Table 2.
Studies Relating Duration of and/or Adherence to Adjuvant Endocrine Therapy to Breast Cancer Outcome
| Lead Author | Study | Findings |
|---|---|---|
| EBCTCG – Early Breast Cancer Trialist Collaborative Group 2001 | Overview analyses of randomized clinical trials evaluating duration of tamoxifen use | Tamoxifen duration 1 year, recurrence reduced 27%; tamoxifen duration 2 years, recurrence reduced 33%; tamoxifen duration 5 years, recurrence reduced 47%; P=trend < 0.00001 |
| Yood 2008 | Cohort of 1,837 US early stage breast cancer patients ≥ 65 years old | Adjuvant tamoxifen < 1 year vs. ≥ 5 years with higher breast cancer mortality (HR 6.26, 95% CI: 3.10–12.64) |
| McCowan 2008 | Resospective cohort of 2080 Scotish early stage breast cancer patients | Adherence to tamoxifen < 80% associated with poorer survival (HR 1.10, 95% CI: 1.001–1.21) |
| Hershman 2010 | Northern California Kaiser Permanente cohort of 8769 women with early stage, hormone-sensitive breast cancer and endocrine therapy adherence (drug availability) | 31% discontinued therapy, 10 years survival was 73.6% 69% continued therapy, 10 year survival was 80.7%; P<0.001 |
| Xu 2012 | Cohort of 116 men with early stage, hormone sensitive breast cancer and hormone therapy adherence | For those adherent, 10 year survival was 79.6%; For those non-adherent, 10 year survival was 50.5%, P=0.008 |
| Markula 2012 | Prospective cohort of 417 patients with early stage breast cancer Sweden and adherence (self-report) to adjuvant endocrine therapy | Non-adherence at the 1-year visit associated with increased early breast cancer events HR 2.97, 95% CI 1.08–8.15 |
| Haque 2012 | Southern California Kaiser Permanente cohort of 22,850 women with early stage breast cancer and endocrine therapy adherence (drug availability) | Women with high adherence had greater recurrence risk reduction (e.g., HR=0.42, 95% CI: 0.36–0.47 for tamoxifen) compared to those with less adherence (HR=0.46, 95% CI: 0.41–0.52 for tamoxifen) but the difference was not statistically significant. |
| Pagani 2013 | International Breast Cancer Study Group trials 13–93 and 14–93 with 690 women with early stage breast cancer or SERM’s | Women with ≥ 4 years of SERM had longer 10-year disease-free survival (71%) compared to < 4 years use (64%), p value = 0.20 |