December 06, 2013 | Early detection of metastatic disease from prostate cancer in lymph nodes can save lives. Stephen M. Bravo, MD, and his team at Sand Lake Imaging hopes to help cure prostate cancer – or at least take it from an acute and life-threatening condition to a chronic, but manageable disease.
Text: Doris Pischitz
Photos: Maximilian Film
Prostate cancer is the second most common cause of deaths from cancer in American men. About one in 36 will die of prostate cancer1. Dr. Stephen M. Bravo’s father, a radiologist at Yale, was one of them. Bravo is Medical Director at Sand Lake Imaging, Orlando, Florida, USA. “I am passionate about trying to make sure that what he experienced is not experienced by other prostate cancer patients. I want to improve survival rates for prostate carcinoma in people who are diagnosed with metastatic disease. That’s what I want to do,” he states.
Earlier Detection of Metastases
Bravo’s team, therefore, found it entirely understandable when Bravo suggested they participate in a clinical study aimed at earlier detection of lymph node metastases. Matthew Hayes, the center’s Technical Director of Cross-Sectional Imaging, explains: “When Dr. Bravo came and he asked me about the possibility of doing these trials with prostate cancer research, I wasn’t surprised at all. This is a subject that is near and dear to Dr. Bravo, so I wanted to facilitate it as much as I possibly could.”
Detecting Abnormal Lymph Nodes
“Traditionally, we had to rely on size criteria to determine whether a lymph node was abnormal. We had to wait till the lymph node achieved the size of at least one centimeter in all dimensions,” Bravo explains the background to the study. Lymph nodes smaller than one centimeter may also harbor disease, especially metastases from prostate cancer, but there was no unique tool to be able to detect this disease early on. And even when a lymph node reached one centimeter in size, it was uncertain as to whether that represented a myelodysplastic invasion from metastatic disease or whether it was just a reactive, normal inflammatory process that frequently occurs in the body, especially in reaction to prostatectomy or radiation therapy. “The goal,” Bravo states, “was to define early lymphatic disease before it became metastatic to a size greater than one centimeter.” This requires both excellent imaging capabilities as well as efficient quantitative 3D visualization tools.
Precision Imaging for Prostate Cancer
Dr. Bravo and his team are using Feraheme (Ferumoxytol) to detect metastatic disease in nodes as small as three millimeters. This drug accumulates in normal lymph nodes but is not absorbed in prostate cancer cells within the lymph nodes. Patients are given the contrast agent on their first day of imaging exams; they also have a computed tomography (CT) scan to localize the smallest of the lymph nodes. Feraheme takes 18 to 24 hours to show up as a hyper-intense lesion under magnetic resonance imaging (MRI). So, the actual MRI imaging is done on the second day using a 3-tesla system. “With the tools that we are using now, we have data demonstrating accuracy, sensitivity, and specificity of approximately 96 percent in detecting lymph node invasion down to the size of two millimeters,” says Bravo.2
Multiple Imaging Modalities
The CT images are then used to determine that the lymph nodes follow the appropriate signal characteristics on the MRI images – that is, that they all absorb the Feraheme contrast agent and show up accordingly on the MRI images. Positive lymph nodes that do not show up on the MRI scan as having absorbed the contrast agent are subsequently treated at affiliated clinics using precise radiation therapy.
The next day, patients have a positron emission tomography/computed tomography (PET∙CT) scan with F18 Sodium Fluoride. PET∙CT is an important diagnostic tool for evaluating body metastatic disease and its accuracy in determining micro-metastatic disease has been proven in several studies for various cancers, including prostate cancer.
With three modalities and gigabytes of images, however, preparation, diagnosing, and reporting of images could have been complicated. Not so at Sand Lake Imaging explains Chief Technologist Hayes: “The biggest challenge for technologists in radiology is that there is a constant pressure to be effective. syngo®.via3 helps us to be efficient, be confident that the data we are sending over to the radiologist is right the first time, and is concise. It’s going to help us be more confident in our job, in our role.” One of the reasons why Sand Lake Imaging decided to go with the imaging software syngo.via was because they don’t have a 3D lab with staff processing images and sending them to the radiologists. Dr. Bravo says: “I think that there is significant added value when combining the different modalities that Siemens has to offer with syngo.via. It clearly allows us to be far more precise and efficient in our workflow. And it’s a fantastic tool that has allowed us to be more communicative with better accuracy and with more efficiency when it comes to discussing the results with our doctors. “
“In addition, we could not be doing the Feraheme research without the advanced visualization tools that syngo.via allows us to utilize to convey and disseminate the information in a prompt, precise, accurate, methodical manner. We need to be able to disseminate that information to physicians, research analysts, and other people in a way that all of them find efficacious and useful for clinical or research purposes,” Bravo adds. “And syngo.via allows us to do just that.”
Doris Pischitz is chief editor at Siemens Healthcare.