Page 76 - Read Online

Table 2: Pitfalls and bottlenecks and possible remedies for circulating chromogranin A and gastrin
interpretation
Pitfalls and Possible causes Remidies suggested
bottleneck
High CrA levels Others disease Keep in mind non-malignant pathological causes of elevated CrA as severe
during diagnostic and cancers hypertension, systemic inflammatory response syndrome, pulmonary obstructive
work up for NETs than NETs disease, bowel disease renal insufficiency, liver or heart failure, chronic gastritis,
chronic hepatitis, pancreatitis, Helicobacter Pylori infection, inflammatory bowel
disease, hyperthyroidism, giant cell arthritis, systemic lupus erythematosous,
exercise-induced physical stress

Doubtful in accuracy Keep in mind malignant pathological causes of elevated CrA others than NETs as
determination breast cancer, hepatocellular carcinoma, pancreatic adenocarcinoma, colon cancer,
ovarian cancer, prostate cancer, medullary thyroid cancer

High individual Recommend only certificated laboratories with high quality control certification
intervariability

Drugs Complete with imaging according to clinical presentation
(PPIs) Repeat determination if doubtful
Stop proton pump inhibitor 2 weeks before or according with drugs half life
Unexpected Doubtful in accuracy
individual changes determination
in patient with
known NETs High individual Recommend only certificated laboratories with high quality control certification
and the same laboratory and assay for each patient
intervariability

Different assay and Report information on lab and normal reference in patient medical record
normal values in
different labs Check for possible new drugs or physiological interference (fasting, exercise etc.)

Samples from different
physiological condition
Recommend CrA determination during long acting SSA therapy at regular interval
Consider drugs after drug injection
interference (SSA)
If crucial data for diagnosis or therapy management retest in same condition
Compare biochemical, clinical and imaging data
High gastrin levels Drugs interference Stop PPIs under careful patient monitoring (in-patient setting or daily checks) and
in patient with (PPIs) switch to H2 receptor antagonist
clinical suspicion If PPIs interruption is not clinically indicated try to tapered the IPPs dose
of gastrinoma If the diagnosis is unclear (fasting serum gastrin < 10× increased, gastric pH < 2,
no tumor imaged), a secretin test is indicated

Concomitant disease Consider atrophic gastric, Helicobacter Pylori infection, renal failure, short bowel
interference syndrome
NETs: neuroendocrine tumors; PPIs: proton pump inhibitors; SSA: somatostatin analogues

CgA values even in the absence of liver metastasis, SHOULD CIRCULATING BIOMARKERS
gastrin levels are generally proportional to tumor burden BE USED IN DISEASE FOLLOW UP?
and highest gastrin levels are present in patients with
metastatic disease. In addition, gastrin seems higher in When specific circulating biomarkers are elevated at
pancreatic compared to duodenal primary tumors, with the diagnosis in a patient there is indication to follow
no discernible difference between sporadic and multiple these over time. If new signs and symptoms emerge, it
endocrine neoplasia (MEN1) or Zollinger Ellison is necessary to test for new paraneoplastic syndromes
syndrome patients. On the contrary, authors of a recent according to clinical presentation. [6]
[46]
consensus agreed that circulating biomarkers levels in
patients with neuroendocrine tumors do not correlate with All guidelines [Table 1] recommend the use of CgA for
tumor grade and do not differentiate low-level malignancy follow up in all NETs even though there is an absence of
from high-grade disease. [12] prospective studies supporting its use.
352
Journal of Cancer Metastasis and Treatment ¦ Volume 2 ¦ August 31, 2016 ¦