Study of adjuvant endocrine treatment for breast cancer reveals cost of noncompliance
Professor Cornelis van de Velde, senior fellow at the central data office for Team (exemestane adjuvant tamoxifen multinationals) trial, told Congress on Europe’s largest cancer, ECCO 15 – ESMO 34 in Berlin, today (Tuesday 22 September) that differences in compliance among the nine countries involved in the trial shed light on his role in the evolution of the patient.
“In the Dutch-Belgian team time trial, more patients with positive nodes compared to other countries (and therefore a higher risk of recurrence), because existing treatment guidelines Dutch (who have since been changed) indicated that only high-risk patients should receive chemotherapy, endocrine therapy or both. Despite this disadvantage, the recurrences of breast cancer in the Netherlands and Belgium were 12% for patients using tamoxifen and 9% of patients treated with exemestane compared with 8% and 7% internationally. This is probably due to better compliance with treatment in the Netherlands, which was significantly better than in other countries.
“Throughout the study, as a cutoff point of two years nine months, the failure of women on tamoxifen was 19.8% and 12.9% women in exemestane. However, these percentages were significantly lower in the Dutch-Belgian team time trial where the failure was 14% for tamoxifen and 9% of patients who discontinued treatment with exemestane study (tamoxifen or exemestane) had significantly greater likelihood of recurrence , the probability was between four and five times higher in this group than among those who continued treatment. This underscores the need for good information to patients about drug side effects and treatment efficacy, “said Professor van de Velde, who is Professor of Surgery at the Leiden University Medical Center (Leiden, Netherlands) and President of the European Society of Surgical Oncology. Compliance with medication in the study team was lower than in any previous study of adjuvant aromatase inhibitors.
The TEAM study is a randomized phase III clinical trial comparing the efficacy of the aromatase inhibitor exemestane versus the current standard “gold” tamoxifen as adjuvant endocrine therapy for hormone-sensitive breast cancer in postmenopausal women. After two years, nine months a total of 9779 women were included in the study of nine countries: France (1230 patients), Germany (1480), Greece (211), Japan (184), Netherlands (2753), Belgium (414), UK / Ireland (1275), and the U.S. (2232).
The trial began in 2001 but in 2004, based on the results of another trial (Intergroup Exemestane Study) which showed a significant survival advantage for patients with exemestane, Team study was changed so that patients who received tamoxifen changed to exemestane after having been on trial for two and a half to three years. The results presented today refer to data from disease-free survival in patients in the trial of no more than two years, nine months and will focus particularly on compliance issues in Dutch / Belgian team patients and on the effects side, and disease-free and overall survival in the overall study.
Professor van de Velde, said: “The adverse side effects were the main reasons that patients discontinued treatment – half of those who discontinued did so because of side effects. Of all patients in the study, tamoxifen interrupt 6.3% and 4.4% discontinued due to exemestane side effects.
Adverse side effects include heart, skin, hormonal, digestive, metabolic, neurological, muscular and skeletal problems. Exemestane was associated with significantly higher rates of arthralgia, carpal tunnel syndrome, diarrhea and high cholesterol levels, but with significantly lower rates of hot flashes, vaginal bleeding and discharge, and thromboembolism than tamoxifen. Fractures and heart disease were similar between the two groups.
“The safety profile has been better for exemestane than for tamoxifen and I think this is a factor that contributes to lower dropout rates among patients treated with exemestane,” said Professor van de Velde.
After two and three quarter years of follow-up among women of exemestane were no cases in less than 11% local tumor recurrence, distant metastasis, breast cancer in the other breast (contralateral breast cancer ) and deaths that occur without a relapse of the disease than women treated with tamoxifen (352 patients with 388 in the exemestane and tamoxifen patients). There were no differences between the two groups of time to contralateral breast cancer or overall survival, and no unexpected safety issues were reported. Patients 70 years or more and women with breast cancer that had spread to only one to three nodes nodes had significantly better disease-free survival than tamoxifen exemestane.
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