in patients with pancreatic cancer

OBJECTIVES

The objective of this study was to determine the most effective way to use dual-phase F-fluoro-2-deoxy-D-glucose (F-FDG) PET/computed tomography (CT) semiquantitative indices to predict prognosis in patients with pancreatic cancer and to guide treatment.

STUDY DESIGN

Prognostic parameters were retrospectively analyzed in 40 patients with histologically proven pancreatic cancer who received F-FDG PET/CT at Ruijin Hospital. Maximum standardized uptake values (SUVs) were determined at 1 h (SUV1) and 2 h (SUV2) after F-FDG injection. The retention index (RI) was defined as the percentage change between SUV1 and SUV2.

RESULTS

RI less than 17% was explored as having a significant independent correlation with prolonged patient survival (P<0.05). Patients with tumor resection and RI less than 17% survived significantly longer than those with or without tumor resection and RI of 17% or higher (P<0.05). Neither SUV1, nor SUV2 showed any prognostic significance, but they did show a positive correlation with tumor diameter (P1<0.01; P2<0.05); RI had a strong positive correlation with tumor, node, and metastasis stage (P<0.01). Two factors were found to be associated with RI, including pancreatitis (P<0.05) and diabetes (P<0.01).

CONCLUSION

RI served as the most accurate parameter to predict disease prognosis in pancreatic cancer and to identify patients who could benefit from surgery. However, pancreatitis and diabetes had a potential impact on RI, reflecting the influence of tumor pathophysiological changes on the metabolism of glucose in pancreatic tumor cells. Therefore, further comprehensive analyses are required.

Utility of PET/CT in diagnosis, staging, assessment of resectability and metabolic response of pancreatic cancer

Pancreatic cancer is one of the most common gastrointestinal tumors, with its incidence staying at a high level in both the United States and China. However, the overall 5-year survival rate of pancreatic cancer is still extremely low. Surgery remains the only potential chance for long-term survival. Early diagnosis and precise staging are crucial to make proper clinical decision for surgery candidates. Despite advances in diagnostic technology such as computed tomography (CT) and endoscopic ultrasound, diagnosis, staging and monitoring of the metabolic response remain a challenge for this devastating disease. Positron emission tomography/CT (PET/CT), a relatively novel modality, combines metabolic detection with anatomic information. It has been widely used in oncology and achieves good results in breast cancer, lung cancer and lymphoma. Its utilization in pancreatic cancer has also been widely accepted. However, the value of PET/CT in pancreatic disease is still controversial. Will PET/CT change the treatment strategy for potential surgery candidates? What kind of patients benefits most from this exam? In this review, we focus on the utility of PET/CT in diagnosis, staging, and assessment of resectability of pancreatic cancer. In addition, its ability to monitor metabolic response and recurrence after treatment will be emphasis of discussion. We hope to provide answers to the questions above, which clinicians care most about.

Preoperative FDG-PET predicts early recurrence and a poor prognosis after resection of pancreatic adenocarcinoma

OBJECTIVE

The aim of this study was to evaluate the clinical utility of preoperative 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) as a prognostic predictor of resectable pancreatic adenocarcinoma.

METHODS

A total of 128 patients with resected pancreatic adenocarcinoma who preoperatively underwent FDG-PET examinations were studied. The maximum standard uptake value (SUVmax) was calculated for each primary lesion. A receiver operating characteristics (ROC) curve was constructed to estimate the optimal cutoff value of the SUVmax. In order to determine which outcomes of interest were appropriately demonstrated, ROC curve analyses were conducted for six outcomes: 6-, 12-, and 24-month disease-free survival (DFS), and 6-, 12-, and 24-month overall survival (OS). A multivariate analysis was conducted to identify prognostic factors.

RESULTS

The ROC curves revealed that the SUVmax predicted the 6-month DFS most optimally (area under the curve 0.757), with a cutoff value of 6.0. Of the 69 patients with an SUVmax ≥ 6.0, 34 (49 %) developed recurrence within 6 months. In contrast, only 3 of 59 (5 %) patients with an SUVmax < 6.0 exhibited early recurrence (p < 0.001). The median OS time was 37 months in patients with an SUVmax < 6.0 and 18 months in patients with an SUVmax ≥ 6.0 (p < 0.001). The multivariate analysis revealed lymph node metastasis (hazard ratio [HR] 2.31; p = 0.001) and an SUVmax ≥ 6.0 (HR 2.05; p = 0.002) to be significantly correlated with a poor survival.

CONCLUSIONS

An SUVmax ≥ 6.0 was a significant predictor of early postoperative recurrence and subsequent poor survival following resection of pancreatic adenocarcinoma.

Predictive value of maximum standardized uptake value (SUVmax) on 18F-FDG PET/CT in patients with locally advanced or metastatic pancreatic cancer

PURPOSE

We investigated the prognostic role of 18F-FDG PET/CT in the prediction of progression-free survival (PFS) and chemotherapeutic response in patients with locally advanced or metastatic pancreatic cancer.

METHODS

We enrolled 21 newly diagnosed patients with locally advanced or metastatic pancreatic cancer who underwent 18F-FDG PET/CT scanning before palliative gemcitabine-based chemotherapy between 2006 and 2012. Maximum standardized uptake value (SUVmax) of the primary tumor was measured by 18F-FDG PET/CT. Chemotherapeutic response was evaluated according to the Response Evaluation Criteria in Solid Tumors. Survival analysis was performed for time to progression using the Kaplan-Meier method. Cox proportional hazard models were used to determine independent prognostic factors.

RESULTS

All pancreatic tumors showed detectable FDG uptake (mean SUVmax = 6.8 ± 3.0, range 2-12) The mean SUVmax values among response groups showed no significant difference (P = 0.853) and chemotherapeutic response was not different according to SUVmax level (P = 0.807). PFS was significantly shorter in the high SUVmax (≥6.8) group than in the low SUVmax (<6.8) group (2.9 vs. 6 months, P = 0.012). Multivariate analysis revealed that SUVmax was an independent prognostic factor for predicting PFS (P = 0.046).

CONCLUSIONS

Higher SUVmax of primary pancreatic tumor is associated with poor PFS and pretreatment SUVmax is an independent prognostic factor for predicting PFS in patients with locally advanced or metastatic pancreatic cancer who received gemcitabine-based palliative chemotherapy. However, pretreatment SUVmax is not associated with chemotherapeutic response.

Usefulness of F-18-fluorodeoxyglucose positron emission tomography to confirm suspected pancreatic cancer: a meta-analysis

INTRODUCTION

Pancreatic cancer is among the five most lethal malignancies in the world. Unfortunately, many malignant tumors go undetected by the current primary diagnostic tools. (18)FDG-PET and (18)FDG-PET/CT might be useful to confirm suspected pancreatic cancer.

METHODS

A meta-analysis was performed using all major search engines. Methodological quality of included studies was assessed as well as quality of the PET-protocol. The following pooled estimates served as primary outcome measures: sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy.

RESULTS

Thirty-five studies were included. Pooled estimates for (18)FDG-PET were: sensitivity 90%, specificity 76%, PPV 90%, NPV 76% and accuracy 86%. Pooled estimates for (18)FDG-PET/CT were: sensitivity 90%, specificity 76%, PPV 89%, NPV 78% and accuracy 86%. The pooled sensitivity and specificity for (18)FDG-PET to differentiate between pancreatic cancer and chronic pancreatitis were 90% and 84%, respectively.

CONCLUSION

Both (18)FDG-PET and (18)FDG-PET/CT offer no benefit over the current primary diagnostic tools in diagnosing pancreatic cancer. However, the (18)FDG-PET/CT systems are still improving. We should investigate the sensitivity and specificity of these new systems while reevaluating the tradeoff between false positive and false negative results. Yet, (18)FDG-PET/CT may have a role in the staging of pancreatic cancer, in survival prediction, and may add to other diagnostic information, like histology.

Prognostic value of 18F-fluorodeoxyglucose positron emission tomography in patients with resectable pancreatic cancer

PURPOSE

We evaluated the prognostic value of (18)F-2-fluoro-2-deoxyglucose positron emission tomography (FDG PET) in patients with resectable pancreatic cancer.

MATERIALS AND METHODS

We retrospectively reviewed the medical records of pancreatic cancer patients who underwent curative resection, which included 64 consecutive patients who had preoperative FDG PET scans. For statistical analysis, the maximal standardized uptake value (SUVmax) of primary pancreatic cancer was measured. Survival time was estimated by the Kaplan-Meier method, and Cox's proportional hazard model was used to determine whether SUVmax added new predictive information concerning survival together with known prognostic factors. p<0.05 indicated statistical significance.

RESULTS

Overall survival (OS) and disease- free survival (DFS) were respectively 42.9 months (27.6-58.2; 95% CI) and 14.9 months (10.1-19.7; 95% CI). When subjects were divided into two groups according to SUVmax with a cutoff value of 3.5, the high SUVmax group (n=32; SUVmax >3.5) showed significantly shorter OS and DFS than the low SUVmax group. Multivariate analysis of OS and DFS showed that both high SUVmax and poor tumor differentiation were independent poor prognostic factors.

CONCLUSION

Our study showed that degree of FDG uptake was an independent prognostic factor in pancreatic cancer patients who underwent curative resection.

FDG-PET in diagnosis, staging and prognosis of pancreatic carcinoma: A meta-analysis

AIM: To investigate the potential role of positron emission tomography (PET) in the diagnosis, staging and prognosis predicting of pancreatic carcinoma (PC).

METHODS: A systematic review of relevant literatures in PubMed, Embase and Cochrane Library was performed. The sensitivity and specificity of diagnostic and staging studies, and HRs for prognosis predicting studies were pooled. The bivariate model was used for diagnostic studies and the random-effect model for prognostic studies. Heterogeneity between included studies was tested using χ² test, and subgroup analysis was performed to explain the heterogeneities. All of the calculations were performed using Stata version 11.0.

RESULTS: A total of 39 studies were included. The pooled sensitivity of PET in diagnosing PC (30 studies, 1582 patients), evaluating N stating (4 studies, 101 patients) and liver metastasis (7 studies, 316 patients) were 0.91 (95%CI: 0.88-0.93), 0.64 (95%CI: 0.50-0.76), and 0.67 (95%CI: 0.52-0.79), respectively; and the corresponding specificity was 0.81 (95%CI: 0.75-0.85), 0.81 (95%CI: 0.25-0.85), and 0.96 (95%CI: 0.89-0.98), respectively. In prognosis analysis (6 studies, 198 patients), significant difference of overall survival was observed between high and low standardized uptake value groups (HR = 2.39, 95%CI: 1.57-3.63). Subgroup analysis showed that PET/CT was more sensitive than PET alone in evaluating liver metastasis of PC, 0.82 (95%CI: 0.48-0.98) and 0.67 (95%CI: 0.52-0.79), respectively.

CONCLUSION: PET can be used as a valuable diagnostic and predictive tool for PC, but its effect in the staging of PC remains indeterminate.

Prognostic value of SUVmax measured by Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography with Computed Tomography in Patients with Pancreatic Cancer

PURPOSE

Recent studies have been conducted on the relationship between fluorodeoxyglucose (FDG) uptake in F-18 FDG PET/CT and prognosis in patients with pancreatic cancer, but these studies have been carried out in small numbers of patients. The aim of this retrospective study was to determine in a large number of patients whether glucose metabolism as assessed by F-18 FDG PET/CT provides prognostic information independent of established prognostic factors in patients with pancreatic cancer.

METHODS

We reviewed retrospectively the medical records of 165 patients (men 105, women 60, mean age 67 ± 10 years) with a diagnosis of pancreatic cancer that had undergone F-18 FDG PET/CT as part of a pretreatment workup from January 2004 to December 2009. Subsequently, all patients underwent surgery, cyberknife, radiotherapy, and/or chemotherapy. For the analysis, patients were classified by age, demographic data, maximum standardized uptake value (SUVmax), size, location, serum level of CA19-9, type of treatment, and AJCC stage. The relationship between FDG uptake and survival was analyzed using the Kaplan-Meier with log-Rank test and Cox's proportional-hazard regression methods.

RESULTS

Median survival for all 165 study subjects was 290 days and median SUV by PET/CT was 5.8 (range: 0-25.1). Patients were allocated to high (> 4.1) and low (≤4.1) SUV groups, and median survivals of these patients were 229 days and 610 days, respectively, which were significantly different (p < 0.0001). Furthermore, SUVmax was found to be significantly related to survival in each stage, i.e., there were 1267 days in stage I, 440 days in stage II, 299 days in stage III, and 143 days in stage IV (p < 0.0001). The median survival was also found to be significantly related to tumor size (p = 0.001), site (p = 0.0298), serum level of CA19-9 (p = 0.0017), distant metastasis (p < 0.0001), and type of treatment (p < 0.0001). Multivariate analysis study revealed that the patients with a low SUV (p = 0.0298), a lower serum level of CA19-9 (p = 0.0071), a lower stage (p = 0.0017), and no distant metastasis (p < 0.0001) had longer survivals. In addition, SUVmax values were found to have a similar hazard ratio of distant metastasis; it was well known predictor. Furthermore, SUVmax values showed a higher hazard ratio than that of other clinicopathologic predictors.

CONCLUSION

The present study shows that SUVmax on F-18 FDG PET/CT can provide a prognostic information in patients with pancreatic cancer.

Imaging of the pancreas: Recent advances

A wide spectrum of anomalies of pancreas and the pancreatic duct system are commonly encountered at radiological evaluation. Diagnosing pancreatic lesions generally requires a multimodality approach. This review highlights the new advances in pancreatic imaging and their applications in the diagnosis and management of pancreatic pathologies. The mainstay techniques include computed tomography (CT), magnetic resonance imaging (MRI), endoscopic ultrasound (EUS), radionuclide imaging (RNI) and optical coherence tomography (OCT).

Advances in diagnosis, treatment and palliation of pancreatic carcinoma: 1990-2010

Several advances in genetics, diagnosis and palliation of pancreatic cancer (PC) have occurred in the last decades. A multidisciplinary approach to this disease is therefore recommended. PC is relatively common as it is the fourth leading cause of cancer related mortality. Most patients present with obstructive jaundice, epigastric or back pain, weight loss and anorexia. Despite improvements in diagnostic modalities, the majority of cases are still detected in advanced stages. The only curative treatment for PC remains surgical resection. No more than 20% of patients are candidates for surgery at the time of diagnosis and survival remains quite poor as adjuvant therapies are not very effective. A small percentage of patients with borderline non-resectable PC might benefit from neo-adjuvant chemoradiation therapy enabling them to undergo resection; however, randomized controlled studies are needed to prove the benefits of this strategy. Patients with unresectable PC benefit from palliative interventions such as biliary decompression and celiac plexus block. Further clinical trials to evaluate new chemo and radiation protocols as well as identification of genetic markers for PC are needed to improve the overall survival of patients affected by PC, as the current overall 5-year survival rate of patients affected by PC is still less than 5%. The aim of this article is to review the most recent high quality literature on this topic.

Pancreatic and hepatobiliary cancers

Morphology-based imaging modalities have replaced classical conventional nuclear medicine modalities for detection of liver or pancreatic lesions. With positron emission tomography and the glucose analog F-18 fluorodeoxyglucose (FDG), a sensitive and specific modality for the detection of hepatic metastases and extrahepatic tumor deposits from hepatocellular or pancreatic cancer is available. F-18 FDG PET can increase the accuracy of staging primary tumors of the liver or the pancreas, and can be used for response monitoring. Radiopharmaceuticals such as Ga-68 DOTATOC and F-18 DOPA allow the specific detection of neuroendocrine pancreatic tumors and their metastatic deposits. Hybrid scanners such as PET-CT integrate morphologic and metabolic information, and allow to increase the sensitivity and specificity of noninvasive imaging in many tumor entities. The development of specific radiopharmaceuticals and technical innovations such as SPECT-CT has increased the reliability of conventional scintigraphic imaging. This chapter focuses on the use of PET-CT in hepatobiliary and pancreatic cancers.

Using 18F-fluorodeoxyglucose positron emission tomography to monitor clinical outcomes in patients treated with neoadjuvant chemo-radiotherapy for locally advanced pancreatic cancer

BACKGROUND

Pancreatic cancer ranks as the fourth leading cause of cancer death in the United States with 5-year survival ranging from 1% to 5%. Positron emission tomography (PET) is a metabolic imaging system that is widely used for the initial staging of cancer and detecting residual disease after treatment. There are limited data, however, on the use of this molecular imaging technique to assess early tumor response after treatment in pancreatic cancer.

METHODS

The objective of the study was to explore the relationship of early treatment response using the F-fluorodeoxyglucose (FDG) PET with surgical outcome and overall survival in patients with locally advanced pancreatic cancer. FDG-PET measurements of maximum standardized uptake value and kinetic parameters were compared with the clinical outcome.

RESULTS

Twenty patients were enrolled in the study evaluating neoadjuvant induction chemotherapy followed by concurrent chemoradiotherapy (chemo-RT) for locally advanced pancreatic cancer. All 20 patients had prestudy PET scans and a total of fifty PET scans were performed. Among patients who were PET responders (> or =50% decrease in standardized uptake value after cycle 1), 100% (2/2) had complete surgical resection. Only 6% (1/16) had surgical resection in the PET nonresponders (<50% decrease). Two patients did not have the second PET scan because of clinical progression or treatment toxicity. Mean survival was 23.2 months for PET responders and 11.3 months for nonresponders (P = 0.234). Similar differences in survival were also noted when response was measured using Patlak analysis.

CONCLUSIONS

FDG-PET can aid in monitoring the clinical outcome of patients with locally advanced pancreatic cancer treated with neoadjuvant chemo-RT. FDG-PET may be used to aid patients who could have complete surgical resection as well as prognosticate patients' survival.

PET and PET/CT for pancreatic malignancies

FDG PET imaging is useful for preoperative diagnosis of pancreatic carcinoma in patients with suspected pancreatic cancer in whom CT fails to identify a discrete tumor mass or in whom FNAs are nondiagnostic. FDG PET imaging is useful for M staging and restaging by detecting CT occult metastatic disease, allowing noncurative resection to be avoided in this group of patients. FDG PET can differentiate post-therapy changes from recurrence and holds promise for monitoring neoadjuvant chemoradiation therapy. The technique is less useful in periampullary carcinoma and marginally helpful in staging except for M staging. As with other malignancies, FDG PET is complementary to morphologic imaging with CT, therefore, integrated PET/CT imaging provides optimal images for interpretation and thus more optimal patient care.

FDG PET imaging of Ela1-myc mice reveals major biological differences between pancreatic acinar and ductal tumours

PURPOSE

The aim was to evaluate FDG PET imaging in Ela1-myc mice, a pancreatic cancer model resulting in the development of tumours with either acinar or mixed acinar-ductal phenotype.

METHODS

Transversal and longitudinal FDG PET studies were conducted; selected tissue samples were subjected to autoradiography and ex vivo organ counting. Glucose transporter and hexokinase mRNA expression was analysed by quantitative reverse transcription polymerase chain reaction (RT-PCR); Glut2 expression was analysed by immunohistochemistry.

RESULTS

Transversal studies showed that mixed acinar-ductal tumours could be identified by FDG PET several weeks before they could be detected by hand palpation. Longitudinal studies revealed that ductal--but not acinar--tumours could be detected by FDG PET. Autoradiographic analysis confirmed that tumour areas with ductal differentiation incorporated more FDG than areas displaying acinar differentiation. Ex vivo radioactivity measurements showed that tumours of solely acinar phenotype incorporated more FDG than pancreata of non-transgenic littermates despite the fact that they did not yield positive PET images. To gain insight into the biological basis of the differential FDG uptake, glucose transporter and hexokinase transcript expression was studied in microdissected tumour areas enriched for acinar or ductal cells and validated using cell-specific markers. Glut2 and hexokinase I and II mRNA levels were up to 20-fold higher in ductal than in acinar tumours. Besides, Glut2 protein overexpression was found in ductal neoplastic cells but not in the surrounding stroma.

CONCLUSION

In Ela1-myc mice, ductal tumours incorporate significantly more FDG than acinar tumours. This difference likely results from differential expression of Glut2 and hexokinases. These findings reveal previously unreported biological differences between acinar and ductal pancreatic tumours.

PET and PET/CT for Pancreatic Malignancies

FDG PET imaging is useful for preoperative diagnosis of pancreatic carcinoma in patients with suspected pancreatic cancer in whom CT fails to identify a discrete tumor mass or in whom FNAs are nondiagnostic. FDG PET imaging is useful for M staging and restaging by detecting CT occult metastatic disease, allowing noncurative resection to be avoided in this group of patients. FDG PET can differentiate post-therapy changes from recurrence and holds promise for monitoring neoadjuvant chemoradiation therapy. The technique is less useful in periampullary carcinoma and marginally helpful in staging except for M staging. As with other malignancies, FDG PET is complementary to morphologic imaging with CT, therefore, integrated PET/CT imaging provides optimal images for interpretation and thus more optimal patient care.

Predictive and prognostic value of FDG-PET

The predictive and prognostic value of fluorodeoxyglucose (FDG)-positron emission tomography (PET) in non-small-cell lung carcinoma, colorectal carcinoma and lymphoma is discussed. The degree of FDG uptake is of prognostic value at initial presentation, after induction treatment prior to resection and in the case of relapse of non-small cell lung cancer (NSCLC). In locally advanced and advanced stages of NSCLC, FDG-PET has been shown to be predictive for clinical outcome at an early stage of treatment. In colorectal carcinoma, limited studies are available on the prognostic value of FDG-PET, however, the technique appears to have great potential in monitoring the success of local ablative therapies soon after intervention and in the prediction and evaluation of response to radiotherapy, systemic therapy, and combinations thereof. The prognostic value of end-of treatment FDG-PET for FDG-avid lymphomas has been established, and the next step is to define how to use this information to optimize patient outcome. In Hodgkin's lymphoma, FDG-PET has a high negative predictive value, however, histological confirmation of positive findings should be sought where possible. For non-Hodgkin's lymphoma, the opposite applies. The newly published standardized guidelines for interpretation formulates specific criteria for visual interpretation and for defining PET positivity in the liver, spleen, lung, bone marrow and small residual lesions. The introduction of these guidelines should reduce variability among studies. Interim PET offers a reliable method for early prediction of long-term remission, however it should only be performed in prospective randomized controlled trials. Many of the diagnostic and management questions considered in this review are relevant to other tumour types. Further research in this field is of great importance, since it may lead to a change in the therapeutic concept of cancer. The preliminary findings call for systematic inclusion of FDG-PET in therapeutic trials to adequately position FDG-PET in treatment time lines.

Detection of disease recurrence and monitoring of therapy

The detection of disease recurrence and treatment monitoring pose high demands on diagnostic modalities. Whereas serum marker levels in most cases allow an assessment of tumor load and a respective response to therapy, they do not confer information on the localization of disease. Although this diagnostic gap is filled by imaging modalities, most techniques based on morphology will come to a limit when fibrotic tissue alterations have to be differentiated from viable tumor tissue in case of suspected recurrence or when residual masses after chemotherapy have to be assessed. The metabolic information on tumor cells gained by fluorodeoxyglucose-positron emission tomography (FDG-PET) imaging appears not only to be more sensitive and reliable in this respect, but also appears to allow assumptions on response to therapy, and ultimately on patient prognosis.

Expression of glucose transporter-1, hexokinase-II, proliferating cell nuclear antigen and survival of patients with pancreatic cancer

OBJECTIVES

18F-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) has been shown to be useful in diagnosis and staging of pancreatic cancer. However, the prognostic value of FDG-PET remains controversial. The aim of this study was to evaluate relations between the factors suggested to be related to the FDG accumulation in tumor tissue, such as glucose transporter-1 (GLUT-1), hexokinase type-II (HK-II), proliferating cell nuclear antigen (PCNA), and survival of pancreatic cancer patients.

METHODS

Histological specimen of pancreatic cancer obtained from seventy-four consecutive patients were evaluated for the expression of GLUT-1, HK-II, and PCNA by visual analysis of immunohistochemical staining of paraffin sections from the tumor specimens using anti-GLUT-1, anti-HK-II, and anti-PCNA antibody, respectively. The percentages of cells strongly expressing GLUT-1, HK-II and PCNA were scored on a 5-point scale (1 = 0-20 percent, 2 = 20-40 percent, 3 = 40-60 percent, 4 = 60-80 percent, 5 = 80-100 percent). After initial treatment, each patient was followed-up and survival time was recorded. Median survival curves of the patients with different levels of GLUT-1, HK-II, and PCNA expression were evaluated using the Kaplan-Meier method. Statistical significance of the differences in survival was calculated with the log rank test.

RESULTS

Median survival of examined patients showed no relation with the levels of GLUT-1 expression, while patients with low expression of HK-II (HK-II index < 3) had significantly shorter survival than those with higher expression of HK-II (HK-II index >/= 3) (6.5 +/- 4.1 versus 12.9 +/- 22.4 months, respectively, p < 0.05). Median survival of examined patients also showed significant relations with the levels of PCNA expression. Patients with low expression of PCNA (PCNA index < 4) had significantly longer survival than those with higher expression of PCNA (PCNA index >/= 4) (11.9 +/- 20.1 versus, 5.8 +/- 10.8 months, respectively, p < 0.01):

CONCLUSIONS

Our results showed that the expression of GLUT-1 had no prognostic value in the examined patients with pancreatic cancer. On the other hand, high levels of HK-II expression and low levels of PCNA expression may allow accurate identification of the patient with longer survival who may benefit from intensive anticancer treatment.

FDG-PET for prediction of survival of patients with metastatic colorectal carcinoma

BACKGROUND

The current study focuses on the prognostic value of pretreatment metabolic activity in metastases as measured with [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET), as an indicator of survival in colorectal cancer.

PATIENTS AND METHODS

In a prospective series of 152 patients with metastatic colorectal cancer, of whom 67 were treated with resection of metastases and 85 with chemotherapy, standardized uptake values (SUV) as measured with FDG-PET, were calculated prior to treatment. Survival probabilities were estimated by Cox proportional regression analysis. For Kaplan-Meier analysis SUV was stratified by the median value. Survival differences were assessed using the log-rank test.

RESULTS

SUV in metastases was a significant predictor for overall survival (hazard ratio 1.17, 95% confidence interval 1.06-1.30, P = 0.002), independent of the subsequent treatment. According to the median value of the patient population a low (SUV <4.26) and high uptake group (SUV >4.26) was defined. The median survival and the 2- and 3-year survival rates were 32 months, 59% and 45%, respectively, in the low-uptake group and 19 months, 37% and 28%, respectively, in the high-uptake group (P = 0.017).

CONCLUSION

A significant survival benefit was observed in patients with low FDG uptake in metastases of colorectal cancer.

Level of Fluorodeoxyglucose Uptake Predicts Risk for Recurrence in Melanoma Patients Presenting With Lymph Node Metastases

BACKGROUND

The incidence of malignant melanoma has increased. Identification of additional prognostic factors may allow the development of individualized strategies. This multivariate analysis was undertaken to evaluate the potential role of the standard uptake value (SUV) in predicting disease-free and overall survival in melanoma patients with lymph node metastases.

METHODS

All melanoma patients with palpable lymph node metastases who where referred for a fluorodeoxyglucose positron emission tomography scan were eligible. The SUV in the lymph node metastasis was calculated. Data were analyzed (Kaplan-Meier), and differences in cumulative survival and the disease-free rate were assessed (log-rank test). Univariate and multivariate analyses (Cox proportional hazard model) were performed to determine independent prognostic factors.

RESULTS

There was no statistical difference in survival for the 38 patients with a high or low SUVmean (P = .11). However, a significant difference was found in disease-free survival (P = .03). Ulceration of the primary melanoma (P = .023) was an independent predictor of survival. For the disease-free survival, multivariate Cox regression showed adjuvant radiation (P = .001), localization of the primary melanoma (P = .017), and a high SUVmean (P = .009) as independent prognostic factors.

CONCLUSIONS

Disease-free survival of melanoma patients was prolonged in those with a low SUVmean value (P = .03) in their lymph node metastasis, as compared with those with a high SUVmean. However, this difference was not found for overall survival. In multivariate analysis, high SUVmean was an independent prognostic factor (P = .009) for disease-free survival. Prospective research should determine whether patients with a high FDG uptake in melanoma lymph node metastases could benefit from adjuvant radiation treatment or chemotherapy.

PET imaging in assessing gastrointestinal tumors

The clinical usefulness of FDG-PET imaging is now firmly established in various situations, such as the preoperative staging of esophageal cancer and recurrent colorectal carcinoma and the detection and staging of recurrent colorectal cancer when there is a clinical or biologic suspicion with inconclusive conventional findings. Encouraging results were obtained in the evaluation of the therapeutic response of various gastrointestinal malignancies, either during the treatment or after its completion. There is no firm consensus regarding its role in pancreatic cancer, either proved or suspected, but it may be valuable in selected clinical situations. Its role seems fairly limited in patients with hepatocellular carcinoma, although PET findings may have prognostic implications. Evaluation of cholangiocarcinoma is an emerging indication, albeit with limited data to date. Finally, PET/CT is very likely to enhance the role of FDG imaging further in the work-up of patients with gastrointestinal tumors.

Dual-phase 18F-fluoro-2-deoxy-D-glucose positron emission tomography as a prognostic parameter in patients with pancreatic cancer

PURPOSE

Recently, dual-phase 18F-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) was shown to be useful in the differentiation between malignant and benign pancreatic lesions. The aim of this prospective study was to evaluate the value of dual-phase FDG-PET as a prognostic parameter in patients with pancreatic cancer.

METHODS

Sixty-five consecutive patients with pancreatic cancer underwent dual-phase FDG-PET. Standardised uptake values at 1 h (SUV1) and 2 h (SUV2) following the injection of FDG were determined, and the retention index (RI) was calculated by dividing the difference between SUV2 and SUV1 by SUV1. The prognostic value of SUV1, SUV2 and RI was analysed, along with the various clinical and biochemical parameters.

RESULTS

Multivariate analysis showed that only three factors had an independent association with longer patient survival: female gender (p<0.01), TNM stage I-III (p<0.05) and RI>10% (p<0.01). Neither SUV1 nor SUV2 showed any prognostic significance. Combination of tumour stage and RI allowed more accurate prognostic evaluation. Patients at stage I-III with RI>10% survived longer than did patients at the same stage with RI<10% (15.3 vs 11.5 months, p<0.01). Patients at stage IV with RI>10% had an intermediate prognosis, with a median survival of 9.5 months; patients at stage IV with RI<10% showed the worst prognosis, with a median survival of 4.9 months (p<0.05).

CONCLUSION

RI calculated with dual-phase FDG-PET can be used not only as a tool for initial diagnosis and staging of pancreatic cancer but also as a strong independent prognostic parameter that can allow accurate identification of those patients who will benefit from intensive anticancer treatment at different stages of the disease.

[11C]Methionine Positron Emission Tomography and Survival in Patients with Bone and Soft Tissue Sarcomas Treated by Carbon Ion Radiotherapy

PURPOSE

The development of the novel carbon ion radiotherapy (CIRT) in the treatment of refractory cancers has resulted in the need for a way to accurately evaluate patient prognosis. We evaluated whether L-[methyl-(11)C]-methionine (MET) uptake and its change after CIRT were the early survival predictors in patients with unresectable bone and soft tissue sarcomas.

EXPERIMENTAL DESIGN

MET positron emission tomography was prospectively performed in 62 patients with unresectable bone and soft tissue sarcomas before and within 1 month after CIRT. Tumor MET uptake was measured with the semiquantitative tumor:nontumor ratio (T/N ratio). The MET uptake in the tumor and relevant clinical parameters were entered into univariate and multivariate survival analysis.

RESULTS

The overall median survival time was 20 months. Patients with a baseline T/N ratio of <or=6 had a significant better survival than patients with a baseline T/N ratio >6 (2-year survival rate: 69.4% versus 32.3%; P = 0.01). Patients with a post-CIRT ratio of <or=4.4 had a better survival than that with a post-CIRT ratio >4.4 (2-year survival rate: 63.7% versus 41.3%; P = 0.01). A significant higher survival rate was observed in patients with post-therapeutic MET uptake change of >30% than patients in lower change group (2-year survival rate: 74.6% versus 41.6%; P = 0.049). The multivariate analysis showed that both baseline and post-CIRT T/N ratio were statistically significant independent predictors of patient survival. Tumors with larger T/N ratio had a significantly poorer prognosis.

CONCLUSIONS

MET uptake as measured by either baseline or post-CIRT T/N ratio was an independent predictor of survival in patients with bone and soft tissue sarcomas treated by carbon ion radiotherapy, whereas post-therapeutic MET uptake change might have potential value for the same purpose.

FDG-PET scanning in the diagnosis of gastrointestinal cancers

This review deals with the current, well-established indications for two-(18F)-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) scanning in patients with gastrointestinal cancers. FDG-PET is a non-invasive, functional imaging technique. FDG exploits the native glucose transporter to enter the cell. Since many tumours have enhanced glucose uptake, FDG is readily accumulated in malignant cells and can be detected by a PET camera. FDG-PET has been established as an important diagnostic tool in clinical oncology. This review deals with the current, well-established indications for FDG-PET scanning in patients with gastrointestinal cancers. In the current practice, FDG-PET is most commonly used to stage oesophageal carcinoma, to detect and stage recurrence of colorectal carcinoma and to differentiate between benign and malignant pancreatic lesions. The benefit of FDG-PET scanning in patients with oesophagus carcinoma is best established in stage IV disease, as the diagnostic accuracy to detect metastatic disease is higher compared to the combination of computed tomography (CT) and endoscopic ultrasound (EUS). In patients with a history of colorectal carcinoma, FDG-PET scanning is particularly effective in diagnosing recurrent disease, especially in those with a rising carcinoembryonic antigen without a suspect lesion on conventional imaging. Large series have indicated that the sensitivity and specificity for detecting recurrent colorectal carcinoma are in the range of 87%-100% and 66%-100%, respectively. Equally, FDG-PET has a high sensitivity (68%-96%) and specificity (78%-100%) in detecting pancreatic carcinoma in patients with a suspicious-looking pancreatic mass on CT scan. Lastly, we focus on the use of FDG-PET as a modality for early monitoring of treatment response in patients with gastrointestinal stromal cell tumours. Without doubt, future developments will further establish the diagnostic role of the FDG-PET scan in the care of patients with gastrointestinal cancers.

18-Fluorodeoxyglucose positron emission tomography in predicting survival of patients with pancreatic carcinoma

The prediction of survival of patients with pancreatic cancer is usually based on tumor staging and grading and on the level of tumor markers. However, accurate tumor staging can be obtained only after resection, and still there is a great difference in survival rates among patients with the same clinicopathologic parameters. Recently the uptake of 18-fluorodeoxyglucose (FDG) by positron emission tomography (PET) has been found to be correlated with survival in patients with pancreatic cancer. This study evaluated the role of 18FDG PET as a prognostic factor for patients with pancreatic cancer. From June 1996 to July 2002, a total of 118 patients underwent PET for pancreatic cancer. The standardized uptake value (SUV) of 18FDG was calculated in 60 of them, and these patients were divided into high (>4) and low (< or =4) SUV groups. They were also evaluated according to the tumor node metastasis (TNM) classification system of the International Union Against Cancer, and by tumor grade, medical or surgical treatment, diabetes, age, sex, and CA 19-9 serum levels. Twenty-nine cancers showed high and 31 showed low SUVs. Survival was significantly influenced by tumor stage (P=0.0001), tumor grade (P=0.01), and SUV (P=0.005). Multivariate analysis showed that only stage (P=0.001) and SUV (P=0.0002) were independent predictors of survival. When patients who were analyzed for SUV were stratified according to the other variables, FDG uptake was related to survival also after stratification for the following: stage III to IVa (P=0.002), stage IVb (P=0.01), tumor resection (P=0.006), moderately differentiated tumors (P=0.01), age less than 65 years (P=0.006), CA 19-9 levels greater than 300 kU/L (P=0.002), and absence of diabetes (P=0.0001). The SUV calculated with 18FDG PET is an important prognostic factor for patients with pancreatic cancer and may be useful in selecting patients for therapeutic management.

Diagnosis of pancreatic cancer using fluorine-18 fluorodeoxyglucose positron emission tomography (FDG PET) --usefulness and limitations in "clinical reality"

The present review will provide an overview of the literature concerning the FDG PET diagnosis of pancreatic cancer and a summary from our experience of 231 cases of pancreatic lesions. FDG PET can effectively differentiate pancreatic cancer from benign lesion with high accuracy. Newly-developed PET scanners can detect small pancreatic cancers, up to 7 mm in diameter, by their high resolution, which could make a great contribution to the early detection of resectable and potentially curable pancreatic cancers. FDG PET is useful and cost-beneficial in the pre-operative staging of pancreatic cancer because an unexpected distant metastasis can be detected by whole-body PET in about 40% of the cases, which results in avoidance of unnecessary surgical procedures. FDG PET is also useful in evaluation of the treatment effect, monitoring after the operation and detection of recurrent pancreatic cancers. However, there are some drawbacks in PET diagnosis. A relatively wide overlap has been reported between semiquantitative uptake values obtained in cancers and those in inflammatory lesions. As for false-positive cases, active and chronic pancreatitis and autoimmune pancreatitis sometimes show high FDG accumulation and mimic pancreatic cancer with a shape of focal uptake. There were 8 false negative cases in the detection of pancreatic cancer by FDG PET, up to 33 mm in diameter, mainly because of their poor cellularity in cancer tissues. In addition, there are 19% of cancer cases with a decline in FDG uptake from 1 hr to 2 hr scan. FDG PET was recently applied to and was shown to be feasible in the differential diagnosis of cystic pancreatic lesions, such as intraductal papillary mucinous tumor of the pancreas. Further investigations are required to clarify the clinical value of FDG PET in predicting prognosis of the pancreatic patients.