Radionuclide Therapy Tied to Neoplasms in Some With Neuroendocrine Tumors

By David Douglas

May 01, 2020

NEW YORK (Reuters Health) - Peptide receptor radionuclide therapy (PRRT) for neuroendocrine tumors may lead to therapy-related myeloid neoplasm (t-MN) in a minority of patients, according to a systematic review.

"This study shows that the risk of t-MN after peptide receptor radionuclide therapy is small but not insignificant," Dr. Mohamad Bassam Sonbol of the Mayo Clinic Cancer Center, in Phoenix, Arizona, told Reuters Health by email. "This emphasizes the importance of counseling patients regarding the risk of t-MN because most of the reported cytogenetic abnormalities carry adverse features with poor prognosis after t-MN diagnosis."

Dr. Sonbol and colleagues identified 21 retrospective and seven prospective studies involving more than 7,300 patients. The incidence of t-NM varied across studies, but a total of 134 cases (2.61%) were reported over a median follow-up of 40 months. The median time until development of t-NM also varied but most were diagnosed after a year of PRRT.

"Cytogenetic abnormalities were reported in 32 patients with the most common abnormality being complex cytogenetics, consistent with myeloid neoplasms following exposure to alkylating agents or irradiation," the researchers write.

Most of the reported cytogenetic abnormalities, they add, "carry adverse prognosis with a survival period of around 12 to 14 months after t-MN diagnosis."

"Therefore," Dr. Sonbol concluded, "close monitoring is warranted to identify such patients early in the disease course when hematologic abnormalities persist. Oncologists should be vigilant and have low threshold for investigating persistent cytopenia especially because most centers that offer PRRT are destination centers and patients are typically followed by their local oncologist in between and after treatments."

Commenting on the findings by email, Dr. Armand Dasari of The University of Texas MD Anderson Cancer Center, in Houston, told Reuters Health that the work "is an important contribution to the field."

"Intriguingly," he added, "although there is a wide range of time from exposure to development of t-MN in the included studies, the median time was relatively short at one year."

"Building on this, future studies should aim to identify risk factors for development of t-MN," Dr. Dasari said.

Such work, he concluded, would help establish PRRT's place in the sequencing of therapies and the need for dose adjustments in high-risk patients. It also would help guide future research to develop safe combination therapies with PRRT and to evaluate the role of re-treatment with PRRT.

SOURCE: JAMA Oncology, online April 16, 2020.