After surgery or chemotherapy, premenopausal breast cancer patients are often asked to continue taking a drug called “tamoxifen” to prevent recurrence. However, because of the side effects of this drug, many patients often discontinue it without following medical advice. A new British study shows that stopping the drug increases the risk of cancer recurrence and death for patients. Researchers at the University of Glasgow in Scotland, UK, reported in the British Journal of Cancer that they followed up on the prescription records and medication intake of 1,263 breast cancer patients and found that some patients did not keep taking itomoxifen as required by their doctors because of side effects such as hot flashes, joint pain, fatigue or weight gain. The researchers identified patients who took less than 80 percent of their medication on schedule as having “low adherence to treatment” and analyzed their risk of cancer recurrence. The study showed that people who were not adhering to their medication had a higher risk of cancer recurrence and death, and that they had to pay an additional cost of nearly £6,000 per person due to hospitalization or other medications. The researchers said that about 13,000 breast cancer patients in the UK are asked by their doctors to take it for five consecutive years, but many patients stop taking it because of side effects, resulting in unnecessary deaths estimated at more than 430 cases a year and millions of pounds of extra spending. Morgan, chief executive of the Breast Cancer Campaign, said tamoxifen was effective but could cause side effects in some people. The study reminds patients that they should take the drug as prescribed; on the other hand, it also cautions doctors that they should help patients to take the drug consistently and try to overcome possible side effects.