Optically measured changes over time during chemotherapy. (A) Oxyhemoglobin concentration (ctO2Hb) decreased duringchemotherapy (90 days) for both groups of patients. (B) Waterconcentration decreased in premenopausal patients during chemotherapy andremained relatively unchanged in postmenopausal patients. (C) Thereduction of water observed after 90 days of chemotherapy was associated withage (r = 0.745; P < 0.001), with younger subjectsexhibiting a greater reduction. Data shown are for 24 pre- and postmenopausalsubjects in whom we had measurement data at 90 days (one patient was excludedbecause she previously underwent an oophorectomy, confounding the effect ofhormones on breast density). The fitted linear regression line is superimposedon the graph.