Tamoxifen benefits premenopausal breast cancer patients

In premenopausal women with estrogen receptor–positive primary breast cancer, 2 years of adjuvant tamoxifen resulted in the long-term reduction of breast cancer–related mortality, compared with patients who received no systemic treatment, a phase III randomized trial showed.

Tamoxifen is the endocrine therapy of choice for most premenopausal patients with ER-positive disease, wrote Dr. Maria Ekholm and her colleagues. “The long-term effect reported in this study is particularly important for young patients with a potentially long life expectancy who are at risk for late relapse, as is commonly seen in [estrogen receptor]-positive breast cancer.”

In the phase III trial, the investigators randomized 564 (362 ER-positive) premenopausal women with stage II breast cancer: 276 received tamoxifen and 288 received no adjuvant treatment, reported Dr. Ekholm, an oncologist at Lund (Sweden) University and her colleagues (J Clin Oncol. 2016 May 9. doi: 10.1200/JCO.2015.65.6272).

Among the group with ER-positive tumors, patients younger than 40 years had the greatest mortality reduction (less than 40 years: hazard ratio, 0.37; 95% confidence interval, 0.17-0.82; greater than 40 years: HR, 0.87; 95% CI, 0.61-1.22; interaction P = .044). Of the 314 deaths, 262 were breast cancer related. Also, tamoxifen had a greater effect in the patient subgroup with grade 3 tumors, compared with subgroups with grade 1 or 2 tumors, Dr. Ekholm and her colleagues found.

ER-positive patients had a high fatality rate during the first few years of follow-up, and tamoxifen had no effect during this time. Tamoxifen’s beneficial effect on cumulative mortality and cumulative breast cancer–related mortality was highest during years 5-15 of follow-up, with relative mortality reductions of nearly 50%, compared with the control group.

“The positive effect of tamoxifen was weaker for the last follow-up period (greater than 15 years), including fewer events and hence lower power, but the [hazard ratios] and estimates of [cumulative mortality] and [cumulative breast cancer–related mortality] indicate a possible carryover effect beyond 15 years,” the investigators wrote.

Dr. Ekholm reported financial ties to Amgen. Two coauthors also reported ties to industry sources.

In premenopausal women with estrogen receptor–positive primary breast cancer, 2 years of adjuvant tamoxifen resulted in the long-term reduction of breast cancer–related mortality, compared with patients who received no systemic treatment, a phase III randomized trial showed.

Tamoxifen is the endocrine therapy of choice for most premenopausal patients with ER-positive disease, wrote Dr. Maria Ekholm and her colleagues. “The long-term effect reported in this study is particularly important for young patients with a potentially long life expectancy who are at risk for late relapse, as is commonly seen in [estrogen receptor]-positive breast cancer.”

In the phase III trial, the investigators randomized 564 (362 ER-positive) premenopausal women with stage II breast cancer: 276 received tamoxifen and 288 received no adjuvant treatment, reported Dr. Ekholm, an oncologist at Lund (Sweden) University and her colleagues (J Clin Oncol. 2016 May 9. doi: 10.1200/JCO.2015.65.6272).

Among the group with ER-positive tumors, patients younger than 40 years had the greatest mortality reduction (less than 40 years: hazard ratio, 0.37; 95% confidence interval, 0.17-0.82; greater than 40 years: HR, 0.87; 95% CI, 0.61-1.22; interaction P = .044). Of the 314 deaths, 262 were breast cancer related. Also, tamoxifen had a greater effect in the patient subgroup with grade 3 tumors, compared with subgroups with grade 1 or 2 tumors, Dr. Ekholm and her colleagues found.

ER-positive patients had a high fatality rate during the first few years of follow-up, and tamoxifen had no effect during this time. Tamoxifen’s beneficial effect on cumulative mortality and cumulative breast cancer–related mortality was highest during years 5-15 of follow-up, with relative mortality reductions of nearly 50%, compared with the control group.

“The positive effect of tamoxifen was weaker for the last follow-up period (greater than 15 years), including fewer events and hence lower power, but the [hazard ratios] and estimates of [cumulative mortality] and [cumulative breast cancer–related mortality] indicate a possible carryover effect beyond 15 years,” the investigators wrote.

Dr. Ekholm reported financial ties to Amgen. Two coauthors also reported ties to industry sources.

In premenopausal women with estrogen receptor–positive primary breast cancer, 2 years of adjuvant tamoxifen resulted in the long-term reduction of breast cancer–related mortality, compared with patients who received no systemic treatment, a phase III randomized trial showed.

Tamoxifen is the endocrine therapy of choice for most premenopausal patients with ER-positive disease, wrote Dr. Maria Ekholm and her colleagues. “The long-term effect reported in this study is particularly important for young patients with a potentially long life expectancy who are at risk for late relapse, as is commonly seen in [estrogen receptor]-positive breast cancer.”

In the phase III trial, the investigators randomized 564 (362 ER-positive) premenopausal women with stage II breast cancer: 276 received tamoxifen and 288 received no adjuvant treatment, reported Dr. Ekholm, an oncologist at Lund (Sweden) University and her colleagues (J Clin Oncol. 2016 May 9. doi: 10.1200/JCO.2015.65.6272).

Among the group with ER-positive tumors, patients younger than 40 years had the greatest mortality reduction (less than 40 years: hazard ratio, 0.37; 95% confidence interval, 0.17-0.82; greater than 40 years: HR, 0.87; 95% CI, 0.61-1.22; interaction P = .044). Of the 314 deaths, 262 were breast cancer related. Also, tamoxifen had a greater effect in the patient subgroup with grade 3 tumors, compared with subgroups with grade 1 or 2 tumors, Dr. Ekholm and her colleagues found.

ER-positive patients had a high fatality rate during the first few years of follow-up, and tamoxifen had no effect during this time. Tamoxifen’s beneficial effect on cumulative mortality and cumulative breast cancer–related mortality was highest during years 5-15 of follow-up, with relative mortality reductions of nearly 50%, compared with the control group.

“The positive effect of tamoxifen was weaker for the last follow-up period (greater than 15 years), including fewer events and hence lower power, but the [hazard ratios] and estimates of [cumulative mortality] and [cumulative breast cancer–related mortality] indicate a possible carryover effect beyond 15 years,” the investigators wrote.

Dr. Ekholm reported financial ties to Amgen. Two coauthors also reported ties to industry sources.