2 Proven Ways to Detect Bone Metastases Early
The most common cancers that spread (metastasize) to skeletal locations are breast, prostate and lung cancers. Today, there are new treatment protocols that can effectively manage bone metastasis, alleviate pain, and increase survival time. However, early detection is essential in order to plan an optimum course of treatment. Until the last decade, most cases of bone mets were diagnosed as symptoms such as pain or fractures appeared, perhaps when the mets had less response to treatment. However, advances in imaging have made it possible to identify bone mets in high risk breast, prostate or lung patients even when they are quite small or in more than one location.
Two types of imaging have emerged as preferred detection methods: whole-body magnetic resonance imaging (MRI) and PET/CT (Positron Emission Tomography/Computed Tomography) using radioactive tracers (radiotracers or isotopes). Not only do these types of imaging excel in early detection, but they are likely to continue to improve.
- Whole-Body MRI makes use of MRI’s ability to produce very high-resolution images of soft tissue. Cancer cells are drawn to bones that have high red marrow content, the inner soft tissue in bones. These locations include the lower backbones (vertebrae), the pelvis, ribs, and the ends of the long bones such as leg and arm bones. Whole-body MRI can even pick up certain types of bone mets before they have grown to a size that a radiotracer would be able to detect. Its accuracy ranges from 95-100%. It has the unique advantage of no radiation exposure. This makes it safe for patients who have already had numerous scans that use ionizing radiation (X-rays, CT scans, bone scintigraphy, etc.) in order to avoid adding more exposure. Plus, whole-body MRI is safe to use with pregnant or breastfeeding women suspected of bone mets.
- PET/CT scans are a nuclear medicine technique. This means that an intravenous (IV) injection of a radioactive substance called a radiotracer is administered before imaging starts, and a special type of camera will pick up where the radioactivity has settled. Radiotracers are isotopes bonded with bone-seeking molecules that collect in locations where tumor-related bone production is occurring. Isotopes are agents that emit gamma rays for a very short period. Since a cyclotron is needed to produce isotopes, the availability of PET/CT scans for bone mets is limited to large medical centers that can house a cyclotron close to the imaging practice. Once injected into the patient, the scan will be scheduled at the optimum time for the isotopes to reach their destinations, and before the gamma rays decay (fade away). A very promising isotope called 18F-Fluoride has shown up to 100% accuracy for very early detection of bone mets.i
Not only is imaging used for early detection of bone mets, it is also useful to evaluate how well the tumors are responding to therapies used to control them. It will be up to the patient’s doctor to prescribe which type of imaging is best in each patient’s case. Clinical factors, availability, and sometimes cost factors will be taken into account.
For high risk bone mets patients who are experiencing pain associated with metastatic tumors, the Sperling Medical Group provides a groundbreaking, noninvasive and painless treatment called MRI-guided Focused Ultrasound (MRgFUS) using the ExAblate® System.In addition, a diagnostic Whole-Body MRI can identify any other areas of very early bone involvement.
For more information, or to schedule a consultation, contact the Sperling Medical Group.
iEven-Sapir E, Metser U, Mishani E, Lievshitz G, et al. The detection of bone metastases in patients with high-risk prostate cancer: 99mTc-MDP Planar bone scintigraphy, single- and multi-field-of-view SPECT, 18F-fluoride PET, and 18F-fluoride PET/CT. J Nucl Med. 2006 Feb;47(2):287-97.
- Bone mets