Can Pancreastatin Levels Guide Therapy in NETS Patients Undergoing TACE?

For patients with neuroendocrine tumors (NETs) that have metastasized to the liver, high levels of serum pancreastatin are predictive of poor outcomes after treatment with transarterial chemoembolization (TACE), according to a new study.

NETs have often metastasized to the liver at the time of initial presentation, and surgical resection is commonly not possible. Patients who could benefit from TACE include “those with symptoms poorly controlled by octreotide therapy, radiographic evidence of liver tumor progression, or liver tumor burden severe enough that any further progression would lead to hepatic insufficiency,” wrote study authors led by Lawrence A. Shirley, MD, of the Ohio State University Wexner Medical Center in Columbus. “However, even with these selection criteria, which patients will optimally benefit from TACE remains unclear.”

Serum pancreastatin has been shown to correlate with survival in patients with NETs, and the researchers hypothesized that if measured throughout the TACE treatment period, it could be used as a prognostic marker to help guide therapy. They retrospectively analyzed results from 188 patients who underwent TACE between 2000 and 2013 at a single institution; 52.1% of the cohort was female, the median age was 58 years, and 91.5% of patients were white. Primary NET locations included the pancreas (22.9%), small bowel (35.6%), colon (5.3%), lung (5.9%), and others, while 31.9% were unknown. Results of the study were published in Annals of Surgical Oncology.

Among 155 patients with available radiographic follow-up, 3 had a complete response, 32 had a partial response, 96 had stable disease, and 4 had progressive disease; 61.1% of patients reported symptom improvement following TACE.

Initial serum pancreastatin levels of 5,000 pg/mL or higher were associated with a median overall survival of 22.1 months, compared with 58.5 months in those with lower levels, for a hazard ratio of 2.39 (95% CI, 1.48–3.83; P < .001). At 36 months, those with preoperative pancreastatin levels greater than 5,000 pg/mL had a survival rate of 31.3%, compared with 68.8% among those with lower levels. Grade 3 tumors and hepatic involvement also correlated with overall survival.

Patients who showed a decrease in serum pancreastatin levels of at least 50% at any point following TACE showed improved survival, with a median overall survival of 53.8 months compared with 29.9 months (P = .032). Those who had an initial drop in pancreastatin levels but then an increase were more likely to have liver progression, at 70.7% compared with 40.7% (P = .005), and more likely to require repeat TACE, at 21.1% compared with only 6.7% (P = .009).

“We propose that serum pancreastatin levels should be measured throughout the TACE treatment period as a method beyond radiographic assessment to determine which patients optimally benefit from this treatment strategy,” the authors concluded.

Some think the marker isn't quite ready for use. Daniel B. Brown, MD, director of interventional oncology at the Vanderbilt-Ingram Cancer Center in Nashville, told Cancer Network that he'd still like to see the use of pancreastatin validated in a prospective trial. "If a lower pancreastatin predicts longer time to progression, patient imaging strategies could be personalized with longer intervals between scans for those with a better prognosis," he said. "Such a measure could save significant money in the healthcare system as a whole."