RSNA13 research roundup: Radioimmunotherapy shows promise as HIV cure

Research detailing the potential for a possible HIV cure and confirming the value of breast tomosynthesis were highlighted Tuesday morning at the Radiological Society of North America's annual conference in Chicago.

Highly active antiretroviral therapy (HAART) has proven to be an effective treatment for patients infected with human immunodeficiency virus (HIV) by suppressing the replication of the virus in the body. But scientists believe a complete cure has been prevented by the fact that latent infected cells remain in the body.

Now researchers led by Ekaterina Dadachova, Ph.D., a professor of radiology, microbiology and immunology at Albert Einstein College of Medicine in New York, are using radioimmunotherapy (RIT) to destroy those latent cells.

In her study, presented today at RSNA, Dadachova and her colleagues administered RIT to blood samples from 15 HIV patients treated with HAART.

RIT--historically used to treat  cancer--uses monoclonal antibodies (designed to recognize and bind to a specific cell antigen) that are paired with a radioactive isotope. The antibody is injected into a patient's bloodstream and delivers the radiation to the intended target cell.

"In RIT, the antibodies bind to the infected cells and kill them by radiation," Dadachova said, in an announcement. "When HAART and RIT are used together, they kill the virus and the infected cells, respectively." In her study, Dadachova said, the ability of RIT to eliminate HIV-infected cells was "profound and specific" and was accomplished without damaging nearby cells.

Dadachova also found that the treatment could work within the central nervous system as well, which is important, she said, since antiretroviral treatments only partially penetrate the blood-brain barrier.

The next step for the researchers is to begin using RIT in clinical trials with HIV patients, Dadachova said.


In another study presented at RSNA Tuesday, researchers from the Hospital of the University of Pennsylvania (HUP) in Philadelphia confirmed the value of breast tomosynthesis.

According to Emily Conant, M.D., chief of breast imaging at HUP, every patient screened for breast cancer at HUP since 2011 has been screened with digital breast tomosynthesis. For the study, Conant and her colleagues compared the imaging results for the 15,633 women screened with DBT in 2011, with the results from the 10,753 women screened with digital mammography in 2010

They found that the recall rate with digital breast tomosynthesis decreased from 10.40 percent to 8.78 percent, while the cancer detection rate increased from 3.51 to 5.24 per 1,000 patients.

Tomosynthesis is "the most exciting improvement to mammography that I have seen in my career, even more important than the conversion from film-screen mammography to digital mammography," Conant said in an announcement. "The coming years will be very exciting, as we see further improvements in this technology."


It has been shown that automated breast density measurement is predictive of breast cancer risk in younger women, but research presented Tuesday at RSNA suggests the risk may also be related to the rate at which breast density changes in women as they age.

In this study, Nicholas Perry, director of the London Breast Institute, and colleagues compared breast density and cancer risk between younger and older women, and how that risk related to changes in breast density as the women aged. The study group included 282 breast cancer cases and 317 health control participants who underwent digital mammography.

The researchers found that breast cancer patients showed higher breast density than healthy participants up to the age of 50, after which those healthy participants demonstrated a significant decline in breast density that followed a linear pattern, while among the cancer patients there was much more variability in breast density regression.

"The results are interesting because there would appear to be some form of different biological density mechanism for normal breasts compared to breasts with cancer, and this appears to be most obvious for younger women," Perry said in an announcement. "This is not like to diminish the current [American Cancer Society] guidelines in any way, but it might add a new facet regarding the possibility of an early mammogram to establish an obvious risk factor which may then lead to enhanced screening for those women with the densest breasts."