68Ga Bombesin PET/MRI in Patients with Biochemically Recurrent Prostate Cancer and Noncontributory Conventional Imaging
Abstract
Background: Data from the American Cancer Society suggest that prostate cancer will continue to be one of the most diagnosed cancers, other than skin cancer, in the United States in men in 2015, with the second highest mortality rate among all cancers (after lung). As many as 40% of the patients diagnosed with prostate cancer will have their cancer return (called recurrence) within 10 years of their initial treatment. This recurrence can come with no outward symptoms or signs of disease; however, usually an increase of the levels of a particular protein found in blood, called prostate-specific antigen (PSA), precedes a clinically detectable recurrence by months to years. While PSA can detect evidence of this recurrence, it cannot differentiate between local, regional, or widespread disease with the necessary precision that is essential for treatment of the disease. In addition to looking for higher-than-expected levels of PSA in the blood, conventional imaging techniques such as ultrasound, CT (x-ray computed tomography) and MRI (magnetic resonance imaging) can be used. These tests are limited in that they are not specific enough; for example, a high level of PSA only indicates that cancer may be present, but not exactly where or how large the tumor is. Nor are these tests sensitive enough; for example, conventional scanning techniques (CT, bone scan) may not distinguish the cancerous mass from other organs or masses in the body when they are too small to look abnormal. Consequently, improved imaging for detection of recurrent prostate cancer continues to be an area of unmet need in patient care. A new radioactive pharmaceutical for positron emission tomography (PET) called 68Ga-RM2 demonstrated potential to show a much clearer and more reliable image of the tumor. 68Ga-RM2 is a synthetic radioactive chemical, which attaches to specific proteins that are expressed in high numbers in several cancerous tumors, including prostate cancer, but not in other parts of the body or in normal prostate tissue. Once the tumor has absorbed the radioactive tracer, it emits rays of light that are detectable by a PET scanner, showing an image of the tumor. This PET image is overlaid with a magnetic resonance (MR) image of the body, so that the tumor is shown in its precise anatomical location. In the first study using 68Ga-RM2 done at Stanford University in 10 men with suspected prostate cancer recurrence due to high PSA values, this test showed uptake in recurrent lesions in 9 patients, while CT scans and bone scans were negative. Objective: We plan to find out in a larger group of patients if using the radioactive pharmaceutical 68Ga-RM2 in a PET/MRI scan will detect recurrent prostate cancer in men with high or rising PSA after treatment better than the current standards of care (CT, bone scans). Specific Aims: We predict that at least 30% of patients will have one or more cancerous occurrences detected with the 68Ga-RM2 tracer using a PET/MR scanner, and that the number of patients with detected cancerous occurrences will be higher for 68Ga-RM2 PET/MRI than for conventional imaging techniques. Ultimate Applicability: This project will take a targeted approach to improving the detection of prostate cancer in patients who have elevated levels of PSA but who show no evidence of tumors on conventional imaging. Furthermore, this project focuses on early detection of sites of disease that can be treated. In this study, we focus on an issue that may be of fundamental importance to the overall survival of patients with prostate cancer. Our proposal addresses the following Prostate Cancer Research Program (PCRP) overarching challenge: develop better tools for early detection of clinically relevant disease. The research plan is in line with the imaging focus area of the 2015 PCRP: development of new anatomic, functional, and molecular imaging approaches for the detection and management of prostate cancer. Risk: T
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 31, 2017
- Source ID
- W81XWH1610604
Entities
People
- Andrei Iagaru
Organizations
- Stanford University
- United States Army