Supplementary materials: Breast-conserving surgery versus mastectomy for older women with triple-negative breast cancer: population-based study

These are peer-reviewed supplementary materials for the article 'Breast-conserving surgery versus mastectomy for older women with triple-negative breast cancer: population-based study' published in the Journal of Comparative Effectiveness Research.

• Supplementary figure 1
• Supplementary figure 2
• Supplementary figure 3
• Supplementary figure 4
• Supplementary Table S1: Cohort inclusion and exclusion criteria
• Supplementary Table S2: Codes used to identity radiation, mastectomy, breast conserving surgery
• Supplementary Table S3: IPTW cox proportional hazards model predicting all-cause mortality
• Supplementary Table S4: IPTW Fine-Gray Subdistribution hazard model for breast cancer death
• Supplementary Table S5a: Multivariate Cox proportional hazards model predicting all-cause mortality after excluding those who survived for only one month
• Supplementary Table S5b: Pairwise comparison - Multivariate Cox proportional hazards model predicting all-cause mortality after excluding those who survived for a month or less
• Supplementary Table S6a: Fine-Gray Subdistribution hazard model for breast cancer death after excluding those who survived for a month or less
• Supplementary Table S6b: Pairwise comparison - Fine-Gray Subdistribution hazard model for breast cancer death after excluding those who survived for a month or less
• Supplementary Table S7a: Continuous age and tumor size broke further - Multivariate Cox proportional hazards model predicting all-cause mortality
• Supplementary Table S7b: Pairwise comparison - Continuous age and tumor size broke further - Multivariate Cox proportional hazards model predicting all-cause mortality
• Supplementary Table S8a: Continuous age and tumor size broke further - Fine-Gray Subdistribution hazard model for breast cancer death
• Supplementary Table S8b: Pairwise comparison - Continuous age and tumor size broke further - Fine-Gray Subdistribution hazard model for breast cancer death
• Supplementary Table S9: Chemotherapy receipt by treatment
• Supplementary Table S10a: Multivariate Cox proportional hazards model predicting all-cause mortality including chemotherapy adjustment
• Supplementary Table S10b: Pairwise Comparison - multivariate Cox proportional hazards model predicting all-cause mortality including chemotherapy adjustment
• Supplementary Table S11a: Fine-Gray Subdistribution hazard model for breast cancer death including chemotherapy adjustment
• Supplementary Table S11b: Pairwise comparison - Fine-Gray Subdistribution hazard model for breast cancer death including chemotherapy adjustment
• Supplementary Table S12: Factors associated with receiving radiotherapy after breast conserving surgery

Purpose: To assess whether the poor prognosis of triple-negative breast cancer (TNBC) necessitates a more aggressive surgical approach. Methods: We examined the association of: breast-conserving surgery (BCS); BCS plus radiotherapy; mastectomy; and mastectomy plus radiotherapy with overall and breast cancer-specific survival of stage I–III TNBC patients aged 66 years and older. We used unweighted and inverse probability of treatment weighted Cox proportional hazards regression and the Fine and Gray sub-distribution model. Results: Among 4333 women, individuals who were selected for BCS, mastectomy or mastectomy plus radiotherapy had lower adjusted overall and breast cancer-specific survival compared with women who had BCS plus radiotherapy. Conclusion: In this population-based study, women with TNBC treated with BCS plus radiotherapy have a better prognosis than those treated with BCS, mastectomy or mastectomy plus radiotherapy. Given the poor prognosis of TNBC and selection bias inherent in observational studies, these findings should be confirmed in further studies such as randomized clinical trials.