About half of early stage breast cancer patients experience severe side effects from their treatment, a new study finds. "It's in patients' best interest to receive their treatments on time and on schedule, whenever possible, to give them the best possible outcome," said study author Dr. Steven Katz. The women were asked to rate the severity of seven common treatment side effects: nausea/vomiting; diarrhea; constipation; pain; arm swelling; shortness of breath; and breast skin irritation. The results showed that 93 percent of the women had at least one of the side effects.