Timing of Neoadjuvant or Adjuvant Chemotherapy to Surgery and Its Impact on Overall Survival among Breast Cancer Patients Pubblico

Qi, Ruowen (Spring 2020)

Permanent URL: https://etd.library.emory.edu/concern/etds/sx61dn49v?locale=it
Published

Abstract

Background: Breast cancer is the second most diagnosed cancer in women, and one in eight women will live with invasive breast cancer during the period of their lifetime in the U.S. according to the research of American Cancer Society. Chemotherapy plus surgical procedures are effective treatments for breast cancer, but the optimal time interval between chemotherapy and surgery for overall survival is still unclear.

Objective: Identify the impact of time of neoadjuvant or adjuvant chemotherapy to surgery on overall survival among female breast cancer patients.

Methods: We divided the study population into two cohorts, neoadjuvant chemotherapy group and adjuvant chemotherapy group, and all the analyses were conducted for the two cohorts separately. To study the impact of the time lag between chemo and surgery on overall survival (OS), we categorized time into three-level time intervals to maximize the discrimination power to predict OS in Cox proportional hazards (PH) model. Univariate, multivariate and propensity score weighting methods based on Cox PH model were used to study the associations between the selected variables and the three-level time intervals, and the associations between variables and overall survival. Hazard ratio with 95% confidence interval and type-3 p-value were calculated to show the association.

Results: Sufficient imbalance in covariates distribution among the three intervals was detected for both cohorts. Multivariate analyses got similar results with propensity score weighting method. After balancing the covariates, it shown the start of surgery after 12 weeks from the start of chemo effectively benefits the overall survival in neoadjuvant chemo group; the start of chemo within 9 weeks from the surgery most contributing to prolonged survival, while receiving chemotherapy later than 12 weeks after the surgery apparently lower the survival rate in adjuvant chemo group.

Conclusion: These results make the importance of timing between chemotherapy and surgery to the overall survival of breast cancer patients clearer. More extensive studies on this time interval are needed for the well-being of breast cancer patients.

Table of Contents

1. Introduction ............................................................................................................... 1

2. Methods ...................................................................................................................... 3

2.1 Study design and target population ....................................................................... 3

2.2 Definition of exploratory and outcome variables ................................................. 4

2.3 Definition of covariates ........................................................................................... 5

2.4 Statistical analysis ................................................................................................... 6

3. Results ......................................................................................................................... 7

3.1 Neoadjuvant chemotherapy population ................................................................ 8

3.2 Adjuvant chemotherapy population .................................................................... 11

4. Discussion ................................................................................................................. 14

5. Conclusion ................................................................................................................ 15

Reference ......................................................................................................................... 17

FIGURES AND TABLES .............................................................................................. 20

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