Patient-specific dose measurement improves therapy for neuroendocrine tumors

Patients with neuroendocrine tumors may benefit from individualized methods to help predict their response to therapy, according to a recent study published in the October issue of the Journal of Nuclear Medicine.

A team of Swedish researchers found that a hybrid planar and SPECT imaging method fell short in accurately measuring the absorbed treatment dose in some patients, but importantly, performed well in those with bone marrow metastases.

“The present study aimed to develop a method for patient-specific determination of activity in bone marrow, enabling a more personalized dosimetry,” Linn Hagmarker, PhD, a student at the department of radiation physics at the Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Sweden, said in a statement.

Neuroendocrine tumors begin in specialized cells and can occur anywhere in the body, including bone marrow. Using imaging to determine the absorbed treatment dose and related toxicity in bone marrow is difficult due to problems in measuring those parameters within small bone marrow cavities. The task is all the more challenging when marrow is littered with metastases, according to the researchers.

An individualized approach could help overcome this, Hagmarker noted, and be used to prevent bone marrow toxicity and identify a patient’s risk for developing acute leukemia.

The team applied their hybrid planar and SPECT imaging method to a cohort of 46 patients treated with 177Lu-dotate for their advanced neuroendocrine tumors. They found the method performed better in patients with skeletal metastases compared to those without. A technique utilizing only planar imaging worked best in those without metastases.

“Different dosimetry methods might be required for individual prediction of hematologic toxicity in patients with and without skeletal metastases,” Hagmarker said.

Going forward, she believes their research may have implications in measuring the acceptable levels of treatment within kidneys, which suggests the organs can tolerate doses above the general limit, according to current evidence.