Source: DGNews  |  Posted 1 year ago

By Karen Dente

BERLIN -- March 14, 2010 -- The presence of the plasma protein blood marker chromogranin A (CgA) has a high diagnostic accuracy in monitoring patients with intestinal carcinoid tumours, according to a study presented here at the 7th European Neuroendocrine Tumor Society Conference (ENETS).

Tommie Mynster, MD, Department of Surgery K, Bispebjerg Hospital, Copenhagen, Denmark, and colleagues investigated 100 patients with intestinal carcinoid tumours positive for CgA to determine the diagnostic accuracy of CgA as a predictor of disease progression, regression, and stable disease compared with changes seen in imaging studies.

CgA, which is released from the dense core vesicles of neuroendocrine cells, is found in plasma, where it can be detected by radioimmunoassay (RIA) specific for the hCgA(340-348) sequence.

“We evaluated patients by events, which was recorded when a computerised tomography, ultrasound scan, or octreotide scintigraphy was followed by another corresponding image,” the authors wrote.

Regression or progression was defined by >50% change in tumour burden. Of 384 events, 145 showed a progression of tumour burden, 178 stable disease, and 61 regression.

Of the group showing progression, CgA increased in 77% and was stable 19%. The diagnostic specificity for CgA in progressive disease was 80%, with positive and negative predictive values of 70% and 85%, respectively.

In the 61 events showing disease regression, plasma CgA decreased in 61% and remained stable in 30%, the specificity was 92%, and the positive and negative predictive values were 60% and 93%, respectively.

For stable disease, the correlation with stable plasma CgA was seen in 65% of the events, with a specificity of 78%.

“Plasma CgA, using this RIA, has a high diagnostic accuracy in monitoring patients with carcinoid tumours and is especially useful in predicting tumour progression,” the researchers concluded.

[Presentation title: Chromogranin A as a Predictor of Progression, Regression or Stable Disease in Ileo-Cecal (Midgut) Carcinoid Tumors. Abstract C68]