Prospective evaluation of some candidate tumor markers in the diagnosis of pancreatic cancer

Clinicopathologic features of small pancreatic adenocarcinoma. A collective study

BACKGROUND

Early diagnosis and complete removal of pancreatic adenocarcinoma (PC) is essential to improve its poor prognosis. It is necessary to find PC when it is small and at an early stage if surgical treatment is to be successful. This is an investigation of the clinicopathologic features of small PC.

METHODS

Thirty-one resected and histopathologically examined cases of small PC, 2 cm or less in greatest dimension, were collected from 7 institutions between 1989 and 1994, and their clinicopathologic features were analyzed in detail.

RESULTS

Eighteen patients (58.1%) had some symptoms or signs at the time of diagnosis, however, the other 13 (41.9%) had no symptoms. There was no sensitive blood test for the detection of small PC. The detection rates of the pancreatic tumor mass on ultrasonography, endoscopic ultrasonography, and computed tomography were 64.5% (20/31), 73.7% (14/19), and 64.5% (20/31), respectively. Only 13 patients (41.9%) were in International Union Against Cancer (UICC) Stage I, and the other 18 were in Stage III or IV due to lymph node metastasis or peritoneal dissemination. The overall 4-year postoperative survival rate was 54.5% and that of patients in Stage I was 77.9%.

CONCLUSIONS

To detect a small PC, a thorough examination may be required in patients with slightly abnormal findings on laboratory tests or imaging modalities, even if the patient is asymptomatic. PC 2 cm or less and belonging to Stage I may be regarded as an early carcinoma, because of its good prognosis.

Diagnosis and staging of pancreatic neoplasms

The relative value of current approaches to the diagnosis and staging of pancreatic cancer is discussed. A rational sequence of testing is recommended based on the clinical presentation of the patient and the local institutional expertise and facilities that are available.

Psychopathology of pancreatic cancer. A psychobiologic probe

Reports of characteristic psychiatric symptoms occurring in patients with pancreatic cancer appear regularly in the literature. A review of this literature reveals that symptoms of depression and/or anxiety may appear in approximately 50% of patients with pancreatic cancer before the diagnosis is made. This review proposes that the psychopathology of pancreatic tumors may be linked to tumor-induced changes in neuroendocrine or acid-base systems. Although confirmatory data are lacking, informed speculation centers on the potential role of adrenocorticotropic hormone, parathyroid hormone, thyrotropin-releasing hormone, glucagon, serotonin, insulin, and bicarbonate in the production of depression and/or anxiety in this disease. Elucidation of the pathophysiology of the psychiatric symptoms in patients with pancreatic cancer may provide a marker for early diagnosis of pancreatic neoplasia as well as a probe into the biologic bases of depression and anxiety.

Serum diagnostic tests for pancreatic cancer

Serological tests for pancreatic cancer have been criticized too harshly as a result of being tested in inappropriate roles. They are never likely to become sufficiently specific for screening an asymptomatic population unless some way can be found of defining a population with a particularly high risk for the disease. Nor are they appropriate in the investigation of the jaundiced patient. The markers that are carried by secreted mucins seem the most promising and in view of the marked heterogeneity of carbohydrate expression on mucins a combination of tests for two or three carefully selected markers is likely to be better than one. The high cost per test that results from using commercially available radioimmunoassay kits with a short shelf-life can be reduced by using enzyme-linked assays which have a much longer shelf-life. These tests are likely to be of most help in the investigation of non-jaundiced patients with unexplained abdominal pain or weight loss. In this group of patients it seems probable that serological tests will compliment scanning techniques but further studies are needed to assess this.

Serum enzymes and other laboratory tests in acute pancreatitis

This review evaluates selective enzymes and blood tests available for the diagnosis and prognosis of acute pancreatitis. It is concluded that serum amylase and lipase measurements represent the best available diagnostic methods. Newer alternative assays still require careful evaluation.

Effect of duct obstruction on histology and on activities of gamma-glutamyl transferase, adenosine triphosphatase, alkaline phosphatase, and amylase in rat pancreas

The effect of pancreatic duct obstruction on the activities of amylase and three nonexocrine pancreatic enzymes was studied in the rat. gamma-Glutamyl transferase (GGTase) activity, which is localized primarily in the plasma membrane of acinar cells, disappeared from the acinar basolateral plasma membrane and declined in specific activity by 80% over a seven-day experimental period. Mg-ATPase, localized primarily in the apical plasma membrane of acinar cells, simultaneously declined in activity in acinar cells but increased in activity in connective tissue. Mg-ATPase specific activity rose 3.5-fold. The histochemical results showed that the ductlike cells resulting from obstruction were derived primarily from acinar cells. Alkaline phosphatase (APase) activity, which is localized in vascular endothelium and the stroma of interlobular ducts, exhibited a dramatic increase in the periacinar, periductal, and interlobular stroma, and specific activity rose 11-fold. Amylase-specific activity declined as did the protein to DNA ratio. Gel electrophoresis showed that the amount of zymogen granule polypeptides declined after duct obstruction, whereas a few other polypeptides increased in amount.

Enzymes, isozymes, and enzyme variants in the diagnosis of cancer. A short review

Changes of enzyme activity in tissues, body fluids, and serum as well as changes of isozymes and enzyme variants in patients with malignancy suggest that these parameters may be used in the diagnosis of some types of cancer. A review of available information indicates that: changes of serum enzymes in patients with malignancies relate to the presence of a heavy tumor burden or of metastases, and cannot be utilized for the early diagnosis of malignancies; changes in isozyme patterns and newly developed enzyme variants may be of greater diagnostic value, although possibly not in the early diagnosis of cancer; study of enzymatic activity in body fluid may offer valuable help in specific situations; and occasionally, determination of enzymes may be of help in establishing susceptibility to malignancies.

Influence of nutritional status on circulatory ribonuclease C levels in patients with cancer

The influence of a variety of clinical and biochemical parameters on the activities in serum of ribonuclease (RNAse) selective for polycytidylic acid (RNAse C) were examined in 90 adult patients with cancer. The clinical data base determined on each patient included: RNAse C level, carcinoembryonic antigen (CEA) level, age, sex, race, presence (or absence of metastases, type of cancer, site of metastasis, renal function blood urea nitrogen [BUN], creatinine), hepatic function (bilirubin, alkaline phosphatase), and nutritional status (percent ideal body weight, percent weight loss, and albumin). Common tumor types studied included: colon (21), lung (18), breast (15), and hepatocellular carcinoma (10). For comparison, 175 nonmalignant control patients were studied to establish the normal range for RNAse. In patients with cancer, RNAse levels were increased in 57% and CEA levels were above 10 ng/dl in 36%. Although patients with BUN greater than 25 mg/dl or creatinine greater than 1.5 mg/dl were not entered on the study, nonetheless, RNAse was significantly (P less than 0.05) associated with both BUN and creatinine. Nutritional status also had an important influence on RNAse levels as both percent weight loss and percent ideal body weight were significantly (P less than 0.05) associated with circulatory RNAse: weight loss resulted in higher RNAse levels. These results account in part for the increased RNAse levels seen in those malignant conditions such as pancreatic and lung cancer commonly associated with weight loss in advanced stage. The possibility that circulatory RNAse C determination will provide a sensitive means for assessing nutritional status in cancer patients will require prospective evaluation.

Human pancreatic secretory protein profiles in the search for tumor markers

Pancreatic cancer secretory protein profiles were shown to be different from normals by a microcomputer-assisted analysis of isoelectric focusing patterns. Two acidic protein band regions (pI 3.0 and 4.5) of the pancreatic carcinoma profiles were significantly increased, and eight protein bands (pI 3.7, 5.0, 5.5, 6.5, 6.9, 7.3, 8.0, greater than 10.0) were significantly decreased. Highly significant decreases occurred at pH 7.3 (chymotrypsinogen) and at pH 5.0 (procarboxypeptidase Al, DNase I) in nonactivated specimens. The ratio between the absorbance points at 2.08 and 2.63 cm from the anode in each protein pattern differentiated the pancreas cancer specimens from the control group. Profiles found for the control group gave pI values similar to those found in the literature. The potential value of these findings in the search for tumor markers warrants further investigation as to whether these specimens can be differentiated from those from chronic pancreatitis patients.

Biologic markers in cancer diagnosis and treatment

We have reviewed several tumor markers that our advocates feel are now clinically useful, involve current assay technology, and are based on already available information. These include, in selected instances, estrogen receptors for breast cancer, thyrocalcitonin for medullary cancer of the thyroid, prostatic acid phosphatase for cancer of the prostate, alpha-fetoprotein for hepatocellular cancer, and carcinoembryonic antigen for monitoring colon cancer. We have considered the potential use of measurement of serum proteases and protein degradation products due to their activity as possible future areas of development, and we have explored measurement of tissue aryl hydrocarbon hydroxylase to identify populations at risk of cancer resulting from chemical carcinogenesis. It is clear that the study of tumor markers is already improving patient care in some specific areas and offers exciting potential for the future.

Efforts at early diagnosis of pancreatic cancer: the Mayo Clinic Experience

By contract with the National Cancer Institute, the authors have prospectively evaluated the diagnostic accuracy of serologic, secretory, endoscopic, and imaging procedures. Ultrasonography, computed tomography, endoscopic retrograde pancreatography, angiography, and pancreatic exocrine function tests have similar sensitivity, specificity, and predictive value in the diagnoses of pancreatic disorders. A newly developed ultrasonic endoscope has been evaluated for human use and preliminary findings suggest that it is safe. This endoscope generates a high resolution of real time images of extraluminal gastrointestinal organs, including the pancreas. This technique may be useful in detecting small premetastatic and resectable cancers of the pancreas.

The diagnosis of "early" pancreatic cancer: the University of Chicago experience

The results of a prospective study designed to investigate patients suspected of having pancreatic cancer are reported. One hundred and two of 238 patients investigated had pancreatic cancer. Ultrasonography, endoscopic retrograde cholangiopancreatography, and cytology were the most reliable tests for the diagnosis of resectable cancer. Computed tomography had a higher sensitivity for unresectable cancer. Factors responsible for delay in diagnosis are discussed. Cancer of the body and tail of the pancreas cannot be diagnosed early by investigating a symptomatic population. Factors influencing mortality in patients who survive over three years following pancreatic resection are discussed.