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Section 5. Medical science
Khodjibekov Marat Khudoykulovich, Rakhmonova Gulbahor Ergashovna, Tashkent Medical Academy E-mail: [email protected]
Opportunities of radiologic diagnostics in case of malignant tumors of pancreas
Abstract: Pancreatic cancer is the 10th most common malignancy and the 4th largest cancer death cause in adults [1]. Surgery offers the only chance of curing these patients. Complete surgical resection is associated with a 5-year survival rate of between 20 and 30 % [1]. About 48,960 people (24,840 men and 24,120 women) will be diagnosed with pancreatic cancer. About 40,560 people (20,710 men and 19,850 women) will die of pancreatic cancer [2]. Rates of pancreatic cancer have been fairly stable over the past several years. Pancreatic cancer accounts for about 3 % of all cancers in the US, and accounts for about 7 % of cancer deaths [3]. The average lifetime risk of developing pancreatic cancer is about 1 in 67 (1.5 %). We review all information's and method during past 20 years. Keywords: pancreas, diagnosis, tumor, imaging.
Imaging methods
The main aim of imaging tests is early detection as well as an accurate staging of lesion extension and possible vessel invasion. This is done in order to choose the best clinical and therapeutic management. Multiple methods have been developed in the last few decades to improve pancreatic cancer detection. However, taken individually these imaging tests have variable sensitivity.
Endoscopic Retrograde Cholangiopancreatography (ERCP)
This procedure allows for visualization of the hepatobiliary tree, sampling of pure pancreatic juice and assessment for genetic analysis of tissue from biopsies and brushings [4]. The role of ERCP in the diagnosis ofpancreatic cancer is considerably reduced, if compared to the past. Due to the post-procedural risk of pancreatitis, it is mainly a therapeutic modality with stent placement in patients with obstructive disease, whereas its diagnostic role has been replaced by EUS and MRCP, where available [4].
Transabdominal Ultrasound (TUS)
Transabdominal US is commonly the first line imaging test for patients with suspected pancreatic cancer, due to its wide availability, safety and low cost. Limitations of pancreas visualization are represented by the patient's body habitus, overlying bowel gas, as well as sonographer experience [4]. The sensitivity of US in detecting pancreatic tumors can be up to 95 %. If the lesion is more than 3 cm. Recent studies have shown an increased sensitivity for small lesions (< 2 cm.), similar to CT scan, as well as a better characterization (adenocarcinoma and neuro-endocrine tumors), and vascular staging [5]. Though US is a sensitive method to detect small liver metastases [4], US alone can't guarantee enough accuracy in diagnosis and staging of pancreatic tumors. Therefore, it should be considered a useful tool for initial assessment in suspected pancreatic lesions.
Intraductal Ultrasound (IDUS)
IDUS is a relatively new ultrasonographic modality that uses small-caliber, high-frequency catheters (5-10 Fr., 12-30 MHz). IDUS can visualize both ductal systems and intraluminal strictures. The imaging process can be performed during ERCP, offering complementary information to this procedure. IDUS seems to be particularly beneficial in the differential diagnosis between pancreatic neoplasms and chronic pancreatitis if a main pancreatic duct stenosis is present, with very high sensitivity and specificity, reaching 100 % and 92 % respectively [6]. This method is also beneficial when an IPMN is suspected, with a more detailed resolution imaging comparing to traditional endosonography [4]. This is also true for the diagnosis of pancreatic mass invading the
common bile duct (CBD), with a high sensitivity and specificity, (respectively > 90 % and > 80 %) [6].
Endoscopic Ultrasound (EUS)
Numerous early publications indicated thatEUS is highly sensitive for the detection ofpancreatic tumors with rates higher than 90 % [6]. The advantage of EUS over classical CT was especially evident for lesions less than 3 cm [1]. Sensitivity of EUS 99 %, CT 55 % [6]. This advantage ofEUS continued when compared to helical CT for lesions up to 1.5 cm: EUS 100 %, CT 67 % [12]. In a recent review of the literature by Hunt et al. EUS had a clearly superior rate in the detection of pancreatic tumors: EUS 97 %, helical CT 73 %.
Computed tomography (CT) and Magnetic resonance imaging (MRI)
Older studies have indicated that CT and MRI perform equally in assessing the respectability ofpancreatic cancer. In a recent comparative study, MRI had a 96 % accuracy versus 81 % of helical CT in predicting resectability ofpancreatic cancer [14]. Contrast enhanced MRI was found to be as accurate as contrast enhanced helical CT in the detection and staging of pancreatic cancer. MRI was more sensitive in the detection of small abdominal metastases [15]. MRI pancre-ato-cholangiography (MRCP) was founded more accurate and noninvasive method for diagnosing of extrahepatic bile ducts and main pancreatic duct. A newly published retrospective study [16] evaluated the sensitivity and specificity of multiphasic thin slice helical CT in the detection ofcancers 2 cm. or smaller at pathological examination. The sensitivity was 97 % and specificity 100 %.
Positron Emission Tomography (PET)
PET has a marginal role in detection and staging of pancreatic cancer, due to poor spatial resolution, whereas it can be relevant in the detection of distant metastases, as in the evaluation of loco regional tumor recurrence [5]. A recent retrospective analysis described pre-radiation FDG-PET parameters as a significant tool in the prediction of prognosis, in patient with locally advanced non-resectable pancreatic cancer [7].
The most used PET radiotracer is 18-fluoro-deoxy-glucose (18-FDG), a glucose analog, which is transported intracellularly via glucose transporters, highly expressed in tumoral cells [4]. Its sensitivity in detecting pancreatic cancer ranges from 71 to 92 %, with a specificity of 64-94 % [8]. Lytras et al. recently reported a comparable accuracy to CT in pancreatic assessment, without any additional information in patients with equivocal findings [9]. Frolich et al. showed an overall specificity of 95 % in detecting liver metastases, with a better yield for larger lesions (specificity of 97 % for > 1 cm.
Autoimmun pancreatitis mimiking multiple pancreatic cancer: case report
masses, whereas 45 % specificity for < 1 cm. ones) [10]. False posi- high positive predictive value in the detection of distal metastases, this
tive results can be reported in several inflammatory diseases like pan- novel method should be considered before pancreatic resection [11].
creatitis, or hyperglycemic states 4. Preliminary studies have shown Conclusions
that a combination offunctional information, provided by FDG-PET Radiologic methods are important for understanding of tumors
and anatomic information provided by CT can be relevant in pan- of pancreas. Main role of radiologic methods is to early detection
creatic cancer imaging. The positive and negative predictive values of pathologic process and find distant metastasis. Combination of
of PET/CT for the diagnosis of pancreatic mass are 91 % and 69 % radiologic methods is superior for detection, good staging, tissue
respectively, allowing a change in patient management. Due to its diagnosis and potential therapy for the tumors of pancreas.
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Kim Myong Jin, Yonsey Severanse Hospital, Seoul, Korea
Khodjibekov Marat Khudoykulovich,
Rakhmonova Gulbahor Ergashovna, Tashkent Medical Academy E-mail: [email protected]
Autoimmun pancreatitis mimiking multiple pancreatic cancer: case report
Abstract: Autoimmune pancreatitis is a rare type of chronic pancreatitis that can mimic pancreatic cancer. Our clinical report was about a case of autoimmune pancreatitis with separated location and false-positive findings of imaging on CT, MRI, ERCP, US, and PET/CT suggestive of pancreatic tumor. When the tumor marker CA 19-9 is not elevated in cases involving a pancreatic mass, pancreatic cancer should be differentiated from mass-forming pancreatitis. However, the results of these auxiliary examinations could not be ignored minimally invasive biopsy was the safest choice in this case, since no other method, including tumor marker assessment, could provide a clear diagnosis.
Keywords: Autoimmun pancreatitis, pancreas, cancer, diagnosis, radiology, positron emission tomography, markers.
