Overall Survival in Breast Reconstruction: An Analysis of the National Cancer Database Open Access

Jean-Baptiste, Omar (Spring 2025)

Permanent URL: https://etd.library.emory.edu/concern/etds/8336h3501?locale=en
Published

Abstract

Introduction

Breast cancer is the most diagnosed cancer in women and a leading cause of cancer-related mortality. Surgical treatment remains a cornerstone of care, with many patients undergoing mastectomy, some of whom opt for reconstruction using implant-based or autologous techniques. While reconstruction is primarily pursued for cosmetic and psychological reasons, its potential association with overall survival remains uncertain, with conflicting findings in the literature. This study aimed to assess the association between breast reconstruction and overall survival in a large, nationally representative cohort.

Methods

We conducted a retrospective cohort analysis using the National Cancer Database (NCDB), including women with stage 0–III breast cancer who underwent mastectomy with or without reconstruction. The primary exposure was surgical type (mastectomy only vs. reconstruction), and the primary outcome was overall survival. Reconstruction included both autologous and implant-based approaches. Age was stratified into five groups (18–30, 31–40, 41–50, 51–65, 66–80). Descriptive and univariable analyses were performed, followed by multivariable Cox proportional hazards modeling. A directed acyclic graph (DAG) was used to select covariates, and time-dependent variables were adjusted accordingly.

Results

Of 176,310 patients included, 122,208 underwent mastectomy only and 54,102 underwent mastectomy with reconstruction. Reconstruction was more common among patients treated at academic centers and among those with higher income, education, and private insurance. In univariable analysis, reconstruction was associated with improved survival (HR 0.32, 95% CI 0.31–0.33). In the multivariable Cox model adjusting for age, stage, comorbidities, insurance, income, and race, reconstruction remained associated with improved survival (HR 0.45, 95% CI 0.42–0.48, p < 0.001).

Discussion

Breast reconstruction after mastectomy was associated with improved overall survival, even after adjusting for demographic and clinical covariates. While this observational study cannot establish causality, it highlights potential survival differences that warrant further investigation. Limitations include missing data, risk of residual confounding, and lack of information on timing of reconstruction. Future prospective studies are needed to clarify mediating factors such as follow-up intensity, quality of life, and treatment adherence.

Table of Contents

List of Figures - 10

1. Introduction - 11

1.1 General Overview of Breast Cancer

1.2 Importance of Surgical Choice

1.3 Uncertainty in Survival Outcomes and Disparities

1.4 Research Question and Study Justification

2. Background - 13

2.1 Introduction to Breast Cancer

2.2 Risk Factors for Breast Cancer

2.2.1 Non-Modifiable Risk Factors

2.2.2 Modifiable Risk Factors

2.3 Pathophysiology and Molecular Subtypes of Breast Cancer

2.4 Survival Outcomes by Stage and Subtype

2.5 Current Treatment Approaches

2.5.1 Surgery

2.5.2 Chemotherapy

2.5.3 Radiation Therapy and Endocrine Therapy

2.5.4 Targeted Therapies

2.6 How Treatment Decisions Are Made

2.7 Surgical Approaches to Breast Cancer Treatment

2.7.1 Historical Evolution of Breast Cancer Surgery

2.7.2 Current Surgical Options

2.7.2.1 Mastectomy vs. Breast-Conserving Surgery (Lumpectomy + Radiation)

2.7.3 Breast Reconstruction Options

2.7.3.1 Implant-Based Reconstruction

2.7.3.2 Autologous (Flap-Based) Reconstruction

2.8 Survival Outcomes and Surgical Choice

2.8.1 Comparative Survival Outcomes of Different Surgical Procedures

2.8.1.1 Mastectomy vs. Breast-Conserving Therapy (BCT)

2.8.1.2 Mastectomy Alone vs. Mastectomy with Reconstruction

2.8.2 Conflicting Evidence on Reconstruction and Survival

2.9 Disparities in Breast Cancer Surgery and Reconstruction

2.9.1 Racial and Ethnic Disparities in Breast Reconstruction

2.9.2 Socioeconomic Disparities in Breast Reconstruction

2.10 Summary of Knowledge Gaps and Study Justification

2.11 Thesis Specific Aims and Hypotheses

3. Methods - 40

3.1 Study Design and Data Source

3.2 Study Population and Patient Selection

3.3 Exposure and Outcome Definitions

3.4 Variables

3.5 Directed Acyclic Graph (DAG) and Confounder Selection

3.6 Statistical Analysis

3.7 Software and Ethical Considerations

4. Results - 48

4.1 Baseline Characteristics

4.1.1 Table 1: Baseline Characteristics of the Study Population

4.1.2 Table 2: Baseline Characteristics Stratified by Surgery Type

4.1.3 Table 3: Baseline Characteristics: Mastectomy Only vs Reconstruction

4.2 Crude Survival Analysis

4.2.1 Table 4: Crude Hazard Ratios for Overall Survival by Demographic and Clinical Factors

4.2.2 Table 5: Kaplan-Meier Estimated Overall Survival at 12 and 60 Months by Surgery Type

4.3 Survival Differences by Demographic Factors

4.3.1 Tables 6–10: Kaplan-Meier Survival Rates by Demographic and Clinical Factors

4.4 Multivariable Survival Analysis

4.4.1 Table 11: Adjusted Cox Proportional Hazards Model

4.5 Sensitivity Analyses

4.5.1 Stratification by Cancer Stage

4.5.1.1 Tables 12–15: Descriptive Statistics for Stages 0, I, II, III

4.5.1.2 Table 16: Adjusted Hazard Ratios by Cancer Stage

4.5.2 Stratification by Age Group

4.5.2.1 Tables 17–21: Descriptive Statistics and Adjusted Hazard Ratios for Age Groups 18–30, 31–40, 41–50, 51–65, 66–80

4.5.3 Stratification by Race/Ethnicity

4.5.3.1 Tables 22–26: Descriptive Statistics and Adjusted Hazard Ratios by Race (White, Black, Hispanic, Asian)

4.5.4 Stratification by Charlson-Deyo Comorbidity Score

4.5.4.1 Table 27: Descriptive Statistics — Charlson Score 0

4.5.4.2 Table 28: Descriptive Statistics — Charlson Score 1

4.5.4.3 Table 29: Descriptive Statistics — Charlson Score 2

4.5.4.4 Table 30: Descriptive Statistics — Charlson Score 3 or Greater

4.5.4.5 Table 31: Adjusted Hazard Ratios for Overall Survival by Charlson Score

5. Discussion - 127

5.1 Summary of Key Findings

5.2 Interpretation of Primary Outcome

5.2.1 Comparison to Prior Studies

5.2.2 Potential Mechanisms Behind Observed Survival Benefit

5.2.3 Residual Confounding and Limitations in Causal Inference

5.3 Stratified Analyses

5.3.1 Institutional and Geographic Patterns of Reconstruction Access

5.3.2 Patient-Level Disparities (Race, Income, Insurance, Education)

5.3.3 Clinical Characteristics and Their Impact (Age, Comorbidity, Stage)

5.3.4 Kaplan-Meier Curves as Descriptive Confirmation

5.3.5 Interpretation of Crude vs Adjusted Survival Estimates

5.4 Sensitivity Analyses

5.4.1 Stratification by Comorbidity Burden

5.4.2 Stratification by Cancer Stage

5.4.3 Stratification by Age Group

5.4.4 Stratification by Race/Ethnicity

5.5 Racial and Socioeconomic Disparities in Reconstruction Rates

5.5.1 Racial Disparities in Access and Utilization

5.5.2 Socioeconomic Disparities by Income, Education, Insurance

5.6 Strengths and Limitations of the Study

5.6.1 Strengths

5.6.2 Limitations

5.7 Clinical and Policy Implications

5.7.1 Clinical Practice Implications

5.7.2 Policy and Health Equity Implications

6. Conclusion - 139

7. References - 142

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