Hemoglobin levels in 95 control subjects and 91 patients with epithelial ovarian cancer according to stage. Hemoglobin levels were significantly lower in patients with ovarian cancer than in control subjects (P < .001). Patients with stages III to IV cancer had significantly lower hemoglobin levels than patients with stages I to II (P < .001). Significance was calculated by 2-sided Student t test. The box plots in the figure represent columns of data as boxes whose extents indicate the 25th and 75th percentiles of the column. The line inside the box represents the median. + marks the value of the mean. Capped bars indicate the minimum and maximum value observed.