Neuroendocrine Tumors Can't Hide From DOTATATE PET

Fran Lowry

June 21, 2012

June 21, 2012 (Miami Beach, Florida) — Molecular imaging with a method that detects hormonally active tissues in the body can improve the care of patients with neuroendocrine cancer, researchers said here at the SNM 2012 Annual Meeting.

A study that assessed the effect of gallium-68 DOTATATE positron emission tomography/computed tomography (PET/CT) to evaluate patients with neuroendocrine tumors before their treatment found that use of the technique changed the type of treatment they were scheduled to receive in more than 35% of cases.

"Patients who were previously considered to be inoperable went on to have surgery, and patients with previously unknown and extensive cancer who were originally slated for surgery were found to be inoperable," senior author Niklaus Schaefer, MD, from the University Hospital of Zurich, Switzerland, said.

Neuroendocrine tumors have different behaviors, prognoses, and therapies depending on their origin, staging, and grading. This makes clinical decision-making challenging for trying to determine the most appropriate treatment for patients with these tumors, Dr. Schaefer said.

Changes in Management

In the prospective study, 61 patients with low- to intermediate-grade neuroendocrine tumors were imaged with gallium-68 DOTATATE PET/CT. About half of the patients were considered to be eligible for surgery to remove their tumor.

The researchers compared the clinical decisions that were made before and after imaging.

They found that gallium-68 DOTATATE PET/CT led to change in management in 36.1% of the patients. Fourteen of 32 (43.8%) patients sent for gallium-68 DOTATATE PET/CT by the surgical department for preoperative exclusion of metastatic disease were reclassified as nonoperable.

Eight of 29 (27.6%) patients with clinical evidence of neuroendocrine tumors with symptoms such as hypertension, flushing, or elevated chromogranin A (a tumor marker) were reclassified as potentially resectable cases.

"These findings were significant, with a P value equal to 0.037," Dr. Schaefer said.

Examples of refined management included a patient with a pancreatic neuroendocrine tumor who was scheduled for a liver transplantation after resection of the primary pancreatic tumor. The patient showed disseminated osseous metastases on gallium-68 DOTATATE PET/CT that had not been seen on contrast-enhanced CT. As a result, his transplantation operation was canceled, and he received palliative care instead.

The second example was a woman who had been in the hospital for 3 weeks awaiting a diagnosis. "She had hypertension [and] flushing, and as last resort she was sent to us to see if there was a neuroendocrine tumor. On the gallium-68 imaging, she was found to have a hindgut carcinoid. She got an endoscopy, had local resection, and was cured of disease," Dr. Schaefer said.

"Molecular imaging can have a significant impact in patient management, sparing patients from futile surgery, or in finding symptomatic patients which might be curable with surgery," he said.

Above all, when patients present with these symptoms, clinicians should think of neuroendocrine cancer, Dr. Schaefer said.

"Neuroendocrine tumors have a very slow growing profile, so if you have a patient with hypertension who is not responding to antihypertensive medication, or who has chronic diarrhea, you really have to think of the disease. And if you think of the disease, you have to search," he told Medscape Medical News.

"PET imaging with gallium-68 DOTATATE can serve as a model for further cost-effective decision-making using molecular imaging," he added.

Best for Patient and Health Resources

"This study is important because it shows the power of the molecular imaging technique to guide therapy in individual patients and affect physician decisions on how to treat patients," Peter C. Herscovitch, 2012-2013 president-elect of the SNM, Reston, Virginia, commented to Medscape Medical News.

"In some cases the results of the therapy may be discouraging to an individual patient because it may show, as one of the images Dr. Schaefer showed, that a patient who was felt to have very localized disease and thought to be amenable to liver transplantation to totally remove their disease from the body, had, in fact, more widespread disease and so was not a candidate for a very major surgical procedure. This was best for the patient, and also the best use of health care resources," Dr. Herscovitch, who was not part of the study, said.

Dr. Schaefer and Dr. Herscovitch report no relevant financial relationships.

SNM 2012 Annual Meeting. Abstract 99. Presented June 10, 2012.

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