Analysis of Breast-Conserving Surgery Plus Whole-Breast Irradiation Versus Mastectomy

A Propensity Score-Matched Analysis of Breast-Conserving Surgery Plus Whole-Breast Irradiation Versus Mastectomy in Breast Cancer

This is a retrospective propensity score-matched analysis of a large institutional cohort of patients in order to compare long-term outcomes and clinicopathologic characteristics between patients treated with breast conserving surgery or mastectomy for breast cancer.

Study Overview

• Status: Completed
• Conditions: Breast Cancer
• Intervention / Treatment: Procedure: Breast-conserving surgery; Procedure: Mastectomy

Detailed Description

The aim of the study is to compare long-term outcomes and clinicopathologic characteristics between patients treated with breast conserving surgery + whole breast irradiation or mastectomy for breast cancer.

Recent observations regarding long-term outcomes among patients with early-stage breast cancer who underwent breast-conserving surgery plus whole-breast irradiation or mastectomy are from a small number of registry-based studies.

Therefore, these findings may overestimate differences in survival between the two groups, compared with randomized controlled trials conducted in the 1980s.

This study performed a propensity score-matched analysis in a cohort of 9710 patients aged <70 years who underwent breast conserving surgery + whole breast irradiation or mastectomy without external radiotherapy for a first primary breast cancer (pT1-2, N0-3a) at the European Institute of Oncology between 2000 and 2008.

Patients were matched by propensity score.

• Study Type: Observational
• Enrollment (Actual): 9710

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: ADULT; OLDER_ADULT; CHILD
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: Female

• Sampling Method: Non-Probability Sample

Study Population

Retrospectively analysis of patients who received treatment for invasive breast cancer at the European Institute of Oncology between January 1, 2000, and December 31, 2008.

The original cohort comprised 9710 eligible patients with breast cancer, of whom 2289 (23.6%) underwent breast conserving surgery + whole breast irradiation and 7421 (76.4%) underwent mastectomy alone.

After propensity score matching, 1970 of the 2289 patients who underwent mastectomy (86.1%) were successfully matched to 1970 patients who underwent breast conserving surgery.

Description

Inclusion Criteria:

• First primary breast cancer
• pT1-2
• pN0-3a
• Surgery performed at European Institute of Oncology between 2000 and 2008

Exclusion Criteria:

• pT>=3
• Neoadjuvant treatment
• Presence of metastatic breast disease at the time of admission or within 3 months

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Breast-conserving surgery; Patients who underwent breast-conserving surgery plus whole-breast irradiation	Procedure: Breast-conserving surgery; Breast conserving surgery plus whole breast irradiation
Mastectomy; Patients who underwent mastectomy	Procedure: Mastectomy; Breast mastectomy

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cumulative incidence of ipsilateral breast tumor recurrence	Incidence of ipsilateral breast tumor recurrence in breast conserving surgery group compared to mastectomy group	10 years
Cumulative incidence of axillary lymph node recurrence	cumulative incidence of axillary lymph node recurrence in breast conserving surgery group compared to mastectomy group	10 years
Cumulative incidence of contralateral breast cancer	Cumulative incidence of contralateral breast cancer in breast conserving surgery group compared to mastectomy group	10 years
Rate of distant metastasis	Incidence of distant metastasis in breast conserving surgery group compared to mastectomy group	10 years
Cumulative incidence of breast cancer specific survival	Cumulative incidence of breast cancer specific survival in breast conserving surgery group compared to mastectomy group	10 years
Rate of overall survival	Incidence of survival in breast conserving surgery group compared to mastectomy group	10 years

Collaborators and Investigators

• Sponsor: European Institute of Oncology
• Investigators: Principal Investigator: Francesca Magnoni, MD, European Institute of Oncology

Study record dates

Study Major Dates

• Study Start (ACTUAL): January 1, 2000
• Primary Completion (ACTUAL): November 1, 2021
• Study Completion (ACTUAL): November 1, 2021

Study Registration Dates

• First Submitted: November 17, 2021
• First Submitted That Met QC Criteria: November 18, 2021
• First Posted (ACTUAL): November 19, 2021

Study Record Updates

• Last Update Posted (ACTUAL): November 19, 2021
• Last Update Submitted That Met QC Criteria: November 18, 2021
• Last Verified: November 1, 2021

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Skin Diseases; Neoplasms; Neoplasms by Site; Breast Diseases; Breast Neoplasms
• Other Study ID Numbers: UID 2762

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No