An experimental technique has enabled doctors to see tumors that were previously invisible. The technique, which uses iron particles developed by Advanced Magnetics, helps doctors to see if prostate cancer has spread to the lymph nodes. The patient is firstly given an injection of iron particles into their blood. These particles are ingested by immune system cells called macrophages which then move to the lymph nodes, and are easily seen using magnetic resonance imaging (MRI). Cancer cells do not absorb iron and they show up with MRI as white spots, thus white areas in lymph nodes suggest that the cancer has spread. Results of a preliminary trial of the technique revealed that the iron particles allowed doctors to see more than 90% of lymph node tumors. Furthermore, more than 70% of these malignant tumors were too small to be seen with conventional imaging techniques. The technique should save people from unnecessary surgery as if prostate cancer has spread to the lymph nodes surgical removal of the gland is usually not adequate and other forms of treatment are needed. It is hoped that it could also be adapted for other cancers, such as breast cancer, where the course of treatment is dependent upon whether cancer cells have spread to the lymph nodes.
SOURCE/REFERENCE: NEJM 2003;348:2491-2499.
