AUTHOR=Bazan Jose G. , Fisher James L. , Park Ko Un , Marcus Elizabeth A. , Bittoni Marisa A. , White Julia R. 

TITLE=Assessing the Impact of CALGB 9343 on Surgical Trends in Elderly-Women With Stage I ER+ Breast Cancer: A SEER-Based Analysis

JOURNAL=Frontiers in Oncology

VOLUME=9

YEAR=2019

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2019.00621

DOI=10.3389/fonc.2019.00621

ISSN=2234-943X

ABSTRACT=<p><bold>Purpose:</bold> Lumpectomy (L) and breast radiotherapy (RT) results in equivalent outcomes in comparison to mastectomy (M) for early-stage breast cancer (BC) based on randomized controlled trials (RCT). Since 2004, RCT support that L without RT yields equivalent survival and acceptable local-regional outcomes in women ≥70-years old with T1N0 hormone-sensitive (ER+) BC on endocrine therapy. Based on this, we hypothesized that M rates should decrease substantially after 2004 in this low-risk elderly population.</p><p><bold>Methods:</bold> We used the Surveillance Epidemiology and End Results registry data to conduct this study. We included women with T1N0 ER+ BC from 2000 to 2014. We compared M rates in women diagnosed from 2000 to 2004 vs. 2005–2012 using the Chi-Square test. Logistic regression analyses was performed to examine demographic/clinical factors associated with mastectomy.</p><p><bold>Results:</bold> 67,506 women met the study criteria. In elderly Stage I ER+ BC, the M rate decreased by 6.3%: 29.0% before 2004 to 22.7% after 2004 (<italic>p</italic> &lt; 0.0001). M rates remained higher in elderly non-Hispanic black (NHB, 27.1%, <italic>p</italic> &lt; 0.0001), non-Hispanic Asian-Pacific-Islander (NHAPI, 30.1%, <italic>p</italic> &lt; 0.0001), and Hispanics (24.4%, <italic>p</italic> = 0.0004) vs. non-Hispanic White (NHW, 21.5%). Treatment in the modern cohort was associated with decreased odds of mastectomy (OR = 0.71, 95% CI 0.68-0.74, <italic>p</italic> &lt; 0.0001) while NH-API race was associated with the highest increased odds of mastectomy (OR = 1.65, 95% 1.53-1.78, <italic>p</italic> &lt; 0.0001). In the modern cohort specifically (2005–2014), Hispanic women (OR = 1.12, <italic>p</italic> = 0.014), NHB women (OR = 1.21, <italic>p</italic> &lt; 0.0001), and NHAPI women (OR = 1.73, <italic>p</italic> &lt; 0.0001) all had higher odds of undergoing mastectomy relative to NHW women after adjusting for all other patient and tumor related factors.</p><p><bold>Conclusions:</bold> In elderly patients with stage I, ER+ BC, M rates have decreased modestly since 2004. These trends are driven mostly be decreases in the M rate in NHW women, but M rates remain ~25% in Hispanic, NHB, and NHAPI women. Further research is needed to identify why M, which is associated with higher cost and morbidity than L alone, has not changed substantially in elderly, low-risk BC.</p>