MD Anderson Research Highlights: ASTRO 2023 Special Edition

Featuring presentations on novel combination therapies and analytical methods

MD Anderson News Release September 29, 2023

The University of Texas MD Anderson Cancer Center’s Research Highlights showcases the latest breakthroughs in cancer care, research and prevention. These advances are made possible through seamless collaboration between MD Anderson’s world-leading clinicians and scientists, bringing discoveries from the lab to the clinic and back.

This special edition features presentations by MD Anderson researchers at the 2023 American Society of Radiation Oncology (ASTRO) Annual Meeting. Information on all MD Anderson ASTRO Annual Meeting content can be found at MDAnderson.org/ASTRO.

Assessing HPV circulating cell-free DNA kinetics could yield valuable insights for cervical cancer (Abstract 107)

Human papillomavirus (HPV) is a primary cause of cervical cancer, and viral HPV DNA can be detected in the blood of patients with cervical cancer. A new study presented by Aaron Seo, M.D., Ph.D., revealed important insights from analyzing the kinetics of this circulating DNA. In this study, researchers found the levels of viral HPV DNA changed dynamically throughout the course of chemoradiation and that treatment with a therapeutic HPV vaccine was associated with a more rapid decline in circulating DNA. These promising findings indicate the need for additional studies to determine how the kinetics of cell-free HPV DNA may provide further information into disease extent, clinical stage and treatment response. Seo will present the results on Oct. 1.

Radiation therapy may prime immune systems of patients with oligometastatic prostate cancer (Abstract 157)

In the EXTEND trial, metastasis-directed treatments using a combination of radiation therapy and hormone therapy improved progression-free survival compared with hormone therapy alone. However, the mechanisms and biomarkers predicting patient responses are not well understood. In a new study presented by Alexander Sherry, M.D., researchers studied the immune systems of patients in this trial and found that radiation plus hormone therapy promoted a stronger immune response than hormone therapy alone. Further, among patients receiving radiation, those with stronger immune responses had better outcomes. This study provides a possible link between metastasis-direction radiation, the systemic immune response and overall disease control. The results pave the way for new studies combining immunotherapies with radiation and hormone therapy and for personalizing treatments based on a patient’s immune system. Sherry will present the findings on Oct. 2.

Lymphopenia during bridging radiation therapy not associated with poorer outcomes in patients with aggressive B-cell lymphomas (Abstract 195)

Bridging radiation therapy has been used as a strategy for disease control in patients with relapsed or refractory aggressive B-cell lymphoma prior to treatment with anti-CD19 chimeric antigen receptor (CAR) T cell therapy. However, there have been concerns about treatment-related lymphopenia, a condition of low white blood cell counts with a documented correlation to adverse patient outcomes in several cancer types. In a retrospective study of 40 patients presented by Gohar Manzar, M.D., Ph.D., researchers found that lymphopenia due to bridging radiation therapy was not associated with worse treatment responses or survival outcomes in these types of B-cell lymphoma patients. The findings support consideration of bridging radiation therapy as a treatment option in this context. Manzar will share the results on Oct. 2.

New MRI technology shows potential in measuring treatment responses for pancreatic cancer (Abstract 224)

Intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) is an emerging imaging technique used to measure tissue characteristics without the use of a contrast agent, but continued research is needed to correlate the measurable characteristics of IVIM with tumor radiation responses. In a study of 12 patients with pancreatic cancer presented by Lucas McCullum, IVIM scans showed significant differences between patients stratified by changes in CA19-9, a pancreatic tumor marker correlated with response. According to the researchers, these findings warrant continued investigation into IVIM as an approach to characterize treatment responses. McCullum will present the results on Oct. 3.

New PET/CT software could simplify and improve radiation treatment planning for lung cancer (Abstract 270)

Currently, radiation treatment planning for patients with non-small cell lung cancer requires two imaging sessions, a gated 4D-computed tomography (CT) scan and a non-gated positron emission tomography (PET)/CT scan. Data from those sessions are used to simulate radiation therapy, yet combining these data from two different sessions can make it challenging to assess treatment response and plan treatments effectively. A new prototype software presented by Tinsu Pan, Ph.D., allows the same information to be gathered in a single imaging session of less than 15 minutes. The imaging is free of misregistration and motion artifacts, without any hardware gating and without the need for an external respiratory monitoring device. This approach could improve not only the patient experience but also the ability of clinicians to assess radiation treatment plans. Pan will present the findings on Oct. 4.

Novel antibody-toxin conjugate targeting CD47 improves immune responses against breast cancer models (Abstract 304)

Macrophages engulf and neutralize malignant cells through a process called phagocytosis. However, tumor cells can avoid phagocytosis by increasing expression of the “don’t eat me” signal, CD47. Blocking CD47 has an antitumor effect driven by the STING pathway, which facilities immune responses to cytoplasmic DNA. However, cytoplasmic DNA is destroyed in the phagocytosis process, limiting effectiveness of CD47 blockade. A new antibody-toxin conjugate engineered in the Wen Jiang Laboratory overcomes this by linking anti-CD47 to listeriolysin O (LLO), a pore-forming protein that allows tumor DNA to escape phagolysosomes and activate STING. LLO-CD47 is a first-in-class antibody-toxin conjugate engineered for cancer immunotherapy. In a preclinical analysis presented by Benjamin Schrank, M.D., Ph.D., LLO-CD47 enhanced macrophage STING signaling and tumor cell phagocytosis, preventing the growth and metastasis of breast tumors. The findings suggest this novel immunotherapy warrants further evaluation as a treatment option for metastatic breast cancer. Schrank will present the results on Oct. 4.

New approach may broaden patients able to receive liver-directed ablative radiotherapy (Abstract 309)

Ablative radiation therapy is designed to deliver high doses of radiation to a tumor while limiting exposure to surrounding
healthy tissue. When treating tumors in the liver, traditional guidelines specify a minimum volume of 700cc of healthy
liver tissue should be spared from potentially damaging doses of radiation, but not all patients can meet that requirement. A new Phase I study presented by Enoch Chang, M.D., shows that ablative radiotherapy can be safely delivered using single photon emission computed tomography (SPECT) image guidance, enabling treatment for patients with lower volumes of functional liver than typically accepted. In a study of 12 patients with colorectal cancer metastases to the liver, no patients experienced dose-limiting toxicities with this approach. If confirmed in larger trials, this approach could broaden the number of patients able to receive liver-directed ablative radiation therapy. Chang will present the findings on Oct. 4

ASTRO awards and honors

-       Kristi Brock, Ph.D., professor of Imaging Physics, named to 2023 class of ASTRO Fellows

-       Wendy Woodward, M.D., Ph.D., professor and chair ad interim of Breast Radiation Oncology, elected vice chair of the ASTRO Science Council