Article Review: Overall Survival with Fulvestrant plusAnastrozole in Metastatic Breast Cancer

Article Review: Overall Survival with Fulvestrant plusAnastrozole in Metastatic Breast Cancer

Citation

Mehta, R. S., Barlow, W. E., Albain, K. S., Vandenberg, T. A., Dakhil, S. R., Tirumali, N. R., … & Livingston, R. B. (2019). Overall survival with fulvestrant plus anastrozole in metastatic breast cancer. New England Journal of Medicine, 380(13), 1226-1234.

Article Summary

Having studied the prolonged progression-free survival and marginally prolonged overall survival of the Anastrozole therapy in metastatic breast cancer patients, the study wanted to get a comparative opinion. The aim of the trial was, therefore, to compare the application of anastrozole therapy alone and one that combined anastrozole therapy with fulvestrant. Effectively, they would measure the prolonged life progression and determine which performed better of the two.

The research took a quantitative type of randomized trial where a total of 694 patients were divided into two groups with random stratification and administered with either of the two therapy methods. All the group’s members had to be postmenopausal women with estrogen-receptor-positive or progesterone-receptor–positive metastatic breast cancer who had a Zubrod’s performance-status score of 0 to 2. Data on the patients were then analyzed for seven years in six months to determine the progression efficacy of the two therapies.

The findings showed that the combinational therapy group had 247 deaths and a median overall survival of 49.8 months. The stand-alone anastrozole therapy had 261 deaths and a median survival of 42.0 months. The findings, therefore, demonstrated that the addition of fulvestrant to anastrozole resulted in a long term survival. The benefit was, however, more prevalent to patients who had previously received adjuvant endocrine therapy.

Research Questions of the study

1. Is the addition of a selective estrogen-receptor down-regulator fulvestrant to anastrozole therapy more effective than treatment with anastrozole alone?
2. What is the long term effect of the combination of fulvestrant and anastrozole to the prolonged progression-free survival of a metastatic hormone-receptor-positive breast cancer patient?

Methods

Study Design

The research took a quantitative analysis of data from patients. The study design was a randomized, open-label trial that compared two groups, one administered with a combination of fulvestrant and anastrozole therapy and the other using anastrozole therapy alone. The trial took place in several centers where the data of the patients were taken for seven years and analyzed by the Southwest Oncology Group Cooperative Group every six months.

Sample size, power and sampling methods

The sample size was 690 eligible participants divided into two groups using stratified randomization according to adjuvant tamoxifen use. All the patients enrolled for the trial were postmenopausal women with estrogen-receptor-positive or progesterone-receptor–positive metastatic breast cancer who had a Zubrod’s performance-status score of 0 to 2. Patients with previous chemotherapy, hormonal therapy, or immunotherapy for metastatic disease were not allowed.

Variables (indicators) Explored

The trial was to measure the efficacy of the fulvestrant and anastrozole therapy over the anastrozole therapy alone. The variables, therefore, used in the measurements were: the median progression-free survival and hazard ration for progression or death.

 Independent variables

The independent indicator was the therapy method used. Two therapy methods were put into the test to see their effectiveness in increasing the efficacy and life survival for patients with metastatic breast cancer. Two groups were each given a different therapy method: one received anastrozole therapy alone, and the other received a combination of fulvestrant and anastrozole therapy. These two therapy methods were the independent variables within the study. The independent variables are quantitative.

Dependent Variables

With the application of the two therapy methods to the different patients, the dependent variable checked out for in both groups was the progression-free survival. With each therapy method, it affected how long the patients would survive without complications or death. The dependent outcome is quantitative.

Reference

Mehta, R. S., Barlow, W. E., Albain, K. S., Vandenberg, T. A., Dakhil, S. R., Tirumali, N. R., … & Livingston, R. B. (2019). Overall survival with fulvestrant plus anastrozole in metastatic breast cancer. New England Journal of Medicine, 380(13), 1226-1234.