Effect of adjuvant chemotherapy on the survival outcomes of elderly breast cancer: A retrospective cohort study based on SEER database

Yunhao Wu; Yana Qi; Jiqiao Yang; Ruoning Yang; Weijing Lui; Ya Huang; Xin Zhao; Ruixian Chen; Tao He; Shan Lu; Zhu Wang; Hongjiang Li; Xin Sun; Qintong Li; Li Zhou; Jie Chen

doi:10.1111/jebm.12506

Effect of adjuvant chemotherapy on the survival outcomes of elderly breast cancer: A retrospective cohort study based on SEER database

J Evid Based Med. 2022 Dec;15(4):354-364. doi: 10.1111/jebm.12506. Epub 2022 Dec 15.

Authors

Yunhao Wu¹, Yana Qi², Jiqiao Yang³, Ruoning Yang³, Weijing Lui³, Ya Huang³, Xin Zhao³, Ruixian Chen³, Tao He³, Shan Lu³, Zhu Wang⁴, Hongjiang Li³, Xin Sun², Qintong Li⁵, Li Zhou⁶, Jie Chen³

Affiliations

¹ Department of Breast Center and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China.
² Chinese Evidence-based Medicine Center, West China Hospital, Sichuan University, Chengdu, China.
³ Department of Breast Center, West China Hospital, Sichuan University, Chengdu, China.
⁴ Laboratory of Molecular Diagnosis of Cancer, West China Hospital, Sichuan University, Chengdu, China.
⁵ Departments of Obstetrics & Gynecology and Pediatrics, West China Second University Hospital, Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, State Key Laboratory of Biotherapy and Collaborative Innovation Center of Biotherapy, Sichuan University, Chengdu, China.
⁶ Public Experimental Technology Center, West China Hospital, Sichuan University, Chengdu, China.

Abstract

Background: Currently, the proportion of standard chemotherapy for elderly patients is much lower than that for young patients, with little evidence from clinical trials supporting the use of chemotherapy for elderly patients. The effectiveness of chemotherapy for the elderly suffering from breast cancer remains to be further verified.

Methods: A total of 75,525 female breast cancer patients aged 70 years or older were hereby identified, all from the Surveillance, Epidemiology, and End Results (SEER) database from January 1, 2010 to December 31, 2016. Kaplan-Meier analysis and multivariable Cox proportional model were performed to evaluate the effectiveness of chemotherapy on overall survival (OS) and breast cancer-specific survival (BCSS). Propensity score matching (PSM) (PSM ratio: 1:1, caliper: 0.2 standard deviation of propensity score) was applied to construct balanced cohorts with or without chemotherapy based on demographic and pathophysiological characteristics.

Results: A total of 33,177 eligible patients were included, with 5273 (15.89%) receiving chemotherapy. Through PSM, 8360 patients were successfully matched, and balances between groups were almost reached. In the matched data set, multivariable Cox analysis reveals that chemotherapy was associated with a 36% and 21% risk reduction on OS (HR = 0.64, 95% CI 0.58 to 0.71) and BCSS (HR = 0.79, 95% CI 0.69 to 0.91), respectively. Furthermore, subgroups with more adjacent lymph nodes involved by tumor, or nonluminal A, were inclined to benefit more from chemotherapy. Moreover, chemotherapy did not increase the chances of dying from heart disease.

Conclusions: The present study provided evidence that chemotherapy may improve the prognosis of elderly breast cancer, especially for those subpopulations that benefit more from chemotherapy treatment.

Keywords: aged; breast cancer; chemotherapy; survival analysis.

MeSH terms

Aged
Breast Neoplasms* / drug therapy
Breast Neoplasms* / pathology
Chemotherapy, Adjuvant / methods
Female
Humans
Prognosis
Proportional Hazards Models
Retrospective Studies