In the past, the most viable treatment for locally advanced breast cancer was radical mastectomy. Today, preoperative chemotherapy in combination with surgery often is a successful alternative, but many types of chemotherapeutic drugs and dosing strategies make selecting the right treatment for each patient challenging.Common methods for determining how breast tumors respond to chemotherapy either provide too little detail, or they are costly and require contrast agents. Diffuse optical spectroscopy and imaging (DOSI) may give physicians a detailed, cost-effective way to foresee how their cancer patients will respond to chemotherapy. The technique has been shown to detect early functional changes of locally advanced breast cancer tissue. Bruce J. Tromberg and his colleagues at the Beckman Laser Institute and Medical Clinic, University of California, Irvine, reported their work to improve predictions of breast cancer chemotherapy response at the BiOS conference in San Jose, Calif., in January. With 11 patients, they compared noninvasive DOSI to postsurgical tissue assessments obtained six to eight weeks later. The researchers used a handheld laser breast scanner employing broadband near-infrared light to measure the absorption and reduced scattering in breast tissue from 650 to 1000 nm. The device quantified the biochemical properties of the tissue, including deoxy-hemoglobin, oxy-hemoglobin, and the percentages of water and lipids.Drops in deoxy-hemoglobin, the single best predictor, indicated lower oxygen consumption and cancer cell death. The researchers found that they could use the deoxy-hemoglobin value to classify patients with 83 percent sensitivity and 100 percent specificity. By contrast, nonresponders’ values of key biochemical components remained relatively constant. In more recent research, Tromberg and colleagues in the Network for Translational Research: Optical Imaging reported additional patient studies using DOSI combined with MRI. Their results show that the methods provide complementary information on tumor metabolism. The information gained by using optical monitoring may influence decisions regarding drug types, the number of therapy cycles, the stage of the disease or the surgical plan. Knowing whether a patient is sensitive to the therapy decreases the treatment risks, saves time and boosts five-year survival rates.