Contemporary approaches for imaging skeletal metastasis

The skeleton is a common site of cancer metastasis. Notably high incidences of bone lesions are found for breast, prostate, and renal carcinoma. Malignant bone tumors result in significant patient morbidity. Identification of these lesions is a critical step to accurately stratify patients, guide treatment course, monitor disease progression, and evaluate response to therapy. Diagnosis of cancer in the skeleton typically relies on indirect bone-targeted radiotracer uptake at sites of active bone remodeling. In this manuscript, we discuss established and emerging tools and techniques for detection of bone lesions, quantification of skeletal tumor burden, and current clinical challenges. Methods are emerging to improve the imaging of skeletal metastasis, in which cancer spreads into bone. Detecting skeletal metastasis is vital for evaluating and treating primary cancers and their complications. This detection is critical for such common cancers as breast, prostate, thyroid, kidney and lung cancer. Daniel Thorek of John Hopkins University School of Medicine in Baltimore, USA and colleagues in New York and Sweden, have reviewed the use, challenges and limitations of existing and emerging imaging techniques. Scans that detect the uptake of various radioactive compounds are the most commonly used methods, but results can be complicated by changes in bone that are not related to cancer. Researchers are developing targeted imaging agents that are incorporated selectively into specific types of cancer cells. Semi-automated and whole-body image systems are also being refined.