Long-term survival rate increased in early breast cancer patients when switching to …
“These results confirm that the strategy of switching to exemestane halfway in the five years of tamoxifen treatment plan provides a clear and lasting benefit for recurrence and overall survival, said study leader, Professor Charles Coombes, Head of oncology at Imperial College in London, told the biggest cancer congress in Europe, ECCO 15 – ESMO 34 in Berlin, today (Tuesday 22 September). “We found that six years after changing the treatment, women who receiving exemestane were 18% more likely to remain free of disease and were 14% less likely to die than those who stayed on tamoxifen. ”
Breast cancer is cancer in women, with 1.29 million cases diagnosed worldwide each year. About 75% of breast cancers are estrogen receptor positive, meaning that estrogen plays in important role in promoting growth. These tumors are usually treated with anti-estrogen. Tamoxifen, the oldest of them, blocks the ability of tumor to use estrogen and is the standard treatment after surgery in women with stage breast cancer. It normally takes five years. Exemestane belongs to a new class of anti-estrogen drugs known as aromatase inhibitors, which interfere with the function of aromatase, an enzyme responsible for estrogen production. Aromatase inhibitors are accepted as an alternative to tamoxifen for postmenopausal women, but the question of how best to use these drugs is still under investigation.
The study examined whether switching to exemestane after two or three years of tamoxifen was effective in the long term, to continue with tamoxifen for the remaining five years of treatment. The results presented in the results of the Berlin update previously reported, providing evidence based on longer follow-up to produce a more solid estimate of the effect of strategy on survival and recurrence of the disease and give a clearer picture of the effects long-term side.
“Our previous analysis based on a shorter follow-up has demonstrated a clear advantage relapse, but so far, the magnitude and duration of overall survival benefit was uncertain. These results show that the update improves relapse does not appear to decrease with the time and have clarified that the survival advantage is robust and durable. ”
The study, which has the greatest track trials to date investigating the impact of changing from tamoxifen to an aromatase inhibitor, involved 4724 postmenopausal women from 37 countries with estrogen receptor positive or receptor unknown breast cancer that their tumors had been cut and had remained free of disease after two or three years on tamoxifen. About half continued with tamoxifen until completion of a total of five years of treatment, while the other half switched to exemestane for the remainder of treatment. The women were followed for an average of 91 months.
The improvement of 18% disease-free survival results from a hazard ratio of 0.82, while 14% improvement in overall survival was calculated from a hazard ratio of 0.86.
“The practice changed in many countries after the first findings were published in 2004, using five years of tamoxifen to the current recommended treatment strategy for these patients switching to exemestane or another aromatase inhibitor after two or three years of tamoxifen. The question that has yet to be clarified is whether to start with tamoxifen and change is better than starting with an aromatase inhibitor, “said Professor Coombes.
Cancer Research UK and Pfizer Inc., which makes exemestane, funded the study.
Source: ECCO-the European CanCer Organization
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