Researchers from the U.S. National Cancer Institute in Bethesda, Md., were set to attend the conference beginning Nov. 12.
"One month from now, I'm supposed to be on a plane with people's visas processed and speeches written and presentations ready to be delivered" at a major meeting of the Russian Society of Clinical Oncology, Sophia Michaelson, adviser to the Russia Program of the Center for Global Health at NCI, told RIA Novosti.
At the conference U.S. researchers were to share clinical experiences and make presentations about research findings.
"But that process is halted right now. ... It's total paralysis. I have Russian government people saying, 'Are these folks from NCI coming? Are you guys OK? Is anyone still there?'" said Michaelson, who was born in Russia but has lived in the United States for 23 years.
The National Institutes of Health, the NIC's parent institution, has furloughed 75 percent of its workforce due to the ongoing shutdown, and furloughed federal workers are barred from working during the shutdown.
Clifford Hudis, head of the American Society of Clinical Oncologists, said in a statement the shutdown will "cause damage to the medical research workforce and systems of the United States for years to come."